Method and apparatus for broadcasting media objects with guaranteed quality of service

• US 7,047,307 B2
• Filed: 09/10/2004
• Issued: 05/16/2006
• Est. Priority Date: 08/01/2000
• Status: Expired due to Fees

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Li, Fulu
• Primary Examiner(s): Salad, Abdullahi
• Application Number:
  US10/939,023
• Publication Number:
  US 20050033856A1
• Time in Patent Office: 613 Days
• Field of Search: 709230-235, 709/217, 709/219, 725/87
• US Class Current: 709/231
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04N 21/2343 involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements video transcoding H04N19/40; media packet handling at the source H04L65/762
• CPC Class Codes: H04N 21/2385 Channel allocation H04N21/266 takes precedence; Bandwidth allocation H04N21/24 takes precedence ; allocation of channels according to the instantaneous demands of the users in time-division multiplex systems H04J3/1682; admission control, resource allocation in open networks H04L12/5692; arrangements for maintenance or administration in data switching networks involving bandwidth and capacity management H04L41/0896; negotiating bandwidth in wireless networks H04W28/16
• CPC Class Codes: H04N 21/26616 for merging a unicast channel into a multicast channel, e.g. in a VOD application, when a client served by unicast channel catches up a multicast channel to save bandwidth data multicast over packet-switching network H04L12/18
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/8456 by decomposing the content in the time domain, e.g. in time segments
• CPC Class Codes: H04N 7/17327 with deferred transmission or handling of upstream communications
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends

Abstract

A method and apparatus for broadcasting media objects for such bandwidth-intensive applications as Media on Demand (MoD) or Video on Demand (VoD) employ a novel StairCase Broadcast (SCB) scheme. A media server in accordance with one example of the invention includes a fragmenter that fragments media objects into multiple segments, with each segment provided to a corresponding streamer. Each streamer periodically and continuously streams data associated with its corresponding media segment on a connection between the server and a media client. A download controller in the media client selectively causes the proper streams to be received for downloading from the server in accordance with the fragmentation of the selected media object and the number of streams that the client can simultaneously receive for downloading. A selector is operable to cause data from each successive segment to be downloaded from the corresponding stream immediately regardless of the position in the period associated with the successive segment. By its design, the method and apparatus of the present invention allow for lossless broadcast of media contents with de-coupled per-media-object server and client bandwidth design considerations.

Claims

1. A method for providing a media object to a client from a server coupled to the client via a connection, the media object being fragmented into segments in accordance with a fragmentation sequence from a first segment to a last segment, each segment comprising a respective number of frames of media content in a respective succession from a first frame to a last frame, the media content associated with each of the segments being provided on a corresponding stream in accordance with the succession from the fist frame to the last frame, the method comprising the steps of:

downloading media content at the client from a first number of the streams on the connection, the first number of the streams including the corresponding stream to the first segment;

halting the downloading of media content from the corresponding stream to the first segment on the connection when the respective number of frames of the first segment have been received on the corresponding stream;

downloading media content at the client from a next stream corresponding to a next segment in the fragmentation sequence on the connection after the halting step;

starting the step of downloading from the next stream at a point in the respective succession between the first frame and the last frame, wherein the corresponding stream to the first segment has a first bandwidth, and the next stream corresponding to the next segment has a second bandwidth different than the first bandwidth; and

constraining the first bandwidth so as to provide a desired service latency including the step of constraining the first bandwidth b_m¹ associated with the first segment s_m¹ in accordance with a desired service latency w_m, such that

$b_m^1=\frac{\underset{i\in <br><br>S_m^1}{\sum <br><br>}<br><br>f_m^i}{w_m},$

wherein denotes f_mⁱ the number of bits in the i-th frame of the media object.

2. A method according to claim 1, wherein the media content associated with each of the segments is continuously and periodically provided on a corresponding stream in accordance with the succession from the first frame to the last frame.

3. A method according to claim 2, wherein each of the corresponding streams has an associated period.

4. A method according to claim 3, wherein the associated period is the time required to download the number of frames of the segment corresponding to the stream.

5. A method according to claim 1, further comprising the step of:

constraining the second bandwidth in accordance with a time needed to playback all of the segments corresponding to the first number of streams at the client.

6. A method according to claim 1, wherein the first number of streams corresponds to the maximum number of streams that the client can process.

7. A method according to claim 1, further comprising the step of:

adjusting the respective number of frames comprising each segment so as to minimize a maximum server bandwidth and a maximum client bandwidth.

8. A method according to claim 1, further comprising the step of:

encoding the media object.

9. A method according to claim 8, wherein the encoding step is performed in accordance with Variable Bit Rate (VBR) encoding.

10. A method for providing a media object to a client from a server coupled to the client via a connection, the media object being fragmented into segments in accordance with a fragmentation sequence from a first segment to a last segment, each segment comprising a respective number of frames of media content in a respective succession from a first frame to a last frame, the media content associated with each of the segments being provided on a corresponding stream in accordance with the succession from the first frame to the last frame, the method comprising steps of:

downloading media content at the client from a first number of the streams on the connection, the first number of the streams including the corresponding stream to the first segment;

halting the downloading of media content from the corresponding stream to the first segment on the connection when the respective number of frames of the first segment have been received on the corresponding stream;

downloading media content at the client from a next stream corresponding to a next segment in the fragmentation sequence on the connection after the halting step;

constraining a total server bandwidth associated with the media object, wherein the number of segments in the fragmentation sequence is K_m, and wherein each of the corresponding streams has an associated bandwidth bⁱ_m, constraining step being performed so that the total server bandwidth B_m satisfies the equation

$B_m=\underset{i=1}{\overset{K_m}{\sum <br><br>}}<br><br>b_m^i.$

11. A method for providing a media object to a client from a server coupled to the client via a connection, the media object being fragmented into segments in accordance with a fragmentation sequence from a first segment to a last segment, each segment comprising a respective number of frames of media content in a respective succession from a first frame to a last frame, the media content associated with each of the segments being provided on a corresponding stream in accordance with the succession from the first frame to the last frame, the method comprising the steps of:

downloading media content at the client from a first number of the streams on the connection, the first number of the streams including the corresponding stream to the first segment;

halting the downloading of media content from the corresponding stream to the first segment on the connection when the respective number of frames of the first segment have been received on the corresponding stream;

downloading media content at the client from a next stream corresponding to a next segment in the fragmentation sequence on the connection after the halting step;

starting the step of downloading from the next stream at a point in the respective succession between the first frame and the last frame;

constraining a maximum client bandwidth associated with the media object;

wherein the number of segments in the fragmentation sequence is K_m, and wherein each of the corresponding streams has an associated bandwidth bⁱ_m, and wherein the first number of streams is U_m, the constraining step being performed so that the total client bandwidth B_c,m(S_m) satisfies the equation

${B_{c,m}<br><br>\left(S_m\right)}^m=\underset{1\le <br><br>i\le <br><br>K_m-U_m+1}{\max }<br><br>\underset{j=i}{\overset{i+U_m-1}{\sum <br><br>}}<br><br>b_m^j.$

12. A method according to claim 11, further comprising the step of:

adjusting the respective number of frames comprising each segment so as to minimize the total server bandwidth and the total client bandwidth.

13. An apparatus for providing a media object to a client from a server coupled to the client via a connection, the media object being fragmented into segments in accordance with a fragmentation sequence from a first segment to a last segment, each segment comprising a respective number of frames of media content in a respective succession from a first frame to a last frame, the media content associated with each of the segments being provided on a corresponding stream in accordance with the succession from the first frame to the last frame, the apparatus comprising:

means for downloading media content at the client from a first number of the streams on the connection, the first number of the streams including the corresponding stream to the first segment;

means for halting the downloading of media content from the corresponding stream to the first segment on the connection when the respective number of frames of the first segment have been received on the corresponding stream;

means for downloading media content at the client from a next stream corresponding to a next segment in the fragmentation sequence on the connection after an operation of the halting means;

means for starting operation of the means for downloading from the next stream at a point in the respective succession between the first frame and the last frame, wherein the corresponding stream to the first segment has a first bandwidth, and the next stream corresponding to the next segment has a second bandwidth different than the first bandwidth;

means for constraining the first bandwidth so as to provide a desired service latency, including means for constraining the first bandwidth b¹_m associated with the first segment S¹_m in accordance with a desired service latency w_m such that

$b_m^1=\frac{\underset{i\in <br><br>S_m^1}{\overset{}{\sum <br><br>}}<br><br><br><br>f_m^i}{w_m}$

wherein f¹_m denotes the number of bits in the i-th frame of the media object.

14. An apparatus according to claim 13, wherein the media content associated with each of the segments is continuously and periodically provided on a corresponding stream in accordance with the succession from the first frame to the last frame.

15. An apparatus according to claim 14, wherein each of the corresponding streams has an associated period.

16. An apparatus according to claim 15, wherein the associated period is the time required to download the number of frames of the segment corresponding to the stream.

17. An apparatus according to claim 13, further comprising:

means for constraining the second bandwidth in accordance with a time needed to play back all of the segments corresponding to the first number of streams at the client.

18. An apparatus according to claim 13, wherein the first number of streams corresponds to the maximum number of streams that the client can process.

19. An apparatus according to claim 13, further comprising:

means for adjusting the respective number of frames comprising each segment so as to minimize a maximum server bandwidth and a maximum client bandwidth.

20. An apparatus according to claim 13, further comprising:

means for encoding the media object.

21. An apparatus according to claim 20, wherein the encoding means is operable in accordance with Variable Bit Rate (VBR) encoding.

22. An apparatus for providing a media object to a client from a server coupled to the client via a connection, the media object being fragmented into segments in accordance with a fragmentation sequence from a first segment to a last segment, each segment comprising a respective number of frames of media content in a respective succession from a first frame to a last frame, the media content associated with each of the segments being provided on a corresponding stream in accordance wit the succession from the first frame to the last frame, the apparatus comprising:

means for downloading media content at the client from a first number of the streams on the connection, the first number of the streams including the corresponding stream to the first segment;

means for halting the downloading of media content from the corresponding stream to the first segment on the connection when the respective number of frames of the first segment have been received on the corresponding stream;

means for downloading media content at the client from a next stream corresponding to a next segment in the fragmentation sequence on the connection after an operation of the halting means;

means for starting operation of the means for downloading from the next stream at a point in the respective succession between the first frame and the last frame; and

means for constraining a total server bandwidth associated with the media object, wherein the number of segments in the fragmentation sequence is K_m, and wherein each of the corresponding streams has an associated bandwidth bⁱ _m, the constraining means being operable so that the total server bandwidth B_m satisfies the equation

$B_m=\underset{i=1}{\overset{K_m}{\sum <br><br>}}<br><br><br><br>b_m^i.$

23. An apparatus for providing a media object to a client from a server coupled to the client via a connection, the media object being fragmented into segments in accordance with a fragmentation sequence from a first segment to a last segment, each segment comprising a respective number of frames of media content in a respective succession from a first frame to a last frame, the media content associated with each of the segments being provided on a corresponding stream in accordance with the succession from the first frame to the last frame, the apparatus comprising:

means for downloading media content at the client from a first number of the streams on the connection, the first number of the streams including the corresponding stream to the first segment;

means for halting the downloading of media content from the corresponding stream to the first segment on the connection when the respective number of frames of the first segment have been received on the corresponding stream;

means for downloading media content at the client from a next stream corresponding to a next segment in the fragmentation sequence on the connection after an operation of the halting means for starting operation of the means for downloading from the next stream at a point in the respective succession between the first frame and the last frame; and

means for constraining a total server bandwidth associated with the media object, wherein the number of segments in the fragmentation sequence is K_m, and wherein each of the corresponding streams has an associated bandwidth bⁱ_m, and wherein the first number of streams is U_m, the constraining means being operable so that the total client bandwidth B_c,m(Sm) satisfies the equation

${B_{c,m}<br><br>\left(S_m\right)}^m=\underset{1\le <br><br>i\le <br><br>K_m-U_m+1}{\max }<br><br>\underset{j=i}{\overset{i+U_m-1}{\sum <br><br>}}<br><br><br><br>b_m^j.$

24. An apparatus according to claim 23, further comprising:

means for adjusting the respective number of frames comprising each segment so as to minimize the total server bandwidth and the total client bandwidth.