CROSS-REFERENCES TO RELATED APPLICATIONSThis application claims the benefit of U.S. provisional application Ser. No. (Attorney Docket No. 19880-003800), entitled “METHOD AND APPARATUS FOR INTERACTIVE PROGRAM GUIDE AND ADVERTISING SYSTEM,” filed Nov. 27, 2000, which is incorporated herein by reference in its entirety for all purposes.[0001]
BACKGROUND OF THE INVENTIONThe present invention relates to communication systems in general. More specifically, the invention relates to techniques to efficiently deliver interactive program guide (IPG) and other multimedia information in a server-centric system.[0002]
Over the past few years, the television industry has seen a transformation in a variety of techniques by which programming is distributed to consumers. Cable television systems are doubling or even tripling system bandwidth with the migration to hybrid fiber coax (HFC) cable plant. Direct broadcast satellite (DBS) systems have also emerged as a viable alternative to customers unwilling to subscribe to local cable systems. A variety of other approaches have also been attempted, which focus primarily on high bandwidth digital technologies, intelligent two-way set top terminals, or other methods to try to offer service differentiated from standard cable and over-the-air broadcast systems.[0003]
With this increase in bandwidth, the number of programming choices has also increased. Leveraging off the availability of more intelligent set top terminals (STTs), several companies have developed elaborate systems for providing an interactive listing of a vast array of channel offerings, expanded textual information about individual programs, and the ability to look forward as much as several weeks in advance to plan television viewing.[0004]
Unfortunately, the existing program guides have several drawbacks. First, these guides tend to require a significant amount of memory at the set top terminal. Second, the terminals may be very slow to acquire the current database of programming information when they are turned on for the first time or are subsequently restarted (e.g., a large database may be downloaded to a terminal using only a vertical blanking interval (VBI) data insertion technique). Such slow database acquisition may disadvantageously result in out of date information or, in the case of services such as pay-per-view (PPV) or video-on-demand (VOD), limited scheduling flexibility for the information provider. Third, the user interface of existing program guides do not usually look like a typical television control interface; rather the user interface looks like a 1980's style computer display (i.e., having blocky, ill-formed text and/or graphics).[0005]
Therefore, efficient and effective techniques to deliver interactive program guide and other multimedia information to a large number of viewers, and which that ameliorate the above-described problems, are highly desirable.[0006]
SUMMARY OF THE INVENTIONThe present invention provides techniques for transmitting multiple “slices” of information for a particular location of a user interface. These techniques can be used to present more information to a viewer on a limited-size viewing area, and are well suited for interactive program guide (IPG) commonly used for television and broadcast distribution systems. The techniques described herein may also be advantageously used for other applications and other guides such as, for example, dining guide, local shopping, news, and others.[0007]
In accordance with an aspect of the invention, multiple slices can be associated with a particular slice location of the IPG page. These multiple slices can be used to present more information (i.e., content) at the slice location. Various schemes can be used to deliver and present the multiple slices in an intelligible manner while reducing the amount of clutter.[0008]
In a first slice delivery and presentation scheme, multiple slices for a particular location of an IPG page are transmitted from the head-end at different times. For example, the multiple slices can be transmitted at different GOP times, and the slices can be appropriately time stamped for presentation at the desired GOP times. In a second scheme, multiple slices are concurrently transmitted for a particular location of an IPG page. In this scheme, a terminal can receive the transmitted slices, select one of the multiple slices for processing, and process and display the selected slice. In a third scheme, one slice is transmitted for each slice location, and additional slices can be transmitted for a particular location by the head-end upon receiving a request from the terminal.[0009]
An embodiment of the invention provides a method for delivering information for a user interface that includes a number of regions. In accordance with the method, which is generally performed at a head-end of an information distribution system, a number of slice locations for a first (e.g., guide) region of the user interface are defined, with each slice location corresponding to a respective area and location in the guide region. A number of (e.g., guide) slices are associated with each of at least one slice location in the guide region. One or more guide slices are encoded for each slice location in the guide region and transmitted.[0010]
A number of sets of guide slices can be transmitted for the slice locations in the guide region, for example, in a time division multiplexed manner in which one set of guide slices is transmitted for each group of pictures (GOP). Alternatively, one set of guide slices may be continually transmitted and additional sets may be transmitted as requested. The transmitted slices can be time-stamped for presentation at the designated times.[0011]
Another embodiment of the invention provides a method for presenting a user interface that includes a number of regions. In accordance with the method, which is generally performed at a terminal, a bitstream comprising packets for a number of slices for a first (e.g., guide) region of the user interface is received. Each slice is designated for presentation at a particular slice location of the guide region, and multiple slices are transmitted for each of at least one slice location of the guide region. Packets for a set of slices for the guide region are retrieved from the bitstream and decoded to form the guide region of the user interface.[0012]
A number of sets of slices may be received for the guide region. In this case, the sets of slices may be decoded and presented at times designated by a header associated with the slices. The sets of slices can be presented in a time division multiplexed manner, or upon receiving a directive to update the slices in the guide region.[0013]
The invention further provides other methods and system elements (i.e., terminal and server) that implement various aspects, embodiments, and features of the invention, as described in further detail below.[0014]
The foregoing, together with other aspects of this invention, will become more apparent when referring to the following specification, claims, and accompanying drawings.[0015]
BRIEF DESCRIPTION OF THE DRAWINGSThe teachings of the invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings.[0016]
FIG. 1 is a block diagram of an embodiment of an information distribution system that can be used to provide interactive program guide (IPG) and is capable of implementing various aspects of the invention;[0017]
FIG. 2A is a diagram of a specific design of an IPG page used to present a program listing and other information to viewers;[0018]
FIGS. 2B and 2C are diagrams of an embodiment of a background video and a guide video, respectively, for the IPG page shown in FIG. 2A;[0019]
FIGS. 3A through 3C are diagrams of data structures (i.e., matrices) of program guide data for a group of IPG pages, and which may be used in conjunction with picture-based encoding, slice-based encoding, and temporal slice persistence encoding, respectively;[0020]
FIG. 3D is a diagram that shows an implementation of demand-cast with the use of temporal slice persistence technique;[0021]
FIG. 4 is a diagram of a specific design of a channel information window (i.e., a spotlight window) that can also be used to efficiently provide IPG information;[0022]
FIG. 5 is a block diagram of an embodiment of terminal capable of providing a display of a user interface and implementing various aspects of the invention;[0023]
FIG. 6 is a diagram of a specific design of an IPG page that can be used to illustrate various aspects and embodiments of multiple slices transmission; and[0024]
FIGS. 7A through 7C are diagrams that illustrate various slice delivery and presentation schemes whereby multiple slices are transmitted for a particular location of an IPG page.[0025]
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common within a figure.[0026]
DESCRIPTION OF THE SPECIFIC EMBODIMENTSA. System[0027]
FIG. 1 is a block diagram of an embodiment of an[0028]information distribution system100 that can be used to provide interactive program guide (IPG) and is capable of implementing various aspects of the invention.Distribution system100 includes a head-end102, (optional) local neighborhood equipment (LNE)104, one or more distribution nodes106 (e.g., a hybrid fiber-coax network), and a number of terminals108 (e.g., set top terminals). EachLNE104 may serve one ormore distribution nodes106, and eachdistribution node106 is typically associated with a respective neighborhood that includes a number ofterminals108.
Head-[0029]end102 produces a number of digital streams that contain encoded information in (e.g., MPEG-2) compressed format. These digital streams are then modulated using a modulation technique that is compatible with acommunication channel162 that couples head-end102 toLNE104 and/ordistribution node106.LNE104 is typically located away from head-end102.LNE104 selects data for viewers in the LNE's neighborhood and re-modulates the selected data into a form suitable for transmission to the associated distribution node(s)106. Althoughsystem100 is depicted as having head-end102 andLNE104 as separate elements, the functions ofLNE104 may be incorporated into head-end102. Also, the elements ofsystem100 can be physically located anywhere, and need not be near each other.
In[0030]distribution system100, program streams may be continually transmitted from the head-end to the terminals (i.e., broadcast) or may be addressed to particular terminals that requested the information via an interactive menu (referred to herein as “demand-cast”). An interactive menu structure suitable for requesting video-on-demand (VOD) is disclosed in commonly assigned U.S. patent application Ser. No. 09/533,006, entitled “METHOD AND APPARATUS FOR PROVIDING A MENU STRUCTURE FOR AN INTERACTIVE INFORMATION DISTRIBUTION SYSTEM,” and incorporated herein by reference. Another example of an interactive menu suitable for requesting multimedia services is an interactive program guide disclosed in commonly assigned U.S. patent application Ser. No. 09/293,526, entitled “DATA STRUCTURE AND METHODS FOR PROVIDING AN INTERACTIVE PROGRAM GUIDE,” filed Apr. 15, 1999, and incorporated herein by reference.
To assist a viewer to select programming, head-[0031]end102 produces information that can be assembled to create an “IPG page” such as that shown in FIG. 2A. Head-end102 produces the components of the IPG page as bitstreams that are compressed prior to transmission.Terminals108 thereafter receive and demodulate the transmission from head-end102 and decode the compressed bitsteams to retrieve the IPG pages.
Within[0032]distribution system100, avideo source112 supplies one or more video sequences for a video portion of the IPG pages (also referred to herein as “barker” videos), anaudio source114 supplies one or more audio signals associated with the video sequences, and aguide data source116 provides program guide data for a guide portion of the IPG pages. The guide data is typically stored and provided in a particular (e.g., text) format, with each guide entry describing a particular program by its title, presentation time, presentation date, descriptive information, channel, and program source. The video sequences, audio signals, and program guide data are provided to anencoder unit120 within head-end102.
Encoder unit[0033]120 (which is described in further detail below) compresses the received video sequences into one or more elementary streams, the audio signals into one or more elementary streams, and the guide videos produced from the guide data into one or more elementary streams. The elementary streams can be produced using a number of encoding techniques such as, for example, “picture-based” encoding, “slice-based” encoding, “temporal slice persistence” (TSP) encoding, “strobecast”, as well as other types of encoding, or a combination thereof.
Picture-based encoding is described in detail in U.S. patent application Ser. No. 09/384,394, entitled “METHOD AND APPARATUS FOR COMPRESSING VIDEO SEQUENCES,” filed Aug. 27, 1999. Slice-based encoding is described in detail in U.S. patent application Ser. No. 09/428,066, entitled “METHOD AND APPARATUS FOR TRANSMITTING VIDEO AND GRAPHICS IN COMPRESSED FORM,” filed Oct. 27, 1999. Temporal slice persistence encoding is described in detail in U.S. patent application Ser. No. (Attorney Docket No. 19880-003410), entitled “TEMPORAL SLICE PERSISTENCE METHOD AND APPARATUS FOR DELIVERY OF INTERACTIVE PROGRAM GUIDE,” filed Oct. 10, 2000. Strobecast encoding and delivery is described in detail in U.S. patent application Ser. No. 09/687,662, entitled “EFFICIENT DELIVERY OF INTERACTIVE PROGRAM GUIDE USING DEMAND-CAST,” filed Oct. 12, 2000. These applications are assigned to the assignee of the invention and incorporated herein by reference.[0034]
In the specific embodiment shown in FIG. 1,[0035]encoder unit120 includes a guidedata grid generator122, acompositor unit124,video encoders126aand126b, and anaudio encoder128. Additional video and/or audio encoders may also be included withinencoder unit120, depending on the particular head-end design. Guidedata grid generator122 receives and formats the guide data into a “guide grid”, e.g.,guide grid region212 in FIG. 2A.
[0036]Compositor unit124 receives and combines the guide grid fromgrid generator122 and a video sequence fromvideo source112, and may further insert advertising video, advertiser or service provider logos, still graphics, animation, other information, or a combination thereof. In an embodiment,compositor unit124 provides a background video (e.g., as shown in FIG. 2B) to afirst video encoder126aand a guide video (e.g., as shown in FIG. 2C) to asecond video encoder126b. For picture-based encoding,compositor unit124 provides a composed video (e.g., as shown in FIG. 2A) to one video encoder. A number of encoders can be used to encode in parallel a number of composed videos for a number of IPG pages, with each IPG page including different guide content.
In an embodiment,[0037]video encoder126ais a real-time (e.g., MPEG-2) encoder that encodes the background video using a particular encoding technique, and provides one or more (e.g., MPEG-2 compliant) bitstreams for the background portion of the IPG page. In an embodiment,video encoder126bis a (e.g., software-based) encoder that encodes the guide video using a particular encoding technique, and provides one or more bitstreams that collectively represent all or a portion of the guide grid. Each video encoder126 is designed to efficiently and effectively encode the respective input video, and may be operated in accordance with slice-based, picture-based, temporal slice persistence, or some other encoding technique. Audio encoder128 (e.g., an AC-3 encoder) receives and encodes the audio signals to form a bitstream for the audio signals. The video and audio encoders provide a number of elementary streams containing (e.g., picture-based or slice-based) encoded video and audio information.
For some applications such as picture-in-picture (PIP) or picture-in-application (PIA),[0038]compositor unit124 may receive a number of video sequences and form a composed video having included therein the video sequences in scaled form (i.e., reduced in size). For example, nine video sequences may be compressed and arranged into a 3×3 grid.Video encoder126athen receives and (e.g., slice-based) encodes the composed video and produces a number of elementary streams, one stream for each video sequence. Each video sequence can thereafter be individually transmitted from the head-end and flexibly recombined with other (e.g., guide) data and/or video at the terminal (e.g., to implement PIP or PIA). PIP and PIA are described in further detail in U.S. patent application Ser. No. 09/635,508, entitled “METHOD AND APPARATUS FOR TRANSITIONING BETWEEN INTERACTIVE PROGRAM GUIDE (IPG) PAGES,” filed Aug. 9, 2000, assigned to the assignee of the invention and incorporated herein by reference.
A[0039]controller130 couples toencoder unit120 and manages the overall encoding process such that the video encoding process is temporally and spatially synchronized with the grid encoding process. For slice-based encoding, this synchronization can be achieved by defining the slice start and stop (macroblock) locations for each slice and managing the encoding process based on the defined slices. Slices may be defined, for example, according to the objects in the IPG page layout.
The encoding process generates a group of pictures (GOP) structure having “intra-coded” (I) pictures and “predicted” (P and B) pictures. For slice-based encoding, the I pictures include intra-coded slices and the P and B pictures include predictive-coded slices. In an embodiment, the intra-coded slices are separated from the predictive-coded slices and transmitted from the head-end via separate packet identifiers (PIDs). Although not shown in FIG. 1, the coded slices may be stored in a storage unit. The individual slices can thereafter be retrieved from the storage unit as required for transmission from the head-end.[0040]
A transport stream generator (TSG)[0041]140 receives and assembles the elementary streams from the video and audio encoders into one or more transport streams.Transport stream generator140 further manages each transport stream and communicates with asession manager150 to form and/or tear down transport streams. In an embodiment, each transport stream is an MPEG-compliant transport stream. In this case,transport stream generator140 may send program tables toterminals108 in a private section of the MPEG transport stream. Such table may include a list of available streams along with the address of the source transport stream generator and other information to identify the particular transport stream to which the table belongs.
[0042]Session manager150 manages the delivery of IPG pages toterminals108 located on one ormore distribution nodes106. In an embodiment, eachdistribution node106 is served by a respective set of one or more transport streams generated by a transport stream generator assigned to that node. The transport streams for each distribution node include broadcast streams (e.g., for IPG pages continually sent from the head-end) and demand-cast streams (e.g., for IPG pages sent from the head-end in response to requests from the terminals). For some implementations,session manager150 may monitor the demand-cast streams and usage byterminals108 and direct the appropriate transport stream generator to generate or tear down demand-cast streams.
An in-band delivery system[0043]160 (e.g., a cable modem) receives and modulates the transport streams fromtransport stream generator140 using a modulation format suitable for transmission overcommunication channel162, which may be, for example, a fiber optic channel that carries high-speed data from the head-end to a number of LNE and/or distribution nodes. Each LNE selects the programming (e.g., the IPG page components) that is applicable to its neighborhood and re-modulates the selected data into a format suitable for transmission over the associated distribution node(s).
Although not shown in FIG. 1 for simplicity,[0044]LNE104 may include a cable modem, a slice combiner, a multiplexer, and a modulator. The cable modem demodulates a signal received from the head-end and extracts the coded video, guide, data, and audio information from the received signal. The coded information is typically included in one or more transport streams. The slice combiner may recombine the received video slices with the guide slices in an order such that a decoder at the terminals can easily decode the IPG without further slice re-organization. The multiplexer assigns PIDs for the resultant combined slices and forms one or more (e.g., MPEG-compliant) transport streams. The modulator then transmits the transport stream(s) to the distribution node(s).
[0045]LNE104 can be programmed to extract specific information from the signal transmitted by the head-end. As such, the LNE can extract video and guide slices that are targeted to the viewers served by the LNE. For example, the LNE can extract specific channels for representation in the guide grid that can be made available to the viewers served by that LNE. In such case, unavailable channels to a particular neighborhood would not be depicted in a viewer's IPG. The IPG may also include targeted advertising, e-commerce, program notes, and others. To support such features, each LNE may recombine different guide slices with different video slices to produce IPG pages that are prepared specifically for the viewers served by that particular LNE. Other LNEs may select different IPG component information that is relevant for their associated viewers. A detailed description ofLNE104 is described in the aforementioned U.S. patent application Ser. No. 09/635,508.
For a server-centric distribution system, the program guide resides at the head-end and a two-way communication system, via a back channel[0046]164, is utilized to support communication with the terminals for delivery of the program guide. Back-channel164 can be used by the terminals to send requests and other messages to the head-end, and may also be used by the head-end to send messages and certain types of data to the terminals. An out-of-band delivery system170 facilitates the exchange of data over the back channel and forwards terminal requests tosession manager150.
Other elements within head-[0047]end102 may also interface with out-of-band delivery system170 to send information toterminal108 via the out-of-band network. Fort example, a spotlight server that produces a spotlight user interface (described below) may interface with out-of-band delivery system170 directly to send spotlight data toterminals108. Off the shelf equipment including network controllers, modulators, and demodulators such as those provided by General Instrument Corporation can be used to implement out-of-band delivery system170.
[0048]Distribution system100 is described in further detail in the aforementioned U.S. patent application Ser. Nos. 09/687,662 and (Attorney Docket No. 19880-003410). One specific implementation of head-end102 is known as the DIVA™ System provided by DIVA Systems Corporation.
B. Interactive Program Guide[0049]
A unique way of providing programming schedule and listing to viewers is a server-centric approach. In this approach, the complete program guide information spanning a particular time period (e.g., two weeks of programming) is generated at a head-end and sent to the terminals in a display-ready compressed video format.[0050]
FIG. 2A is a diagram of a specific design of an[0051]IPG page200 used to present a program listing and other information to viewers. In this design,IPG page200 includes aguide region210, avideo region220, anicon region240, aprogram description region250, alogo region260, and a time-of-day region270. Other designs for the IPG page with different layouts, configurations, and combinations and arrangements of regions and objects can be contemplated and are within the scope of the invention. In an embodiment, guideregion210 includes aguide grid region212 and atime slot region218.Time slot region218 includes a firsttime slot object218aand a secondtime slot object218bthat indicate the (e.g., half-hour) time slots for which program guide is being provided on the IPG page.Guide grid region212 is used to display program listing for a group of channels. In the design shown in FIG. 2A, the program listing shows the available programming in two half-hour time slots.Guide grid region212 includes a number of channel objects214athrough214jused to display program information for the group of channels. A pair ofchannel indicators216aand216bwithinguide grid region212 identifies the current cursor location.
[0052]Program description region250 is used to present descriptive information relating to a particular program selected from the program listing, or may be used to present other information.Video region220 may be used to display images, videos, text, or a combination thereof, which may be used for advertisements, previews, or other purposes. In the design shown in FIG. 2A,video region220 displays a barker video.Logo region260 may include a logo of a service operator or other entity, and may be optionally displayed. Time-of-day region270 may be configured by the user and may also be optionally displayed.
[0053]Icon region240 is used to display various icons. Each icon can represent a filter or a link to either another IPG page or a particular interface. Each filter selects a particular type of programming to be included in the program listing shown inguide region210. For example, a “Pay Per View” (PPV)icon241 may be a filter that selects only PPV programming to be included in the program listing. A “Favorites”icon242 may be a filter that selects only channels designated by the viewer to be among his or her favorites. A “Movies”icon243 may be a filter that selects only movies or movie channels. A “Kids”icon244 may be a filter that selects only channels for children or programming appropriate or produced for viewing by children. A “Sports”icon245 may be a filter that selects only sports channels or sports-related programming. A “Music”icon246 may be a link to a music interface. And an “Options”icon247 may be a link to a menu of IPG options that the viewer may select amongst. Such options may include (1) configuration and selection/deselection information of IPG related services, (2) custom information for deactivating some of the filters or accessing a custom condensed listing menus, and (3) other features and functionality.
FIG. 2B is a diagram of an embodiment of a[0054]background video280 forIPG page200. In this embodiment,background video280 includesvideo region220,icon region240,program description region250, andlogo region260. As noted above,background video280 can be efficiently (slice-based) encoded by a video encoder. In other designs,background video280 may include additional and/or different regions than that shown in FIG. 2B.
FIG. 2C is a diagram of an embodiment of a[0055]guide video290 forIPG page200. In this embodiment, guidevideo290 includesguide region210, which includesguide grid region212 andtime slot region218.Guide video290 can also be efficiently (slice-based) encoded by a video encoder. In other designs, guidevideo290 may include additional and/or different regions than that shown in FIG. 2C.
As shown in FIG. 2C, two program titles are provided for each channel object[0056]214 inguide grid region212, with each title corresponding to a respective half-hour time slot. In an embodiment, a “mask or reveal” feature can be used to display (i.e., reveal) a desired program title and hide (i.e., mask) the other program title. For example,channel12 includes the program titles “Hemingway” and “Dragon Tails”. If the 9:00-9:30 time slot is selected (as shown in FIG. 2A), the program title “Hemingway” can be revealed and the other program title “Dragon Tails” can be masked from view. And if the 9:30-10:00 time slot is selected, the program title “Hemingway” can be masked and the other program title “Dragon Tails” can be revealed. The underlying video frame to be encoded can thus include various objects and items, some of which may be shown and others of which may be hidden. This mask or reveal technique can be used for any region of the IPG page.
The mask or reveal feature and the user interaction processing are described in the aforementioned U.S. patent application Ser. Nos. 09/293,526 and 09/533,006.[0057]
A program guide for a large number of channels for a long time period can be very extensive. For example,[0058]480 IPG pages would be needed to provide program guide for two weeks of programming for200 channels, if each IPG page includes a program listing for 10 channels in two half-hour time slots as shown in FIG. 2A. A large amount of system resources (e.g., bandwidth) would be needed to continually transmit the complete program guide.
In an embodiment, to conserve system resources, only a limited number of IPG pages are continually sent (broadcast) by the head-end, and remaining IPG pages may be sent as requested by viewers. The specific number of IPG pages to be broadcasted and their selection are dependent on the particular system implementation, and may be defined by a time depth and a program depth for the program guide. The time depth refers to the amount of time programming for a particular channel group is provided by the broadcast video PIDs. And the channel depth refers to the number of channels available through the program guide (in comparison to the total number of channels available in the system).[0059]
In an embodiment, a number of video PIDs can be used to send the program guide for the current and (possibly) near look-ahead time slots, one or more audio PIDs can be used to send an audio barker, and (optionally) one or more data PIDs (or other data transport method) can be used to send the program description data, overlay data, and/or other data. The elementary streams carrying the IPG are sent in one or more transport streams.[0060]
For the portion of the program guide that is broadcasted by the head-end, a viewer is able to quickly retrieve and display IPG pages formed from the broadcast streams whenever desired.[0061]
If the viewer desires a program listing or other contents that is not provided by the broadcast streams, then a demand-cast session may be initiated, for example, as described in the aforementioned U.S. patent application Ser. No. 09/635,508 and (Attorney Docket No. 19880-003410). For this demand-cast session, the terminal sends a message to the head-end, via the back channel, requesting the desired contents. The head-end processes the request, retrieves the desired contents from an appropriate source, generates a video stream for the desired contents and assigns it with another video PID (and related audio and data PIDs, if any), and incorporates the video stream into a transport stream. Preferably, the desired video stream is inserted into the transport stream currently being tuned/selected by the requesting terminal or sent in another transport stream. The head-end further informs the terminal which PID should be received and from which transport stream the demand-cast video stream should be demultiplexed. The terminal then retrieves the desired video PID from the transport stream.[0062]
C. Data Structures and Encoding Techniques[0063]
FIG. 3A is a diagram of a data structure[0064]300 (i.e., a matrix) of program guide data for a group of IPG pages, and which may be used in conjunction with picture-based encoding. In this representation, the horizontal axis represents the video sequences for different IPG pages to be transmitted, and the vertical axis represents time indices for the video sequences. In this specific example, ten video sequences are generated and labeled asIPG pages1 through10. Each video sequence is composed of a time sequence of pictures. In this specific example, each group of 15 pictures for each video sequence forms a group of pictures (GOP) for that video sequence.Matrix300 is illustratively shown to include ten GOPs for ten IPG pages, but can be designed to have any defined M×N dimension.
As shown in FIG. 3A,[0065]matrix300 is a two-dimensional array of elements, with each element representing a picture (or frame). For simplicity, each element inmatrix300 is illustratively shown to include a guide portion and a video portion on the left and right halves of the picture, respectively. The element in the first column of the first row represents the guide portion (g1) and video portion (v1) ofIPG page1 at time index t1, the element in the second column of the first row represents the guide portion (g2) and video portion (v1) ofIPG page2 at time index t1, and so on. In the specific example shown FIG. 3A, the guide portion for each IPG page is different (i.e., g1, g2, . . . , g10) but the video portion (e.g., v1) is common for all ten IPG pages.
Each of the ten video sequences in[0066]matrix300 can be coded as a GOP. For example, the video sequence forIPG page1 can be coded as a GOP comprised of the coded picture sequence: I1, B1, B1, P1, B1, B1, P1, B1, B1, P1, B1, B1, P1, B1,and B1, where I represents an intra-coded picture, P represents a uni-directionally predictive-coded picture, and B represents a bi-directionally predictive-coded picture.
In the example shown in FIG. 3A,[0067]matrix300 includes a group of intra-coded pictures312 and a group of predictive-codedpictures314 that can be used to fully represent the ten IPG pages. In an embodiment, intra-coded picture group312 includes ten intra-coded pictures at time index t1for the ten IPG pages. These intra-coded pictures can be assigned toPIDs1 through10, which may also be referred to as I-PIDs1 through10 to denote that these PIDs include intra-coded pictures. In an embodiment, predictive-codedpicture group314 includes 14 predictive-coded pictures of one of the IPG pages for time indices t2through t15. Predictive-coded picture group314 is also assigned a PID, and may also be referred to as the base-PID or PRED-PID to denote that this PID includes predictive-coded pictures. The base-PID may comprise the following picture sequence: B1, B1, P1, B1, B1, P1, B1, B1, P1, B1, B1, P1, B1, and B1.
For each IPG page, between time t[0068]1to t15, the guide portion does not change and only the video portion changes. In each column, the 14 prediction error frames contain zero data for the guide portion and video prediction error for the video portion. Therefore, the content of the base-PID is the same for each IPG page and may be sent only once per group of EPG pages in the matrix for each GOP period.
If a viewer wants to view the guide data for a particular group of channels (i.e., a particular IPG page), a demultiplexer at the terminal selects the I-PID for the selected IPG page and recombines the selected I-PID with the base-PID to produce a recombined stream, which is then decoded by the video decoder. Picture-level recombination is described in further detail in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410).[0069]
FIG. 3B depicts an embodiment of a[0070]data structure320 that may be used in conjunction with slice-based encoding. In this example, ten IPG pages are available, with each page represented by a respective guide portion (g) and a common video portion (v). For example,IPG page1 is represented as (g1/v1),IPG page2 is represented as (g2/v1), and so on. Indata structure320, ten guide portions g1through g10are associated with the video portion (v1). Slice-based encoding is described in the aforementioned U.S. patent application Ser. Nos. (Attorney Docket No. 19880-003410) and 09/635,508.
As shown in FIG. 3B, the coded slices for the guide and video portions of the IPG pages can be assigned to a number of PIDs. In FIG. 3B, only the content that is assigned a PID is delivered to the terminals. The intra-coded guide portions g[0071]1through g10are assigned toPID1 throughPID10, respectively. One of the common intra-coded video portion v1(e.g., for IPG page10) is assigned toPID11. In this form, substantial bandwidth saving is achieved by delivering the intra-coded video portion v1only once. Finally, the predictive-coded pictures g1/v2through g1/v15are assigned toPID12. Again, a substantial saving in bandwidth is achieved by transmitting only one group of fourteen predictive-coded pictures, g1/v2through g1/vI15. The PID assignment and decoding processes are described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410).
FIG. 3C is a diagram of a[0072]data structure340 that can be used in conjunction with temporal slice persistence encoding.Data structure340 is a matrix representation for program guide data for a number of IPG pages based on the partitioning of the IPG page shown in FIGS. 2B and 2C. As shown by the shaded portions in FIG. 3C, a video sequence is formed which contains only the video portion of the IPG page (i.e., the portion containing time-varying information). In an embodiment, the coded video sequence contains only slices that belong to the video region. The coded video sequence is assigned a particular PID (e.g., V-PID) and transmitted from the head-end.
For each IPG page, the guide portion (i.e., the portion containing the information specific to that IPG page) is sent in a separate picture frame. Since the guide portion does not change over time, only one picture for each GOP is coded and transmitted. The coded guide frame contains only the slices that belong to the guide portion of a frame. The slice-coded guide portion for each IPG page is assigned a respective PID (e.g., G-PID) and also transmitted from the head-end.[0073]
The presentation times of the guide frames and motion video frames are assigned in accordance with a “temporal slice persistence” fact. In an embodiment (not represented in FIG. 3C), the guide PIDs (i.e., G-[0074]PID1, G-PID2, and so on) are time stamped to be presented at the end of each GOP at t=15. At t=15, the last motion video frame in the GOP is dropped and the viewer-selected guide page is presented. To achieve this, the video decoder re-combines the selected guide G-PID (e.g., G-PID1) and the video V-PID via one of the picture-based recombination methods described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410).
The selected guide page is decoded and displayed at t=15, with only the region that contains the guide portion slices being updated on the screen. From that time on, the guide portion of the screen is not updated (i.e., the guide slices temporally persist on the screen) until the viewer selects another guide page. This selection then updates the slices in the guide portion and rewrites the new guide portion on the screen. Similarly, the V-PID frames only change the video portion of the screen and do not update the guide portion, since these motion video frames do not include slices in the guide portion.[0075]
The embodiments disclosed with respect to FIG. 3C can be used for broadcast of IPG pages and can further be used for a demand-cast of IPG pages in response to viewer requests. For demand-cast, the head-end can time stamp the requested page to be processed and quickly displayed on the screen in a suitable time index within a GOP to reduce delays. The guide frames and motion video frames can be encoded, delivered, decoded, and displayed in various manners, as described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410).[0076]
In another embodiment that is supported by FIG. 3C, the V-PID is encoded to include P and B pictures (e.g., a GOP of I-B-B-P-B-B-P-B-B-P-B-B-P-B-B), and any B picture in the V-PID can be dropped and replaced with a B-coded guide frame that includes “intra-coded” macroblocks. This can be achieved by adjusting the encoding threshold selection that decides whether a macroblock is better to be encoded as intra-coded or as predictive-coded. Any B-coded frame can be dropped and replaced since it is not used as a reference for prediction by any other pictures in a GOP. The guide page frames can be time stamped to be presented, for example, at t=2. Other embodiments for encoding and decoding the guide frames are described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410).[0077]
FIG. 3D is a diagram that shows an implementation of demand-cast with the use of temporal slice persistence technique. In the example shown in FIG. 3D, a viewer request is received and processed by the head-end, and the requested guide PID is time stamped to be displayed at t=3. In this example, the V-PID is coded to include B frames (e.g., I-B-B-P-B-B-P . . . ), and the B frame at t=3 is dropped and replaced with a B-coded requested guide PID that includes intra-coded macroblocks. The B frame of the V-PID can be dropped at anytime in a GOP since it is not used as a reference for prediction by any other frame in the GOP.[0078]
The temporal slice persistence technique can be advantageously employed in a broadcast scenario whereby a large number of guide PIDs (in the order of hundreds) can be efficiently delivered. Since the guide PIDs do not carry full motion barker video, huge bandwidth savings can be achieved. The barker video can be sent as a separate video stream (e.g., V-PID or another PID). The temporal slice persistence technique can also be used to implement other combinations of coding and decoding of guide frames, full motion video frames, and (possibly) other multimedia information in a GOP. The temporal slice persistence technique employs picture-based recombination techniques with slice-based sub-picture updating mechanisms, as described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410).[0079]
By exploiting known characteristics of the IPG pages and the temporal slice persistence technique, the transmission of redundant information can be minimized, for example, by employing efficient client-server communication and acknowledgement techniques. For example, the guide portion of a requested IPG page may be sent a limited number of times (e.g., once) in response to a viewer request for the page. This “strobecast” of IPG pages can greatly reduce the load for demand-cast, and may (possibly) be used for the delivery of other contents from the head-end. Strobecast techniques are described in detail in the aforementioned U.S. patent application Ser. No. 09/687,662.[0080]
D. Spotlight Window[0081]
FIG. 4 is a diagram of a specific design of a channel information window[0082]400 (also referred to as a “spotlight window”) that can also be used to efficiently provide IPG information. The spotlight window can be generated and overlay on top of a video display (e.g., whenever selected by a viewer). In this design,spotlight window400 includes aspecific portion410, alocal portion420, and acommon portion430.Specific portion410 includes information specific to a particular broadcast channel being described byspotlight window400.Local portion420 includes information targeted for delivery to the terminals within a particular locality. Andcommon portion430 includes features that are common for a number of spotlight windows (i.e., the background that is common for all broadcast channels and localities). FIG. 4 shows a specific design, and additional and/or different information, layouts, configurations, and arrangements may also be provided for each portion ofspotlight window400.
In the design shown in FIG. 4,[0083]specific portion410 includes the channel number (e.g., “13”), the broadcast channel name (e.g., “USA”), the program title (e.g., “Tremors II: . . . ”), the time period of the program (e.g., “9:00-11:00”), the program rating (e.g., “PG”), the copyright or release year (e.g., “1998”), and a brief description (e.g., “The creature from . . . ”).
[0084]Local portion420 includes, for example, a logo for the service provider or other branding related information. A different logo may be provided for each region served by a different service provider.Local portion420 may also be partitioned into a number of smaller sub-portions, with each sub-portion being used to provide different information (e.g., targeted advertisements, locality specific announcements) and may further be associated with a particular localization level (e.g., an entire region, a neighborhood, or a set of terminals).
[0085]Common portion430 includes afilter icon region440 and anoperational icon region450.Filter icon region440 includes a number of filter icons used to filter the programs to be displayed in the program guide, e.g., an “All” filter icon, a “Fav” or favorites filter icon, a “Movies” filter icon, a “Kids” filter icon, and a “Sports” filter icon. These filter icons can be designed to provide filtering functionality.Operational icon region450 includes a close caption icon (“CC”), a secondary audio programming icon (“SAP”), and a stereo icon (“Z,900 ”).
In an embodiment, all or portions of the spotlight window are generated at the head-end and sent to the terminals. In this manner, the head-end has control over the particular arrangement (i.e., the layout and configuration) for the spotlight window and the information to be included in the various fields and portions of the spotlight window. Bitmap for all or portions the spotlight window may be encoded at the head-end, packetized, and sent to the terminals (e.g., via an out-of-band network). The spotlight data can be processed by a separate spotlight server that does not interfere with the operations of the session manager or the transport stream processor to send the spotlight data via the out-of-band network.[0086]
Techniques for generating, encoding, and delivering spotlight window is described in U.S. patent application Ser. No. 09/691,495, entitled “SYSTEM AND METHOD FOR LOCALIZED CHANNEL INFORMATION WINDOW,” filed Oct. 18, 2000, assigned to the assignee of the invention and incorporated herein by reference.[0087]
E. Terminal[0088]
FIG. 5 is a block diagram of an embodiment of[0089]terminal108, which is also referred to as a set top terminal (STT) or user terminal.Terminal108 is capable of producing a display of a user interface and implementing various aspects of the invention.Terminal108 includes atuner512, ademodulator514, a transport demultiplexer (DEMUX)518, anaudio decoder520, avideo decoder530, an on-screen display (OSD)processor532, avideo compositor534, aframe store memory536, acontroller550, and amodulator570. User interaction is supported via aremote control unit580.Tuner512 receives a radio frequency (RF) signal comprising, for example, a number of quadrature amplitude modulated (QAM) signals from a downstream (forward) channel. In response to a control signal TUNE,tuner512 tunes to and processes a particular QAM signal to provide an intermediate frequency (IF) signal.Demodulator514 receives and demodulates the IF signal to provide an information stream (e.g., an MPEG transport stream) that is sent to transportstream demultiplexer518.
[0090]Transport stream demultiplexer518, in response to a control signal TD produced bycontroller550, demultiplexes (i.e., extracts) an audio stream A and a video stream V. The audio stream A is provided toaudio decoder520, which decodes the audio stream and provides a decoded audio stream to an audio processor (not shown) for subsequent processing and presentation. The video stream V is provided tovideo decoder530, which decodes the compressed video stream V and provides an uncompressed video stream VD tovideo compositor534.OSD processor532, in response to a control signal OSD produced bycontroller550, produces a graphical overlay signal VOSD that is provided tovideo compositor534.
[0091]Video compositor534 merges the graphical overlay signal VOSD and the uncompressed video stream VD to produce a composed video stream (i.e., the underlying video images with the graphical overlay).Frame store unit536 receives and stores the composed video stream on a frame-by-frame basis according to the frame rate of the video stream.Frame store unit536 thereafter provides the stored video frames to a video processor (not shown) for subsequent processing and presentation on a display device. In an embodiment, during transitions between streams for a user interface, the buffers in the terminal are not reset, and the user interface seamlessly transitions from one screen to another.
[0092]Controller550 includes an input/output (I/O)module552, aprocessor554,support circuitry556, an infrared receiver (I/R)558, and amemory560. Input/output module552 provides an interface betweencontroller550 andtuner512, demodulator514 (for some designs),transport demultiplexer518,OSD processor532,frame store unit536,modulator570, and aremote control unit580 viainfrared receiver558.
[0093]Processor554 interfaces with I/O module552, support circuitry556 (which may include power supplies, clock circuits, cache memory, and the like), and amemory560.Processor554 also coordinates the execution of software routines stored inmemory560 to implement the features and perform the functions supported by the terminal.
[0094]Memory560 stores software routines that support various functions and features, and further stores data that may be used for the user interface. In the embodiment shown in FIG. 5,memory560 includes auser interaction routine562, a PID mapping table564, anoverlay storage566, and astream processing routine568.User interaction routine562 processes user interactions to perform various functions to provide the desired user interface menu. For example,user interaction routine562 can implement a mask or reveal feature to display (reveal) the desired portion of the IPG page and hide (mask) the undesired portion.User interaction routine562 may further perform various functions to achieve a demand-cast for a desired IPG page. The mask or reveal is described in U.S. patent application Ser. Nos. 09/293,526 and 09/533,006.
[0095]Stream processing routine568 coordinates the recombination of video streams to form the desired video sequences. Stream processing routine3468 employs a variety of methods to recombine slice-based streams, some of which are described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410). In one recombination method, aPID filter516 withindemodulator514 is utilized to filter the undesired PIDs and retrieve the desired PIDs from the transport stream. The packets to be extracted and decoded to form a particular IPG page are identified by PID mapping table564. For most recombination methods, afterstream processing routine568 has processed the streams into the proper order, the slices are sent to video decoder530 (e.g., an MPEG-2 decoder) to form uncompressed IPG pages suitable for display.
Although[0096]controller550 is depicted as a general-purpose processor that may be programmed to perform specific control functions to implement various aspects of the invention, the controller may also be implemented in hardware as an application specific integrated circuit (ASIC).
In a specific design,[0097]remote control unit580 includes an 8-position joystick, a numeric pad, a “Select” key, a “Freeze” key, and a “Return” key. User manipulations of the joystick or keys on the remote control device are transmitted tocontroller550 via an infrared (IR) link or an RF link.Controller550 is responsive to the user manipulations and executes the appropriate portion ofuser interaction routine562 to process the user manipulations.
FIG. 5 shows a specific design of[0098]terminal108. Other designs of the terminal can also be implemented to perform the functions described herein, and these alternative designs are within the scope of the invention.
F. Multi-layer User Interface[0099]
An aspect of the invention provides techniques for transmitting multiple “slices” of information for a particular location of a video screen. These techniques can be used to provide more information to a viewer for a given limited-size viewing area, and are well suited for interactive program guide (IPG) commonly used for television and broadcast distribution systems. However, the techniques described herein may also be advantageously used for other applications and other guides such as, for example, dining guide, local shopping, news, and others.[0100]
For clarity, many aspects and embodiments of the invention are described below in the context of an interactive program guide provided via a number of IPG pages. Referring back to FIG. 2A, an IPG page can be designed having a number of regions (or portions). Each region can be used to provide a different type of information. Each region is typically defined to be of a specific size and shape and is further placed at a specific location on the IPG page. The specific size, shape, and location of each region and the arrangement of the regions on the IPG page are typically selected based on the desired IPG page design.[0101]
FIG. 6 is a diagram of a specific design of an[0102]IPG page600 that can be used to illustrate various aspects and embodiments of the invention. As shown in FIG. 6 and described above, the LPG page can be partitioned into a number of regions including aguide region610, avideo region620, afilter icon region640, and aprogram description region650.
As described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410), various techniques can be used to reduce the amount of data to be transmitted from the head-end to the terminals for the IPG page. For example, a video stream for[0103]video region620 can be continually transmitted from the head-end to the terminals, guide data forguide region610 can be transmitted continually (e.g., once for each GOP) or a limited number of times, and the data inprogram description region650 can be transmitted via a data stream.
To efficiently encode and transmit the regions of the IPG page, each transmitted region can be defined with a set of slices. As shown in FIG. 6, guide[0104]region610 can be defined with a set of M guide slices andvideo region620 can be defined with a set of N video slices. Other regions may also be defined with their respective sets of slices, and arbitrary slice shapes can be defined for any region. Note that in MPEG-2, a slice cannot be defined exceeding a macroblock row and this is within the scope of the invention. Slice-based encoding, temporal slice persistence encoding, or strobecast encoding method can then be applied to encode and transmit the content from the head-end.
For the IPG page design shown in FIG. 2A, the guide listing[0105]214 for each channel, which is also referred to as a channel element, can be defined as a guide slice. Each guide slice is associated with a specific location in the guide region of the page and typically includes a slice start code that identifies the start and the end of the slice. The M guide slices for the M channel elements of the guide region can be encoded (e.g., a priori) at the head-end, stored in a storage unit, and transmitted to the terminal as needed. By processing the slice start code, a decoder at the terminal is able to determine where to place the decoded slice on the IPG page, which can be used in any of slice-based, temporal slice-persistence, and strobecast encoding methods.
In accordance with an aspect of the invention, multiple slices can be associated with a particular location of the IPG page. These multiple slices can be used to present more information (i.e., content) in a given spatial area of the IPG page.[0106]
Multiple slices can be defined for each channel element of the guide region to provide additional information about program titles or selectively different information. In one embodiment, each channel element may first be associated with a respective slice that provides the guide data for the channel (e.g., the channel number, channel short name, and program title, as shown in FIG. 2A). Each channel element may further be associated with another slice that provides, for example, a short description of the program that may be initiated, e.g., upon the viewer selecting a related object.[0107]
Multiple slices may be interchangeably provided for the channel listings to provide a slow-moving listing. This same “slice-looping” behavior may be applied to banners or other objects in other regions of the user interface (e.g., to catch the attention of the viewer). In general, for each slice location, multiple slices of information can be encoded to provide alternative or additional information.[0108]
Various techniques can be used to present the multiple slices in an intelligible manner while reducing the amount of clutter. The presentation of the additional slices can also be in different manner, such as looping and text extension depending on the desired user interface functionality.[0109]
1. Delivery and Presentation Schemes[0110]
The delivery and presentation of the multiple slices for a particular location of the IPG page can be achieved based on numerous schemes, some of which are described below.[0111]
FIG. 7A is a diagram that illustrates a first slice delivery and presentation scheme whereby multiple slices for a particular location of an IPG page are transmitted from the head-end at different times. In the example shown in FIG. 7A, a video sequence containing only slices that belong to the video region of the IPG page (i.e., the portion containing time-varying information) is coded, assigned a particular PID, and transmitted from the head-end. The guide portion (i.e., the portion containing the information specific to that IPG page) is coded as a set of slices, assigned another PID, and also transmitted from the head-end.[0112]
Each of the multiple slices can be used to provide different information to the terminals. The multiple slices can be transmitted at different GOP times, and the slices can be appropriately time stamped for presentation at the desired GOP times. In the example shown in FIG. 7A, two different slices are alternately provided for a particular channel element of the IPG page (i.e., a particular slice location) at different GOP times. For the first guide slice location, a first slice (e.g.,[0113]slice1 in set A) can be time stamped for presentation at a first GOP time, a second slice (e.g.,slice1 in set B) can be time stamped for presentation at the next GOP time, the first slice (e.g.,slice1 in set A) can be time stamped for presentation at the following GOP time, and so on. Any number of slice sets (e.g., A, B, C, and so on) can be time division multiplexed (TDM) and this is within the scope of the invention. Moreover, the TDM can be achieved based on any particular transmission pattern, and needs not be a regular repeating pattern. For example, the second slice may be transmitted for every P times the first slice is transmitted.
In an embodiment, each transmission (e.g., at each GOP) for a particular IPG page may include a complete set of guide slices for the guide region of the IPG page (e.g., guide[0114]slices1 through M, forslice locations1 through M, respectively). Alternatively, a transmission may include a partial set of guide slices for the guide region (e.g., just the guide slices that are new for the GOP). For guide slices transmitted once per GOP, these slices can be intra-coded in the manner described above in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410).
In an embodiment, the terminal processes the received guide slices and can continually update the IPG page as new slices are received for the page. As described above, since the guide data is typically static over time, one set of intra-coded slices for the guide data can be transmitted by the head-end for each GOP. In this case, the processing at the terminal for the guide region can be achieved on a GOP-by-GOP basis. For each GOP, the terminal recombines the guide slices with other slices for the IPG page (e.g., the video slices), decodes the recombined slices, and displays the decoded slices. If a particular guide slice is not transmitted for the current GOP, the terminal can skip the non-transmitted slice and not update the slice previously decoded for this location, as described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410). By presenting multiple slices for a particular location in a time division multiplexed manner, more content can be displayed within a particular spatial region.[0115]
The guide slices can be encoded, time stamped, transmitted, and decoded in the manner described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410). Encoding and decoding techniques for guide slices transmitted a limited number of times (e.g., once) is described in the aforementioned U.S. patent application Ser. No. (Attorney Docket No. 19880-003410).[0116]
FIG. 7B is a diagram that illustrates a second slice delivery and presentation scheme whereby multiple slices are concurrently transmitted for a particular location of an IPG page. For this scheme, the terminal can receive the transmitted slices, select one of the multiple slices for processing, and process and display the selected slice.[0117]
The guide slice to be displayed at a particular location on the IPG page may be selected, for example, based on user interaction. In an embodiment, the slices for the channel elements of the guide listing (e.g., slice set A) can be initially processed and displayed. The viewer can thereafter highlight a particular channel element, for example, by clicking on the channel element. In response to the user selection, the terminal can retrieve, process, and display another slice (e.g.,[0118]slice1 in set B) for the highlighted channel element. The particular slice selected for decoding and display may be based, for example, on the particular key selected by the viewer. In an embodiment, only the highlighted channel element may be updated in response to the user interaction, and the other channel elements in the guide region need not be updated.
The multiple slices for the particular location may be transmitted in the same GOP time (as shown in FIG. 7B) or may be transmitted at different GOP times. Although two slice sets are illustratively shown in FIG. 7B, any number of slice sets may be transmitted for the guide region of the IPG page. Furthermore, the transmission at any particular GOP time may include a full or partial set of slices for the guide region.[0119]
FIG. 7C is a diagram that illustrates a third slice delivery and presentation scheme whereby one slice is transmitted for a particular location, and additional slices can be transmitted by the head-end upon receiving a request from the terminal. This third scheme is similar to the second scheme described above, except that the additional slices are not transmitted from the head-end until requested by the terminal. This scheme utilizes less bandwidth for the broadcast slices than the second scheme, but requires (e.g., out-of-band or in-band) signaling to send requests for slices.[0120]
At the terminal, the transmitted (e.g., broadcast) slices are initially received, processed, and displayed. Upon receiving an indication to display a different slice for a particular location of the IPG page, the terminal can send a request for the selected slice to the head-end. The head-end processes the request and sends the requested slice back to the terminal, which then processes and presents the slice. The requested slice can be transmitted a limited number of times (e.g., once) in response to the request, as described in the aforementioned U.S. patent application Ser. No. 09/687,662.[0121]
In accordance with MPEG-2 standard, each slice typically is associated with a slice start code that defines the start location and the stop location for the slice. Typically, the slice is decoded and presented at a particular location in the screen identified by the slice start code. In one embodiment, the transport stream can include multiple of slice start codes for a particular slice, and the terminal can select one of the slice start codes for the slice. With this embodiment, the slice can be placed at the location defined any of the transmitted slice start codes. In another embodiment, the head-end can defined the slice start code for a particular slice based on user interaction at the terminal. In yet another embodiment, the terminal is able to arrange (i.e., modify) the slice start codes such that the slice can be placed at any desired location in the screen. Various other techniques for presenting the slice at a desired location may also be contemplated and are within the scope of the invention.[0122]
2. PID Assignment[0123]
For the above-described slice delivery and presentation schemes, the multiple slices can be assigned to the same or different PIDs, depending on various factors. In a first embodiment, the slices for the guide portion for each IPG page can be assigned to a respective PID. The terminal simply processes the appropriate PID for the guide portion of the selected IPG page and displays all slices transmitted with that PID. This embodiment can be used with the first scheme described above. For example, slices A and B to be presented at a particular location on the IPG page but received at different GOP times may be assigned the same PID.[0124]
In a second embodiment, a set of “primary” slices for the guide portion for each IPG page can be assigned one PID, and each set of “secondary” slices for the guide portion for the page can be assigned another respective PID. The terminal can initially process and display the primary slices. If a particular primary slice (e.g., a particular channel element) is highlighted, a second PID can be processed and the secondary slice for the location identified for the highlighted primary slice can be retrieved. The retrieved secondary slice can then be decoded and displayed in place of the highlighted primary slice. Other primary slices are not affected and therefore not updated.[0125]
The second embodiment can be used with the second and third schemes described above. For example, for the second scheme shown in FIG. 7B, slice set A can be assigned one PID and slice set B can be assigned another PID. And for the third scheme shown in FIG. 7C, the broadcast slice set A can be assigned one PID and the demand-cast slice set B can be assigned another PID.[0126]
For clarity, the use of multiple slices for a particular location of the IPG page has been specifically described for the delivery of program guide data for the guide portion of the IPG page. However, the use of multiple slices can also be applied to other regions of the IPG page, including the video region, the filter icon region, and the program description region. Generally, a primary (or default) set of slices (e.g., slice set A) for a particular region can be sent to the terminal, which initially decodes and presents these slices. One or more secondary (additional) sets of slices (e.g., slice set B) can also be sent for the region to provide additional information. The secondary sets of slices may be decoded and presented in a time division multiplexed manner with the primary set of slices, as shown in FIG. 7A. Alternatively, a particular secondary set of slices (e.g., slice set B) may be decoded and presented in response to an event (e.g., a user interaction).[0127]
In general, depending on the encoding scheme employed (e.g., slice-based, termporal slice persistence, strobecast, and so on) and presentation schedule, different PID assignment schemes can be utilized and are within the scope of this invention.[0128]
3. Other Aspects[0129]
As an example of an application using the above-described aspects of the invention, multiple sets of slices may be sent for multiple video streams. A primary set of slices may be decoded and presented for the IPG page. A secondary set of slices may be decoded and presented, for example, in response to a user selection of a particular filter icon or a particular channel element. An audio stream associated with the selected video stream can also be decoded and presented.[0130]
In an embodiment, each slice transmitted from the head-end includes a slice start code that identifies the start and stop locations of the slice. The terminal typically retrieves and processes the transmitted slice and places the decoded slice at the specific location identified by the slice start code.[0131]
In an alternative embodiment, the terminal may also elect to display a received slice at a different location than that indicated by the slice start code. The presentation of a particular slice at a different location may be achieved by modifying the slice start code (or some other property of the slice). Presentation of a received slice at different locations (e.g., any location selected by the viewer or terminal) allows the terminal to flexibly generate multiple views and functionality for the user interface.[0132]
The viewer or terminal-selected placement of the transmitted slices may be used, for example, to generate a customized IPG page. As an example, slices for the guide listing for all channels in the current time slot may be transmitted. The terminal can generate a custom IPG page by recombining the slices for the desired channel elements (in any desired order). The recombined slices can then be decoded and displayed. The slice start codes may be modified by the terminal such that the slice for each channel element is recombined at the appropriate location in the custom IPG page.[0133]
As noted above, the techniques described herein can also be advantageously used for other applications and other guides. For example, the techniques described above can be used to deliver stock quotes, sports scores, headline news, traffic reports, other guides, and so on, which may be displayed, for example, on a portion of a screen via the use of multiple slices for each of these news items. As an example, a first viewer may elect to have stock quotes continually displayed on the bottom portion of the IPG page, and a second viewer may elect to have news flashes continually displayed on the top portion of the IPG page. The news items can be transmitted via multiple slices, and a particular slice can be selected by the viewer and displayed at a designated or viewer-selected location on the IPG page.[0134]
The foregoing description of the preferred embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Thus, the invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.[0135]