Delay Gating for Voice Arbitration

Abstract

A first network microphone device (NMD) is configured to (i) detect a wake word included in a voice input, (ii) transmit, to a second NMD, an indication that the first NMD detected the wake word, (iii) receive, from the second NMD, an indication that the second NMD detected the wake word, (iv) begin processing the voice input to determine a response, (v), determine a delay time for transmitting an arbitration message indicating that the first NMD will respond to the voice input, and (a) if the first NMD receives, during the delay time, an arbitration message indicating that the second NMD will respond, refrain from transmitting the arbitration message or (b) if the first NMD does not receive, during the delay time, an arbitration message indicating that the second NMD will respond, (i) transmit the arbitration message to the second NMD, and (ii) respond to the voice input.

Description

TECHNICAL FIELD

The present technology relates to consumer goods and, more particularly, to methods, systems, products, features, services, and other elements directed to voice-assisted control of media playback systems or some aspect thereof.

BACKGROUND

Options for accessing and listening to digital audio in an out-loud setting were limited until in 2003, when SONOS, Inc. filed for one of its first patent applications, entitled “Method for Synchronizing Audio Playback between Multiple Networked Devices,” and began offering a media playback system for sale in 2005. The SONOS Wireless HiFi System enables people to experience music from many sources via one or more networked playback devices. Through a software control application installed on a smartphone, tablet, or computer, one can play what he or she wants in any room that has a networked playback device. Additionally, using a controller, for example, different songs can be streamed to each room that has a playback device, rooms can be grouped together for synchronous playback, or the same song can be heard in all rooms synchronously.

Given the ever-growing interest in digital media, there continues to be a need to develop consumer-accessible technologies to further enhance the listening experience.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages of the presently disclosed technology may be better understood with regard to the following description, appended claims, and accompanying drawings where:

FIG. 1A is a partial cutaway view of an environment having a media playback system configured in accordance with aspects of the disclosed technology.

FIG. 1B is a schematic diagram of the media playback system of FIG. 1A and one or more networks;

FIG. 2A is a functional block diagram of an example playback device;

FIG. 2B is an isometric diagram of an example playback device that includes a network microphone device;

FIGS. 3A-3E are diagrams showing example playback device configurations in accordance with aspects of the disclosure;

FIG. 4A is a functional block diagram of an example controller device in accordance with aspects of the disclosure;

FIGS. 4B and 4C are controller interfaces in accordance with aspects of the disclosure;

FIG. 5 is a functional block diagram of certain components of an example network microphone device in accordance with aspects of the disclosure;

FIG. 6 is a diagram of an example voice input in accordance with aspects of the disclosure;

FIG. 7 is a flow diagram for a playback device configured to perform delay-gated voice arbitration in accordance with aspects of the disclosure.

The drawings are for purposes of illustrating example embodiments, but it should be understood that the inventions are not limited to the arrangements and instrumentality shown in the drawings. In the drawings, identical reference numbers identify at least generally similar elements. To facilitate the discussion of any particular element, the most significant digit or digits of any reference number refers to the Figure in which that element is first introduced. For example, element 103a is first introduced and discussed with reference to FIG. 1A.

DETAILED DESCRIPTION

I. Overview

Voice control can be beneficial in a “smart” home that includes smart appliances and devices that are connected to a communication network, such as wireless audio playback devices, illumination devices, and home-automation devices (e.g., thermostats, door locks, etc.). A network microphone device (NMD) may be used to control smart home devices. In various implementations described in greater detail below, an NMD may be implemented to control a playback device (e.g., a playback device that incorporates the NMD), such as to adjust volume, change playback state (e.g., pause/play), select a song, and/or perform myriad other operations.

An NMD is a networked computing device that typically includes an arrangement of microphones, such as a microphone array, that is configured to detect sounds present in the NMD's environment. The detected sound may include a person's speech mixed with background noise (e.g., music being output by a playback device or other ambient noise). In practice, an NMD typically filters detected sound to remove the background noise from the person's speech to facilitate identifying whether the speech contains a voice input indicative of voice control. If so, the NMD may take action based on such a voice input.

A voice input will typically include a wake word followed by an utterance comprising a user request. A wake word is typically a predetermined word or phrase used to “wake up” an NMD and cause it to invoke a particular voice assistant service (“VAS”) to interpret the intent of the voice input. In practice, an NMD will typically transmit the voice input, or at least a portion thereof (e.g., the utterance portion), to the VAS corresponding to the particular wake word contained in the voice input. For example, a user might speak the wake word “Alexa” to invoke the AMAZON VAS, “Ok, Google” to invoke the GOOGLE VAS, “Hey, Siri” to invoke the APPLE VAS, or “Hey, Sonos” to invoke a VAS offered by SONOS, among other examples. In practice, a wake word may also be referred to as, for example, an activation-, trigger-, wakeup-word or -phrase, and may take the form of any suitable word, combination of words (e.g., a particular phrase), and/or some other audio cue.

An NMD often employs a wake-word engine, which is typically onboard the NMD, to identify whether sound detected by the NMD contains a voice input that includes a particular wake word. The wake-word engine may be configured to identify (i.e., “spot”) a particular wake word using one or more identification algorithms. This wake-word identification process is commonly referred to as “keyword spotting.” In practice, to help facilitate keyword spotting, the NMD may buffer sound detected by a microphone of the NMD and then use the wake-word engine to process that buffered sound to determine whether a wake word is present.

When a wake-word engine spots a wake word in detected sound, the NMD may determine that a wake-word event (i.e., a “wake-word trigger”) has occurred, which indicates that the NMD has detected sound that includes a potential voice input. The occurrence of the wake-word event typically causes the NMD to perform additional processes involving the detected sound. In some implementations, these additional processes may include outputting an alert (e.g., an audible chime and/or a light indicator) indicating that a wake word has been identified and extracting detected-sound data from a buffer, among other possible additional processes. Extracting the detected sound may include reading out and packaging a stream of the detected-sound data according to a particular format and transmitting the packaged detected-sound data to an appropriate VAS for interpretation.

In turn, the VAS corresponding to the wake word that was identified by the wake-word engine receives the transmitted sound data from the NMD over a communication network. A VAS traditionally takes the form of a remote service implemented using one or more cloud servers configured to process voice inputs (e.g., AMAZON's ALEXA, APPLE's SIRI, MICROSOFT's CORTANA, GOOGLE'S GOOGLE ASSISTANT, etc.). In some instances, certain components and functionality of the VAS may be distributed across local and remote devices. Additionally, or alternatively, a VAS may take the form of a local service implemented at an NMD or a media playback system comprising the NMD such that a voice input or certain types of voice input (e.g., rudimentary commands) are processed locally without intervention from a remote VAS.

In any case, when a VAS receives detected-sound data, the VAS will typically process this data, which involves identifying the voice input and determining an intent of words captured in the voice input. The VAS may then provide a response back to the NMD with some instruction according to the determined intent. Based on that instruction, the NMD may cause one or more smart devices to perform an action.

In operation, the action that the VAS instructs the NMD to take based on identifying a voice input can take a variety of forms. For example, the instruction may take the form of VAS response data that is indicative of a given VAS response corresponding to the voice input for the NMD to play back. The VAS response may generally involve the NMD outputting various types of audio and/or visual indications. For instance, a VAS response may comprise playing back chimes, spoken words, audible tones, and/or various other forms of audio played back in response to a voice input. Some of these VAS responses may indicate whether the VAS and/or the NMD will perform a given action (e.g., begin music playback, output requested information, etc.) specified by the voice utterance of the voice input. VAS responses may take various other forms as well.

In some implementations, an NMD may form part of a system comprising multiple NMDs. Indeed, a growing number of environments today have multiple NMDs. For instance, a household may include multiple NMD-equipped playback devices to fill more areas and/or rooms of a home with music and/or to provide more areas with voice-enabled services.

In environments having multiple NMDs, some or all of the NMDs may identify a same wake word. For example, when multiple NMDs in a given environment are configured to identify the same ALEXA wake word, and more than one of the NMDs identify the same wake word, each identifying NMD may trigger its respective internal voice capture components to extract detected-sound data for evaluation by a VAS. When more than one NMD identifies a common wake word, a VAS, which may be located in the cloud, may typically determine which of the NMDs identified the wake word with a highest confidence level. The VAS will then select a given NMD that identified the wake word with the highest confidence level, and after selecting the given NMD that identified the wake word with the highest measure of confidence, may cause the selected NMD to take one or more actions, which may take the form of one or more outputs, as some examples.

The non-selected NMDs may enter an idle state after determining that they have not been selected to perform extraction of detected-sound data. The selected NMD will also return to an idle state after extracting detected-sound data and/or generating any outputs. Once an NMD enters and idle state, an NMD may remain in the idle state until the NMD identifies another wake word.

When a user speaks the same wake word a subsequent time, and more than one NMD again identifies the same wake word, the VAS repeats the process of selecting a given one of the NMDs that identified the wake word with the highest confidence level. The NMD selected for the next interaction may be the previously-selected NMD if the previously-selected NMD identified the wake word with the highest confidence level or may be another NMD if an NMD other than the previously-selected NMD identified the wake word with the highest confidence level. The process of selecting, from multiple NMDs that have identified a particular wake word, a given NMD to extract sound-data that may contain a voice input and/or take one or more actions based on the voice input may be referred to herein as “arbitration.”

Other types of VASes are implemented locally, such as the VAS provided by SONOS, such that captured sound data need not be sent to the cloud. A similar type of arbitration may take place, where instead of transmitting confidence levels for the detected wake word to a remote server, the NMDs participating in a local arbitration may send a message to each either a centralized location device (e.g., a group coordinator) other to each other NMD that is participating in the arbitration. An arbitration winner may then be determined by comparing the respective confidence levels of each participating device.

Example devices, systems, and methods disclosed herein present a new approach to local arbitration that may provide various advantages. More specifically, this disclosure describes in various embodiments NMDs are configured to locally arbitrate between one another based on a time delay, rather than an exchange of confidence information between participating devices.

While some embodiments described herein may refer to functions performed by given actors, such as “users” and/or other entities, it should be understood that this description is for purposes of explanation only. The claims should not be interpreted to require action by any such example actor unless explicitly required by the language of the claims themselves.

II. Example Operating Environment

FIGS. 1A and 1B illustrate an example configuration of a media playback system 100 (or “MPS 100”) in which one or more embodiments disclosed herein may be implemented. Referring first to FIG. 1A, the MPS 100 as shown is associated with an example home environment having a plurality of rooms and spaces, which may be collectively referred to as a “home environment,” “smart home,” or “environment 101.” The environment 101 comprises a household having several rooms, spaces, and/or playback zones, including a master bathroom 101a, a master bedroom 101b (referred to herein as “Nick's Room”), a second bedroom 101c, a family room or den 101d, an office 101e, a living room 101f, a dining room 101g, a kitchen 101h, and an outdoor patio 101i. While certain embodiments and examples are described below in the context of a home environment, the technologies described herein may be implemented in other types of environments. In some embodiments, for example, the MPS 100 can be implemented in one or more commercial settings (e.g., a restaurant, mall, airport, hotel, a retail or other store), one or more vehicles (e.g., a sports utility vehicle, bus, car, a ship, a boat, an airplane), multiple environments (e.g., a combination of home and vehicle environments), and/or another suitable environment where multi-zone audio may be desirable.

Within these rooms and spaces, the MPS 100 includes one or more computing devices. Referring to FIGS. 1A and 1B together, such computing devices can include playback devices 102 (identified individually as playback devices 102a-102o), network microphone devices 103 (identified individually as “NMDs” 103a-102i), and controller devices 104a and 104b (collectively “controller devices 104”). Referring to FIG. 1B, the home environment may include additional and/or other computing devices, including local network devices, such as one or more smart illumination devices 108 (FIG. 1B), a smart thermostat 100, and a local computing device 105 (FIG. 1A). In embodiments described below, one or more of the various playback devices 102 may be configured as portable playback devices, while others may be configured as stationary playback devices. For example, the headphones 102o (FIG. 1B) are a portable playback device, while the playback device 102d on the bookcase may be a stationary device. As another example, the playback device 102c on the patio may be a battery-powered device, which may allow it to be transported to various areas within the environment 101, and outside of the environment 101, when it is not plugged in to a wall outlet or the like.

With reference still to FIG. 1B, the various playback, network microphone, and controller devices 102-104 and/or other network devices of the MPS 100 may be coupled to one another via point-to-point connections and/or over other connections, which may be wired and/or wireless, via a local area network (“LAN”) 111 including a network router 109. For example, the playback device 102j in the Den 101d (FIG. 1A), which may be designated as the “Left” device, may have a point-to-point connection with the playback device 102a, which is also in the Den 101d and may be designated as the “Right” device. In a related embodiment, the Left playback device 102j may communicate with other network devices, such as the playback device 102b, which may be designated as the “Front” device, via a point-to-point connection and/or other connections via the LAN 111. As noted above, one or more of the devices operating on the LAN 111 may implement a location VAS.

As further shown in FIG. 1B, the MPS 100 may be coupled to one or more remote computing devices 106 via a wide area network (“WAN”) 107. In some embodiments, each remote computing device 106 may take the form of one or more cloud servers. The remote computing devices 106 may be configured to interact with computing devices in the environment 101 in various ways. For example, the remote computing devices 106 may be configured to facilitate streaming and/or controlling playback of media content, such as audio, in the home environment 101.

In some implementations, the various playback devices, NMDs, and/or controller devices 102-104 may be communicatively coupled to at least one remote computing device associated with a VAS and at least one remote computing device associated with a media content service (“MCS”). For instance, in the illustrated example of FIG. 1B, remote computing devices 106a are associated with a VAS 190 and remote computing devices 106b are associated with an MCS 192. Although only a single VAS 190 and a single MCS 192 are shown in the example of FIG. 1B for purposes of clarity, the MPS 100 may be coupled to multiple, different VASes and/or MCSes. In some implementations, VASes may be operated by one or more of AMAZON, GOOGLE, APPLE, MICROSOFT, SONOS or other voice assistant providers. In some implementations, MCSes may be operated by one or more of SPOTIFY, PANDORA, AMAZON MUSIC, or other media content services.

As further shown in FIG. 1B, the remote computing devices 106 further include remote computing device 106c configured to perform certain operations, such as remotely facilitating media playback functions, managing device and system status information, directing communications between the devices of the MPS 100 and one or multiple VASes and/or MCSes, among other operations. In one example, the remote computing devices 106c provide cloud servers for one or more SONOS Wireless HiFi Systems.

In various implementations, one or more of the playback devices 102 may take the form of or include an on-board (e.g., integrated) network microphone device. For example, the playback devices 102a-e include or are otherwise equipped with corresponding NMDs 103a-c, respectively. A playback device that includes or is equipped with an NMD may be referred to herein interchangeably as a playback device or an NMD unless indicated otherwise in the description.

In some cases, one or more of the NMDs 103 may be a stand-alone device. For example, the NMDs 103f and 103g may be stand-alone devices. A stand-alone NMD may omit components and/or functionality that is typically included in a playback device, such as a speaker or related electronics. For instance, in such cases, a stand-alone NMD may not produce audio output or may produce limited audio output (e.g., relatively low-quality audio output).

The various playback and network microphone devices 102 and 103 of the MPS 100 may each be associated with a unique name, which may be assigned to the respective devices by a user, such as during setup of one or more of these devices. For instance, as shown in the illustrated example of FIG. 1B, a user may assign the name “Bookcase” to playback device 102d because it is physically situated on a bookcase. Similarly, the NMD 103f may be assigned the named “Island” because it is physically situated on an island countertop in the Kitchen 101h (FIG. 1A). Some playback devices may be assigned names according to a zone or room, such as the playback devices 102e, 102l, 102m, and 102n, which are named “Bedroom,” “Dining Room,” “Living Room,” and “Office,” respectively. Further, certain playback devices may have functionally descriptive names. For example, the playback devices 102a and 102b are assigned the names “Right” and “Front,” respectively, because these two devices are configured to provide specific audio channels during media playback in the zone of the Den 101d (FIG. 1A). The playback device 102c in the Patio may be named portable because it is battery-powered and/or readily transportable to different areas of the environment 101. Other naming conventions are possible.

As discussed above, an NMD may detect and process sound from its environment, such as sound that includes background noise mixed with speech spoken by a person in the NMD's vicinity. For example, as sounds are detected by the NMD in the environment, the NMD may process the detected sound to determine if the sound includes speech that contains voice input intended for the NMD and ultimately a particular VAS. For example, the NMD may identify whether speech includes a wake word associated with a particular VAS.

In the illustrated example of FIG. 1B, the NMDs 103 are configured to interact with the VAS 190 over a network via the LAN 101 and the router 109. Interactions with the VAS 190 may be initiated, for example, when an NMD identifies in the detected sound a potential wake word. The identification causes a wake-word event, which in turn causes the NMD to begin transmitting detected-sound data to the VAS 190. In some implementations, the various local network devices 102-105 (FIG. 1A) and/or remote computing devices 106c of the MPS 100 may exchange various feedback, information, instructions, and/or related data with the remote computing devices associated with the selected VAS. Such exchanges may be related to or independent of transmitted messages containing voice inputs. In some embodiments, the remote computing device(s) and the media playback system 100 may exchange data via communication paths as described herein and/or using a metadata exchange channel as described in U.S. application Ser. No. 15/438,749, filed on Feb. 21, 2017 and titled “Voice Control of a Media Playback System,” which is herein incorporated by reference in its entirety.

Upon receiving the stream of sound data, the VAS 190 determines if there is voice input in the streamed data from the NMD, and if so the VAS 190 will also determine an underlying intent in the voice input. The VAS 190 may next transmit a response back to the MPS 100, which can include transmitting the response directly to the NMD that caused the wake-word event. The response is typically based on the intent that the VAS 190 determined was present in the voice input. As an example, in response to the VAS 190 receiving a voice input with an utterance to “Play Hey Jude by The Beatles,” the VAS 190 may determine that the underlying intent of the voice input is to initiate playback and further determine that intent of the voice input is to play the particular song “Hey Jude.” After these determinations, the VAS 190 may transmit a command to a particular MCS 192 to retrieve content (i.e., the song “Hey Jude”), and that MCS 192, in turn, provides (e.g., streams) this content directly to the MPS 100 or indirectly via the VAS 190. In some implementations, the VAS 190 may transmit to the MPS 100 a command that causes the MPS 100 itself to retrieve the content from the MCS 192.

In certain implementations, NMDs may facilitate arbitration amongst one another when voice input is identified in speech detected by two or more NMDs located within proximity of one another. For example, the NMD-equipped playback device 102d in the environment 101 (FIG. 1A) is in relatively close proximity to the NMD-equipped Living Room playback device 102m, and both devices 102d and 102m may at least sometimes detect the same sound. In such cases, this may require arbitration as to which device is ultimately responsible for providing detected-sound data to the remote VAS. Examples of arbitrating between NMDs may be found, for example, in previously referenced U.S. application Ser. No. 15/438,749.

In certain implementations, an NMD may be assigned to, or otherwise associated with, a designated or default playback device that may not include an NMD. For example, the Island NMD 103f in the Kitchen 101h (FIG. 1A) may be assigned to the Dining Room playback device 102l, which is in relatively close proximity to the Island NMD 103f. In practice, an NMD may direct an assigned playback device to play audio in response to a remote VAS receiving a voice input from the NMD to play the audio, which the NMD might have sent to the VAS in response to a user speaking a command to play a certain song, album, playlist, etc. Additional details regarding assigning NMDs and playback devices as designated or default devices may be found, for example, in previously referenced U.S. patent application Ser. No. 15/438,749.

Further aspects relating to the different components of the example MPS 100 and how the different components may interact to provide a user with a media experience may be found in the following sections. While discussions herein may generally refer to the example MPS 100, technologies described herein are not limited to applications within, among other things, the home environment described above. For instance, the technologies described herein may be useful in other home environment configurations comprising more or fewer of any of the playback, network microphone, and/or controller devices 102-104. For example, the technologies herein may be utilized within an environment having a single playback device 102 and/or a single NMD 103. In some examples of such cases, the LAN 101 (FIG. 1B) may be eliminated and the single playback device 102 and/or the single NMD 103 may communicate directly with the remote computing devices 106a-d. In some embodiments, a telecommunication network (e.g., an LTE network, a 5G network, etc.) may communicate with the various playback, network microphone, and/or controller devices 102-104 independent of a LAN.

a. Example Playback & Network Microphone Devices

FIG. 2A is a functional block diagram illustrating certain aspects of one of the playback devices 102 of the MPS 100 of FIGS. 1A and 1B. As shown, the playback device 102 includes various components, each of which is discussed in further detail below, and the various components of the playback device 102 may be operably coupled to one another via a system bus, communication network, or some other connection mechanism. In the illustrated example of FIG. 2A, the playback device 102 may be referred to as an “NMD-equipped” playback device because it includes components that support the functionality of an NMD, such as one of the NMDs 103 shown in FIG. 1A.

As shown, the playback device 102 includes at least one processor 212, which may be a clock-driven computing component configured to process input data according to instructions stored in memory 213. The memory 213 may be a tangible, non-transitory, computer-readable medium configured to store instructions that are executable by the processor 212. For example, the memory 213 may be data storage that can be loaded with software code 214 that is executable by the processor 212 to achieve certain functions.

In one example, these functions may involve the playback device 102 retrieving audio data from an audio source, which may be another playback device. In another example, the functions may involve the playback device 102 sending audio data, detected-sound data (e.g., corresponding to a voice input), and/or other information to another device on a network via at least one network interface 224. In yet another example, the functions may involve the playback device 102 causing one or more other playback devices to synchronously playback audio with the playback device 102. In yet a further example, the functions may involve the playback device 102 facilitating being paired or otherwise bonded with one or more other playback devices to create a multi-channel audio environment. Numerous other example functions are possible, some of which are discussed below.

As just mentioned, certain functions may involve the playback device 102 synchronizing playback of audio content with one or more other playback devices. During synchronous playback, a listener may not perceive time-delay differences between playback of the audio content by the synchronized playback devices. U.S. Pat. No. 8,234,395 filed on Apr. 4, 2004, and titled “System and method for synchronizing operations among a plurality of independently clocked digital data processing devices,” which is hereby incorporated by reference in its entirety, provides in more detail some examples for audio playback synchronization among playback devices.

To facilitate audio playback, the playback device 102 includes audio processing components 216 that are generally configured to process audio prior to the playback device 102 rendering the audio. In this respect, the audio processing components 216 may include one or more digital-to-analog converters (“DAC”), one or more audio preprocessing components, one or more audio enhancement components, one or more digital signal processors (“DSPs”), and so on. In some implementations, one or more of the audio processing components 216 may be a subcomponent of the processor 212. In operation, the audio processing components 216 receive analog and/or digital audio and process and/or otherwise intentionally alter the audio to produce audio signals for playback.

The produced audio signals may then be provided to one or more audio amplifiers 217 for amplification and playback through one or more speakers 218 operably coupled to the amplifiers 217. The audio amplifiers 217 may include components configured to amplify audio signals to a level for driving one or more of the speakers 218.

Each of the speakers 218 may include an individual transducer (e.g., a “driver”) or the speakers 218 may include a complete speaker system involving an enclosure with one or more drivers. A particular driver of a speaker 218 may include, for example, a subwoofer (e.g., for low frequencies), a mid-range driver (e.g., for middle frequencies), and/or a tweeter (e.g., for high frequencies). In some cases, a transducer may be driven by an individual corresponding audio amplifier of the audio amplifiers 217. In some implementations, a playback device may not include the speakers 218, but instead may include a speaker interface for connecting the playback device to external speakers. In certain embodiments, a playback device may include neither the speakers 218 nor the audio amplifiers 217, but instead may include an audio interface (not shown) for connecting the playback device to an external audio amplifier or audio-visual receiver.

In addition to producing audio signals for playback by the playback device 102, the audio processing components 216 may be configured to process audio to be sent to one or more other playback devices, via the network interface 224, for playback. In example scenarios, audio content to be processed and/or played back by the playback device 102 may be received from an external source, such as via an audio line-in interface (e.g., an auto-detecting 3.5 mm audio line-in connection) of the playback device 102 (not shown) or via the network interface 224, as described below.

As shown, the at least one network interface 224, may take the form of one or more wireless interfaces 225 and/or one or more wired interfaces 226. A wireless interface may provide network interface functions for the playback device 102 to wirelessly communicate with other devices (e.g., other playback device(s), NMD(s), and/or controller device(s)) in accordance with a communication protocol (e.g., any wireless standard including IEEE 1002.11a, 1002.11b, 1002.11g, 1002.11n, 1002.11ac, 1002.15, 4G mobile communication standard, and so on). A wired interface may provide network interface functions for the playback device 102 to communicate over a wired connection with other devices in accordance with a communication protocol (e.g., IEEE 1002.3). While the network interface 224 shown in FIG. 2A include both wired and wireless interfaces, the playback device 102 may in some implementations include only wireless interface(s) or only wired interface(s).

In general, the network interface 224 facilitates data flow between the playback device 102 and one or more other devices on a data network. For instance, the playback device 102 may be configured to receive audio content over the data network from one or more other playback devices, network devices within a LAN, and/or audio content sources over a WAN, such as the Internet. In one example, the audio content and other signals transmitted and received by the playback device 102 may be transmitted in the form of digital packet data comprising an Internet Protocol (IP)-based source address and IP-based destination addresses. In such a case, the network interface 224 may be configured to parse the digital packet data such that the data destined for the playback device 102 is properly received and processed by the playback device 102.

As shown in FIG. 2A, the playback device 102 also includes voice processing components 220 that are operably coupled to one or more microphones 222. The microphones 222 are configured to detect sound (i.e., acoustic waves) in the environment of the playback device 102, which is then provided to the voice processing components 220. More specifically, each microphone 222 is configured to detect sound and convert the sound into a digital or analog signal representative of the detected sound, which can then cause the voice processing component 220 to perform various functions based on the detected sound, as described in greater detail below. In one implementation, the microphones 222 are arranged as an array of microphones (e.g., an array of six microphones). In some implementations, the playback device 102 includes more than six microphones (e.g., eight microphones or twelve microphones) or fewer than six microphones (e.g., four microphones, two microphones, or a single microphones).

In operation, the voice-processing components 220 are generally configured to detect and process sound received via the microphones 222, identify potential voice input in the detected sound, and extract detected-sound data to enable a VAS, such as the VAS 190 (FIG. 1B), to process voice input identified in the detected-sound data. The voice processing components 220 may include one or more analog-to-digital converters, an acoustic echo canceller (“AEC”), a spatial processor (e.g., one or more multi-channel Wiener filters, one or more other filters, and/or one or more beam former components), one or more buffers (e.g., one or more circular buffers), one or more wake-word engines, one or more voice extractors, and/or one or more speech processing components (e.g., components configured to recognize a voice of a particular user or a particular set of users associated with a household), among other example voice processing components. In example implementations, the voice processing components 220 may include or otherwise take the form of one or more DSPs or one or more modules of a DSP. In this respect, certain voice processing components 220 may be configured with particular parameters (e.g., gain and/or spectral parameters) that may be modified or otherwise tuned to achieve particular functions. In some implementations, one or more of the voice processing components 220 may be a subcomponent of the processor 212.

In some implementations, the voice-processing components 220 may detect and store a user's voice profile, which may be associated with a user account of the MPS 100. For example, voice profiles may be stored as and/or compared to variables stored in a set of command information or data table. The voice profile may include aspects of the tone or frequency of a user's voice and/or other unique aspects of the user's voice, such as those described in previously-referenced U.S. patent application Ser. No. 15/438,749.

As further shown in FIG. 2A, the playback device 102 also includes power components 227. The power components 227 include at least an external power source interface 228, which may be coupled to a power source (not shown) via a power cable or the like that physically connects the playback device 102 to an electrical outlet or some other external power source. Other power components may include, for example, transformers, converters, and like components configured to format electrical power.

In some implementations, the power components 227 of the playback device 102 may additionally include an internal power source 229 (e.g., one or more batteries) configured to power the playback device 102 without a physical connection to an external power source. When equipped with the internal power source 229, the playback device 102 may operate independent of an external power source. In some such implementations, the external power source interface 228 may be configured to facilitate charging the internal power source 229. As discussed before, a playback device comprising an internal power source may be referred to herein as a “portable playback device.” On the other hand, a playback device that operates using an external power source may be referred to herein as a “stationary playback device,” although such a device may in fact be moved around a home or other environment.

The playback device 102 further includes a user interface 240 that may facilitate user interactions independent of or in conjunction with user interactions facilitated by one or more of the controller devices 104. In various embodiments, the user interface 240 includes one or more physical buttons and/or supports graphical interfaces provided on touch sensitive screen(s) and/or surface(s), among other possibilities, for a user to directly provide input. The user interface 240 may further include one or more of lights (e.g., LEDs) and the speakers to provide visual and/or audio feedback to a user.

As an illustrative example, FIG. 2B shows an example housing 230 of the playback device 102 that includes a user interface in the form of a control area 232 at a top portion 234 of the housing 230. The control area 232 includes buttons 236a-c for controlling audio playback, volume level, and other functions. The control area 232 also includes a button 236d for toggling the microphones 222 to either an on state or an off state.

As further shown in FIG. 2B, the control area 232 is at least partially surrounded by apertures formed in the top portion 234 of the housing 230 through which the microphones 222 (not visible in FIG. 2B) receive the sound in the environment of the playback device 102. The microphones 222 may be arranged in various positions along and/or within the top portion 234 or other areas of the housing 230 so as to detect sound from one or more directions relative to the playback device 102.

By way of illustration, SONOS, Inc. presently offers (or has offered) for sale certain playback devices that may implement certain of the embodiments disclosed herein, including a “PLAY:1,” “PLAY:3,” “PLAY:5,” “PLAYBAR,” “CONNECT:AMP,” “PLAYBASE,” “BEAM,” “CONNECT,” and “SUB.” Any other past, present, and/or future playback devices may additionally or alternatively be used to implement the playback devices of example embodiments disclosed herein. Additionally, it should be understood that a playback device is not limited to the examples illustrated in FIG. 2A or 2B or to the SONOS product offerings. For example, a playback device may include, or otherwise take the form of, a wired or wireless headphone set, which may operate as a part of the media playback system 100 via a network interface or the like. In another example, a playback device may include or interact with a docking station for personal mobile media playback devices. In yet another example, a playback device may be integral to another device or component such as a television, a lighting fixture, or some other device for indoor or outdoor use.

b. Example Playback Device Configurations

FIGS. 3A-3E show example configurations of playback devices. Referring first to FIG. 3A, in some example instances, a single playback device may belong to a zone. For example, the playback device 102c (FIG. 1A) on the Patio may belong to Zone A. In some implementations described below, multiple playback devices may be “bonded” to form a “bonded pair” which together form a single zone. For example, the playback device 102f (FIG. 1A) named “Bed 1” in FIG. 3A may be bonded to the playback device 102g (FIG. 1A) named “Bed 2” in FIG. 3A to form Zone B. Bonded playback devices may have different playback responsibilities (e.g., channel responsibilities). In another implementation described below, multiple playback devices may be merged to form a single zone. For example, the playback device 102d named “Bookcase” may be merged with the playback device 102m named “Living Room” to form a single Zone C. The merged playback devices 102d and 102m may not be specifically assigned different playback responsibilities. That is, the merged playback devices 102d and 102m may, aside from playing audio content in synchrony, each play audio content as they would if they were not merged.

For purposes of control, each zone in the MPS 100 may be represented as a single user interface (“UI”) entity. For example, as displayed by the controller devices 104, Zone A may be provided as a single entity named “Portable,” Zone B may be provided as a single entity named “Stereo,” and Zone C may be provided as a single entity named “Living Room.”

In various embodiments, a zone may take on the name of one of the playback devices belonging to the zone. For example, Zone C may take on the name of the Living Room device 102m (as shown). In another example, Zone C may instead take on the name of the Bookcase device 102d. In a further example, Zone C may take on a name that is some combination of the Bookcase device 102d and Living Room device 102m. The name that is chosen may be selected by a user via inputs at a controller device 104. In some embodiments, a zone may be given a name that is different than the device(s) belonging to the zone. For example, Zone B in FIG. 3A is named “Stereo” but none of the devices in Zone B have this name. In one aspect, Zone B is a single UI entity representing a single device named “Stereo,” composed of constituent devices “Bed 1” and “Bed 2.” In one implementation, the Bed 1 device may be playback device 102f in the master bedroom 101h (FIG. 1A) and the Bed 2 device may be the playback device 102g also in the master bedroom 101h (FIG. 1A).

As noted above, playback devices that are bonded may have different playback responsibilities, such as playback responsibilities for certain audio channels. For example, as shown in FIG. 3B, the Bed 1 and Bed 2 devices 102f and 102g may be bonded so as to produce or enhance a stereo effect of audio content. In this example, the Bed 1 playback device 102f may be configured to play a left channel audio component, while the Bed 2 playback device 102g may be configured to play a right channel audio component. In some implementations, such stereo bonding may be referred to as “pairing.”

Additionally, playback devices that are configured to be bonded may have additional and/or different respective speaker drivers. As shown in FIG. 3C, the playback device 102b named “Front” may be bonded with the playback device 102k named “SUB.” The Front device 102b may render a range of mid to high frequencies, and the SUB device 102k may render low frequencies as, for example, a subwoofer. When unbonded, the Front device 102b may be configured to render a full range of frequencies. As another example, FIG. 3D shows the Front and SUB devices 102b and 102k further bonded with Right and Left playback devices 102a and 102j, respectively. In some implementations, the Right and Left devices 102a and 102j may form surround or “satellite” channels of a home theater system. The bonded playback devices 102a, 102b, 102j, and 102k may form a single Zone D (FIG. 3A).

In some implementations, playback devices may also be “merged.” In contrast to certain bonded playback devices, playback devices that are merged may not have assigned playback responsibilities, but may each render the full range of audio content that each respective playback device is capable of. Nevertheless, merged devices may be represented as a single UI entity (i.e., a zone, as discussed above). For instance, FIG. 3E shows the playback devices 102d and 102m in the Living Room merged, which would result in these devices being represented by the single UI entity of Zone C. In one embodiment, the playback devices 102d and 102m may playback audio in synchrony, during which each outputs the full range of audio content that each respective playback device 102d and 102m is capable of rendering.

In some embodiments, a stand-alone NMD may be in a zone by itself. For example, the NMD 103h from FIG. 1A is named “Closet” and forms Zone I in FIG. 3A. An NMD may also be bonded or merged with another device so as to form a zone. For example, the NMD device 103f named “Island” may be bonded with the playback device 102i Kitchen, which together form Zone F, which is also named “Kitchen.” Additional details regarding assigning NMDs and playback devices as designated or default devices may be found, for example, in previously referenced U.S. patent application Ser. No. 15/438,749. In some embodiments, a stand-alone NMD may not be assigned to a zone.

Zones of individual, bonded, and/or merged devices may be arranged to form a set of playback devices that playback audio in synchrony. Such a set of playback devices may be referred to as a “group,” “zone group,” “synchrony group,” or “playback group.” In response to inputs provided via a controller device 104, playback devices may be dynamically grouped and ungrouped to form new or different groups that synchronously play back audio content. For example, referring to FIG. 3A, Zone A may be grouped with Zone B to form a zone group that includes the playback devices of the two zones. As another example, Zone A may be grouped with one or more other Zones C-I. The Zones A-I may be grouped and ungrouped in numerous ways. For example, three, four, five, or more (e.g., all) of the Zones A-I may be grouped. When grouped, the zones of individual and/or bonded playback devices may play back audio in synchrony with one another, as described in previously referenced U.S. Pat. No. 8,234,395. Grouped and bonded devices are example types of associations between portable and stationary playback devices that may be caused in response to a trigger event, as discussed above and described in greater detail below.

In various implementations, the zones in an environment may be assigned a particular name, which may be the default name of a zone within a zone group or a combination of the names of the zones within a zone group, such as “Dining Room+Kitchen,” as shown in FIG. 3A. In some embodiments, a zone group may be given a unique name selected by a user, such as “Nick's Room,” as also shown in FIG. 3A. The name “Nick's Room” may be a name chosen by a user over a prior name for the zone group, such as the room name “Master Bedroom.”

Referring back to FIG. 2A, certain data may be stored in the memory 213 as one or more state variables that are periodically updated and used to describe the state of a playback zone, the playback device(s), and/or a zone group associated therewith. The memory 213 may also include the data associated with the state of the other devices of the media playback system 100, which may be shared from time to time among the devices so that one or more of the devices have the most recent data associated with the system.

In some embodiments, the memory 213 of the playback device 202 may store instances of various variable types associated with the states. Variables instances may be stored with identifiers (e.g., tags) corresponding to type. For example, certain identifiers may be a first type “a1” to identify playback device(s) of a zone, a second type “b1” to identify playback device(s) that may be bonded in the zone, and a third type “c1” to identify a zone group to which the zone may belong. As a related example, in FIG. 1A, identifiers associated with the Patio may indicate that the Patio is the only playback device of a particular zone and not in a zone group. Identifiers associated with the Living Room may indicate that the Living Room is not grouped with other zones but includes bonded playback devices 102a, 102b, 102j, and 102k. Identifiers associated with the Dining Room may indicate that the Dining Room is part of Dining Room+Kitchen group and that devices 103f and 102i are bonded. Identifiers associated with the Kitchen may indicate the same or similar information by virtue of the Kitchen being part of the Dining Room+Kitchen zone group. Other example zone variables and identifiers are described below.

In yet another example, the MPS 100 may include variables or identifiers representing other associations of zones and zone groups, such as identifiers associated with Areas, as shown in FIG. 3A. An Area may involve a cluster of zone groups and/or zones not within a zone group. For instance, FIG. 3A shows a first area named “First Area” and a second area named “Second Area.” The First Area includes zones and zone groups of the Patio, Den, Dining Room, Kitchen, and Bathroom. The Second Area includes zones and zone groups of the Bathroom, Nick's Room, Bedroom, and Living Room. In one aspect, an Area may be used to invoke a cluster of zone groups and/or zones that share one or more zones and/or zone groups of another cluster. In this respect, such an Area differs from a zone group, which does not share a zone with another zone group. Further examples of techniques for implementing Areas may be found, for example, in U.S. application Ser. No. 15/682,506 filed Aug. 21, 2017 and titled “Room Association Based on Name,” and U.S. Pat. No. 8,483,853 filed Sep. 11, 2007, and titled “Controlling and manipulating groupings in a multi-zone media system.” Each of these applications is incorporated herein by reference in its entirety. In some embodiments, the MPS 100 may not implement Areas, in which case the system may not store variables associated with Areas.

The memory 213 may be further configured to store other data. Such data may pertain to audio sources accessible by the playback device 102 or a playback queue that the playback device (or some other playback device(s)) may be associated with. In embodiments described below, the memory 213 is configured to store a set of command data for selecting a particular VAS when processing voice inputs.

During operation, one or more playback zones in the environment of FIG. 1A may each be playing different audio content. For instance, the user may be grilling in the Patio zone and listening to hip hop music being played by the playback device 102c, while another user may be preparing food in the Kitchen zone and listening to classical music being played by the playback device 102i. In another example, a playback zone may play the same audio content in synchrony with another playback zone. For instance, the user may be in the Office zone where the playback device 102n is playing the same hip-hop music that is being playing by playback device 102c in the Patio zone. In such a case, playback devices 102c and 102n may be playing the hip-hop in synchrony such that the user may seamlessly (or at least substantially seamlessly) enjoy the audio content that is being played out-loud while moving between different playback zones. Synchronization among playback zones may be achieved in a manner similar to that of synchronization among playback devices, as described in previously referenced U.S. Pat. No. 8,234,395.

As suggested above, the zone configurations of the MPS 100 may be dynamically modified. As such, the MPS 100 may support numerous configurations. For example, if a user physically moves one or more playback devices to or from a zone, the MPS 100 may be reconfigured to accommodate the change(s). For instance, if the user physically moves the playback device 102c from the Patio zone to the Office zone, the Office zone may now include both the playback devices 102c and 102n. In some cases, the user may pair or group the moved playback device 102c with the Office zone and/or rename the players in the Office zone using, for example, one of the controller devices 104 and/or voice input. As another example, if one or more playback devices 102 are moved to a particular space in the home environment that is not already a playback zone, the moved playback device(s) may be renamed or associated with a playback zone for the particular space.

Further, different playback zones of the MPS 100 may be dynamically combined into zone groups or split up into individual playback zones. For example, the Dining Room zone and the Kitchen zone may be combined into a zone group for a dinner party such that playback devices 102i and 102l may render audio content in synchrony. As another example, bonded playback devices in the Den zone may be split into (i) a television zone and (ii) a separate listening zone. The television zone may include the Front playback device 102b. The listening zone may include the Right, Left, and SUB playback devices 102a, 102j, and 102k, which may be grouped, paired, or merged, as described above. Splitting the Den zone in such a manner may allow one user to listen to music in the listening zone in one area of the living room space, and another user to watch the television in another area of the living room space. In a related example, a user may utilize either of the NMD 103a or 103b (FIG. 1B) to control the Den zone before it is separated into the television zone and the listening zone. Once separated, the listening zone may be controlled, for example, by a user in the vicinity of the NMD 103a, and the television zone may be controlled, for example, by a user in the vicinity of the NMD 103b. As described above, however, any of the NMDs 103 may be configured to control the various playback and other devices of the MPS 100.

c. Example Controller Devices

FIG. 4A is a functional block diagram illustrating certain aspects of a selected one of the controller devices 104 of the MPS 100 of FIG. 1A. Such controller devices may also be referred to herein as a “control device” or “controller.” The controller device shown in FIG. 4A may include components that are generally similar to certain components of the network devices described above, such as a processor 412, memory 413 storing program software 414, at least one network interface 424, and one or more microphones 422. In one example, a controller device may be a dedicated controller for the MPS 100. In another example, a controller device may be a network device on which media playback system controller application software may be installed, such as for example, an iPhone™, iPad™ or any other smart phone, tablet, or network device (e.g., a networked computer such as a PC or Mac™).

The memory 413 of the controller device 104 may be configured to store controller application software and other data associated with the MPS 100 and/or a user of the system 100. The memory 413 may be loaded with instructions in software 414 that are executable by the processor 412 to achieve certain functions, such as facilitating user access, control, and/or configuration of the MPS 100. The controller device 104 is configured to communicate with other network devices via the network interface 424, which may take the form of a wireless interface, as described above.

In one example, system information (e.g., such as a state variable) may be communicated between the controller device 104 and other devices via the network interface 424. For instance, the controller device 104 may receive playback zone and zone group configurations in the MPS 100 from a playback device, an NMD, or another network device. Likewise, the controller device 104 may transmit such system information to a playback device or another network device via the network interface 424. In some cases, the other network device may be another controller device.

The controller device 104 may also communicate playback device control commands, such as volume control and audio playback control, to a playback device via the network interface 424. As suggested above, changes to configurations of the MPS 100 may also be performed by a user using the controller device 104. The configuration changes may include adding/removing one or more playback devices to/from a zone, adding/removing one or more zones to/from a zone group, forming a bonded or merged player, separating one or more playback devices from a bonded or merged player, among others.

As shown in FIG. 4A, the controller device 104 also includes a user interface 440 that is generally configured to facilitate user access and control of the MPS 100. The user interface 440 may include a touch-screen display or other physical interface configured to provide various graphical controller interfaces, such as the controller interfaces 440a and 440b shown in FIGS. 4B and 4C. Referring to FIGS. 4B and 4C together, the controller interfaces 440a and 440b includes a playback control region 442, a playback zone region 443, a playback status region 444, a playback queue region 446, and a sources region 448. The user interface as shown is just one example of an interface that may be provided on a network device, such as the controller device shown in FIG. 4A, and accessed by users to control a media playback system, such as the MPS 100. Other user interfaces of varying formats, styles, and interactive sequences may alternatively be implemented on one or more network devices to provide comparable control access to a media playback system.

The playback control region 442 (FIG. 4B) may include selectable icons (e.g., by way of touch or by using a cursor) that, when selected, cause playback devices in a selected playback zone or zone group to play or pause, fast forward, rewind, skip to next, skip to previous, enter/exit shuffle mode, enter/exit repeat mode, enter/exit cross fade mode, etc. The playback control region 442 may also include selectable icons that, when selected, modify equalization settings and/or playback volume, among other possibilities.

The playback zone region 443 (FIG. 4C) may include representations of playback zones within the MPS 100. The playback zones regions 443 may also include a representation of zone groups, such as the Dining Room+Kitchen zone group, as shown. In some embodiments, the graphical representations of playback zones may be selectable to bring up additional selectable icons to manage or configure the playback zones in the MPS 100, such as a creation of bonded zones, creation of zone groups, separation of zone groups, and renaming of zone groups, among other possibilities.

For example, as shown, a “group” icon may be provided within each of the graphical representations of playback zones. The “group” icon provided within a graphical representation of a particular zone may be selectable to bring up options to select one or more other zones in the MPS 100 to be grouped with the particular zone. Once grouped, playback devices in the zones that have been grouped with the particular zone will be configured to play audio content in synchrony with the playback device(s) in the particular zone. Analogously, a “group” icon may be provided within a graphical representation of a zone group. In this case, the “group” icon may be selectable to bring up options to deselect one or more zones in the zone group to be removed from the zone group. Other interactions and implementations for grouping and ungrouping zones via a user interface are also possible. The representations of playback zones in the playback zone region 443 (FIG. 4C) may be dynamically updated as playback zone or zone group configurations are modified.

The playback status region 444 (FIG. 4B) may include graphical representations of audio content that is presently being played, previously played, or scheduled to play next in the selected playback zone or zone group. The selected playback zone or zone group may be visually distinguished on a controller interface, such as within the playback zone region 443 and/or the playback status region 444. The graphical representations may include track title, artist name, album name, album year, track length, and/or other relevant information that may be useful for the user to know when controlling the MPS 100 via the controller interface.

The playback queue region 446 may include graphical representations of audio content in a playback queue associated with the selected playback zone or zone group. In some embodiments, each playback zone or zone group may be associated with a playback queue comprising information corresponding to zero or more audio items for playback by the playback zone or zone group. For instance, each audio item in the playback queue may comprise a uniform resource identifier (URI), a uniform resource locator (URL), or some other identifier that may be used by a playback device in the playback zone or zone group to find and/or retrieve the audio item from a local audio content source or a networked audio content source, which may then be played back by the playback device.

In one example, a playlist may be added to a playback queue, in which case information corresponding to each audio item in the playlist may be added to the playback queue. In another example, audio items in a playback queue may be saved as a playlist. In a further example, a playback queue may be empty, or populated but “not in use” when the playback zone or zone group is playing continuously streamed audio content, such as Internet radio that may continue to play until otherwise stopped, rather than discrete audio items that have playback durations. In an alternative embodiment, a playback queue can include Internet radio and/or other streaming audio content items and be “in use” when the playback zone or zone group is playing those items. Other examples are also possible.

When playback zones or zone groups are “grouped” or “ungrouped,” playback queues associated with the affected playback zones or zone groups may be cleared or re-associated. For example, if a first playback zone including a first playback queue is grouped with a second playback zone including a second playback queue, the established zone group may have an associated playback queue that is initially empty, that contains audio items from the first playback queue (such as if the second playback zone was added to the first playback zone), that contains audio items from the second playback queue (such as if the first playback zone was added to the second playback zone), or a combination of audio items from both the first and second playback queues. Subsequently, if the established zone group is ungrouped, the resulting first playback zone may be re-associated with the previous first playback queue or may be associated with a new playback queue that is empty or contains audio items from the playback queue associated with the established zone group before the established zone group was ungrouped. Similarly, the resulting second playback zone may be re-associated with the previous second playback queue or may be associated with a new playback queue that is empty or contains audio items from the playback queue associated with the established zone group before the established zone group was ungrouped. Other examples are also possible.

With reference still to FIGS. 4B and 4C, the graphical representations of audio content in the playback queue region 446 (FIG. 4B) may include track titles, artist names, track lengths, and/or other relevant information associated with the audio content in the playback queue. In one example, graphical representations of audio content may be selectable to bring up additional selectable icons to manage and/or manipulate the playback queue and/or audio content represented in the playback queue. For instance, a represented audio content may be removed from the playback queue, moved to a different position within the playback queue, or selected to be played immediately, or after any currently playing audio content, among other possibilities. A playback queue associated with a playback zone or zone group may be stored in a memory on one or more playback devices in the playback zone or zone group, on a playback device that is not in the playback zone or zone group, and/or some other designated device. Playback of such a playback queue may involve one or more playback devices playing back media items of the queue, perhaps in sequential or random order.

The sources region 448 may include graphical representations of selectable audio content sources and/or selectable voice assistants associated with a corresponding VAS. The VASes may be selectively assigned. In some examples, multiple VASes, such as AMAZON's Alexa, MICROSOFT's Cortana, etc., may be invokable by the same NMD. In some embodiments, a user may assign a VAS exclusively to one or more NMDs. For example, a user may assign a first VAS to one or both of the NMDs 102a and 102b in the Living Room shown in FIG. 1A, and a second VAS to the NMD 103f in the Kitchen. Other examples are possible.

d. Example Audio Content Sources

The audio sources in the sources region 448 may be audio content sources from which audio content may be retrieved and played by the selected playback zone or zone group. One or more playback devices in a zone or zone group may be configured to retrieve for playback audio content (e.g., according to a corresponding URI or URL for the audio content) from a variety of available audio content sources. In one example, audio content may be retrieved by a playback device directly from a corresponding audio content source (e.g., via a line-in connection). In another example, audio content may be provided to a playback device over a network via one or more other playback devices or network devices. As described in greater detail below, in some embodiments audio content may be provided by one or more media content services.

Example audio content sources may include a memory of one or more playback devices in a media playback system such as the MPS 100 of FIG. 1, local music libraries on one or more network devices (e.g., a controller device, a network-enabled personal computer, or a networked-attached storage (“NAS”)), streaming audio services providing audio content via the Internet (e.g., cloud-based music services), or audio sources connected to the media playback system via a line-in input connection on a playback device or network device, among other possibilities.

In some embodiments, audio content sources may be added or removed from a media playback system such as the MPS 100 of FIG. 1A. In one example, an indexing of audio items may be performed whenever one or more audio content sources are added, removed, or updated. Indexing of audio items may involve scanning for identifiable audio items in all folders/directories shared over a network accessible by playback devices in the media playback system and generating or updating an audio content database comprising metadata (e.g., title, artist, album, track length, among others) and other associated information, such as a URI or URL for each identifiable audio item found. Other examples for managing and maintaining audio content sources may also be possible.

e. Example Network Microphone Devices

FIG. 5 is a functional block diagram showing an NMD 503 configured in accordance with embodiments of the disclosure. The NMD 503 includes voice capture components (“VCC”) 560; at least one wake-word engine 570 and at least one voice extractor 572, each of which is operably coupled to the VCC 560; and a local arbitrator 576, audio output processing components 515 operably coupled to the local arbitrator 576, and at least one audio input interface 519 operably coupled to the audio output processing components 515, both of which may form a portion of the audio processing components 216 discussed above. The NMD 503 further includes the microphones 222 and the at least one network interface 224 described above and may also include other components, such as audio amplifiers, speakers, a user interface, etc., which are not shown in FIG. 5 for purposes of clarity.

The microphones 222 of the NMD 503 are configured to provide detected sound, S_D, from the environment of the NMD 503 to the VCC 560. The detected sound Sp may take the form of one or more analog or digital signals. In example implementations, the detected sound Sp may be composed of a plurality signals associated with respective channels 562 that are fed to the VCC 560.

Each channel 562 may correspond to a particular microphone 222. For example, an NMD having six microphones may have six corresponding channels. Each channel of the detected sound Sp may bear certain similarities to the other channels but may differ in certain regards, which may be due to the position of the given channel's corresponding microphone relative to the microphones of other channels. For example, one or more of the channels of the detected sound Sp may have a greater signal to noise ratio (“SNR”) of speech to background noise than other channels.

As further shown in FIG. 5, the VCC 560 includes an AEC 564, a spatial processor 566, and one or more buffers 568. In operation, the AEC 564 receives the detected sound Sp and filters or otherwise processes the sound to suppress echoes and/or to otherwise improve the quality of the detected sound S_D. That processed sound may then be passed to the spatial processor 566.

The spatial processor 566 is typically configured to analyze the detected sound S_D and identify certain characteristics, such as a sound's amplitude (e.g., decibel level), frequency spectrum, directionality, etc. In one respect, the spatial processor 566 may help filter or suppress ambient noise in the detected sound Sp from potential user speech based on similarities and differences in the constituent channels 562 of the detected sound Sp, as discussed above. As one possibility, the spatial processor 566 may monitor metrics that distinguish speech from other sounds. Such metrics can include, for example, energy within the speech band relative to background noise and entropy within the speech band—a measure of spectral structure—which is typically lower in speech than in most common background noise. In some implementations, the spatial processor 566 may be configured to determine a speech presence probability, examples of such functionality are disclosed in U.S. patent application Ser. No. 15/984,073, filed May 18, 2018, titled “Linear Filtering for Noise-Suppressed Speech Detection,” which is incorporated herein by reference in its entirety.

In operation, the one or more buffers 568—one or more of which may be part of or separate from the memory 213 (FIG. 2A)—capture data corresponding to the detected sound S_D. More specifically, the one or more buffers 568 capture detected-sound data that was processed by the upstream AEC 564 and spatial processor 566. In some implementations, the NMD 503 may include an additional buffer 569 (shown in dashed lines) that stores information (e.g., metadata or the like) regarding the detected sound Sp that was processed by the upstream AEC 564 and spatial processor 566. This other buffer 569 may be referred to as a “sound metadata buffer.” When the wake-word engine 570 identifies a wake-word trigger (discussed below), the sound metadata buffer 569 may pass to the network interface 224 sound characteristic information corresponding to the wake-word trigger (e.g., spectral and/or gain information of the environment of the NMD and/or the voice input comprising the wake word). The network interface 224 may then provide this information to a remote server that may be associated, e.g., with the MPS 100. In one aspect, the information stored in the additional buffer 569 does not reveal the content of any speech but instead is indicative of certain unique features of the detected sound itself. In a related aspect, the metadata may be communicated between computing devices, such as the various computing devices of the MPS 100 without implicating privacy concerns. In practice, the MPS 100 can use the data to adapt and fine-tune voice processing algorithms, including sensitivity tuning as discussed below.

In any event, the detected-sound data form a digital representation (i.e., sound-data stream), S_DS, of the sound detected by the microphones 222. In practice, the sound-data stream S_DS may take a variety of forms. As one possibility, the sound-data stream S_DS may be composed of frames, each of which may include one or more sound samples. The frames may be streamed (i.e., read out) from the one or more buffers 568 for further processing by downstream components, such as the wake-word engine 570 and the voice extractor 572 of the NMD 503.

In some implementations, at least one buffer 568 captures detected-sound data utilizing a sliding window approach in which a given amount (i.e., a given window) of the most recently captured detected-sound data is retained in the at least one buffer 568 while older detected-sound data are overwritten when they fall outside of the window. For example, at least one buffer 568 may temporarily retain 20 frames of a sound specimen at given time, discard the oldest frame after an expiration time, and then capture a new frame, which is added to the 19 prior frames of the sound specimen.

In practice, when the sound-data stream S_DS is composed of frames, the frames may take a variety of forms having a variety of characteristics. As one possibility, the frames may take the form of audio frames that have a certain resolution (e.g., 16 bits of resolution), which may be based on a sampling rate (e.g., 44,100 Hz). Additionally, or alternatively, the frames may include information corresponding to a given sound specimen that the frames define, such as metadata that indicates frequency response, power input level, SNR, microphone channel identification, and/or other information of the given sound specimen, among other examples. Thus, in some embodiments, a frame may include a portion of sound (e.g., one or more samples of a given sound specimen) and metadata regarding the portion of sound. In other embodiments, a frame may only include a portion of sound (e.g., one or more samples of a given sound specimen) or metadata regarding a portion of sound.

In any case, downstream components of the NMD 503 may process the sound-data stream S_DS. For instance, the wake-word engine 570 is configured to apply or more identification algorithms to the sound-data stream S_DS (e.g., streamed sound frames) to spot potential wake words in the detected-sound S_D. When the wake-word engine 570 spots a potential wake word, the work-word engine 570 provides an indication of a “wake-word event” (also referred to as a “wake-word trigger”). In the illustrated example of FIG. 5, the wake-word engine 570 outputs a signal, S_W, that indicates the occurrence of a wake-word event to the voice extractor 572.

In multi-VAS implementations, the NMD 503 may include a VAS selector 574 (shown in dashed lines) that is generally configured to direct the voice extractor's extraction and transmission of the sound-data stream S_DS to the appropriate VAS when a given wake-word is identified by a particular wake-word engine (and a corresponding wake-word trigger), such as the wake-word engine 570 and at least one additional wake-word engine 571 (shown in dashed lines). In such implementations, the NMD 503 may include multiple, different wake-word engines and/or voice extractors, each supported by a particular VAS. Similar to the discussion above, each wake-word engine may be configured to receive as input the sound-data stream S_DS from the one or more buffers 568 and apply identification algorithms to cause a wake-word trigger for the appropriate VAS. Thus, as one example, the wake-word engine 570 may be configured to identify the wake word “Alexa” and cause the NMD 503 to invoke the AMAZON VAS when “Alexa” is spotted. As another example, the wake-word engine 571 may be configured to identify the wake word “Ok, Google” and cause the NMD 503 to invoke the GOOGLE VAS when “Ok, Google” is spotted. In single-VAS implementations, the VAS selector 574 may be omitted.

In response to the wake-word event (e.g., in response to the signal S_W indicating the wake-word event), the voice extractor 572 is configured to receive and format (e.g., packetize) the sound-data stream S_DS. For instance, the voice extractor 572 packetizes the frames of the sound-data stream S_DS into messages.

After the voice extractor 572 packetizes the frames of the sound-data stream S_DS into messages, the NMD 503 may perform some form of extraction. The extraction may take various forms which will now be described.

According to one implementation, referred to as “extraction” (and as opposed to “local extraction”), the voice extractor 572 transmits or streams these messages, M_V, that may contain voice input in real time or near real time to a remote VAS, such as the VAS 190 (FIG. 1B), via the network interface 224. The VAS 190 may receive the messages of the sound-data stream from NMD 503 and any other NMDs that have identified a same wake word based on a detected sound.

According to the local extraction implementation, the voice extractor 572 transmits or streams these messages, M_V, that may contain voice input in real time or near real time to local (e.g., playback or network microphone) device on the same local area network as NMD 503 via the network interface 224. The local device receives messages of the sound-data stream from NMD 503 and any other NMDs that have identified a same wake word based and performs arbitration by selecting the NMD that identified the given wake word with the highest confidence level.

In any case, the VAS is configured to process the sound-data stream S_DS contained in the messages M_V sent from the NMD 503. More specifically, the VAS is configured to identify voice input based on the sound-data stream S_DS. Referring to FIG. 6, a voice input 680 may include a wake word portion 680a and a voice utterance portion 680b. The wake word portion 680a corresponds to detected sound that caused the wake-word event. For instance, the wake word portion 680a corresponds to detected sound that caused the wake-word engine 570 to output the wake word event signal S_W to the voice extractor 572. The voice utterance portion 680b corresponds to detected sound that potentially comprises a user request following the wake-word portion 680a.

In the standard extraction implementation, the VAS may first process the wake word portion 680a within the sound-data stream S_DS to verify the presence of the wake word. In some instances, the VAS may determine that the wake word portion 680a comprises a false wake word (e.g., the word “Election” when the word “Alexa” is the target wake word). In such an occurrence, the VAS may send a response to the NMD 503 (FIG. 5) with an indication for the NMD 503 to cease extraction of sound data, which may cause the voice extractor 572 to cease further streaming of the detected-sound data to the VAS. The wake-word engine 570 may resume or continue monitoring sound specimens until it spots another potential wake word, leading to another wake-word event. In some implementations, the VAS may not process or receive the wake word portion 680a but instead processes only the voice utterance portion 680b.

In any case, the VAS processes the voice utterance portion 680b to identify the presence of any words in the detected-sound data and to determine an underlying intent from these words. The words may correspond to a certain command and certain keywords 684 (identified individually in FIG. 6 as a first keyword 684a and a second keyword 684b). A keyword may be, for example, a word in the voice input 680 identifying a particular device or group in the MPS 100. For instance, in the illustrated example, the keywords 684 may be one or more words identifying one or more zones in which the music is to be played, such as the Living Room and the Dining Room (FIG. 1A). Command criteria may be based on the inclusion of certain keywords within the voice input, among other possibilities. Additionally, or alternately, command criteria for commands may involve identification of one or more control-state and/or zone-state variables in conjunction with identification of one or more particular commands. Control-state variables may include, for example, indicators identifying a level of volume, a queue associated with one or more devices, and playback state, such as whether devices are playing a queue, paused, etc. Zone-state variables may include, for example, indicators identifying which, if any, zone players are grouped.

To determine the intent of the words, the VAS is typically in communication with one or more databases associated with the VAS (not shown) and/or one or more databases (not shown) of the MPS 100. Such databases may store various user data, analytics, catalogs, and other information for natural language processing and/or other processing. In some implementations, such databases may be updated for adaptive learning and feedback for a neural network based on voice-input processing. In some cases, the voice utterance portion 680b may include additional information, such as detected pauses (e.g., periods of non-speech) between words spoken by a user, as shown in FIG. 6. The pauses may demarcate the locations of separate commands, keywords, or other information spoke by the user within the voice utterance portion 680b.

After processing the voice input, the VAS may send a response to the MPS 100 with an instruction to perform one or more actions based on an intent it determined from the voice input. For example, based on the voice input, the VAS may direct the MPS 100 to initiate playback on one or more of the playback devices 102, control one or more of these devices (e.g., raise/lower volume, group/ungroup devices, etc.), turn on/off certain smart devices, among other actions. After receiving the response from the VAS, the wake-word engine 570 of the NMD 503 (FIG. 5) may resume or continue to monitor the sound-data stream S_DS until it spots another potential wake-word, as discussed above.

NMD 503 may also include a local arbitrator 576. Local arbitrator 576 may configure the NMD 503 to take various roles, such an arbitrator-related role. In an implementation, local arbitrator 576 may configure an NMD to be either an arbitrator or a non-arbitrator. If the NMD is configured to be an arbitrator, the NMD may perform some or all arbitration functions related to selecting a particular NMD amongst multiple NMDs (including itself) as the device from which VAS responses will be output and the source device from which sound data will be extracted, for instance based on determining that the particular NMD identified a given wake word with the highest confidence level. If the NMD is not configured to be a non-arbitrator, the NMD may be configured not to perform the function of arbitration, and to defer the function of performing arbitration to a local device that is designated as an arbitrator and/or to a remote network device, such as a VAS that is configured to perform arbitration. Local arbitrator 576 may designate an NMD as an arbitrator or non-arbitrator in various manners, for instance based on the NMD's role, based on a selection by a user, etc.

Local arbitrator 576 may determine whether to designate an NMD as an arbitrator or non-arbitrator based on receiving one or more messages, such as UPnP eventing messages, as one example. Local arbitrator 576 may determine whether to designate an NMD as an arbitrator or non-arbitrator in various other manners as well.

Returning to FIG. 5, in general, the one or more identification algorithms that a particular wake-word engine, such as the wake-word engine 570, applies are configured to analyze certain characteristics of the detected sound stream S_DS and compare those characteristics to corresponding characteristics of the particular wake-word engine's one or more particular wake words. For example, a particular wake-word engine 570 may apply one or more identification algorithms to spot spectral characteristics in the detected sound stream S_DS that match the spectral characteristics of the engine's one or more wake words, and thereby determine that the detected sound Sp comprises a voice input including a particular wake word.

In some implementations, the one or more identification algorithms may be third-party identification algorithms (i.e., developed by a company other than the company that provides the NMD 103). For instance, operators of a voice service (e.g., AMAZON) may make their respective algorithms (e.g., identification algorithms corresponding to AMAZON's ALEXA) available for use in third-party devices (e.g., NMDs 103), which are then trained to identify one or more wake words for the particular voice service. Additionally, or alternatively, the one or more identification algorithms may be first-party identification algorithms that are developed and trained to identify certain wake words that may not be particular to a given voice service. Other possibilities also exist.

In practice, a wake-word engine may include a sensitivity level setting that is modifiable. The sensitivity level may define a degree of similarity between a word identified in the detected sound stream S_DS and the wake-word engine 570's one or more particular wake words that is considered to be a match (i.e., that triggers the NMD 103 to invoke the corresponding VAS). In other words, the sensitivity level defines how closely, as one example, the spectral characteristics in the detected sound stream S_DS must match the spectral characteristics of the engine's one or more wake words to be a wake-word trigger.

In this respect, the sensitivity level generally controls how many false positives that the wake-word engine 570 identifies. For example, if a wake-word engine 570 is configured to identify the wake-word “Alexa” with a relatively high sensitivity, then false wake words of “Election” or “Lexus” would cause the wake-word engine 570 to flag the presence of the wake-word “Alexa.” On the other hand, if this example wake-word engine 570 is configured with a relatively low sensitivity, then the false wake words of “Election” or “Lexus” would not cause the wake-word engine 570 to flag the presence of the wake-word “Alexa.”

In practice, a sensitivity level may take a variety of forms. In example implementations, a sensitivity level takes the form of a confidence threshold that defines a minimum confidence (i.e., probability) level for a wake-word engine that serves as a dividing line between triggering or not triggering a wake-word event when the wake-word engine is analyzing detected sound for its particular wake word. In this regard, a higher sensitivity level corresponds to a lower confidence threshold (and more false positives), whereas a lower sensitivity level corresponds to a higher confidence threshold (and fewer false positives). For example, lowering a wake-word engine's confidence threshold configures it to trigger a wake-word event when it identifies words that have a lower likelihood that they are the actual particular wake word, whereas raising the confidence threshold configures the engine to trigger a wake-word event when it identifies words that have a higher likelihood that they are the actual particular wake word. Other examples of sensitivity levels are also possible.

In example implementations, sensitivity level parameters (e.g., the range of sensitivities) for a particular wake-word engine can be updated, which may occur in a variety of manners. As one possibility, a VAS or other third-party provider of a given wake-word engine may provide to the NMD 503 a wake-word engine update that modifies one or more sensitivity level parameters for the given wake-word engine.

As another possibility, a remote server associated with the MPS 100 may update (or define in the first instance) sensitivity level parameters for a given wake-word engine, which it may do periodically or aperiodically. In some such cases, the remote server may define or otherwise update sensitivity level parameters for wake-word engines based on data regarding characteristics of detected sound (e.g., spectral and/or gain characteristics) associated with past occurrences of wake-word triggers (i.e., identifications of the respective particular wake-words for the given engines). In practice, the remote server may receive such data from NMDs when wake-word triggers occur or from another source of wake-word related sound data (e.g., Internet databases or the like). In any case, the remote server may be configured to perform operations based on such data (e.g., train predictive models and/or run simulations) to determine sensitivity parameters for a given wake-word engine to balance false positives and true identifications of the particular wake word.

In example embodiments, a wake-word engine 570 may take a variety of forms. For example, a wake-word 570 may take the form of one or more modules that are stored in memory of the NMD 503 (e.g., the memory 213; FIG. 2A). As another example, a wake-word engine 570 may take the form of a general-purpose or special-purpose processor, or a module thereof. In this respect, multiple wake-word engines 570 may be part of the same component of the NMD 103 or each wake-word engine may take the form of a component that is dedicated for the particular wake-word engine. Other possibilities also exist. If a wake-word engine 570 identifies the presence of a wake word in the detected sound stream Sp, the wake-word trigger signal S_W may be passed to the voice extractor 572 to begin extraction for processing voice input, as discussed above.

With reference still to FIG. 5, an NMD may be configured as a playback device that includes the at least one audio interface 519, as discussed above. The audio interface 519 is generally configured to receive audio in a variety of forms from a variety of sources (e.g., an analog music signal or digital data of an Internet podcast). In this regard, the audio interface 519 may take the form of an analog and/or digital line-in receptacle that physically connects the NMD 503 to an audio source and/or may take the form of, or otherwise leverage, the network interface 224. that receive audio data via a communication network. In any case, the audio interface 519 provides an audio stream, A_S, to the audio output processing components 515, which in turn process the audio stream A_S prior to the NMD 103 outputting processed audio, A_P, via the speakers 218. In this respect, the audio output processing components 515 may be the same or similar to the audio processing components 218 discussed above.

In some embodiments, one or more of the components described above can operate in conjunction with the microphones 222 to detect and store a user's voice profile, which may be associated with a user account of the MPS 100. In some embodiments, voice profiles may be stored as and/or compared to variables stored in a set of command information or data table. The voice profile may include aspects of the tone or frequency of a user's voice and/or other unique aspects of the user, such as those described in previously-referenced U.S. patent application Ser. No. 15/438,749.

In some embodiments, one or more of the components described above can operate in conjunction with the microphones 222 to determine the location of a user in the home environment and/or relative to a location of one or more of the NMDs 103. Techniques for determining the location or proximity of a user may include one or more techniques disclosed in previously-referenced U.S. patent application Ser. No. 15/438,749, U.S. Pat. No. 9,084,058 filed Dec. 29, 2011, and titled “Sound Field Calibration Using Listener Localization,” and U.S. Pat. No. 8,965,033 filed Aug. 31, 2012, and titled “Acoustic Optimization.” Each of these applications is herein incorporated by reference in its entirety.

In some embodiments, the MPS 100 is configured to temporarily reduce the volume of audio content that it is playing while identifying the wake word portion 610 of a voice input. For instance, the MPS 100 may restore the volume after processing the voice input 600. Such a process can be referred to as ducking, examples of which are disclosed in previously-referenced U.S. patent application Ser. No. 15/438,749.

III. Example Use Cases

Turning now to FIG. 7, an example flow diagram for a playback device configured to perform arbitration of voice inputs in accordance with aspects of this disclosure is depicted. As shown in FIG. 7, the playback device 102 may be any NMD-equipped playback device of the MPS 100 as discussed above and shown by way of example in FIG. 1B, and may carry out the depicted operations in response to a user speaking a voice input that includes a wake word and a voice utterance. In this regard, and as suggested above, the operations shown in FIG. 7 may be carried out by each NMD-equipped playback device that detects the voice input (i.e., the playback device 102 and one or more other playback devices) until a winner of the arbitration is determined.

Beginning at block 701, the playback device 102 may detect, via one or more microphones, a wake word spoken by a user. For example, the user may speak “Hey Sonos” or another suitable wake word, such as “Hey Google” or “Alexa”, followed by a voice utterance such as “Play the Beatles.” In some implementations, the playback device 102 may provide one or more indications that the wake word was detected, such as playing a chime or illuminating a status light on the playback device 102, among other possibilities.

At block 702, the playback device 102 may transmit an indication to one or more other playback devices of the MPS that the playback device 102 detected the wake word at block 701. The one or more other playback devices may be selected in various ways. As one possibility, the one or more other playback devices may include every other candidate playback device in the MPS 100 that is NMD-enabled and configured to detect the particular wake word that the playback device 102 detected. For instance, if the playback device 102 detected the wake word “Hey Sonos” it might not transmit an indication to an NMD-enabled playback device that is only configured to detect the wake word “Alexa.” Other examples are also possible.

Further, because each other playback device that detects the wake word is also carrying out the operations shown in FIG. 7, it follows that, at block 703, the playback device 102 may receive a respective indication from one or more other playback devices that those other playback devices also detected the wake word. In this regard, it will be understood that the playback device 102 may receive fewer indications at block 703 that it sent at block 702, as some candidate NMD-enabled devices might not have detected the wake word. Based on the indications received at block 703, the playback device 102 may determine which other playback devices are involved in the arbitration.

At block 704, the playback device 102 may begin an arbitration session, during which a winner of the arbitration between the playback device 102 and the one or more other playback devices that sent an indication at block 703 will be determined. In this regard, it should be understood that the operations at block 702-704 may be performed in any order after detecting the wake word at block 701. For instance, the playback device 102 may begin an arbitration session after detecting the wake word and then send/receive indications to/from the one or more other playback devices during the arbitration session. If no indications are received from any other playback devices within a threshold period of time (e.g., a threshold period of time that may run in parallel to the other operations shown in FIG. 7), which may indicate that no other playback devices detected the wake word, the playback device 102 may terminate the arbitration session and discontinue any operations related to arbitration. Other examples are also possible.

At 705, the playback device 102 may begin processing of the voice input. In general, processing of the voice input may involve applying one or more automatic speech recognition (ASR) and/or natural language understanding (NLU) algorithms to determine an intent of the voice utterance contained within the input (e.g., one or more media playback system commands). In some implementations, the playback device 102 may process the voice input concurrently with the other operations shown in FIG. 7 related to arbitration between devices. Further, it should again be noted that the operations shown in FIG. 7 are not necessarily limited to being executed in the order they are depicted. For example, the playback device may begin processing the voice input at block 706 upon detecting the wake word at block 701, and in parallel with the other operations shown in FIG. 7 related to arbitration. In this way, the playback device 102 may reduce the likelihood of delay in providing a response to the voice command should it win the arbitration, or should it determine that arbitration is not necessary (e.g., if no other devices detected the wake word).

At block 706, the playback device 102 may determine a delay time for transmitting an arbitration message to each of the one or more other playback devices that are involved in the arbitration. In this regard, the arbitration message may include an indication that the playback device 102 is the winner of the arbitration and will handle the response(s) to the voice input. Similarly, each of the one or more other playback devices that are involved in the arbitration also determines a delay time for sending a similar arbitration message to the playback device 102. Accordingly, if the playback device 102 receives such an arbitration message from one of the other playback devices before it reaches the end of its delay time, the playback device 102 may determine that it is not the winner of the arbitration (i.e., it lost the arbitration) and may refrain from sending its own arbitration message at the end of the delay time. Further, to the extent the playback device 102 has not yet completed voice processing, it may discontinue doing so.

On the other hand, if the playback device 102 reaches the end of its delay time without receiving an arbitration message from one of the other playback devices that are involved in the arbitration, the playback device 102 may transmit its arbitration message to each of the other playback devices, thereby causing them to refrain from sending their respective arbitration messages, processing the voice input, and ultimately responding to the voice input.

The delay time that the playback device 102 determines (and that each of the one or more other playback devices involved in the arbitration determines, respectively) at block 706 may be based on various factors. For instance, the delay time may be based on a quality level, or confidence level, that the playback device 102 identified the wake word correctly.

In practice, a confidence level may take various forms. For example, the confidence level may be a metric calculated based on audio properties of the received wake word. Examples of some such metrics that may be used to calculate the confidence level may include a signal-to-noise ratio (SNR), a frequency spectrum of the identified wake word, a direction of the identified wake word, an amplitude (e.g., decibel level) of the identified wake word, etc. A confidence level may take various other forms as well.

The delay time calculated by the playback device 102 may be inversely proportional to the confidence level of the wake word detection, such that a wake word detection with high confidence corresponds to a lower delay time than a wake word detection with relatively lower confidence. In this way, the playback device with the highest confidence level in its wake word detection may determine the shortest wait time, and thus may be expected to transmit its arbitration message announcing itself as the winner of the arbitration before any of the other involved devices. Further information related to determining a confidence level can be found in Appendix A.

The delay time may be determined based on other criteria as well. For example, the delay time determined by a given playback device may be initially determined based on the confidence level associated with its wake word detection, but then adjusted based on one or more characteristics of the given playback device. As one possibility, some playback device models (e.g., playback devices that include multiple spatially distant microphones, such as a sound bar) may be inherently better at suppressing noise and accurately detecting wake words. As such, these models of playback devices may tend to have higher confidence levels than other models of playback devices whose sound detection hardware is not as robust, even when the other models of playback devices are an equally good or even better choice to win a given arbitration. For this reason, a playback device that has relatively more sound detection capability might increase its initially determined delay time by some incremental amount as a way to normalize delay times between different models of playback devices. In a similar way, a playback device that has relatively less sound detection capability might decrease its initially determined delay time by some incremental amount. Other examples are also possible.

At block 707, the playback device 102 may wait until the end of the delay time that was determined at block 706. In this regard, the reference point from which the delay time begins can be determined in various ways. As one example, as shown in FIG. 7, the delay time may begin running as soon as the delay time is determined, as represented by the horizontal dashed line extending from the bottom of block 706. However, the delay time may run from other other reference points as well. As another example, the playback device 102 may keep track of a timestamp on its internal clock at which the wake word is detected at block 701. After the delay time is determined at block 706, the playback device 102 may determine, based on its current time stamp, how much of the delay time remains and then wait for the difference. Still further, the playback device 102 may first complete processing of the voice input at block 711, with its determined delay time then running from that point. Other reference points are also possible.

If the playback device 102 reaches the end of its delay time without receiving an indication from one of the other playback devices involved in the arbitration (discussed below), the playback device 102 may transmit, at block 710, an arbitration message to each other playback devices involved in the arbitration indicating that the playback device 102 won the arbitration. Thereafter, if the playback device 102 has already completed voice processing in parallel, as shown at block 711, the playback device 102 may provide one or more responses to the voice input at block 712. Alternatively, if voice processing has not yet completed, the playback device 102 will first complete voice processing at block 711 and then provide one or more responses to the voice input at block 712. For instance, the one or more responses may take the form of an acknowledgement of a command contained in the voice utterance (e.g., a media playback system command) and/or the execution of the command, among other possibilities.

Alternatively, before reaching the end of its delay time, the playback device 102 may receive, at block 708, an arbitration message from one of the other playback device involved in the arbitration indicating that the other playback device won the arbitration. Based on receiving such an indication, the playback device 102 may termination its current arbitration session at block 709. Accordingly, it will not reach block 710 and will not transmit its own arbitration message. Further, if the playback device 102 has not yet completed processing of the voice input, it may discontinue such processing.

It will be appreciated that determining the winner of a voice input arbitration in this manner may be advantageous for various reasons. For example, many existing approaches for both remote and local arbitration of voice inputs involve each playback device that detected the wake word transmitting an indication of its own confidence level to either a centralized arbitration device (e.g., a cloud server) or to each other playback device that is involved in the arbitration. The respective confidence levels are then compared, either by the centralized arbitration device or by each participating device, and a winner is determined based on the highest score. In some cases, the winning and/or losing device(s) must then be notified (e.g., if it did not perform a comparison itself) that it should, or should not, respond to the voice command. Accordingly, these existing approaches require, at a minimum, each participating device to transmit an indication of its own confidence level to one or more other devices for comparison, and may involve still further messaging between devices to notify the winner and losers.

On the other hand, the approach discussed herein does not require any device to transmit an indication of its own confidence level. Indeed, only a single message is transmitted to resolve the arbitration—namely, the arbitration message from the first playback device to reach the end of its delay time, declaring itself the winner. This may provide for a reduction in network traffic, which may increase available bandwidth for other communications. Further, a playback device that would otherwise continue voice processing until an arbitration decision based on mutual comparison of confidence levels is determined might be able to discontinues such voice processing (i.e., when it receives another playback device's winning arbitration message) earlier than it otherwise would have, and advantageously reallocate those computational resources elsewhere.

In some implementations, it may be possible to even further reduce network traffic related to arbitration by having the playback devices that participate in a given arbitration do so without knowledge of the other participating playback devices. That is, the playback device 102 may forego transmitting an indication at block 702 to other NMD-enabled playback devices in the MPS 100 that it detected a wake word. Accordingly, the playback device 102 also will not receive any such messages at block 703. Rather, the arbitration message that is transmitted by the winning playback device (e.g., discussed at block 710 below) may be transmitted to all NMD-enabled playback devices in the MPS 100. Any device that has an active arbitration session when it receives such a message may terminate the arbitration session.

Further, the approach disclosed herein may provide a failover for situations in which one or more of the playback devices participating in the arbitration experiences a network issue or similar problem that might delay it from transmitting an indication of its confidence level (or another necessary message) that is required for existing arbitration approaches. Such a delay may force another device that is expecting to receive a confidence level from the delayed device to wait, which may prolong the arbitration decision-making process. Conversely, if a playback device that is involved in an arbitration under the new approach discussed herein experiences a network failure or other delay, it has no effect on the other devices. Rather, each other device will proceed until it either reaches the end of its delay time or receives an indication that another device won the arbitration.

In some implementations, a VAS may include a feedback period during which an NMD-enabled playback device may continued to listen for voice input after an initial wake word is detected and the voice input is processed, such that a user does not have to continually repeat the wake word for sequential voice inputs. In these cases, the playback devices that lose the arbitration according to the approach discussed above may nonetheless continued to listen for additional inputs. Further information related to feedback sessions following arbitration can be found in Appendix B.

In view of the above, it will be appreciated that determining the winner of a voice input arbitration according to the new approach discussed herein may be advantageous for various reasons. For example, many existing approaches for both remote and local arbitration of voice inputs involve each playback device that detected the wake word transmitting an indication of its own confidence level to either a centralized arbitration device (e.g., a cloud server) or to each other playback device that is involved in the arbitration. The respective confidence levels are then compared, either by the centralized arbitration device or by each participating device, and a winner is determined based on the highest score. In some cases, the winning and/or losing device(s) must then be notified (e.g., if it did not perform a comparison itself) that it should, or should not, respond to the voice command. Accordingly, these existing approaches require, at a minimum, each participating device to transmit an indication of its own confidence level to one or more other devices for comparison, and may involve still further messaging between devices to notify the winner and losers.

On the other hand, the approach discussed herein does not require any device to transmit an indication of its own confidence level. Indeed, only a single message is transmitted to resolve the arbitration—namely, the arbitration message from the first playback device to reach the end of its delay time, declaring itself the winner. This may provide for a reduction in network traffic, which may increase available bandwidth for other communications. Further, a playback device that would otherwise continue voice processing until an arbitration decision based on mutual comparison of confidence levels is determined might be able to discontinues such voice processing (i.e., when it receives another playback device's winning arbitration message) earlier than it otherwise would have, and advantageously reallocate those computational resources elsewhere.

In some implementations, it may be possible to even further reduce network traffic related to arbitration by having the playback devices that participate in a given arbitration do so without knowledge of the other participating playback devices. That is, the playback device 102 may forego transmitting an indication at block 702 to other NMD-enabled playback devices in the MPS 100 that it detected a wake word. Accordingly, the playback device 102 also will not receive any such messages at block 703. Rather, the arbitration message that is transmitted by the winning playback device (e.g., discussed at block 710 below) may be transmitted to all NMD-enabled playback devices in the MPS 100. Any device that has an active arbitration session when it receives such a message may terminate the arbitration session.

Further, the approach disclosed herein may provide a failover for situations in which one or more of the playback devices participating in the arbitration experiences a network issue or similar problem that might delay it from transmitting an indication of its confidence level (or another necessary message) that is required for existing arbitration approaches. Such a delay may force another device that is expecting to receive a confidence level from the delayed device to wait, which may prolong the arbitration decision-making process. Conversely, if a playback device that is involved in an arbitration under the new approach discussed herein experiences a network failure or other delay, it has no effect on the other devices. Rather, each other device will proceed until it either reaches the end of its delay time or receives an indication that another device won the arbitration.

It will be appreciated that there may be situations in which two playback devices participating in an arbitration may reach the end of their respective delay times at approximately the same time, such that both playback devices transmit an arbitration message declaring themselves the winner. In practice, this will generally correspond to a situation in which the two playback devices detected the wake word at the same time and then determined a similar delay time. In this situation, either playback device may be an equally good choice to win the arbitration and provide one or more responses to the voice input. Thus, a tie-breaker that is based on readily available playback device information may be used to select one of the playback devices as the arbitration winner. For example, the playback devices will generally be aware of identifying information for each other playback device in the MPS 100, such as a MAC address, an IP address, etc. Accordingly, in a tie-breaker scenario, the playback device with the lower MAC address or IP address may designate itself the winner of the arbitration, and the playback device with the higher MAC address or IP address will termination its arbitration session.

Numerous other tie-breaker criteria are also possible, including whether or not one or both of the playback devices are active playing back media (where an active playback device is favored over idle playback device), the frequency of wake word detection by each device (where more frequent wake word detection (e.g., a more heavily used playback device) is favored over less wake word detection), historic arbitrations between the two playback devices (where the device that more frequently wins arbitrations is favored), a battery status of each playback device, and so on.

CONCLUSION

The description above discloses, among other things, various example systems, methods, apparatus, and articles of manufacture including, among other components, firmware and/or software executed on hardware. It is understood that such examples are merely illustrative and should not be considered as limiting. For example, it is contemplated that any or all of the firmware, hardware, and/or software aspects or components can be embodied exclusively in hardware, exclusively in software, exclusively in firmware, or in any combination of hardware, software, and/or firmware. Accordingly, the examples provided are not the only way(s) to implement such systems, methods, apparatus, and/or articles of manufacture.

The specification is presented largely in terms of illustrative environments, systems, procedures, steps, logic blocks, processing, and other symbolic representations that directly or indirectly resemble the operations of data processing devices coupled to networks. These process descriptions and representations are typically used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it is understood to those skilled in the art that certain embodiments of the present disclosure can be practiced without certain, specific details. In other instances, well known methods, procedures, components, and circuitry have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the forgoing description of embodiments.

When any of the appended claims are read to cover a purely software and/or firmware implementation, at least one of the elements in at least one example is hereby expressly defined to include a tangible, non-transitory medium such as a memory, DVD, CD, Blu-ray, and so on, storing the software and/or firmware.

The present technology is illustrated, for example, according to various aspects described below. Various examples of aspects of the present technology are described as numbered examples (1, 2, 3, etc.) for convenience. These are provided as examples and do not limit the present technology. It is noted that any of the dependent examples may be combined in any combination, and placed into a respective independent example. The other examples can be presented in a similar manner.

Claims

1. A first network microphone device (NMD) comprising: at least one microphone;at least one processor;a non-transitory computer-readable medium; andprogram instructions stored on the non-transitory computer-readable medium that are executable by the at least one processor such that the first NMD is configured to: detect, via the at least one microphone, a wake word included in a voice input;transmit, to a second NMD, an indication that the first NMD detected the wake word;receive, from the second NMD, an indication that the second NMD detected the wake word;begin processing the voice input to thereby determine a response to the voice input;determine a delay time for transmitting an arbitration message, the arbitration message indicating that the first NMD will respond to the voice input; andif the first NMD receives, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, refrain from transmitting the arbitration message indicating that first NMD will respond to the voice input; orif the first NMD does not receive, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, (i) transmit the arbitration message to the second NMD indicating that the first NMD will respond to the voice input, and (ii) respond to the voice input.

2. The first NMD of claim 1, further comprising program instructions stored on the non-transitory computer-readable medium that are executable by the at least one processor such that the first NMD is configured to: if the first NMD receives, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, terminate voice processing of the voice input by the first NMD.

3. The first NMD of claim 1, wherein the program instructions that are executable by the at least one processor such that the first NMD is configured to determine the delay time comprise program instructions that are executable by the at least one processor such that the first NMD is configured to: determine a reference point from which the delay time begins counting, wherein the reference point comprises a timestamp at which the delay time is determined.

4. The first NMD of claim 1, wherein the program instructions that are executable by the at least one processor such that the first NMD is configured to determine the delay time comprise program instructions that are executable by the at least one processor such that the first NMD is configured to: determine a reference point from which the delay time begins counting, wherein the reference point comprises a timestamp at which the first NMD detected the wake word.

5. The first NMD of claim 1, further comprising program instructions stored on the non-transitory computer-readable medium that are executable by the at least one processor such that the first NMD is configured to: transmit, to a third NMD, an indication that the first NMD detected the wake word;receive, from the third NMD, an indication that the second NMD detected the wake word;wherein the program instructions that are executable by the at least one processor such that the first NMD is configured to, if the first NMD receives, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, refrain from transmitting the arbitration message comprise program instructions that are executable by the at least one processor such that the first NMD is configured to, if the first NMD receives, during the delay time, an arbitration message indicating that the third NMD will respond to the voice input, refrain from transmitting the arbitration message; andwherein the program instructions that are executable by the at least one processor such that the first NMD is configured to, if the first NMD does not receive, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, transmit the arbitration message to the second NMD indicating that the first NMD will respond to the voice input comprise program instructions that are executable by the at least one processor such that the first NMD is configured to, if the first NMD does not receive, during the delay time, an arbitration message indicating that the third NMD will respond to the voice input, transmit the arbitration message to the third NMD indicating that the first NMD will respond to the voice input.

6. The first NMD of claim 1, wherein the first NMD and the second NMD are members of a media playback system comprising at least one other NMD, and wherein the program instructions that are executable by the at least one processor such that the first NMD is configured to transmit, to the second NMD, an indication that the first NMD detected the wake word comprise program instructions that are executable by the at least one processor such that the first NMD is configured to transmit, to each other NMD in the media playback system, an indication that the first NMD detected the wake word.

7. The first NMD of claim 1, wherein the first NMD is configured to detect at least two different wake words associated with two respective voice assistant services, and wherein the program instructions that are executable by the at least one processor such that the first NMD is configured to transmit, to the second NMD, the indication that the first NMD detected the wake word comprise program instructions that are executable by the at least one processor such that the first NMD is configured to transmit, to the second NMD, an indication of a particular wake word that the first NMD detected.

8. The first NMD of claim 1, wherein the program instructions that are executable by the at least one processor such that the first NMD is configured to receive, from the second NMD, an indication that the second NMD detected the wake word comprise program instructions that are executable by the at least one processor such that the first NMD is configured to, while processing the voice input, receive, from the second NMD, an indication that the second NMD detected the wake word.

9. A non-transitory computer-readable medium, wherein the non-transitory computer-readable medium is provisioned with program instructions that, when executed by at least one processor, cause the first NMD to: detect, via at least one microphone of the first NMD, a wake word included in a voice input;transmit, to a second NMD, an indication that the first NMD detected the wake word;receive, from the second NMD, an indication that the second NMD detected the wake word;begin processing the voice input to thereby determine a response to the voice input;determine a delay time for transmitting an arbitration message, the arbitration message indicating that the first NMD will respond to the voice input; andif the first NMD receives, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, refrain from transmitting the arbitration message indicating that first NMD will respond to the voice input; orif the first NMD does not receive, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, (i) transmit the arbitration message to the second NMD indicating that the first NMD will respond to the voice input, and (ii) respond to the voice input.

10. The non-transitory computer-readable medium of claim 9, further comprising program instructions that, when executed by at least one processor, cause the first NMD to: if the first NMD receives, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, terminate processing of the voice input by the first NMD.

11. The non-transitory computer-readable medium of claim 9, wherein the program instructions that, when executed by at least one processor, cause the first NMD to determine the delay time comprise program instructions that are executable by the at least one processor such that the first NMD is configured to: determine a reference point from which the delay time begins counting, wherein the reference point comprises a timestamp at which the delay time is determined.

12. The non-transitory computer-readable medium of claim 9, wherein the program instructions that, when executed by at least one processor, cause the first NMD to determine the delay time comprise program instructions that are executable by the at least one processor such that the first NMD is configured to: determine a reference point from which the delay time begins counting, wherein the reference point comprises a timestamp at which the first NMD detected the wake word.

13. The non-transitory computer-readable medium of claim 9, further comprising program instructions that, when executed by at least one processor, cause the first NMD to: transmit, to a third NMD, an indication that the first NMD detected the wake word;receive, from the third NMD, an indication that the second NMD detected the wake word;wherein the program instructions that, when executed by at least one processor, cause the first NMD to, if the first NMD receives, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, refrain from transmitting the arbitration message comprise program instructions that, when executed by at least one processor, cause the first NMD to, if the first NMD receives, during the delay time, an arbitration message indicating that the third NMD will respond to the voice input, refrain from transmitting the arbitration message; andwherein the program instructions that, when executed by at least one processor, cause the first NMD to, if the first NMD does not receive, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, transmit the arbitration message to the second NMD indicating that the first NMD will respond to the voice input comprise program instructions that, when executed by at least one processor, cause the first NMD to, if the first NMD does not receive, during the delay time, an arbitration message indicating that the third NMD will respond to the voice input, transmit the arbitration message to the third NMD indicating that the first NMD will respond to the voice input.

14. The non-transitory computer-readable medium of claim 9, wherein the first NMD and the second NMD are members of a media playback system comprising at least one other NMD, and wherein the program instructions that, when executed by at least one processor, cause the first NMD to transmit, to the second NMD, an indication that the first NMD detected the wake word comprise program instructions that, when executed by at least one processor, cause the first NMD to transmit, to each other NMD in the media playback system, an indication that the first NMD detected the wake word.

15. The non-transitory computer-readable medium of claim 9, wherein the first NMD is configured to detect at least two different wake words associated with two respective voice assistant services, and wherein the program instructions that, when executed by at least one processor, cause the first NMD to transmit, to the second NMD, the indication that the first NMD detected the wake word comprise program instructions that, when executed by at least one processor, cause the first NMD to transmit, to the second NMD, an indication of a particular wake word that the first NMD detected.

16. The non-transitory computer-readable medium of claim 9, wherein the program instructions that, when executed by at least one processor, cause the first NMD to receive, from the second NMD, an indication that the second NMD detected the wake word comprise program instructions that, when executed by at least one processor, cause the first NMD to, while processing the voice input, receive, from the second NMD, an indication that the second NMD detected the wake word.

17. A method carried out by a first NMD, the method comprising: detecting, via at least one microphone of the first NMD, a wake word included in a voice input;transmitting, to a second NMD, an indication that the first NMD detected the wake word;receiving, from the second NMD, an indication that the second NMD detected the wake word;beginning processing the voice input to thereby determine a response to the voice input;determining a delay time for transmitting an arbitration message, the arbitration message indicating that the first NMD will respond to the voice input; andif the first NMD receives, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, refraining from transmitting the arbitration message indicating that first NMD will respond to the voice input; orif the first NMD does not receive, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, (i) transmitting the arbitration message to the second NMD indicating that the first NMD will respond to the voice input, and (ii) responding to the voice input.

18. The method of claim 17, further comprising: if the first NMD receives, during the delay time, an arbitration message indicating that the second NMD will respond to the voice input, terminating voice processing of the voice input by the first NMD.

19. The method of claim 17, wherein the first NMD and the second NMD are members of a media playback system comprising at least one other NMD, and wherein transmitting, to the second NMD, an indication that the first NMD detected the wake word comprises transmitting, to each other NMD in the media playback system, an indication that the first NMD detected the wake word.

20. The method of claim 17, wherein the first NMD is configured to detect at least two different wake words associated with two respective voice assistant services, and wherein transmitting, to the second NMD, the indication that the first NMD detected the wake word comprises transmitting, to the second NMD, an indication of a particular wake word that the first NMD detected.