Method and apparatus for efficient transmissions of programs

• US 5,701,582 A
• Filed: 03/22/1995
• Issued: 12/23/1997
• Est. Priority Date: 08/23/1989
• Status: Expired due to Term

• Current Assignee: Deta Technology Development LLC (Intellectual Ventures LLC)
• Original Assignee: Delta Beta Pty. Ltd.
• Inventors: DeBey, Henry C.
• Primary Examiner(s): Pan, Daniel H.
• Application Number:
  US08/408,440
• Time in Patent Office: 1,007 Days
• Field of Search: 395/100, 395/800, 395/353, 364/DIG. 1, 364/DIG. 2, 358/342, 348/96, 348/220, 348/7, 348/12, 348/17, 348/13, 455/17, 455/5.1, 455/4.1, 455/6.1, 455/4.2, 235/380, 340/825.25, 360/77.12
• US Class Current: 725/103
• CPC Class Codes: G09B 5/065 Combinations of audio and video presentations, e.g. videotapes, videodiscs, television systems
• CPC Class Codes: G09B 5/12 different stations being capable of presenting different information simultaneously G09B5/14 takes precedence
• CPC Class Codes: H04N 21/2221 being a cable television head-end CATV in broadcast systems H04H20/78
• CPC Class Codes: H04N 21/23109 by placing content in organized collections, e.g. EPG data repository details of retrieval of video data and associated meta data in video databases G06F16/739
• CPC Class Codes: H04N 21/232 Content retrieval operation locally within server, e.g. reading video streams from disk arrays storage management G06F3/0604; details of querying and searching of video data from a database G06F16/739
• CPC Class Codes: H04N 21/236 Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary stream multiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/26216 involving the channel capacity, e.g. network bandwidth admission control, resource allocation in open networks H04L12/5692; flow control in packet networks H04L47/10; establishing a schedule or organising the servicing of application requests taking into account QoS H04L67/61
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/434 Disassembling of a multiplex stream, e.g. demultiplexing audio and video streams, extraction of additional data from a video stream; Remultiplexing of multiplex streams; Extraction or processing of SI; Disassembling of packetised elementary stream demultiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6581 Reference data, e.g. a movie identifier for ordering a movie or a product identifier in a home shopping application
• CPC Class Codes: H04N 21/8456 by decomposing the content in the time domain, e.g. in time segments
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends

Abstract

A system and method of optimizing transmission of a program to multiple users over a distribution system, with particular application to video-on-demand for a CATV network. The system includes, at a head end of the CATV network a scheduling and routing computer for dividing the video program stored in long term fast storage or short term fast storage into a plurality of program segments, and a subscriber distribution node for transmitting the program segments in a redundant sequence in accordance with a scheduling algorithm. At a receiver of the CATV network there is provided a buffer memory for storing the transmitted video program segments for subsequent playback whereby, in use, the scheduling algorithm can ensure that a user'"'"'s receiver will receive all of the program segments in a manner that will enable continuous playback in real time of the program. Under the control of controller the receiver distinguishes received program segments by a segment identifier so that redundant segments captured in capture memory are then stored in buffer memory from which the segments can be retrieved and decompressed in data compressor for immediate or subsequent viewing. In one embodiment, the method of this invention includes dividing at least some segments into fragments, and transmitting one fragment of each segment during a playback interval of a duration, for example, equal to a playback time of a segment.

Claims

1. A method of transmitting a program to multiple users over a distribution system, the method comprising:

at a head end of the distribution system, providing a program divided into a plurality of segments; and

transmitting the segments from the head end to users'"'"' receivers such that, at least some of the segments are transmitted more than once, at different times, from the head end so as to enable multiple receivers of users requesting playback of the program at different times to simultaneously receive the segments required for continuous playback of the program.

2. The method of claim 1 wherein some of the segments are transmitted in a sequence which is different from a sequence in which such segments are subsequently played back.

3. The method of claim 2 further comprising storing each segment at users'"'"' receivers only once even if the same segment has been received more than once during the transmission of the program.

4. The method of claim 1 wherein at any given time the head end of the distribution system is not dedicated to transmitting the program to a predetermined number of receivers.

5. The method of claim 1 further comprising selecting a maximum response time corresponding to a maximum time interval a user need wait to commence playing back the program.

6. The method of claim 5 wherein each of the segments represents a portion of the program which playing time is equal to one maximum response time.

7. The method of claim 6 wherein the transmission of each set of the segments is separated in time by a time interval essentially equal to the maximum response time.

8. The method of claim 7 wherein the first segment of the program is transmitted during every maximum response time interval.

9. The method of claim 8 wherein a bandwidth limit is imposed so that at most a predetermined maximum number of segments is transmitted during any given maximum response time interval and further comprising delaying the transmission of a number of the segments exceeding the maximum number until an interval in which the number of segments scheduled for transmission is less than the predetermined maximum number.

10. The method of claim 8 further comprising imposing a bandwidth limit and transmitting a segment in an interval prior to the interval when it is scheduled for transmission if the number of segments scheduled for that interval exceeds the limit.

11. The method of claim 1 further comprising storing predetermined segments of predetermined programs at receivers of at least some of the users even if such predetermined programs are not presently being requested by the users in whose receivers the segments are stored.

12. A system for transmitting a program to multiple users comprising:

means for providing a program divided into a plurality of segments at a head end; and

means for transmitting the segments from the head end to users'"'"' receivers such that at least some of the segments are transmitted more than once, at different times, so as to enable multiple receivers of users requesting the program at different times to simultaneously receive the segments required for continuous playback of the program.

13. A method of transmitting a program to multiple users over a distribution system, comprising:

at a head end of the distribution system, providing a program divided into a plurality of segments; and

transmitting the segments from the head end to users'"'"' receivers, such that at least some of the segments are simultaneously sent to more than one receiver with no requirement at any time to dedicate the head end of the distribution system to any specific receivers.

14. The method of claim 13 wherein the segments represent portions of the program having equal playback time.

15. A system for transmitting a program to users comprising:

means for dividing a program into segments;

means for dividing at least some of the segments into a plurality of fragments;

means for transmitting at successive intervals at least one fragment of the plurality of fragments of each segment that has been divided into the plurality of fragments; and

means for receiving and storing the fragments of the segments, which have been divided into the plurality of segments, necessary for continuous playback of the program.

16. The system of claim 15 wherein each segment is consecutively numbered and the means for receiving accepts fragments relating to the segments that have numbers higher than the segment currently being played back.

17. The system of claim 15 wherein the fragments of each segment are consecutively numbered and the fragments are played back in numerical order.

18. The system of claim 17 wherein the played back fragments are deleted from the means for receiving and storing.

19. A method of transmitting a program to multiple users over a distribution system comprising:

providing a program divided into a plurality of segments wherein at least some of the segments are divided into a plurality of fragments;

during each predetermined time interval transmitting one fragment of each segment to users'"'"' receivers; and

during each predetermined interval accepting at the receivers the fragments of the segments which have not yet been played back and deleting from the receivers the fragments of the segments which have been played back.

20. A method of transmitting a program to multiple users over a distribution system comprising:

providing a program divided into a plurality of segments wherein at least some of the segments are divided into a plurality of fragments; and

during each predetermined time interval transmitting one fragment of each segment to users'"'"' receivers;

wherein each of the segments is divided into a number of fragments corresponding to a sequential position of such a segment in the program.

21. A method of transmitting a program to multiple users over a distribution system comprising:

providing a program divided into a plurality of segments wherein at least some of the segments are divided into a plurality of fragments;

during each predetermined time interval transmitting one fragment of each segment to users'"'"' receivers; and

receiving and permanently storing fragments of initial segments of the program.

22. A method of transmitting a program to multiple users over a distribution system comprising:

providing a program divided into a plurality of segments wherein at least some of the segments are divided into a plurality of fragments; and

during each predetermined time interval transmitting one fragment of each segment to users'"'"' receives;

wherein segments of the plurality of segments at an ending potion of the program are divided into fewer fragments than a sequential number of the segments in the ending portion of the program.

23. A method of transmitting a program to multiple users over a distribution system comprising:

providing a program divided into a plurality of segments wherein at least some of the segments are divided into a plurality of fragments; and

during each predetermined time interval transmitting one fragment of each segment to users'"'"' receivers;

wherein segments of the plurality of segments belonging to a beginning portion of the program are transmitted more frequently than segments of the plurality of segments belonging to an ending portion of the program.

24. A receiver for receiving a program supplied to multiple users over a distribution system from a head end, said program being divided into a plurality of program segments, the receiver comprising:

a buffer storage means for storing a plurality of program segments transmitted from the head end of the distribution system; and

a processing means including means for determining whether segments already held in said buffer storage means will be presented on the distribution system prior to playback and removing the segments that will be presented a again prior to playback from the buffer storage means whereby, in use, the program segments required for continuous playback of the program will always be available at the receiver.

25. A method of transmitting a program to multiple users over a distribution system, the method comprising:

at a head end of the distribution system, providing a program divided into a plurality of segments; and

transmitting the segments from the head end to users'"'"' receivers such that, at least some of the segments are transmitted more than once at different times from the head end so as to enable multiple receivers of users requesting playback of the program at different times to simultaneously receive the segments required for continuous playback of the program;

wherein at least some of the segments represent a portion of the program having playing time essentially equal to one maximum response time, which is a maximum time interval a user needs to wait to commence playing back the program, and wherein transmission of each set of segments of the plurality of segments is separated in time by a time interval essentially equal to the maximum response time.

26. A method of transmitting a program to multiple users over a distribution system, the method comprising:

at a head end of the distribution system, providing a program divided into a plurality of segments; and

transmitting the segments from the head end to users'"'"' receivers such that, at least some of the segments are transmitted more than once at different times from the head end so as to enable multiple receivers of users requesting playback of the program at different times to simultaneously receive the segments required for continuous playback of the program;

wherein at most a maximum number of segments, of the plurality of segments, is transmitted during a predetermined time interval, the transmission of other segments of the plurality of segments, exceeding the maximum number, is delayed until an interval in which the number of segments scheduled for transmission is less than the predetermined maximum number.

27. A method of transmitting a program to multiple users over a distribution system, the method comprising:

at a head end of the distribution system, providing a program divided into a plurality of segments; and

transmitting the segments from the head end to users'"'"' receivers such that, at least some of the segments are transmitted more than once at different times from the head end so as to enable multiple receivers of users requesting playback of the program at different times to simultaneously receive the segments required for continuous playback of the program; and

transmitting a given segment of the plurality of segments in a time interval occurring prior to a time interval when the given segment is scheduled for transmission, if a number of segments, scheduled for the interval when the given segment is scheduled for transmission exceeds a predetermined limit.

28. A method of transmitting a program to multiple users over a distribution system, comprising:

at a head end of the distribution system, providing a program divided into a plurality of segments; and

transmitting the segments from the head end to users'"'"' receivers, such that at least some of the segments are simultaneously sent to more than one receiver with no requirement at any time to dedicate the head end of the distribution system to any specific receivers;

wherein each of the segments is divided into fragments such that the segments representing an ending portions of the program are divided into a greater number of fragments than the segments representing a beginning portions of the program.

29. The method of claim 28 wherein each of the segments is divided into a number of fragments that corresponds to a sequential position of such a segment in the program, so that the first segment is divided into one fragment, the second segment is divided into two fragments, the third segment is divided into three fragments and so forth.

30. The method of claim 29 wherein during each predetermined time interval at least one fragment of each segment is transmitted.

31. A method of transmitting a program to multiple users over a distribution system comprising:

providing a program divided into a plurality of segments wherein at least some of the segments are divided into a plurality of fragments; and

during each predetermined time interval transmitting at least one fragment of each segment to users'"'"' receivers;

wherein initial segments of the program are divided into a greater number of fragments than that corresponding to the sequential position of such segments in the program and subsequent segments are divided into a number of fragments corresponding to the position of segments in the program.

32. The method of claim 31 further comprising during each predetermined interval accepting at the receivers the fragments of the segments which have not yet been played back and deleting from the receivers the fragments of the segments which have been played back.

33. A method of transmitting a program to multiple users over a distribution system comprising:

providing a program divided into a plurality of segments wherein at least some of the segments are divided into a plurality of fragments;

during each predetermined time interval transmitting at least one fragment of each segment to users'"'"' receivers; and

wherein the fragments of the segments that represent an ending portion of the program are not accepted at the receivers when initial segments of the program are being played to a user in order to decrease the storage requirement of the receivers.

34. The method of claim 33 wherein the initial segments of the program are divided into a greater number of fragments than that corresponding to the sequential position of such segments in the program and subsequent segments are divided into a number of fragments corresponding to the position of segments in the program.

35. The method of claim 33 wherein the segments belonging to a beginning portion of the program are transmitted more frequently than the segments belonging to the ending portion of the program.

36. The method of claim 33 wherein the predetermined interval is essentially equal to a playback interval of a segment.

37. A receiver for receiving a program supplied to multiple users over a distribution system from a head end, said program being divided into a plurality of program segments, the receiver comprising:

a buffer storage means for storing a plurality of program segments transmitted from the head end of the distribution system; and

means for determining whether segments presented on the distribution system will be presented again prior to playback and rejecting the segments that will be presented again, but accepting the segments that will not be presented again for storing in the buffer storage means.