Timestamp modification for seamless branching

• US 6,490,405 B1
• Filed: 06/29/1998
• Issued: 12/03/2002
• Est. Priority Date: 06/29/1998
• Status: Expired due to Term

• Current Assignee: Zhigu Holdings Limited
• Original Assignee: Microsoft Corporation
• Inventors: Powell, William C., Speed, Robin
• Primary Examiner(s): Chevalier, Robert
• Application Number:
  US09/106,444
• Time in Patent Office: 1,618 Days
• Field of Search: H04/N.591, H04/N.585, H04/N.5781, 386/65, 386/96, 386/98, 386/99, 386/104, 386/105, 386/106, 386/124, 386/125, 386/126, 386/39, 386/40, 386/45, 386/109, 386/111, 386/112, 386/66, 386/84
• US Class Current: 386/207
• CPC Class Codes: H04N 21/6125 involving transmission via Internet transmission by internet of broadcast information H04H60/82
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 5/85 on discs or drums
• CPC Class Codes: H04N 5/926 by pulse code modulation H04N5/919 takes precedence
• CPC Class Codes: H04N 5/93 Regeneration of the television signal or of selected parts thereof
• CPC Class Codes: H04N 7/173 with two-way working, e.g. subscriber sending a programme selection signal

Abstract

The modification of timestamps of streams of data packets for seamless branching is disclosed. In one aspect of the invention, a computerized system has a plurality of multimedia play devices, and a multimedia read device. Each play device receives and plays data intended for that device. The multimedia read device reads a stream of packets of data, decodes the packets into data, and sends the data to a corresponding play device at appropriate times. The appropriate time is based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream. The invention has applications including digital video disc (DVD) playback.

Claims

1. A computerized system comprising:

a plurality of multimedia play devices, each device receiving and playing data intended for the device; and

,

a multimedia read device reading a stream of packets, decoding the packets into data, and sending the data to a corresponding multimedia play device at appropriate times,

the appropriate times being based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream.

2. The computerized system of claim 1, wherein each packet of the stream has a corresponding substream, and the multimedia read device comprises:

a plurality of substream decoders, each substream decoder receiving packets of a corresponding substream, decoding the packets into data and sending the data to a corresponding multimedia play device at the appropriate times;

a demultiplexer receiving packets and sending each packet, including a relative timestamp, to the substream decoder corresponding to the substream of the packet; and

,

a stream decoder decoding the stream of the packets, and sending each packet to the demultiplexer with a relative timestamp.

3. The computerized system of claim 1, wherein the relative timestamps are calculated by the multimedia read device according to the formula:

4. The computerized system of claim 1, wherein the accumulated time gaps resulting from branches within the stream are calculated by the multimedia read device according to the formula:

5. The computerized system of claim 1, wherein the accumulated time gaps resulting from branches within the stream are calculated by the multimedia read device according to the formula:

6. The computerized system of claim 1, wherein at least one of the plurality of multimedia play device is selected from the group of multimedia play devices comprising:

a video display device, and an audio device.

7. The computerized system of claim 6, wherein the video display device comprises a monitor.

8. The computerized system of claim 6, wherein the audio device comprises an amplifier coupled to at least one speaker.

9. The computerized system of claim 1, wherein the multimedia read device comprises a digital-video disc (DVD) player.

10. A multimedia read device for reading a stream of packets, each packet having a corresponding substream, comprising:

a plurality of substream decoders, each substream decoder receiving packets of a corresponding substream, decoding the packets into data and providing the data as output at the appropriate times;

a demultiplexer receiving packets and sending each packet, including a relative timestamp, to the substream decoder corresponding to the substream of the packet; and

,

a stream decoder decoding the stream of the packets, and sending each packet to the demultiplexer with a relative timestamp,

wherein the appropriate times are based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream.

11. The multimedia read device of claim 10, wherein the relative timestamps are calculated by the stream decoder according to the formula:

12. The multimedia read device of claim 10, wherein the accumulated time gaps resulting from branches within the stream are calculated by the stream decoder according to the formula:

13. The multimedia read device of claim 10, wherein the stream of packets is read by the multimedia read device from a digital video disc (DVD).

14. A computer comprising:

a processor;

a computer-readable medium;

a multimedia read device reading a stream of packets, decoding the packets into data, and providing the data as output at the appropriate times;

a program executed by the processor from the medium to maintain the appropriate times based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream.

15. The computer of claim 14, wherein the relative timestamps are calculated by the program according to the formula:

16. The computer of claim 14, wherein the accumulated time gaps resulting from branches within the stream are calculated by the program according to the formula:

17. The computer of claim 14, wherein the computer-readable medium comprises a memory.

18. The computer of claim 14, wherein the multimedia read device comprises a digital video disc (DVD) player.

19. A computerized method for processing a stream of packets, each packet having a corresponding substream, comprising:

determining whether the stream at an absolute timestamp comprises a branch;

upon determining that the stream at the absolute timestamp comprises information other than a branch,

reading a packet within the stream at the absolute timestamp,

calculating a relative time as the absolute time minus an accumulated time based on accumulated time gaps resulting from branches within the stream, and,

providing the packet, along with the relative time, as an output; and

,

upon determining that the stream at the absolute timestamp comprises a branch,

setting a from-time as the absolute time,

performing the branch, such that the absolute time is advanced;

incrementing the accumulated time by the absolute time, as advanced, minus the from-time.

20. The computerized method of claim 19, wherein the stream of packets is read from a digital video disc (DVD).

21. A computer-readable medium having computer-executable instructions that when executed, perform actions comprising reading a stream of packets, decoding the packets into data, and providing the data as output at the appropriate times, the computer-executable instructions maintaining the appropriate times based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream.

22. The computer-readable medium of claim 21, wherein the relative timestamps are calculated by the computer-executable instructions according to the formula:

23. The computer-readable medium of claim 21, wherein the accumulated time gaps resulting from branches within the stream are calculated by the computer-executable instructions according to the formula:

24. The computer-readable medium of claim 21, wherein the medium is selected from the group of mediums consisting of:

a floppy disk, a compact-disc read-only-memory (CD-ROM), and a memory.

25. A computerized method for processing a stream of DVD packets, comprising:

reading a packet within the stream;

determining whether the packet is part of a new segment within the stream;

upon determining that the packet is part of a new segment within the stream,

calculating an accumulated time;

determining whether the packet has a timestamp; and

, upon determining that the packet has a timestamp,

extracting the timestamp from the packet,

modifying the timestamp to account for the accumulated time, and

reencoding the timestamp as modified within the packet.

26. The computerized method of claim 25, wherein the stream of packets is read from a digital video disc (DVD).

27. The computerized method of claim 25, further comprising passing the reencoded timestamp to a substream decoder.

28. The computerized method of claim 25, wherein modifying the timestamp to account for the accumulated time further comprises calculating relative timestamps according to the formula:

29. A computerized system comprising:

a plurality of multimedia play devices, each device receiving and playing data intended for the device; and

a multimedia read device reading a stream of packets, decoding the packets into data, and sending the data to a corresponding multimedia play device at appropriate times,

the appropriate times being based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream, wherein the relative timestamps are calculated by the multimedia read device according to the formula;

30. A computerized system comprising:

a plurality of multimedia play devices, each device receiving and playing data intended for the device; and

a multimedia read device reading a stream of packets, decoding the packets into data, and sending the data to a corresponding multimedia play device at appropriate times, wherein the appropriate times are based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream, wherein the accumulated time gaps resulting from branches within the stream are calculated by the multimedia read device according to the formula;

31. A computerized system comprising:

a plurality of multimedia play devices, each device receiving and playing data intended for the device; and

a multimedia read device reading a stream of packets, decoding the packets into data, and sending the data to a corresponding multimedia play device at appropriate times,

the appropriate times being based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream, wherein the accumulated time gaps resulting from branches within the stream are calculated by the multimedia read device according to the formula;

32. A multimedia read device for reading a stream of packets, each packet having a corresponding substream, comprising:

a plurality of substream decoders, each substream decoder receiving packets of a corresponding substream, decoding the packets into data and providing the data as output at the appropriate times;

a demultiplexer receiving packets and sending each packet, including a relative timestamp, to the substream decoder corresponding to the substream of the packet; and

a stream decoder decoding the stream of the packets, and sending each packet to the demultiplexer with a relative timestamp,

wherein the appropriate times are based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream, wherein the relative timestamps are calculated by the stream decoder according to the formula;

33. A multimedia read device for reading a stream of packets, each packet having a corresponding substream, comprising:

a plurality of substream decoders, each substream decoder receiving packets of a corresponding substream, decoding the packets into data and providing the data as output at the appropriate times;

a demultiplexer receiving packets and sending each packet, including a relative timestamp, to the substream decoder corresponding to the substream of the packet; and

a stream decoder decoding the stream of the packets, and sending each packet to the demultiplexer with a relative timestamp,

wherein the appropriate times based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream, wherein the accumulated time gaps resulting from branches within the stream are calculated by the stream decoder according to the formula;

34. A computer comprising:

a processor;

a computer-readable medium;

a multimedia read device reading a stream of packets, decod ing the packets into data, a nd providing the data as output at the appropriate times;

a program executed by the processor from the medium to maintain the appropriate times based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream, wherein the relative timestamps are calculated by the program according to the formula;

35. A computer comprising:

a processor;

a computer-readable medium;

a multimedia read device reading a stream of packets, decoding the packets into data, and providing the data as output at the appropriate times;

a program executed by the processor from the medium to maintain the appropriate times based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream, wherein the accumulated time gaps resulting from branches within the stream are calculated by the program according to the formula;

36. A computer-readable medium having a program stored thereon for execution on a suitably equipped computer having a multimedia read device coupled thereto, the device reading a stream of packets, decoding the packets into data, and providing the data as output at the appropriate times, the program maintaining the appropriate times based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream, wherein the relative timestamps are calculated by the program according to the formula:

37. A computer-readable medium having a program stored thereon for execution on a suitably equipped computer having a multimedia read device coupled thereto, the device reading a stream of packets, decoding the packets into data, and providing the data as output at the appropriate times, the program maintaining the appropriate times based on relative timestamps accounting for accumulated time gaps resulting from branches within the stream, wherein the accumulated time gaps resulting from branches within the stream are calculated by the program according to the formula:

38. A digital video disc player, wherein each packet of a plurality of packets has a corresponding substream, and the digital video disc player comprises:

a plurality of substream decoders, each substream decoder to receive a plurality of packets of a corresponding substream, each packet having a relative timestamp, to decode the packets into data, and to send the data to a corresponding multimedia play device at the relative timestamp;

a demultiplexer to receive packets and send each packet, including a relative timestamp, to the substream decoder corresponding to the substream of the packet; and

a decoder to decode the plurality of the packets, calculate accumulated time gaps that result from branches within the plurality of packets for each of the plurality of packets, calculate a relative timestamp that accounts for the accumulated time gaps, and send each packet to the demultiplexer with the corresponding relative timestamp.

39. The digital video disc player of claim 38, wherein the decoder calculates each of the plurality of relative timestamps as a plurality of accumulated time gaps resulting from branches within the plurality of packets subtracted from an absolute timestamp from the plurality of packets.

40. The digital video disc player of claim 38, wherein the accumulated time gaps resulting from branches within the plurality of packets are calculated by the decoder as an absolute time as discerned from an absolute timestamp from the plurality of packets at the branch that is subtracted from the sum of the accumulated time gaps resulting from branches within the plurality of packets and an absolute time as discerned from an absolute timestamp from the plurality of packets immediately after a branch.

41. The digital video disc player of claim 38, wherein the digital video disc player is part of a computer having a processor, a computer-readable random-access memory medium, and another computer-readable medium, wherein a computer program operable to execute on the computer-readable random-access memory medium by the processor of the computer, to calculate the relative timestamp, and send the relative timestamp to the decoder.

42. The digital video disc player of claim 38, wherein the multimedia play device is selected from the group of multimedia play devices comprising:

a video display device, and an audio device.

43. The digital video disc player of claim 42, wherein the video display device comprises a monitor.

44. The digital video disc player of claim 42, wherein the audio device comprises an amplifier coupled to at least one speaker.

45. The digital video disc player of claim 38, wherein the digital video disc player is an internal component of a computer.

46. The digital video disc player of claim 38, wherein the digital video disc player is a component within a stereo system.

47. A computer comprising:

a processor;

a computer-readable medium;

a multimedia read device reading a stream of packets, decoding the packets into data, and providing the data as output at the appropriate times; and

logic on the computer-readable medium and executable by the processor from the computer-readable medium to maintain the appropriate times based on a plurality of relative timestamps in account of a plurality of accumulated time gaps that result from branches within the stream.

48. The computer of claim 47, wherein each of the plurality of relative timestamps are calculated as a plurality of accumulated time gaps resulting from branches within the stream subtracted from an absolute timestamp from the stream.

49. The computer of claim 47, wherein the accumulated time gaps resulting from branches within the stream are calculated by the logic as an absolute time as discerned from an absolute timestamp from the stream at the branch that is subtracted from the sum of the accumulated time gaps resulting from branches within the stream and an absolute time as discerned from an absolute timestamp from the stream immediately after a branch.

50. The computer of claim 47, wherein the computer-readable medium comprises a memory.

51. The computer of claim 47, wherein the multimedia read device comprises a digital video disc (DVD) player.

52. A method for processing a stream of packets, each packet having a corresponding substream, comprising:

reading a stream of packets;

decoding the packets into data;

accounting for accumulated time gaps resulting from branches within the stream;

determining a plurality of times based on relative timestamps and the accumulated time gaps; and

sending the data to a corresponding multimedia play device at the plurality of times.

53. The method of claim 52, wherein the stream of packets is read from a digital video disc (DVD).

54. A computer-readable medium having a program stored thereon for execution on a suitably equipped computer having a multimedia read device coupled thereto, the program, when executed, directing the device to perform tasks comprising:

reading a stream of packets;

decoding the packets into data;

accounting for accumulated time gaps resulting from branches within the stream;

determining a plurality of times based on relative timestamps and the accumulated time gaps; and

sending the data to a corresponding multimedia play device at the plurality of times.

55. The computer-readable medium of claim 54, wherein each of the plurality of relative timestamps are calculated as a plurality of accumulated time gaps resulting from branches within the stream subtracted from an absolute timestamp from the stream.

56. The computer-readable medium of claim 54, wherein the accumulated time gaps resulting from branches within the stream are calculated as an absolute time as discerned from an absolute timestamp from the stream at the branch that is subtracted from the sum of the accumulated time gaps resulting from branches within the stream and an absolute time as discerned from an absolute timestamp from the stream immediately after a branch.

57. The computer-readable medium of claim 54, wherein the medium is selected from the group of mediums consisting of:

a floppy disk, a compact-disc read-only-memory (CD-ROM), and a memory.