The present invention relates generally to a switched digital video system for distributing content to a subscriber over a system such as a satellite or cable television system, and more particularly to a switched digital video system in which advertising can be targeted to selected groups of subscribers.
Switched digital video (SDV) refers to an arrangement in which broadcast channels are only switched onto the network when they are requested by one or more subscribers, thereby allowing system operators to save bandwidth over their distribution network. In conventional cable or satellite broadcast systems, every broadcast channel is always available to all authorized subscribers. In contrast, a switched digital video channel is only available when requested by one or more authorized subscribers. Also, unlike video on-demand, which switches a singlecast interactive program to a user, switched digital video switches broadcast streams, making each stream available to one or more subscribers who simply join the broadcast stream just as they would with normal broadcast services. That is, once a switched service is streamed to a subscriber, subsequent subscribers associated with the same service group as the first subscriber can tune to the same broadcast stream. The switched digital video will often share the same resource managers and underlying resources with other on-demand services.
As noted, switched digital video is largely a tool to save bandwidth. From the subscriber perspective, he or she still receives the same broadcast video service when using a switched broadcast technique; ideally the user is not able to discern that the stream was switched at all. If each one of the digital broadcast channels is being watched by subscribers in the same service group, the switched digital video approach does not yield any bandwidth savings. However, a more likely situation statistically is that only a certain number of the digital broadcast channels are being watched by subscribers in the same service group at any given time. Those channels not requested by a subscriber need not be broadcast, thereby saving bandwidth.
One way to support switched digital video is to utilize a session manager to manage SDV sessions. The subscriber will set up an SDV session with the session manager when an SDV program is requested. The session manager will determine if the requested channel is already being sent to the corresponding service group that the subscriber belongs to. The subscriber will be assigned to join the existing SDV session if the requested channel is available at the service group or assigned to a new SDV session if the requested channel is not available at the service group. The Session Manager will negotiate with the edge devices to allocate resources required for the session. The edge device (e.g., a digital modulator such as a QAM modulator) needs to dynamically retrieve the MPEG single program transport stream that carries the requested broadcast program (typically via IP unicast or multicast) and generates the MPEG multiple program transport stream. As part of the session setup response message, the video tuning parameters such as frequency and MPEG program number are sent back to the subscriber to access the requested broadcast channel.
As with other types of broadcast programming, advertising forms an important part of SDV programming. The revenues generated from advertisers subsidize and in some cases pay entirely for the programming. Even in subscriber-based television systems such as cable and satellite television systems, the revenues from advertisements subsidize the cost of the programming, and were it not for advertisements, the monthly subscription rates of such systems could be many times higher than at present.
Traditional broadcast television systems broadcast the same television signal to each person viewing a particular station. Thus, each person viewing a particular channel will necessarily view the same programming content as well as the same advertisements embedded in the programming content. However, with modern digital television systems such as SDV systems more personalized television service is possible. For instance, in SDV systems, a group of subscriber households can be selectively addressed through a cable node serving that group. Similarly, individual subscriber households can be selectively addressed though their set top terminals. In other words, the service provider can send different data to different subscribers or groups of subscribers.
Typically, a particular advertiser will purchase a particular “spot”, i.e., an advertising opportunity in a particular channel at a particular time, based on the likelihood that members of that advertiser's target audience will be watching that particular channel at that particular time. For instance, advertisers typically have a particular demographic group of individuals that they wish to reach with their advertising. For example, the manufacturer of a low-cost beer probably has a primary target audience of males between the ages of 21 and 39, living in households with a household annual income of less than $75,000 per year. As another example, a manufacturer of laundry detergent may have a primary target audience of women between 19-59 years of age with no particular preference regarding household income. As another example, a manufacturer of expensive beer may wish to have a target audience similar to that of the manufacturer of low-cost beer in that it comprises males between the ages of 21 and 39. However, this manufacturer's target demographic audience may include a different economic profile, e.g., males between the ages of 21 and 39, living in households with annual household incomes of over $60,000 per year. Another advertiser that manufactures children's toys appropriate for children between 5 and 10 years of age might have a target audience of children between the ages of 5 and 10 and, depending upon the particular toys, a desired annual household income range.
In terms of advertising, SDV systems can allow each set top terminal to receive its own copy of a channel. More specifically, when a set top terminal in a particular service group requests an SDV program, the SDV manager can direct the headend to deliver a unicast video stream to a particular port on the QAM modulator servicing the set top terminal that made the request. The QAM modulator, in turn, delivers a single copy of the channel supporting the unicast video stream to the appropriate service group. The SDV manager then directs the set top terminal that made the request to tune to that particular channel supporting the unicast video stream by sending a force tune message. This process used to unicast an SDV channel is similar to the process used in video on demand (VOD) since in both cases each set top terminal receives its own copy of the channel. Such an approach is sometimes referred to as SDV unicasting.
Since SDV unicasting can provide each set top terminal with its own copy of a channel, it allows different renditions of a program to be sent to different set top terminals. Each rendition, which can include different advertising targeted to each individual set top terminal, is carried on a different unicast stream between the headend and the hubs. Unfortunately, a large bandwidth is needed when unicasting SDV channels. In fact, with SDV unicasting there may be no bandwidth savings at all when multiple viewers request the same SDV programming. As a result, the bandwidth required to provide many dedicated channels at peak viewing times can be much greater than the available RF spectrum between the hub and the set top terminals. This problem can be overcome by deploying more QAM modulators to reduce the size of the service groups, but this approach is time-consuming and expensive.
In accordance with one aspect of the invention, a switched digital video (SDV) system is provided which includes an SDV manager for coordinating a SDV session requested by a subscriber terminal. The system also includes a plurality of edge devices for receiving a transport stream that includes programming content and transmitting the transport stream over an access network to the subscriber terminal on one of a plurality of SDV channels. The SDV manager is configured to monitor bandwidth and cause the edge device to deliver the SDV session to the subscriber terminal in a SDV unicast stream when sufficient unused bandwidth is available or as a SDV multicast stream when sufficient unused bandwidth is not available.
In accordance with another aspect of the invention, a method for providing SDV programming to subscribers includes monitoring unused bandwidth of an access network between one or more edge devices and a plurality of subscriber terminals. At least a first of the subscriber terminals tuned to a SDV multicast rendition of a program that is delivered over the access network is caused to tune to a first SDV unicast rendition of the program when sufficient bandwidth is available on the access network.
The selective addressability of modern digital television service systems renders more targeted TV advertising possible. As a result, demographic data may be used to provide different subscribers of the same television program different advertisements that are particularly directed to them. In order to effectively target advertising to subscribers it is necessary to understand certain attributes of the target subscriber, such as demographic and psychograph attributes, and to acquire any data relevant to determining the appropriateness of an ad for the particular subscriber. Such data can include past viewing habits, previous purchasing selections, self-reporting through, e.g, user profiles, and the like.
As previously mentioned, advertising can be precisely targeted to individual subscribers when switched digital video (SDV) unicasting is employed, but only with a significant increase in the amount of bandwidth that is required. As detailed below, a method is provided for delivering SDV programming with advertising that is less precisely targeted whenever there is insufficient bandwidth to target individual subscribers. For instance, targeted advertising can be provided at the level of the service group instead of at the individual subscriber level. In this case all subscribers in the same service group will receive the same rendition of an SDV program with the same advertising. However, when there is unused or excess bandwidth available, some of those subscribers can be provided with their own renditions of a program, which can contain ads targeted to their precise demographic and other attributes, by delivering the program using SDV unicasting.
Some or even all of the hubs are connected to multiple users, typically via distribution networks such as local cable access networks (e.g., HFC networks). For simplicity of explanation only, each hub is shown as being connected to a distinct HFC network, which in turn communicates with end user equipment as illustrated. In particular hubs 130, 132 and 134 in
In addition to the switch or router 170, each hub can include an array of radio frequency transmitter edge devices such as edge QAM modulators 150. The number of edge devices 150 in each hub may vary as needs dictate. As used herein, the term “QAM” refers to modulation schemes used for sending signals over cable access networks. Such modulation schemes might use any constellation level (e.g. QAM-16, QAM-64, QAM-256 etc.) depending on the details of a cable access network. A QAM may also refer to a physical channel modulated according to such schemes. Typically, a single QAM modulator can output a multiplex of ten or twelve programs, although the actual number will be dictated by a number of factors, including the communication standard that is employed. The edge QAM modulators usually are adapted to: (i) receive Ethernet frames that encapsulate the transport packets, (ii) de-capsulate these frames and remove network jitter, and (iii) transmit radio frequency signals representative of the transport stream packets to end users, over the HFC network. Each transport stream is mapped to a downstream QAM channel. Each QAM channel has a carrier frequency that differs from the carrier frequency of the other channels. The transport streams are mapped according to a channel plan designed by the MSO that operates the network.
Each hub 130, 132 and 134 also includes an edge resource manager 160 for allocating and managing the resources of the edge devices 150. The edge resource manager 160 communicates with and receives instructions from the session manager located in the headend 110.
When a viewer selects an SDV program using a subscriber terminal such as a set top terminal, the SDV system actively switches the channel carrying that program onto one of the QAMs that serves that particular set top terminal. The set top terminals are generally arranged into service groups and each of the service groups is assigned to, and serviced by, one or more QAM modulators. For example, in the arrangement depicted in
SDV programming and the advertisements associated therewith may be supplied by a multicasting technique or a unicasting technique. If SDV multicasting is employed, when a set top terminal in a particular service group requests an SDV program, the SDV manager directs the QAM modulator servicing that particular service group to issue an Internet Group Management Protocol (IGMP) Join request to receive the multicast stream. The QAM modulator then delivers a single copy of the channel supporting the program to that service group. The SDV manager directs the set top terminal that made the request to tune to the appropriate channel. Any other set top terminals in the same service group which request the same programming are also directed to tune to that channel. That is, when multicasting is employed, a single video stream is provided from the headend to the hub and the video stream is carried on a single channel from the hub to the appropriate service group. Accordingly, multicasting minimizes bandwidth usage between the headend and the hub as well as between the hub and service group.
In terms of advertising, SDV multicasting allows different renditions of a program to be sent to different service groups. Each rendition, which can include different advertising targeted to the set top terminals in those service groups, is carried on a different multicast stream between the headend and the hubs. Stated differently, the multicasting of SDV programming allows advertising to be targeted down to the granularity of a service group. That is, each set top terminal in a service group can receive a rendition of an SDV channel tailored to that service group.
On the other hand, as previously noted SDV unicasting allows a different rendition of a program to be sent to each individual set top terminal in a service group since each terminal receives its own copy of a program. That is, the unicasting of SDV programming allows targeted advertising down to the granularity of a set top terminal Unfortunately, the price of this fine degree of granularity is that a large amount of bandwidth is needed.
In order to offer more targeted advertising than is possible by the exclusive use of SDV multicasting without the need to deploy additional edge devices to increase bandwidth, SDV unicasting may be used to deliver programming to selected subscribers only when excess or unused bandwidth is available. Other subscribers will continue to receive programming using SDV multicasting. Since SDV systems are typically designed with a sufficient number of QAMs per service group to allow for peak viewership and a peak diversity in the channels being viewed, there generally will be unused bandwidth available whenever the system is not operating during peak periods. A higher precision in advertising delivery can thus be achieved by using SDV multicasting in combination with SDV unicasting whenever the necessary bandwidth is available.
Referring to
It should be noted that the headend 110 shown in
Referring now to the headend 110 depicted in
To implement SDV multicasting, multiple renditions of a program are created—one rendition for each service group. Each rendition will include different advertising based on the characteristics of the service group. To this end, as shown in
The demographic data located in the database 217 can be acquired in any of a variety of different ways. For example, subscriber viewing history, subscriber geography and subscriber self-reporting in response to questionnaires and the like may all be used to populate the target group demographic database 217. Of course, target group demographic database 217 need not necessarily physically reside in the SDV manager 215, but rather may be discrete or combined with other components. In addition, while in
The various renditions of the program specified by the SDV manager 215 are all multicast from the headend to the hubs. When a set top terminal requests the program, the SDV manager directs the edge device servicing that set top terminal to issue an IGMP join request to receive the appropriate multicast stream for that particular set top terminal. The appropriate multicast stream is the stream that includes the rendition of the program that matches the service group to which the set top terminal belongs. For example, returning to an earlier example, one rendition of the program may include an advertisement for low-cost beer. This rendition may be directed to a service group that includes a significant number of males between the ages of 21 and 39 living in a household with annual incomes of less than $75,000 per year who spend more than 50% of their viewing time watching sporting events
After the edge device has been directed to receive the multicast stream that includes the appropriate rendition of the programming, the edge device delivers a single copy of the channel containing the content of the multicast stream to the service group to which the set top terminal that made the request belongs. Finally, the SDV manager directs the set top terminal to tune to the channel on which the programming is available.
Referring to
If SDV unicasting as described above is used instead of SDV multicasting, an essentially unlimited number of renditions of a program can be provided. Therefore, very precise targeting of subscribers can be achieved down to the level of an individual set top terminal, although larger target groups may also be employed. Another advantage of SDV unicasting is that the number of target groups and the criteria used to define them can be dynamically adjusted. Since the SDV manager 215 controls in real time the ads that are being inserted into the programming as the program is being streamed from the streaming server 240, the SDV manager 215 can even adjust or rearrange the target groups based on its knowledge of the upcoming ads that are to be inserted from the advertising server 230. Once the SDV manager 215 redefines one or more target groups based on an upcoming ad, the set top terminals that are affected can be directed by the SDV manager to tune to the appropriate new channel for their target group.
In order to determine when it may be appropriate to switch selected set top terminals from receiving SDV multicast sessions to receiving SDV unicast sessions, the edge resource manager 160 shown in
The SDV manager 160 may use the bandwidth information it receives from the edge device or devices in any manner to assign and terminate unicast sessions. For instance, the SDV manager 160 may passively use this information to assign switched unicast sessions whenever subscribers change channels. When the SDV manager 160 receives a channel change request from a set top terminal, and the requested channel is already being viewed by one or more subscribers in the service group, the SDV manager 160 decides whether to assign a unique unicast stream to the subscriber or whether to assign the subscriber to an existing multicast stream that is already being delivered to that service group. The one or more subscribers who are selected to receive an SDV unicast session may be based not only on the available bandwidth, but on other factors as well. For instance, as determined from the target group demographic database 217, some subscribers may be more desirable candidates for receiving targeted advertising than other subscribers. In this case, if only a limited number of the subscribers switching channels can be accommodated with a unicast session, only the more desirable subscribers will be switched. The most desired subscribers can be selected based on a variety of factors. For example, such subscribers may be those subscribers who are anticipated to generate the highest advertising revenue as a result of receiving a targeted advertisement.
Alternatively, the SDV manager 160 may actively use the available bandwidth information to establish switched unicast sessions for existing subscribers, even when they are not requesting a channel change. In this case the SDV manager 160 first identifies an appropriate number of high value subscribers in a service group based on the available bandwidth and the programming they are currently receiving. The SDV manager 160 then causes additional renditions of the programming to be created for each of the subscribers who are selected. The SDV manager 160 sends a force tune message to the appropriate set top terminals to force them to tune to the respective channel on which their respective rendition of the SDV unicast program is being delivered.
When establishing a new SDV unicast session, the edge resource manager will attempt to place the service on the same edge device that is already delivering the program to the subscriber using SDV multicasting. In this way the subscriber's set top terminal does not need to tune to a new RF frequency, but rather only needs to access the new MPEG program information associated with the SDV unicast session. This so-called “QAM affinity” enables the set top terminal to switch to the SDV unicast session in a faster and smoother manner than it could if it had to tune to a different RF frequency. In fact, such a switch to the SDV unicast session may even appear seamless to the subscriber. This faster response occurs because set top terminals can access new program information in significantly less time than is needed to tune to a new RF frequency.
When the SDV manager 160 determines that one or more unicast sessions need to be terminated because the bandwidth is needed for other purposes, it will examine the subscribers who are currently receiving unicast sessions and who belong to the service group in communication with the edge device on which the bandwidth is needed. This determination may be performed on any appropriate basis. For instance, heuristics may be used to select the unicast sessions that should be released. For example, the SDV manager may reclaim unicast sessions that do not have immediately upcoming ad opportunities, thus maximizing the revenue potential of the remaining unicast streams that will have ads inserted in the immediate future. The SDV manager 160 may also use the information available in the target group demographic database 217 to assist in the selection of those subscribers whose unicast session should be terminated.
Similar to the initiation of a unicast session, a unicast session may be terminated to reclaim bandwidth by sending a force tune message when the subscriber changes channels. This termination method will generally be the most transparent to the subscriber. Alternatively, a switched unicast session can be terminated by sending the force tune message when the next ad insertion point arrives in the unicast program. This termination method may be somewhat less transparent to the subscriber, though it should still be relatively imperceptible to the subscriber if QAM affinity has been achieved. Another method to terminate a unicast session, and the most aggressive and potentially most perceptible to the subscriber, is to send a force tune message to the subscriber's set top terminal in mid-program. Terminating the session in this way will not be concealed by the presentation of black frames and could appear to be abrupt. However, even this disruption can be minimized if the subscriber is directed to a multicast rendition of the program that is being transmitted by the same QAM or other edge device on which the unicast rendition of the program was being transmitted.
One example of a set top terminal 400 is shown in more detail in
Set-top terminal 400 includes an in-band tuner 402, which tunes to a channel signal selected by a consumer (not shown) via user interface 404. User interface 404 may be any control device such as a remote control, mouse, microphone, keyboard, or display. NTSC demodulator 440 and digital demodulator 442 are responsive to in-band tuner 402. NTSC demodulator 440 includes components responsive to receive analog versions of a channel signal. A digital demodulator 442, which as shown is a QAM demodulator, but, which may be any type of digital demodulator device, includes components responsive to receive digital versions of a channel signal, and to output video information. QAM demodulator 442 receives and processes digital data packets from one or more digital sources, such as a digital television signal, an MPEG transport stream, or a media stream from an external network connection, such as cable modem 415 (if available), using well-known methods and techniques. Video decoder 444 is responsive to receive and decode video information. Video information that may require format translation or modification for compatibility with capabilities of set top terminal 400 may be passed to encoder 441 for formatting. Video information that is in a format preferred for use by MPEG Decoder/Multi Media Processor 449 may be passed directly to MPEG Decoder/Multi Media Processor 449. Encoder 441 is operative to perform predetermined coding techniques (for example, MPEG-2, MPEG-4, and others) to produce an encoded video signal for transmission to MPEG Decoder/Multi Media Processor 449, or for storage. MPEG Decoder/Multi-Media Processor 449 is operative to perform predetermined coding techniques to arrange video information into displayable formats, in accordance with well-known methods and techniques. Internal arrangements of MPEG Decoder/Multi-Media Processor 449 are well known, and may include analog-to-digital converters, one or more storage media and/or buffers, and general or special-purpose processors or application-specific integrated circuits, along with demultiplexers for demultiplexing and/or synchronizing at least two transport streams (for example, video and audio).
An electronic program guide (EPG) 455 is also provided in set-top terminal 400. The EPG 455 is an interactive, on-screen display feature that displays information analogous to TV listings found in local newspapers or other print media. An EPG provides information about each program being broadcast within the time period covered by the EPG, which typically ranges from the next hour up to several days. The information contained in an EPG includes programming characteristics such as, for example, channel number, program title, start time, end time, elapsed time, time remaining, a brief description of the program's content and possibly the names of individuals associated with the program such as the actors, writers and director. The EPG, which is generally received along with the programming content, may be updated on a periodic basis so that the consumer can make appropriate selection for upcoming programs. For example, the electronic program guide 455 may display programs in a tabular format by channel and time so that the user can make selections of desired content. In some cases, instead of transmitting it along with the programming, the electronic program guide 455 may be downloaded via a telephone line, cable connection, satellite up-link, or radio broadcast antenna.
An on-screen display unit 450 is provided in set top terminal 400. The on-screen display unit 450 is used to display information such as control menus and the like as well as information received from the service provider or MSO that needs to be directly presented to the user regardless of the particular programming or channel that the user is currently viewing. In particular, on-screen display unit 450 displays the information provided by the EPG 455. Accordingly, on-screen display unit 450 can forward the information directly to the display unit 470, where it may appear as an overlay, pop up, or scrolling text ticker that is superimposed on the current programming being viewed. Alternatively, the information from the on-screen display unit 450 may even replace the current programming that appears on the display unit 470.
DVR subsystem 460 is provided for recording programs received from the access network. DVR subsystem 460 can control the channel tuned by tuner 402 and record programming on a manual or timer control basis. Additionally, the DVR subsystem 460 can buffer incoming programs to enable a view to pause or replay a portion of a live program.
Set-top terminal may also optionally include a demographics database 490 to store the demographic information concerning the subscriber that is to be sent to the headend.
Set-top terminal 400 further includes a computer-readable storage medium 406. Computer-readable storage medium 406 may be any local or remote device capable of recording or storing data, and in particular may be, or may include, a read only memory (“ROM”), flash memory, random access memory, a hard disk drive, all types of compact disks and digital videodisks, and/or magnetic tape. Various application programs (e.g., an SDV application) may reside on storage medium 406. The applications residing on storage medium 406 may be computer programs that include software components implemented according to well-known software engineering practices for component-based software development and stored in computer-readable memories, such as storage medium 406. The applications, however, may be any signal processing methods and/or stored instructions, in one or more parts, that electronically control functions set forth herein. Storage medium 406 may also include other programs to provide additional functionality. For example, a network interface program 408 may be provided that represents aspects of the functional arrangement of various computer programs that pertain to the receipt and processing of content and other data over a broadband system.
The various components of set top terminal 400 discussed above may all operate under the overall control of a processor 465. Moreover, it is contemplated that the processor 465, tuner 402, video decoder 449, user interface 404, onscreen display unit 450 and the other components shown in
Among its other advantages, the system and techniques described herein allow SDV unicast sessions to be delivered to subscribers by using underutilized network resources, thus allowing precisely targeted advertising to be presented whenever possible without the need to deploy additional infrastructure such as QAM modulators.
The processes described above, including but not limited to those presented in connection with the headend and set-top terminal may be implemented in general, multi-purpose or single purpose processors. Such a processor will execute instructions, either at the assembly, compiled or machine-level, to perform that process. Those instructions can be written by one of ordinary skill in the art following the description of presented above and stored or transmitted on a computer readable storage medium. The instructions may also be created using source code or any other known computer-aided design tool. A computer readable storage medium may be any medium capable of carrying those instructions and include a CD-ROM, DVD, magnetic or other optical disc, tape, silicon memory (e.g., removable, non-removable, volatile or non-volatile), packetized or non-packetized wireline or wireless transmission signals.