System and method for media stream indexing and synchronization

• US 6,941,508 B2
• Filed: 10/01/2003
• Issued: 09/06/2005
• Est. Priority Date: 03/31/1997
• Status: Expired due to Term

• Current Assignee: Espial Incorporated (Enghouse Systems Limited)
• Original Assignee: Kasenna, Inc. (Enghouse Systems Limited)
• Inventors: Smith, Kevin P., Abbott, Michael J., Close, Paul
• Primary Examiner(s): Ludwig, Matthew J.
• Application Number:
  US10/677,581
• Publication Number:
  US 20040064831A1
• Time in Patent Office: 706 Days
• Field of Search: 715/500.1, 715/522, 715/513, 715/723, 345/721, 345/723, 345/731, 345/732
• US Class Current: 715/203
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/4331 Caching operations, e.g. of an advertisement for later insertion during playback
• CPC Class Codes: H04N 21/4341 Demultiplexing of audio and video streams
• CPC Class Codes: H04N 21/44016 involving splicing one content stream with another content stream, e.g. for substituting a video clip
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/812 involving advertisement data advertising per se G06Q30/02
• CPC Class Codes: H04N 21/8146 involving graphical data, e.g. 3D object, 2D graphics
• CPC Class Codes: H04N 21/8455 involving pointers to the content, e.g. pointers to the I-frames of the video stream
• CPC Class Codes: H04N 21/8456 by decomposing the content in the time domain, e.g. in time segments
• CPC Class Codes: H04N 21/8547 involving timestamps for synchronizing content
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests

Abstract

An indexing method for allowing a viewer to control the mode of delivery of program material. By mapping from time to data position, data delivery can begin at any selected time in the program material. The indexing method also provides for controlling data delivery to begin at the beginning of a frame of data. A synchronizing method is provided to minimize a time offset between audio and vide data, particularly in environments using groups of pictures.

Claims

1. A method for locating program material at a specified time T, comprising:

accessing a group, wherein said group comprises at least one series and said at least one series comprises at least on segment, wherein said at least one segment references a corresponding atom containing media data representing the program material;

determining a specified segment during which the specified time T occurs within one of said at least one series;

converting the specified time T to a time T_seg relative to said specified segment;

converting said time T_seg to a data position relative to a specified atom corresponding to said specified segment, thereby locating media data representing the program material at the specified time T.

2. The method of claim 1, wherein the act of converting said time T_seg to a data position comprises converting said time T_seg to a time T_atom relative to said specified atom.

3. The method of claim 2, wherein the act of converting said time T_seg to a data position comprises:

determining an index number from said time T_atom using an index duration; and

converting said index number to said data position.

4. The method of claim 3, wherein the act of converting said index number to said data position comprises:

looking up said index number in an index file, wherein said index file correlates said index number with a corresponding data position.

5. The method of claim 4, wherein the act of converting said index number to said data position further comprises:

constructing said index file so that said corresponding data position is a beginning of a frame of media data.

6. The method of claim 4, wherein the act of converting said index number to said data position further comprises:

constructing said index file so that said corresponding data position is a beginning of a group of pictures of media data, said group of pictures including at least one frame of media data.

7. The method of claim 6, wherein said corresponding data position in said index file is the same for each of said at least one frame of media data in said group of pictures.

8. The method of claim 7, further comprising rounding said index number to locate an index boundary.

9. The method of claim 3, wherein said index duration is a duration of one frame of media data.

10. The method of claim 9, further comprising:

constructing an index file, wherein the act of converting said index number to said data position is performed by looking up said index number in said index file, wherein said data position corresponds to a beginning of a frame of media data.

11. The method of claim 3, further comprising rounding said index number to locate an index boundary.

12. The method of claim 11, wherein said index boundary is a beginning of a frame of media data.

13. The method of claim 11, wherein said index boundary is a beginning of a group of pictures of media data.

14. The method of claim 2, wherein said specified segment is defined by an offset from a beginning of said specified atom, and a duration, wherein said time T_seg is determined by calculating an elapsed time into said specified segment at which the specified time T occurs.

15. The method of claim 14, wherein said time T_atom is determined by adding said offset to said time T_seg.

16. The method of claim 1, wherein one of said at least one series is an ordered sequence of a plurality of segments.

17. The method of claim 1, wherein said group is a parallel arrangement of a plurality of series.

18. The method of claim 1, further comprising performing the act of determining a specified segment, the act of converting the specified time T to a time T_seg relative to said specified segment, and the act of converting said time T_seg to a data position relative to a specified atom corresponding to said specified segment for each of said at least one series in said group.

19. An apparatus for locating program material at a specified time T, comprising:

means for accessing a group, wherein said group comprises at least one series and said at least one series comprises at least one segment, wherein said at least one segment references a corresponding atom containing media data representing the program material;

means for determining a specified segment during which the specified time T occurs within one of said at least one series;

means for converting the specified time T to a time T_seg relative to said specified segment; and

means for converting said time T_seg to a data position relative to a specified atom corresponding to said specified segment, thereby locating media data representing the program material at the specified time T.

20. A computer program product comprising a computer usable medium having computer readable program code embodied in said medium for enabling a processor in a computer system to locate program material at a specified time T, said computer readable program code comprising instructions for:

accessing a group, wherein said group comprises at least one series and said at least one series comprises at least one segment, wherein said at least one segment references a corresponding atom containing media data representing the program material;

determining a specified segment during which the specified time T occurs within said at least one series;

converting the specified time T to a time T_seg relative to said specified segment; and

converting said time T_seg to a data position relative to a specified atom corresponding to said specified segment to thereby locate media data representing the program material at time T.

21. The computer program product of claim 20, wherein the computer readable program code further comprises instructions for:

converting said time T_seg to a time T_atom relative to said specified atom.

22. The computer program product of claim 21, wherein said computer readable program code further comprises instructions for:

determining an index number from said time T_atom using an index duration; and

converting said index number to said data position.