System and method for network delivery of low bit rate multimedia content

• US 20020150123A1
• Filed: 04/10/2002
• Published: 10/17/2002
• Est. Priority Date: 04/11/2001
• Status: Abandoned Application

• Current Assignee: Cyber Operations LLC
• Original Assignee: Cyber Operations LLC
• Inventors: Ro, Sookwang
• Application Number:
  US10/119,878
• Publication Number:
  US 20020150123A1
• Time in Patent Office: Days
• US Class Current: 370/465
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/23614 Multiplexing of additional data and video streams arrangements for simultaneous broadcast of plural pieces of information H04H20/28
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/23805 Controlling the feeding rate to the network, e.g. by controlling the video pump
• CPC Class Codes: H04N 21/2389 Multiplex stream processing, e.g. multiplex stream encrypting
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• 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 21/4341 Demultiplexing of audio and video streams
• CPC Class Codes: H04N 21/4348 Demultiplexing of additional data and video streams
• CPC Class Codes: H04N 21/4385 Multiplex stream processing, e.g. multiplex stream decrypting
• CPC Class Codes: H04N 21/44209 Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896
• CPC Class Codes: H04N 21/643 Communication protocols network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP], H04L65/65
• CPC Class Codes: H04N 21/654 Transmission by server directed to the client
• CPC Class Codes: H04N 21/6582 Data stored in the client, e.g. viewing habits, hardware capabilities, credit card number arrangements where receivers interact with the broadcast H04H20/38
• CPC Class Codes: H04N 5/21 Circuitry for suppressing or minimising disturbance, e.g. moiré or halo

Abstract

A method for transmitting low bit rate multimedia content can include separately encoding corresponding audio and video packets that represent the multimedia content and generating a system media stream comprising the corresponding audio and video packets. A network communication rate indicating a bandwidth available for transmitting the system media stream can be compared to a media transmission rate indicating a bandwidth needed to transmit the system media stream. The media transmission rate can be adjusted upon on a determination that the media transmission rate is greater than the network communication rate. The system media stream then can be decoded and presented at a remote location.

Claims

1. A computer-implemented method for communicating low bit rate multimedia content, said method comprising the steps of:

encoding corresponding audio and video packets that represent the multimedia content;

time stamping a header of each of the corresponding audio and video packets with a time providing synchronization information for the corresponding audio and video packets;

generating a system media stream comprising the corresponding audio and video packets;

negotiating a communication rate for communicating the system media stream;

decoding the corresponding audio and video packets of the system media stream; and

presenting the multimedia content represented by the decoded audio and video packets based on the synchronization information provided in the headers of the audio and video packets.

2. The method according to claim 1, wherein the time used in said time stamping step comprises a time generated by a precision clock that is precise to less than 1 microsecond.

3. The method according to claim 1, wherein said encoding step comprises encoding the corresponding audio and video packets using an MPEG-1 compression standard.

4. The method according to claim 1, wherein said negotiating step comprises the steps of:

determining a network communication rate indicating a bandwidth available for communicating the system media stream;

determining a media transmission rate indicating a bandwidth used to communicate the system media stream;

determining whether the media transmission rate is greater than the network communication rate; and

adjusting the media transmission rate upon on a determination that the media transmission rate is greater than the network communication rate.

5. The method according to claim 4, wherein said adjusting step comprises reducing a size of the corresponding audio and video packets in the system media stream to reduce the media transmission rate.

6. The method according to claim 4, wherein said adjusting step comprises smoothing video packets in the system media stream to reduce the media transmission rate to at least the network communication rate.

7. The method according to claim 6, wherein said smoothing step comprises the steps of:

determining a skipping rate necessary to render the media transmission rate less than the network communication rate; and

generating a revised system media stream by discarding video frames within the video packets at the determined skipping rate.

8. The method according to claim 7, further comprising the step of generating a network header comprising the skipping rate for the system media stream,

wherein said presenting step further comprises presenting the multimedia content based on the skipping rate provided in the network header.

9. The method according to claim 4, further comprising the step of generating a network header comprising the media transmission rate for the system media stream,

wherein said step of determining the media transmission rate comprises reading the network header.

10. The method according to claim 1, further comprising the step of intelligently managing the system media stream to timely present the multimedia content in said presenting step.

11. The method according to claim 10, wherein said managing step comprises the steps of:

determining a time interval between a first video packet and a second video packet in the system media stream to determine whether the first and second video packets are received at a predetermined rate; and

adding a lag time to the synchronization information of the second video packet upon a determination that the time interval is less than the predetermined rate,

wherein a sum of the lag time and the time interval equals the predetermined rate.

12. The method according to claim 11, wherein the predetermined rate comprises a range of about 27 msec to about 39 msec.

13. The method according to claim 11, wherein the predetermined rate comprises about 33 msec.

14. The method according to claim 11, further comprising the step of discarding the second video packet upon a determination that the time interval is greater than the predetermined rate.

15. The method according to claim 10, wherein said managing step comprises the steps of:

receiving a first video packet of the system media stream;

determining whether a second video packet is received within a specified time after receiving the first video packet, the specified time corresponding to a predetermined rate for receiving packets; and

emulating the second video packet upon a determination that the second video packet was not received within the specified time.

16. The method according to claim 15, wherein said emulating step comprises duplicating the first video packet.

17. The method according to claim 15, wherein said emulating step comprises estimating the second video packet based on the first video packet.

18. The method according to claim 15, wherein the specified time is about 39 msec.

19. A computer-readable medium having computer-executable instructions for performing the steps recited in claim 1.

20. A computer-implemented method for transmitting low bit rate multimedia content, said method comprising the steps of:

encoding corresponding audio and video packets that represent the multimedia content, the audio and video packets comprising synchronization information for the corresponding audio and video packets;

generating a system media stream comprising the corresponding audio and video packets;

determining a network communication rate indicating a bandwidth available for transmitting the system media stream;

determining a media transmission rate indicating a bandwidth used to transmit the system media stream;

determining whether the media transmission rate is greater than the network communication rate; and

adjusting the media transmission rate upon on a determination that the media transmission rate is greater than the network communication rate.

21. The method according to claim 20, further comprising the steps of:

decoding the corresponding audio and video packets of the system media stream; and

presenting the multimedia content represented by the decoded audio and video packets based on the synchronization information provided in the headers of the audio and video packets.

22. The method according to claim 20, wherein said adjusting step comprises reducing a size of one of the corresponding audio and video packets in the system media stream to reduce the media transmission rate.

23. The method according to claim 20, wherein said adjusting step comprises smoothing video packets in the system media stream to reduce the media transmission rate to at least the network communication rate.

24. The method according to claim 23, wherein said smoothing step comprises the steps of:

determining a skipping rate necessary to render the media transmission rate less than the network communication rate; and

generating a revised system media stream by discarding video frames within the video packets at the determined skipping rate.

25. The method according to claim 24, further comprising the steps of:

generating a network header comprising the skipping rate for the system media stream;

decoding the corresponding audio and video packets of the system media stream; and

presenting the multimedia content represented by the decoded audio and video packets based on the synchronization information provided in the headers of the audio and video packets and on the skipping rate provided in the network header.

26. The method according to claim 20, further comprising the step of generating a network header comprising the media transmission rate for the system media stream,

wherein said step of determining the media transmission rate comprises reading the network header.

27. A computer-readable medium having computer-executable instructions for performing the steps recited in claim 20.

29. The method according to claim 28, wherein the predetermined rate comprises a range of about 27 msec to about 39 msec.

30. The method according to claim 28, wherein the predetermined rate comprises about 33 msec.

31. The method according to claim 28, further comprising the step of discarding the second video packet upon a determination that the time interval is greater than the predetermined rate.

32. A computer-readable medium having computer-executable instructions for performing the steps recited in claim 28.

28. A computer-implemented method for receiving low bit rate multimedia content in a system media stream, the system media stream comprising encoded audio and video packets representing the multimedia content, and each audio and video packet comprising synchronization information for synchronizing corresponding audio and video packets, said method comprising the steps of:

determining a time interval between a first video packet and a second video packet in the system media stream to determine whether the first and second video packets are received at a predetermined rate;

adding a lag time to the synchronization information of the second video packet upon a determination that the time interval is less than the predetermined rate, wherein a sum of the lag time and the time interval equals about the predetermined rate;

decoding the first and second video packets and their corresponding audio packets; and

presenting the multimedia content represented by the decoded packets based on the synchronization information provided in the headers of the first and second video packets and their corresponding audio packets.

33. A computer-implemented method for receiving low bit rate multimedia content in a system media stream, the system media stream comprising encoded audio and video packets representing the multimedia content, and each audio and video packet comprising synchronization information for synchronizing corresponding audio and video packets, said method comprising the steps of:

receiving a first video packet of the system media stream;

determining whether a second video packet of the system media stream is received within a specified time after receiving the first video packet, the specified time corresponding to a predetermined rate for receiving packets;

emulating the second video packet upon a determination that the second video packet was not received within the specified time, the emulated video packet comprising synchronization information for synchronizing the emulated video packet to the audio packet corresponding to the second video packet;

decoding the first video packet, the emulated video packet, and corresponding audio packets; and

presenting the multimedia content represented by the decoded packets based on the synchronization information provided in the headers of the first video packet, the emulated video packet, and the corresponding audio packets.

34. The method according to claim 33, wherein said emulating step comprises duplicating the first video packet.

35. The method according to claim 33, wherein said emulating step comprises estimating the second video packet based on the first video packet.

36. The method according to claim 33, wherein the specified time is about 39 msec.

37. A computer-readable medium having computer-executable instructions for performing the steps recited in claim 33.

39. The system according to claim 38, wherein the predetermined rate comprises a range of about 27 msec to about 39 msec.

40. The system according to claim 38, wherein the predetermined rate comprises about 33 msec.

41. The system according to claim 38, wherein said intelligent stream management module is further operable to perform the step of discarding the second video packet upon a determination that the time interval is greater than the predetermined rate.

38. A system for receiving low bit rate multimedia content in a system media stream, the system media stream comprising encoded audio and video packets representing the multimedia content, and each audio and video packet comprising synchronization information for synchronizing corresponding audio and video packets, said system comprising:

a demultiplexor operable to receive the system media stream and to transmit the video and audio packets for presentation based on the synchronization information; and

an intelligent stream management module operable to intelligently manage the system media stream to timely transmit the video and audio packets to said demultiplexor by;

receiving a first video packet and a second video packet in the system media stream;

determining a time interval between the first video packet and the second video packet to determine whether the first and second video packets are received at a predetermined rate;

adding a lag time to the synchronization information of the second video packet upon a determination that the time interval is less than the predetermined rate, wherein a sum of the lag time and the time interval equals about the predetermined rate; and

transmitting the first and second video packets to said demultiplexor based on the synchronization information for the first and second video packets and their corresponding audio packets.

42. A system for receiving low bit rate multimedia content in a system media stream, the system media stream comprising encoded audio and video packets representing the multimedia content, and each audio and video packet comprising synchronization information for synchronizing corresponding audio and video packets, said system comprising:

a demultiplexor operable to receive the system media stream and to transmit the video and audio packets for presentation based on the synchronization information; and

an intelligent stream management module operable to intelligently manage the system media stream to timely transmit the video and audio packets to said demultiplexor by;

receiving a first video packet of the system media stream;

determining whether a second video packet of the system media stream is received within a specified time after receiving the first video packet, the specified time corresponding to a predetermined rate for receiving video packets;

emulating the second video packet upon a determination that the second video packet was not received within the specified time, the emulated video packet comprising synchronization information for synchronizing the emulated video packet to the audio packet corresponding to the second video packet; and

transmitting the first video packet, the emulated video packet, and corresponding audio packets to said demultiplexor based on the synchronization information for the first video packet, the emulated video packet, and the corresponding audio packets.

43. The system according to claim 42, wherein the emulating step comprises duplicating the first packet.

44. The system according to claim 42, wherein the emulating step comprises estimating the second packet based on the first packet.

45. The system according to claim 42, wherein the specified time is about 39 msec.

47. The system according to claim 46, wherein said compensation module is operable for reducing a size of the audio and video packets in the system media stream to reduce the media transmission rate.

48. The system according to claim 46, wherein said compensation module is operable for smoothing video packets in the system media stream to reduce the media transmission rate to at least the network communication rate.

49. The system according to claim 48, wherein said compensation module is operable for smoothing video packets by:

determining a skipping rate necessary to render the media transmission rate less than the network communication rate; and

generating a revised system media stream by discarding video frames within the video packets at the determined skipping rate.

50. The system according to claim 46, further comprising a network header generation module operable for generating a network header comprising the media transmission rate for the system media stream,

wherein said supervisor module is operable for determining the media transmission rate by reading the network header.

51. The system according to claim 46, further comprising a demultiplexor operable to receive the system media stream and to transmit the video and audio packets for presentation based on the synchronization information.

52. The system according to claim 51, further comprising an intelligent stream management module operable to intelligently manage the system media stream to timely transmit the video and audio packets to said demultiplexor.

46. A system for transmitting low bit rate multimedia content, comprising:

a video encoder operable to encode a video packet that represents video of the multimedia content, the video packet comprising synchronization information to synchronize the video packet with a corresponding audio packet;

an audio encoder operable to encode an audio packet that represents audio of the multimedia content, the audio packet comprising synchronization information to synchronize the audio packet with a corresponding video packet;

a multiplexor operable to generate a system media stream comprising the audio and video packets;

a supervisor module operable for determining a network communication rate indicating a bandwidth available for transmitting the system media stream, a media transmission rate indicating a bandwidth used to transmit the system media stream, and whether the media transmission rate is greater than the network communication rate; and

a compensation module operable for adjusting the media transmission rate upon on a determination that the media transmission rate is greater than the network communication rate.