Patent Application
20090049485
IBM® is a registered trademark of International Business Machines Corporation, Armonk, N.Y., U.S.A. Other names used herein may be registered trademarks, trademarks or product names of International Business Machines Corporation or other companies.
1. Field of the Invention
This invention relates to digital video distribution networks and particularly to switching channels.
2. Description of the Related Art
In modern digital video transmission networks, one of the biggest challenges is providing viewers with a high quality experience. Providing viewers the high quality experience generally requires effectively managing operations that are simple in analog systems, such as switching channels. In analog television, video and audio portions of television transmissions are inherently synchronized with each other. A video signal and an audio signal can be initiated simultaneously from any part of an analog television signal. In digital television, the video signal and the audio signal are transmitted by separate packet streams (also known also as “packetized elementary streams” or PES). The PES are synchronized on the receiving end (at a digital television or a digital set-top-box (STB) connected to the digital TV) during playback. To preserve bandwidth, the video signal is encoded in such a way that each video frame will typically require information from additional encoded frames to be properly decoded. Thus, a waiting time is required for the additional frames to be transmitted prior to decoding. Further, PES buffering at the receiving end may be required to smooth out jitter in the transmission time of the received streams. The waiting time and the PES buffering can cause a significant delay in switching channels, on the order of a few seconds.
To manage bandwidth usage, some recent digital video distribution networks use one of multicast and unicast transmission architectures. In traditional broadcast transmission architectures, all of the TV channels that are available in an area (either off-the-air or through cable or satellite TV content providers) are transmitted to each and every TV receiver in that area. In contrast, with digital video distribution architectures (such as multicast and unicast transmissions), TV channels are selectively transmitted to smaller subsets of receivers that include viewers interested in the specific channels. These digital video distribution architectures, also referred to as switched broadcast, have been designed primarily to carry video programming over relatively low bandwidth links. The low bandwidth links provide point-to-point or point-to-multipoint “last mile” links that connect end-user premises (e.g., residences) to higher capacity core (or “backbone”) distribution networks.
Other types of service providers may also use the digital video distribution networks. Telephony service providers, for example, may use switched broadcast technologies to carry video programming using digital subscriber loop (DSL) technologies. Using the DSL technologies, the video programming is transmitted over the same twisted pair wires the telephone service providers use to provide telephony and, more recently, Internet services to residential customers. Fiber-to-the-node (FFTN) and fiber-to-the-curb (FFTC) are examples of distribution technologies in which a high-bandwidth core network (using fiber cabling) extends to a (small or large) residential neighborhood or the curbside and then uses twisted pair to provide services to end-users. Note that telephony, Internet, and TV services can all be transmitted over a common/converged transport communications layer based to Internet Protocol (IP) technologies. Television services using IP are commonly referred to as IPTV.
While switched broadcast distribution architectures permit the use of relatively low bandwidth in last mile access networks used to carry broadband services, the switched broadcast distribution architectures further exacerbate the delays in switching channels in digital video distribution networks. Generally, only a small number of channels are carried to a receiver at a viewer's premises. The number of channels could be on the order of two or three channels, especially when considering high-definition TV (HDTV) programming. Therefore, in addition to the switching delays previously discussed, an additional delay may occur if a newly selected channel is not among the small number of channels already transmitted to the receiver. With the unicast transmission, the newly selected channel (or the digital streams that comprise the newly selected channel) will need to be retrieved from a location in the digital video distribution network such as the TV service provider location itself. With the multicast transmissions, the newly selected channel may need to be retrieved from the distribution network outside of the neighborhood depending on whether neighbors are already viewing the newly selected channel.
When a user changes to a new channel, if the multicast transmission is employed and if it happens that a “neighbor” also receives the new channel, then the new channel can be streamed from a common upstream node, which is generally nearby. On the other hand, if no neighbor was watching the new channel, the new channel will be retrieved from content-providing servers located upstream in the distribution network such as at a super headend of the digital video distribution network.
An implementation of channel switching in a digital TV network that uses the switched broadcast technologies can result in a slow process, which may offset the potential benefits in using digital TV networks including multiple camera-views, rich data services like advanced interactive TV programming guides, and so on. Given the high level of expectation that TV viewers have already gained viewing analog broadcasts for many years, the speed of channel switching is a key quality of experience element for digital video transmission networks. Microsoft's IPTV offering (available from Microsoft Corporation of Redmond, Wash.) attempts to address this issue through a fast channel switch technology that relies on back-end servers that aid channel switching. Microsoft's fast channel switch technology is a client-server based solution that requires a coordinated deployment of matched server (in a video home office or VHO) and client (in a digital STB) components to implement complementary portions of a proprietary scheme. In any case, since requests for changing a channel must traverse the entire core network to reach a VHO, the equivalent of a head-end in a cable system, talking advantage of this feature entails a switching time that is at least as long as the round-trip delay between the STB and the VHO. Another proposed technology uses an adjacent multicast group join-leave method. The method permits the transmission of multiple join requests to multicast groups of viewers that receive the desired new channel (the switched to channel), as well as the adjacent channels to the new channel. However, the use of adjacent channels is a restrictive concept. The use of adjacent channels makes the presumption of “old-style” channel surfing (i.e., changing channels in a consecutive numerical order) common in analog TV systems.
What are needed are a method and a computer program product to provide for fast switching of channels in a digital video distribution network.
The shortcomings of the prior art are overcome and additional advantages are provided through the provision of a method for switching channels on a video playback device, the device receiving content from a plurality of channels transmitted by a digital video distribution network, the method including establishing a context for selecting additional channels; receiving a selection for another channel; updating the context with the selection; and transmitting the selection to the device and providing the additional channels for fast channel switching.
Also disclosed is a computer program product stored on machine-readable media, the media including instructions for switching channels on a video playback device, the device receiving content from a plurality of channels transmitted by a digital video distribution network, the product having instructions for establishing a context for selecting additional channels wherein the context includes an algorithm, the algorithm executed by at least one of the device, customer premise equipment, the network, a remote site accessed via the Internet, and a television service provider; receiving a selection for another channel wherein the selection is performed by activating one input device; updating the context with another selection wherein the context includes at least one of a time, a day, a person, a group of people, a viewing pattern, a type of content, a transmission bandwidth, a storage characteristic of a set-top box, and a subscription level; transmitting the selection to the device and providing the additional channels for fast channel switching; and adjusting at least one of a bandwidth of the additional channels using a number of the additional channels requested and adjusting a time interval for transmitting the additional channels using the number.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with advantages and features, refer to the description and to the drawings.
As a result of the summarized invention, technically we have achieved a solution that provides for fast switching of TV channels transmitted by a digital video distribution network, the solution includes a method for switching channels on a video playback device, the device receiving content from a plurality of channels transmitted by a digital video distribution network, the method including establishing a context for selecting additional channels; receiving a selection for another channel; updating the context with the selection; and transmitting the selection and the additional channels for fast channel switching.
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains the preferred embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
The teachings provide a method and computer product for fast channel switching in a digital video distribution network. The teachings provide for generating and using context-based observations to learn from past viewing patterns of a subscriber and to predict the “next” channel to be selected. Predicted “next” channels are transmitted by the digital video distribution network to a point in the network close to the subscriber to provide the fast channel switching.
In some embodiments, the method and computer product are client based and do not require a matching server component at a head-end (or high tier) of the television distribution network such as a VHO. The teachings can be used with at least one of multicast and unicast television transmissions and, furthermore, may include use of backend servers if a channel switch request reaches the backend server. A context-based learning module (representing a client component), may reside in at least one of a TV set, a set-top-box attached to the TV set, a remote control, a residential gateway (which may be located at the boundary between a home premises and a providers network(s)), and, in certain embodiments, within the distribution network away from the home premises. When the context-based learning module is located within the distribution network, advanced channel switching services may be provided as a service by third party providers, including a digital service video provider.
For convenience, some acronyms used herein are now introduced. A “video home office” is referred to as a VHO. A “set-top box” is referred to as a STB. A “television” is referred to as a TV. “Fiber-to-the-node” is referred to as FTTN. A “digital subscriber loop” is referred to as DSL. A “DSL access multiplexer” is referred to as DSLAM. “Customer-premises equipment” is referred to as CPE. “High definition television” is referred to as HDTV. “Internet Protocol” is referred to as IP.
Again referring to
Referring to
Finally, referring to
Note that when channels are unicast to subscribers 140, or when the network nodes 203 are not multicast enabled, then requests for channel switching are serviced by the VHO 201 as in the case with subscriber A 205.
From the above discussion, it is noted that time for a channel switch is decreased the shorter the request for the channel switch propagates through the distribution network 200 provided by the service provider 100. In traditional TV systems, where all the channels (excluding on-demand channels) are transmitted to all the subscribers at all times, the request for switching a channel does not propagate beyond the set-top box in the subscriber's premises. For the digital video distribution network 200, the average switching time will decrease with a decrease in the frequency of occurrence of situations similar to the one encountered by subscriber A 205 or an increase of the frequency of occurrence of situations similar to the one encountered by subscriber D 208.
Since only a small number of channels can be carried at once to the premises of subscribers 140, there is a benefit in carefully selecting which channels are transmitted to subscribers 140 in order to affect the aforementioned frequencies in a favorable manner. According to the teachings herein, selection is achieved by sending requests for multiple channels that are associated with each other based on a viewing context of a requestor of switching channels.
The method 300 creates a pool of the most likely channels to be viewed in the future by the subscriber 140 and hence proactively request the most likely channels from the service provider 100. Specifically, the method shown in
The pool of potential next channels can be influenced by the current viewing context in a straightforward manner such as based on channel popularity, channel content, such as news, but also in a more elaborate manner. For example, if the currently viewed program is a sports event, e.g., football, and it is Sunday afternoon and a request for a channel selection is made by one subscriber 140 and an associated profile identifies the subscriber 140 as a sports fan, then it is highly probable that the channel selection is for another sports event. Therefore, some channels included in the pool of potential next channels can also be sports events. Channels may be selected for the pool in an even more refined manner to include only football games, or college football games, or football games covering local teams, or football games that are competitive in the final minutes of coverage, and so on. To select a more refined pool of potential next channels, a set of channel metadata available through electronic program guides (EPGs) provided by the TV service provider 100 can be used. In addition, when the set-top box 204 is networked, e.g., Internet-capable, an on-line information provider may provide the metadata.
From the above discussion, it is seen that the viewing context is derived from a variety of situations some of which are system independent (such as time and day), some of which are viewer dependent (such as a person profile), some of which are content dependent in broad terms (such as sports events), or narrow terms (such as local football games within five minutes to finish with less than a seven point differential), and so on. Thus, the viewing context can be used to create an elaborate pool of potential next channels that can be dynamically adjusted to reflect different conditions.
Referring to
The use of the method 300 usually requires the use of computing resources such as a computer processor, storage and memory. In one exemplary embodiment of the teachings herein, the computing resources may reside within the premises of the subscriber 140. Examples of the computing resources include the TV STB 204, the residential gateway, the remote control unit, or a combination of CPE devices. The method 300 uses these computing resources as the CPE. In another exemplary embodiment of the teachings herein, the computing resources may reside remotely to the premises of the subscriber 140 such as within a data server at the VHO 201 (shown in
In building the pool of next channels 304 in
By analyzing the historical data, context-sensitive learning algorithms may determine automatically the most probable additional channels that may be requested by the subscriber 140. In addition, interactive procedures can be employed for confirming the validity of an observed behavioral pattern. For example when the algorithm, based on historical data analysis, determines that a particular channel switching pattern occurs, the algorithm may ask if the subscriber 140 wants the algorithm to learn the switching pattern. Further, the algorithm may ask under which profile to store the switching pattern (family, person, etc.). The subscriber 140 may even enter through the remote control favorite shows that the subscriber 140 may want to watch. Such an action allows the CPEs to proactively request the desired channels from the TV service provider 100 so that the desired channels can be available for viewing by the time the desired program starts. In alternative embodiments, the subscriber 140 does not have to explicitly request changing of channels. In an exemplary embodiment of the interactive aspects discussed herein, a special window may be superimposed on the TV set displaying a menu of actions for selection that the subscriber 140 can navigate through using the remote control. The window may also provide editing capabilities for the subscriber 140 to enter information about personal preferences.
The exemplary method 300 depicted in
When the node 203 involved in the execution of the method 400 is a DSLAM distribution node 203, each subscriber 140 is served by a separate link 202 from the DSLAM node 203. Hence, subscribers 140 can be identified by the links 202 out of the DSLAM node 203 that serve them. According to the method 400 in
If a requested channel does not exist at the node 203 (404 no), then the node 203 will add the requested channel in a request channel pool 411 and transmit 412 the channel request upstream to be serviced by the next available node 203 in the network 200 where this method 400 is repeated again 413. When the requested channels are received from an upstream node 414, the requested channels are added in a next channel pool 415 and the method 400 continues from step 406 as before. In an alternative embodiment, steps 411 and 412 may be performed in tandem for each requested channel, i.e., for each requested channel that is not available at the node 203, a separate channel request is sent upstream.
The combination of the exemplary methods depicted in
Different embodiments may be used in preparing the channels for transmission 407 in
In yet another embodiment, the number of additional channels 503 is increased using short duration streams of the additional channels 503. The additional channels 503 are stored on the CPE (e.g., the STB 204 in
Instead of the CPE requesting additional channels, the service provider 100 may schedule the staggered transmission of the additional channels 602. However, the scheduling technique requires that the service provider 100 maintains information about the viewing patterns of the subscriber 140, in which case the service provider 100 may use the context-sensing learning algorithms as well.
The embodiment of
The capabilities of the present invention can be implemented in software, firmware, hardware or some combination thereof. For example, the CPE can include a processor, a communications bus, memory, storage, input devices, and output devices wherein the CPE can receive an input, the processor can execute instructions from at least one of the software and the firmware, and provide an output. The software and the firmware can include a computer program product stored on machine-readable media that can be executed by the CPE.
As one example, one or more aspects of the present invention can be included in an article of manufacture (e.g., one or more computer program products) having, for instance, computer usable media. The media has embodied therein, for instance, computer readable program code means for providing and facilitating the capabilities of the present invention. The article of manufacture can be included as a part of a computer system or sold separately.
Additionally, at least one program storage device readable by a machine, tangibly embodying at least one program of instructions executable by at least one of the CPE and higher tier processing systems in the digital video distribution network 100 to perform the capabilities of the present invention can be provided.
The flow diagrams depicted herein are just examples. There may be many variations to these diagrams or the steps (or operations) described therein without departing from the spirit of the invention. For instance, the steps may be performed in a differing order, or steps may be added, deleted or modified. All of these variations are considered a part of the claimed invention.
While the preferred embodiment to the invention has been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described.
