Granted Patent B1

US 7,106,749 · App. 09/574,096 · Granted Sep 12, 2006

Abstract

Claims (50)

1. A method for processing a data stream comprising:

receiving a transport stream (TS);

storing at least a portion of the TS, said at least a portion of the TS having a beginning and comprising a plurality of TS packets;

determining, from among the plurality of TS packets, at least one TS packet comprising a candidate access point;

storing in an index store a byte offset of the candidate access point; and

storing in the index store a plurality of indications of byte offset, each byte offset being associated with an arrival time of a received TS packet.

2. A method according to claim 1 and wherein the storing indications of byte offset step comprises repeatedly storing in the index store, at predefined intervals of time, a byte offset of a recently received TS packet.

3. A method according to claim 1 and wherein the byte offset of the candidate access point and the byte offset of the recently received TS packet each comprises a byte offset relative to the beginning.

4. A method according to claim 1 and wherein the TS comprises an MPEG-2 TS.

5. A method according to claim 1 and wherein the TS comprises an at least partially scrambled TS.

6. A method according to claim 1 and wherein the TS comprises a video stream.

7. A method according to claim 1 and wherein the TS comprises an audio stream.

8. A method according to claim 1 and also comprising:

utilizing the index for accessing at least a part of the portion of the TS.

9. A method according to claim 8 and wherein the utilizing step comprises:

determining a desired presentation time of a point to be accessed, said point being associated with the at least a part of the portion of the TS;

determining an arrival time associated with the desired presentation time; and

determining, based at least in part on at least one byte offset stored in the index store, a byte offset of an access point closely temporally associated with the arrival time.

10. A method according to claim 9 and wherein said determining a desired presentation time comprises determining a desired presentation time based on at least one of the following: at least one desired characteristic of a presentation mode; and at least one random access characteristic.

11. A method according to claim 9 and wherein said determining an arrival time comprises determining an arrival time based on the desired presentation time and on a predetermined relationship between arrival time and presentation time.

12. A method according to claim 9 and wherein the utilizing step also comprises:

decoding the at least a part of the portion of the TS for presentation beginning from the access point.

13. A method according to claim 9 and wherein the utilizing step also comprises:

descrambling the at least a part of the portion of the TS for presentation beginning from the access point.

14. A method according to claim 9 and wherein the access point comprises a packet comprising at least one of the following:

a packet having a bit turned on in a standard TS header field;

an ECM;

an EMM;

an Adaptation Field (AF) field;

a private data field within the AF;

an SI private table;

a private descriptor; a private stream; and

a visible field in a partially scrambled stream.

15. A method according to claim 14 and wherein the private stream comprises a private PES stream with associated PTS.

16. A method according to claim 14 and wherein the packet having a bit turned on comprises a packet having a payload_unit_start_indicator (pusi) bit turned on.

17. A method according to claim 14 and wherein the AF comprises at least one of the following: a PCR; and a random access indicator.

18. A method for processing a data stream comprising:

determining a desired presentation time of a point in the data stream to be accessed;

determining an arrival time associated with the desired presentation time; and

determining a position of an access point closely temporally associated with the arrival time.

19. Apparatus for processing a data stream comprising:

a data stream receiver operative to receive a transport stream (TS);

TS storage apparatus operative to store at least a portion of the TS, said at least a portion of the TS having a beginning and comprising a plurality of TS packets;

candidate determining apparatus operative to determine, from among the plurality of TS packets, at least one TS packet comprising a candidate access point;

candidate offset storage apparatus operative to store in an index store a byte offset of the candidate access point; and

arrival time storage apparatus operative to store in the index store a plurality of indications of byte offset, each byte offset being associated with an arrival time of a received TS packet.

20. Apparatus for processing a data stream comprising:

presentation determining apparatus operative to determine a desired presentation time of a point in the data stream to be accessed;

arrival determining apparatus operative to determine an arrival time associated with the desired presentation time; and

position determining apparatus operative to determine a position of an access point closely temporally associated with the arrival time.

Assignments (6)