KR100487684B1 - Computer-implemented method for indexing locations in a video stream, interactive video delivery system, video display device - Google Patents

Abstract

A system and method for displaying graphical icons such as slider bars on a subscriber's television or display device for indexing to different locations within a video stream in an interactive video delivery system. The interactive video delivery system preferably includes at least one media server for storing one or more video streams, and one or more subscribers each including a display device such as a television. Televisions display slider bars or other graphical icons, which are used to index at different locations within the video stream. While the video is being delivered, the user can use or adjust the knob on the slider bar, preferably using a remote control, to indicate what he wants to "jump" to different locations in the movie or video stream. The media server receives the slider bar user input from the subscriber device and starts outputting the normal playback stream at the desired location.

Description

Computer-implemented method for indexing locations in a video stream, interactive video delivery system, video display device

The following references are incorporated herein by reference.

ISO / IEC MPEG specifications, referred to as ISO / IEC 13818, are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION The present invention relates generally to video delivery and video-on-demand systems, in particular slider bars on subscriber televisions or display units for indexing to locations in the video stream. And a video delivery system and method for displaying the video data).

Video-on-demand or video delivery systems allow a plurality of subscribers or users to select and watch movies or other audio / video sequences stored on one or more video servers or media servers. Video servers are connected to a plurality of subscribers or users through data transmission channels such as broadcast cable systems or satellite broadcast systems. Video servers store a plurality of movies or other audio / video sequences, and each user can select one or more movies from the video servers to watch. Each user includes a television set or other viewing device as well as associated decoding logic to select and watch the desired movies. When the user selects a movie, the selected movie is sent on one of the data transfer channels for each user's television set.

Full-motion digital video requires large amounts of storage and data transmission bandwidth. Therefore, video-on-demand systems use various forms of video compression algorithms to reduce the amount of storage and data transfer bandwidth required. In general, other video compression methods exist for still graphic images and full-motion video. Video compression methods for still graphic images or single video frames are referred to as intraframe compression methods, and compression methods for motion video are referred to as interframe compression methods.

Examples of video data compression for still graphic images are run-length encoding (RLE) and Joint Photographic Experts Group (JPEG) compression. The RLE compression method works by checking for replicated pixels within a single line of a bit map and storing the number of consecutive replicated pixels rather than the data for that pixel itself. JPEG compression is a group of related standards that provide either lossless (no deterioration of quality) or lossy (unable to detect severe degradation) compression forms. Although JPEG compression was originally designed for the compression of still images rather than video, JPEG compression is used in some motion video applications.

In contrast to compression algorithms for still images, most video compression algorithms are designed to compress full motion video. Video compression algorithms for motion video use the concept referred to as interframe compression, which includes only storing differences between successive frames in the data file. Interframe compression generally stores the entire image of a key frame or frame of reference in a moderately compressed format. Consecutive frames are compared with the key frame, and only the differences between the key frame and the consecutive frames are stored. Periodically, new key frames are stored, such as when new scenes are displayed, and subsequent comparisons start from this new reference point. It should be noted that the interframe compression ratio can be kept constant while the video quality changes. Alternatively, the interframe compression ratios can be content-dependent, i.e., if the video clip being compressed can contain many unexpected scene changes from one image to another, the compression is less effective. Can be. Examples of video compression using interframe compression techniques are MPEG, DVI and Indeo, among others.

MPEG background

The compression standard, referred to as Moving Pictures Experts Group (MPEG) compression, is a set of methods for compressing and decompressing full motion video images using the interframe compression technique described above. MPEG compression can produce compression ratios of 200: 1 or more using both motion compensation and discrete cosine transform (DCT) processing.

The MPEG standard requires that sound be recorded at the same time as video data, and that video and audio data are interleaved in a single file in an attempt to maintain video and audio synchronized during playback. The audio data is also typically compressed, and the MPEG standard specifies audio compression methods such as MPEG Layer II, also known as the Philips trade name 'MUSICAM'.

The MPEG stream includes three types of pictures referred to as intra (I) frames, prediction (P) frames, and bidirectional interpolation (B) frames. I or intra frames contain video data for the entire frame of video and are typically placed every 10 to 15 frames. Intra frames provide entry points in a file for random access and are generally only compressed appropriately. The predictive frames are encoded with respect to past frames, ie previous intra frames or predictive frames. Therefore, P frames contain only changes to the previous I or P frame. In general, prediction frames receive a very high amount of compression and are used as a reference for future prediction frames. Therefore, I and P frames are used as references for subsequent frames. Bidirectional pictures contain the maximum amount of compression and require past and future criteria to be encoded. Bidirectional frames are not used for the references to other frames.

After the I frames are generated, the MPEG encoder divides each I frame into a grid of 16 x 16 pixel squares called macro blocks. Each I frame is divided into macro blocks to perform motion compensation. Each subsequent picture after the I frame is also divided into these same macro blocks. The encoder then searches for an exact or near exact match between the reference picture macro block and the block in successive pictures. If a match is found, the encoder carries a vector motion code or motion vector. The vector motion code or motion vector only contains information about the difference between the reference frame and each successive picture. Blocks in successive pictures that do not change anything with respect to the block in the reference picture or frame are ignored. In general, for frame (s) following a reference frame, ie P and B frames subsequent to a reference I or P frame, only small portions of these frames differ from the corresponding portions of each reference frame. Therefore, for these frames only the differences are captured, compressed and stored. Therefore, the amount of data actually stored for these frames is significantly reduced.

After the motion vectors are generated, the encoder then tracks the changes using spatial redundancy. Therefore, after finding changes in the location of the macro blocks, the MPEG algorithm also reduces the data by describing the difference between the corresponding macro blocks. This is done through a mathematical process referred to as discrete cosine transformation or DCT. This process divides the macro block into four sub-blocks and finds changes in color and brightness. Human perception is more sensitive to brightness than color changes. Therefore, the MPEG algorithm is more effective at reducing the color space more than the brightness.

Each picture or frame includes a picture header that identifies the frame and includes information about the frame. The MPEG standard includes sequence headers that identify the beginning of a video sequence. Sequence headers are only required once before the start of the video sequence. However, the MPEG-2 standard allows a sequence header to be sent before any I frame or P frame. The sequence header contains information related to the video sequence, including frame rate and picture size, among other information.

MPEG video streams used in digital television set applications generally include a sequence header before an I frame and a P frame. This is necessary to facilitate channel surfing between different video channels, which is an important user requirement. In general, when a user switches to a new channel, the video for that new channel can be displayed only after the next sequence header appears in the stream. This is because the sequence header contains important information about the video sequence required by the decoder before the sequence can be displayed. If the sequence header is not included before each I frame and / or P frame, when the user switches to a new channel, the video of the new channel may not be displayed immediately, ie the video may be displayed until the next sequence head. none.

Sequence headers in an MPEG encoded stream include presentation timestamps used to provide a timestamp or time base in the encoded stream.

Track playback streams

In an interactive video-on-demand (NVOD) or near-video-on-demand (NVOD) system, users can selectively fast forward and / or fast reverse through the movie they are watching. Very desirable. Therefore, some video-on-demand systems include fast forward and fast reverse streams, referred to as trick playback systems for each movie. Each fast forward or fast reverse trick play stream is then sent to the user at the appropriate point the viewer is watching instead of the normal play stream, thus simulating the fast forward or fast reverse of the movie being watched. Therefore, a single video stream, such as a movie, is encoded at a different presentation speed so that in addition to the normal playback presentation speed, the video file can operate at either fast forward or fast reverse speed.

Indexing

Interactive video-on-demand systems including trick play streams require a method for indexing between trick play streams as well as indexing between trick play streams. In other words, if the user watches a movie and selects a fast forward for a period of time, a mechanism is needed to cause the video server to switch from the normal playback stream to the appropriate point or frame in the fast forward stream. When the user wants to resume watching at the normal playback speed, there is also a need for a mechanism that allows the video server to switch from the frame viewed in the fast forward stream to the appropriate point or frame in the normal playback stream. Therefore, the video server should be able to determine suitable positions in the video files if a switchover occurs when outputting from the first video file at the first display speed to the second video file at the second display speed.

Other forms of indexing systems and methods are desirable to enable a user to easily index to other locations or locations within a movie. For example, it would be highly desirable for a user to be able to selectively and immediately jump to any location within the video stream without having to watch trick play fast forward or fast reverse streams during processing. Therefore, it is desirable for an improved indexing system and method to effectively index to other locations within a video stream in a video delivery system. It would also be desirable to have an improved indexing system and method that allows a user to selectively jump instantly to any location within the video stream. Improved indexing systems and methods that do not require trick playback systems and reduce the processing burden of the media server are also desirable.

1 illustrates a video delivery system including one or more media servers and one or more subscribers.

2 illustrates a user watching a television set displaying a slider bar for indexing into a video stream in accordance with the present invention.

3 shows the media server of FIG.

4 is a block diagram illustrating the media server computer system of FIG.

5 is a flow chart illustrating generation of index lookup tables for normal play streams and trick play streams in accordance with the present invention.

6 illustrates index lookup tables for a normal play stream and a trick play stream in accordance with the present invention.

FIG. 7 is a flow diagram illustrating the operation of a set top box that receives user input regarding user operation of a slider bar and provides related information to a media server.

8 is a flow diagram illustrating the operation of a media server indexing a new location in a normal playback system based on user input received from a set top box in accordance with the present invention.

Summary of the Invention

The present invention includes a system and method for displaying graphical icons, such as sliders, on a subscriber's television set or display device for indexing to another location within a video stream in an interactive video delivery system. The interactive video delivery system preferably comprises at least one media server storing one or more video streams, and one or more subscriber units each comprising a display device such as a television set.

In a preferred embodiment, the media server stores normal playback streams and may store one or more corresponding trick playback streams, i.e., fast forward and / or fast reverse video streams, for each normal playback stream. In a preferred embodiment, the media server stores the normal playback video streams preferably compressed using various types of video compression methods, preferably the MPEG method. The system of the present invention creates an index table or lookup table for each normal playback stream that can be indexed at different locations in the stream. When generating an index table for a normal play stream, the system first analyzes the normal play stream to generate a normal play time standard based on the presentation time stamps contained in the normal play stream. The system then preferably creates an index table or lookup table for the normal playback stream using the normal playback time criteria. Each index table includes an array of two-tuples, the two-tuples being the normal playback time reference and the index or offset within each stream. The index tables can index at other locations in the stream. If the media server stores trick play streams, the system also preferably creates index tables for trick play streams that enable indexing between the normal play stream and the trick play stream.

Interactive applications operating on set top boxes coupled to television sets display graphical icons such as slider bars on the television set screen. In an alternative embodiment, the media server provides graphical data displaying a slider bar on the screen. In a preferred embodiment, the slider bar is displayed when the user pauses the movie. When the slider bar is displayed, the user can use or adjust the slider bar's knob, preferably using a remote control device, to indicate the desire to 'jump' to another position in the movie or video stream. .

In a preferred embodiment, the subscriber device or set top box receives user input and calculates a value from 0 to 100 representing a relative position within the movie or stream based on the user manipulation of the slider bar. The set top box then provides these values to the media server. The media server receives a value representing the slider bar user input from the subscriber device and calculates a normal play time value based on the received user input. The media server receives a value from 0 to 100 and uses the movie length to calculate the corresponding normal play time value. For example, if the user adjusts the slider bar to place the 'knob' of the slider bar in the very center of the slider bar, the subscriber device provides 50 outputs to the media server. If the movie length is exactly two hours, the media server outputs one hour of normal playback time.

The media server then uses each index table in the normal playback video stream. After the media server calculates a new normal play time, the media server uses the calculated normal play time to retrieve the appropriate offset in the normal play stream index table. This offset is then used to start playback of the normal playback stream at the retrieved offset. The set top box then adjusts the position of the knob on the slider bar to reflect the exact position of the output video stream. The media server can also optionally check the current normal playback time and the offset of the output normal playback stream to stop the normal playback stream at the appropriate point before outputting the stream at the retrieved offset.

In one embodiment, when the user first manipulates the slider bar to jump to a new position in the video stream, the media server caches the current normal play time and the byte offset of the normal play stream. Therefore, if the user wishes to return later to the original position in the movie before any slide bar adjustments are made, the user presses a key on the remote control or selects the return option of the slider bar. This selection allows the media server to retrieve the appropriate normal play time and offset within the normal play stream index table. This offset is then used to play the normal playback stream at the position where the stream is first before any slider bar adjustments.

Therefore, the present invention effectively allows indexing to other locations in the normal playback stream. The present invention displays graphical icons such as slider bars that provide a simple and convenient mechanism for selecting a location within a video stream. The present invention produces a normal playback time criterion that is used as a common criterion, thus simplifying the indexing process.

When the following detailed description of the preferred embodiment is considered in connection with the following figures, a better understanding of the present invention can be obtained.

Video delivery system

1 illustrates a video server or video delivery system 30 for storing and transmitting video streams. System 30 may be a video-on-demand (VOD) or near-video-on-demand (NVOD) system, or other form, capable of transmitting or playing a video or multimedia stream to one or more users, preferably multiple users. It is desirable to be a video delivery system. In this specification, the term 'video stream' is used to refer to a file or sequence that represents a video display. The term "video stream" also encompasses a multimedia stream that includes both video and audio components.

As shown, in one embodiment video delivery system 30 includes one or more media servers or video servers 50 connected to a plurality of subscribers 52 over broadband network 40. As discussed below, each media server 50 preferably includes a general purpose computer system 60 (FIG. 2). The broadband network 40 is preferably a network suitable for multimedia contents such as ATM (asynchronous transmission mode) network, satellite broadcasting network, or IP / RTP (Internet Protocol / Real Time Protocol) network. Subscriber 52 preferably includes a display device such as a television set, a computer, or the like. The media server 50 provides a video or multimedia stream to each subscriber 52 via the broadband network 40.

The media server 50 may transmit or play a plurality of video or multimedia streams. In the preferred embodiment, the system 50 may transmit or play the normal playback stream at any of several designated locations. As used herein, the term "normal playstream" refers to a video stream designated to play at normal or standard display speed. In one embodiment, each normal play stream may also have one or more trick play streams involved that may include one or more fast forward and / or fast reverse streams. As used herein, the term "trick play stream" refers to a fast forward and / or fast reverse video stream, preferably compressed streams, which are played from a normal play stream and have a different display rate than the information play stream. .

The normal playback stream is preferably a compressed video stream. The invention works regardless of the form or format of the video stream. Therefore, the normal playback stream includes MPEG-1, MPEG-2, Motion JPEG, QuickTime, and the like, and can be compressed in any of various forms. Moreover, the present invention operates independently of the frame rate and other display characteristics.

Figure 2-Subscriber Device

2 shows a user viewing subscriber device 52 in accordance with a preferred embodiment of the present invention. As shown, subscriber device 52 includes a television set or other display device 53. Television set 53 includes a display screen 59 for displaying video images, as is well known in the art. The television set or display device 53 may include any of various types of display devices, including digital TVs or high-definition televisions (HDTVs), computer systems with video monitors, or other types of display devices.

Subscriber device 52 also includes a set top box 57 or other logic coupled to television set 53. The set top box 57 is coupled to the network 40 and connected to a cable 58 coupled to the media server 50. Set top box logic 57 may be included within television set 53 or may include an adapter card inserted into a bus of a computer system. The term "set top box" refers herein to any form of external logic or server, or any form of logic contained within a television set or other display device, such as video or audio decompression, for display of multimedia content. To perform a processing function related to, to execute an interactive application, or to display the slider bar 54 of the present invention.

As shown, the display screen 59 of the television set 53 displays a graphic icon 54 for the user to index to the desired location of the video stream. In a preferred embodiment, graphic icon 54 is slider bar 54. Slider bar 54 includes a small knob or cursor 55 that can be moved within slider bar 54. As used herein, the term "slider bar" includes both slider bar 54 and knob 55. The term "slider bar" as used herein is intended to include other graphical icons for indicating locations within the video stream. As shown, a user using the remote controller 56 preferably manipulates a button or dial on the remote controller 56 to control the movement of the knob 55 in the slider bar 54. The user can manipulate or adjust knob 55 in slider bar 54 to "jump" to a position in the desired movie or video stream to be watched. Thus, if the user starts watching a movie and wants to "fast forward" or "jump" to the end of the movie, the user simply uses the remote controller 56 to move the knob 55 in the slider bar 54 to the slider bar ( 54 from left to right, ie from the beginning of the movie to almost the end of the movie.

In response to user manipulation of knob 35 in slider bar 54, set top box 57 receives a signal. The set top box 57 calculates the information based on the received user input and provides the information back to each video server 50 providing a video output stream. As will be described further below, in response to user manipulation or adjustment of the slider bar 54, the video server 50 supplies the video output at a desired position in the video stream indicated by the manipulated slider bar 54.

In the preferred embodiment, the slider bar 54 is displayed by the set top box 57 connected to the television set 53. In the preferred embodiment, the slider bar 54 is only displayed when the user stops the video stream. When the slider bar 54 is displayed, the set top box 57 updates the movement of the knob 55 in the slider bar 54 to reflect the current position of the video stream or movie being played on the television set 53. Thus, when slider bar 54 is displayed on screen 58, knob 55 is displayed at a suitable location within slider bar 54 relative to the position of the video stream being displayed. In an alternative embodiment, the slider bar 54 is displayed continuously and the position of the slider bar knob 55 is updated when each video stream is provided to the television set 53 via the set top box 57.

In an alternative embodiment of the invention, the slider bar graphic icon 54 is provided directly by the video server 50 with the output movie video stream. In this embodiment, the video server 50 displays only the slider bar 54 when a stop command is received or when another user input is received indicating that the slider bar 54 is to be used. Media server 50 displays knobs or cursors 55 at appropriate positions in slider bar 54 to reflect the current position of the movie being displayed.

Figure 3-Media Server

In FIG. 3, in a preferred embodiment the media server or video server 50 includes a computer system 60. Media server computer system 60 preferably includes various standard components, including one or more processors, one or more buses, hard drives, and memory. 4 is a block diagram illustrating components included in the media server computer system 60 of FIG. 4 is merely illustrative and may be used when other computer architectures are desired. As shown, computer system 60 includes at least one processor 80 coupled to system memory 84 via chipset logic 82. Chipset 82 preferably includes a PCI bridge for interfacing to PCI (Peripheral Component Interconnect) bus 86. Computer system 60 includes a RAID (redundancy array of low cost disks) disk array 90 or other storage medium for storing normal playback streams and any corresponding trick playback streams. Computer system 60 may include either or both of MPEG decoder 74 and MPEG encoder 76, which are shown as being connected to PCI bus 86. Computer system 60 also includes video circuitry 88 as shown.

Again in FIG. 3, computer system 60 includes or is coupled to one or more digital storage devices or media storage devices. For example, in the embodiment of FIG. 2, computer system 60 couples to media storage 62 via cable 64. Media storage 62 may be present in addition to or instead of a disk storage system within computer system 60. Media storage 62 includes one or more composite RAID drives for storing normal playback streams and any corresponding trick playback streams. Alternatively, media storage 62 may instead include one or more CD-ROM drives and / or one or more digital video disc (DVD) storage, or other forms of media, for storing digital video or multimedia content. Can be. Computer system 60 may also include one or more internal CD-ROM drives or may be coupled to one or more separate digital video disc (DVD) storage. Computer system 60 may also connect to other forms of digital or analog storage, if desired.

Compressed normal play streams, and any related trick play streams, may be included in storage media in media server 50 such as, for example, CD-ROMs or digital video discs (DVDs). The media server 50 reads each normal play or trick play stream from the storage medium and provides the data to one or more display units or viewers (subscribers) 52. The media server 50 may output video data using various communication media such as, for example, asynchronous transmission mode (ATM), integrated service digital network (ISDN), or via satellite. As noted above, subscriber display unit 52 may include a computer television set, computer system, or other system with a display screen for displaying video content.

As mentioned above, media server 50 generally indexes to other locations within the normal playback video stream based on user selection. As will be described further below, the media server 50 uses these tables to create index tables for various normal playback streams and index them at different locations within the various streams. In a preferred embodiment, the function of creating and indexing the index table is performed by the media server 50 in software, where the software is provided by the floppy disk 72. In alternative embodiments, computer system 60 includes one or more of the index table creation and indexing functions, or dedicated hardware to perform these functions. In a third embodiment, the set of related streams, i.e. the normal play stream and the associated trick play stream, comprise indexing information embedded in them to provide indexing between the streams.

Note that media server 50 may include two or more interconnected computers, if desired. Note that any one of various types of video delivery systems may be used in accordance with the present invention if desired.

Figure 5-Create Index Lookup Table

5 is a diagram illustrating generation of an index lookup table according to the present invention. It is assumed here that the normal playback stream is stored in the system. If more than one trick play stream is stored in the system, it is desirable that the other streams encode the same content for display at different rates. The method of FIG. 5 is used to create an index table for a normal playback stream so that it can be indexed to another location within the stream in accordance with the present invention. The method of FIG. 5 may also be used to create an index table for indexing between normal playback video tricks and trick playback video streams, if desired.

As shown, in step 102 the system of the present invention receives or examines a normal playback video system or multimedia stream. As discussed above, a normal playback stream includes a video data stream that is used to represent a video sequence, such as a television set fragment or a movie, on a screen, such as a television set or computer system. In a preferred embodiment, the normal playback stream is a compressed stream, preferably an MPEG-2 compressed stream, and other forms of compression may be used if desired.

In step 104 the system of the present invention preferably analyzes the time stamp in the stream. In the preferred embodiment where the stream is an MPEG stream, the system parses the display time stamp from the sequence header in the stream. As mentioned, the display time stamp is used to provide a time base for the video sequence.

As discussed above, an MPEG encoded stream includes a plurality of I-frames that are intracoded pictures, and a plurality of B and P frames that are intercoded frames. I frames each contain video data for the entire frame of video and are periodically placed in a sequence. P and B frames contain change information for the previous or subsequent frames. Each picture or frame includes a picture header that identifies the frame and includes information about the frame. The MPEG encoded stream further includes one or more sequence headers containing some information about the video sequence, including frame rate and picture size, among other information. The sequence header includes a display time stamp indicating the playback time of the video sequence.

In step 106, the system maps the display time stamp to the "normal playback time" standard. Thus, the system of the present invention determines multimedia indexing based on the concept of "normal play time" which may be related to "position" in a multimedia title. The normal play time standard is used to index to another position in the normal play stream in accordance with the present invention. The normal play time standard may be used for indexing between streams having different display speeds, that is, between normal play and trick play streams. With respect to the trick play stream, the position at the time when the contents at each position are conceptually and substantially the same, i.e. when the same or substantially the same image in the sequence is being provided, taking into account the difference in resolution and other encoding parameters specific to the stream, Is equally defined between the normal playback video stream and / or the trick playback video streams with different display rates.

When generating a normal play time reference, the system of the present invention examines the display time stamp to keep track of the original or base display time stamp at the start of the movie. The system then subtracts the base or original display time stamp from the subsequent time stamp to determine the normal playback time value for the normal playback stream. That is, to calculate the normal playback time for a given point in the normal playback stream, the system determines the base display time from the future mark time stamp at each point or location in the normal playback stream to determine the normal playback time for that location. Reduce the stamp.

In a preferred embodiment, the normal playback time (NPT) for a location in the multimedia stream is the time from the start of the title to each location as measured by the indication of normal speed forward or normal playback stream, one to one with clock time. Have a corresponding relationship. Thus, every second the normal playback movie is advanced and the normal playback time is one second forward. In a fast forward title or fast forward trick playback stream, if the FF stream is five times faster, the normal playback time is five times faster when the user is watching. In general, any particular scene in a movie is identified by normal play time. Thus, if a particular scene occurs at X minutes in the movie at normal playback time, this position or scene is called X minutes. This particular scene is also located in either of the other trick play streams at X minutes of normal play time.

Note that other methods may be used to create index tables for normal play streams and trick play streams. In an alternative embodiment, the system of the present invention creates an index lookup table using an offset list for each GOP (group of pictures). In another embodiment, the system uses the presentation time stamp in the video stream for indexing. Other methods of creating index tables may be used if desired. Note that other methods may be used to create a normal playback time (NPT) reference index table for a normal playback system.

In step 108 the system generates an index lookup table for each multimedia normal playback stream. The index lookup table for a normal playback multimedia stream includes an index or array of two tuples, each tuple containing a normal playback time and an offset in each stream. If a trick play stream is present in the system at step 110, the system optionally generates an index lookup table for the trick play stream. An index lookup table for normal play, fast forward, and fast reverse streams is shown in FIG. 6. As shown, each tuple includes a normal playback time value and a corresponding file offset in the stream. For a normal play stream, the normal play time entry includes the normal play time value calculated in step 106. For trick playback systems with constant bit rate encoding, a proportional ratio is introduced to the normal playback time value of the index lookup table to compensate for the different display speeds.

The index lookup table specifies the indexing or entry based on the normal playback time and file offset, respectively, so that the multimedia server 50 can start or stop playback at a particular normal playback time point in the multimedia stream. The index lookup table for the normal playback stream is used in accordance with the present invention so that the media server 50 outputs video data for the normal playback video stream at various locations indicated by the user input to the slider bar 54. do. The index lookup table for the trick play stream allows the multimedia server 50 to transmit to and from the same location of the stream having different display rates, i.e., between the normal play stream and the trick play stream.

In one embodiment, the index lookup table contains only tuples that indicate valid locations for starting, stopping, or inter-stream transmission of the stream. Note that although the actual display speed from the beginning of the stream to its location will vary for different streams, equivalent positions in multimedia streams with different display speeds will have the same NPT value. Note that even if they have the same NPT value, equivalent positions in multimedia streams having different display rates will have different byte offsets due to the difference in length of estimated streams having different display rates.

The creation of the lookup table is independent of any particular form of video compression or MPEG representation. In a preferred embodiment where MPEG compression is used, an index lookup table is generated by examining the entire MPEG file, taking a random access point in the MPEG file, and converting from the display time stamp in the MPEG file to a normal reproduction time reference. Conceptually, each index table contains an array of normal play times for a scene, and any particular image or frame in a movie may be identified by the normal play time value. As mentioned above, an index table is created for normal play streams and some trick play streams, for example fast forward and fast reverse streams. Each offset stored in the index table is indexing from the normal playback time to the byte offset in the MPEG file at which a particular scene begins.

Therefore, in a preferred embodiment, the system of the present invention uses a normal play time criterion for the index table. In an alternative embodiment, the system of the present invention creates an index lookup table using an offset list for each GOP (group of pictures). As mentioned above, you can use other methods of creating index tables if you wish.

Figure 7-Set Top Box Operation

7 is a flowchart illustrating the operation of the set top box 57. 7 illustrates the operation of the set top box 57 with respect to the operation of the slider bar 54 and the user operation of the knob 55 on the slider bar 54. As shown, in step 160 set-top box 57 displays slider bar 54 and knob 55 on the television set screen, as shown in FIG. In the preferred embodiment, the user presses the pause button on the remote controller 56 such that the slider bar 54 is displayed. That is, the slider bar 54 is displayed when the user presses the pause button. In another embodiment, the user's remote control 56 includes a dedicated button or menu selection that causes the slider bar 54 to be displayed or not. Thus, in the flow chart of FIG. 7, it is assumed that set top box 57 displays slider bar 54 in response to user input from remote controller 56.

In step 162, set top box 57 updates the position of slider bar knob 55 in slider bar 54 based on the position of the video stream received from media server 50. Thus, when the slider bar 54 is displayed, the set top box 57 updates the position of the slider bar knob 55 to the position where the video stream or movie is being played. Thus, slider bar knob 55 displays the relative portion of the displayed movie. Note that step 162 is an optional step that can be omitted, that is, the slider bar knob 55 may be updated based on the user's operation of the slider bar 54 and not based on normal playback of the movie or video stream.

When the user enters the slider bar knob 55 as determined in step 164, in step 165 the set top box 57 calculates a relative value within the selected range based on the new position of the knob 55. Thus, it is assumed herein that a user using the remote controller 56 or other device has manipulated the slider bar knob 55 of the slider bar 54 to jump or index to another location in the video stream or movie. When it is determined in step 164 that a user input has been received, the set top box 57 calculates a value within a predetermined range. In a preferred embodiment, the predetermined range is a value between 0 and 100, where 0 is the absolute start of the movie or stream, 100 is the absolute end of the movie or stream, and a value between them represents a relative position in the stream. Thus, after the user operates the slider bar knob 55, the set top box 57 examines the new position of the knob 55. That is, the received user input is analyzed to calculate a relative value between 0 and 100 based on the new position of knob 55 in step 166. After calculating this new relative value in step 166, the set top box 57 provides the calculated value to the media server 50 in step 168. As will be explained further below, this calculated value is received by the media server 50 and used to input the video stream at a new location based on the user manipulation of the slider bar knob 55.

Figure 8-Media Server Operation

8 is a flowchart for explaining the operation of the media server 50 for transmitting the normal playback video stream in response to the user operation of the slider bar 54. As shown in FIG. Here, the video stream or the multimedia stream is output from the media server 50 to the subscriber unit 52, and the user can adjust the knobs of the slider bar 54 to index or "jump" to other parts or positions in the stream or movie. Suppose you have adjusted 55).

In step 202, media server 50 receives information from set top box 57 generated in response to user input from slider bar 54. User input is initially provided by the user to the television set and / or set top box 57, which is provided to the media server from the set top box 57 in step 202. In a preferred embodiment, the user input received in step 202 is provided by subscriber device or set-top box 57 and is preferably 0-100, indicating a relative position in the movie based on user manipulation of slider bar 54. Contains a value within the range.

In step 204 the media server 50 determines a new normal play time value based on the received user input. In step 204, the media server 50 calculates the normal play time value using a value within a predetermined range, that is, a value within 0-100, and also using the movie time length stored in the memory of the media server 50. . For example, if the user adjusts the knob of the slider bar so that the knob is positioned exactly in the middle of the slider bar 54, the set top box 57 provides 50 output to the media server 50. If the movie length is exactly 2 hours, the media server 50 outputs the normal playback time value of one hour. The normal regeneration time value is calculated as 0.5 x 2 hours = 1 hour. In another example, if the user adjusts the slider bar 54 such that the knob 55 is positioned exactly one third of the position in the slider bar 54, i.e., one third from the left, the subscriber device may request a media server 50. Gives 33 outputs. If the movie length is exactly two hours, the media server 50 outputs a normal playback time value of 40 minutes, which is 1/3 of the movie length.

In a preferred embodiment, the program running on the media server adjusts the movie time length by 0-100 factors received from the set-top box, and the media so that the movie or video sequence is located at the resulting normal play time (NPT) value. Ask the server. Note that other methods may be used to determine the correct normal playback time based on the user input received at step 204. For example, in one embodiment, set top box 57 performs step 204. In this embodiment, the set top box 57 receives or takes the movie length value at the beginning of the movie or video stream and stores this movie length value in memory. Thus, when set-top box 57 receives a user input that locates a knob in slider bar 54, set-top box 57 calculates the normal playback time to be provided to the media server using the movie length in step 202. . In this embodiment, the set top box 57 must access the index table, which is stored in the media server 50 or set top box 57.

After the new normal playback time is determined based on the user input received in step 204, the media server 50 indexes the new location in the normal playback stream based on the normal playback time determined in step 204. Accordingly, in step 206 the media server retrieves an offset from the normal play stream index table using the normal play time calculated in step 204. In step 208 the media server 50 outputs the normal playback stream at the indexed position or at the offset position determined in step 206.

Therefore, in response to the user operating the knob of the slider bar 54, the media server 50 selects each video stream at a new position in the stream based on the user operation of the knob 55 in the slider bar 54. FIG. Output This provides a very intuitive way for the user to fast forward and / or fast reverse within the video stream. In other words, this provides a simple and intuitive mechanism that allows the user to jump to any desired position in the video stream.

Thus, a change in the position of the output of each stream output at a given normal playback time is achieved by using the associated file offset as a point to find a tuple in each index table for the closest normal playback time to start playing the stream.

In one embodiment of the present invention, the set top box 57 includes a cache memory for storing the position of the slider bar knob 55 prior to the user's manipulation of the slider bar knob 55. Thus, if a user watches a movie for 20 minutes, wants to advance or rewind to various other parts of the movie, and then wants to return to the original position of the movie to resume watching, the user may select the knob before any user manipulation of the slider bar. It is possible to select a button of the remote controller 56 to position the slider bar knob 55 to the position where it was.

Therefore, the present invention includes a system and method for providing a graphical icon or slider bar for indexing to another location within a normal playback video stream. The present invention examines the display time stamp in the sequence header of the normal playback stream to generate a normal playback time reference. The system then creates an index table or lookup table for the stream. The index table for the stream includes the normal play time value and the corresponding offset into each stream. During playback, when the user manipulates or adjusts the slider bar knob, the subscriber device or set-top box uses its respective index table to intelligently jump or index to the appropriate location within the normal playback stream and output the stream at this new location. To start.

Although the system and method of the present invention have been described in connection with the described embodiments, it is not intended to be limited to the specific forms set forth below but alternatives may be included as appropriate within the spirit and scope of the invention as defined in the appended claims. , Modifications and equivalents are intended to be included.

Claims (26)

A computer implemented method for indexing locations in a video stream in a video delivery system, the method comprising: The video delivery system includes a media server and a subscriber device coupled to the media server, the subscriber device comprising a display screen, the method comprising: Displaying the video stream received from the media server on the display screen of the subscriber device; Displaying a graphic icon on the display screen of the subscriber device for indexing to locations in the video stream, the graphic icon being adjustable to result in changes in the position of the received video stream. Steps, Receiving input from a user indicating a desired change in output position of the video stream; The subscriber device providing information to the media server in response to receiving the input from the user; In response to receiving the information from the subscriber device, the media server determining a new output location for the video stream; and And in response to the step of determining the new output location, the media server outputting the video stream at the new location. The method of claim 1, Receiving the input comprises receiving adjustments to the graphical icon. The computer-implemented method for indexing to locations in a video stream. The method of claim 2, The graphic icon includes an adjustable knob that can be adjusted to cause changes in the position of the received video stream, and receiving the input includes moving the knob in the graphic icon to a new position of the graphic icon. And moving the index to locations in the video stream. The method of claim 1, The media server stores an index table corresponding to the video stream, the index table including a plurality of tuples, each of the tuples being a first value and an offset into the position of the video stream. The media server determining a new location of the video stream in response to the received user input, the media server indexing the index lookup table to obtain an offset into the video stream. And a computer-implemented method for indexing to locations in a video stream. The method of claim 4, wherein Each of the plurality of tuples comprises a normal playback time value and an offset into the video stream, Providing the information by the subscriber device comprises providing the subscriber device with a value within a predetermined range indicating a relative position within the video stream based on the received user input; Determining, by the media server, a new output location for the video stream, the media server determining a normal playback time value based on the received value within the predetermined range. Computer-implemented method for indexing The method of claim 5, And said predetermined range is a value from 0 to 100. The computer-implemented method for indexing to locations in a video stream. The method of claim 1, The graphical icon includes a slider bar comprising a knob, the knob indexing locations in the video stream, located at a location in the slider bar to indicate a location of the output video stream received by the subscriber device. Computer-implemented method for. The method of claim 1, Receiving user input to pause the video stream, The step of displaying the graphical icon on the display screen of the subscriber device is computer implemented for indexing to locations in the video stream, the response being performed in response to receiving the user input to pause the video stream. Way. The method of claim 8, The graphic icon includes an adjustable knob that can be adjusted to cause changes in the position of the received video stream, the method comprising: In response to displaying the graphic icon on the display screen of the subscriber device, updating the position of the knob on the graphic icon, wherein the updating comprises: according to the current position of the output stream; A computer-implemented method for indexing positions in a video stream that updates the position of the knob on a graphical icon. The method of claim 1, And the subscriber device comprises a television set. The computer-implemented method for indexing to locations in a video stream. The method of claim 1, And the subscriber device comprises a television set and a set top box coupled to the television set. In an interactive video delivery system that enables a user to index locations in a video stream, A media server for outputting a video stream, the media server capable of selectively outputting the video stream at other locations of the video stream, and A subscriber device coupled to the media server receiving the video stream output from the media server, the subscriber device comprising: A display screen displaying the video stream received from the media server, wherein the display screen of the subscriber device also displays a graphic icon for indexing to locations in the video stream, the graphic icon of the received video stream; The display screen, adjustable to cause changes in position, An input for receiving from the user an input representing a desired change in output position of the video stream, and Means for providing information to the media server in response to receiving input from the user, The media server includes an input for receiving the information; The media server outputs the video stream at a new location in response to receiving the information from the media server. The method of claim 12, And the subscriber device input comprises an input for receiving adjustments to the graphical icon. The method of claim 13, The graphical icon includes an adjustable knob that can be adjusted to cause changes in the position of the received video stream, the knob within the graphical icon is movable to a new position within the graphical icon, The subscriber device input includes an input for receiving an adjustment to the knob in the graphical icon. The method of claim 12, The media server includes means for determining a new output location for the video stream in response to receiving the information from the subscriber device. The method of claim 15, wherein the media server A memory for storing an index table corresponding to the video stream, the index table including a plurality of tuples, each of the tuples including a first value and a second offset value that is an offset to a location of the video stream Further comprising the memory, And the means for determining a new output location for the video stream indexes the index lookup table stored in the memory to obtain an offset into the video stream. The method of claim 16, Each of the plurality of tuples comprises a normal playback time value and an offset into the video stream, The means for providing the information provides a value within a predetermined range indicating a relative position in the video stream based on the received user input, And the means for determining a new output location for the video stream determines a normal playback time value based on the received value within the predetermined range. The method of claim 17, And the predetermined range is a value from 0 to 100. The method of claim 12, The graphical icon includes a slider bar comprising a knob, the knob being located at a position within the slider bar to indicate a position of the output video stream received by the subscriber device. The method of claim 12, The input for receiving an input from the user indicating a desired change in output position of the video stream from the user operates in response to receiving the user input to pause the video stream, The subscriber devices display the graphical icon on the display screen in response to receiving the user input to pause the video stream. The method of claim 20, The graphic icon includes an adjustable knob that can be adjusted to cause changes in the position of the received video stream, The subscriber device further comprises means for updating the position of the knob on the graphic icon in response to the subscriber device displaying the graphic icon on the display screen of the subscriber device, wherein the means for updating comprises: And update the position of the knob on the graphic icon according to the current position of the output stream. The method of claim 12, And the subscriber device comprises a television set. The method of claim 12, And the subscriber device comprises a television set and a set top box coupled to the television set. A video display device that enables a user to index to locations in a video stream, A video stream input adapted to receive a video stream input from a media server, A display screen displaying the received video stream, wherein the display screen of the video display device also displays a graphic icon for indexing to locations in the video stream, the graphic icon changing a position of the received video stream The display screen, which can be adjusted to cause the An input for receiving from the user an input representing a desired change in output position of the video stream, and Means for providing information to the media server in response to receiving input from the user, And the video display device receives and displays the video stream at a new location in response to providing the information to the media server. The method of claim 24, And the input for receiving an input from a user comprises an input for receiving an adjustment to the graphical icon. The method of claim 24, The graphic icon includes an adjustable knob that can adjust to cause changes in the position of the received video stream, the knob within the graphic icon is movable to a new position of the graphic icon, And the input for receiving an input from a user comprises an input for receiving an adjustment to the knob within the graphical icon.