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

• US 6,801,947 B1
• Filed: 10/20/2000
• Issued: 10/05/2004
• 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): Etienne, Ario
• Assistant Examiner(s): SALAD, ABDULLAHI ELMI
• Application Number:
  US09/693,191
• Time in Patent Office: 1,446 Days
• Field of Search: 709/231, 709/230, 709/217, 709/232, 709/235, 709/238, 725/87, 725/101, 345/723
• 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. An apparatus for providing a media object over a connection comprising:

a media server having;

a fragmenter that fragments the media object into a plurality K_m of segments, the segments having a sequence from a first segment to a last segments, the media object having a plurality N_m of frames of media data, the fragment including initialization logic to initialize the fragmentation to K_m=N_m segments, each segment containing one frame;

means for determining a corresponding bandwidth required to download each segment and means for combining two successive segments in the sequence into a new segment so as to minimize a total variance between the corresponding bandwidth for each of the K_m segments, the media object;

a plurality of streamers, each streamer being coupled to the fragmenter for receiving a respective one of the plurality of segments, each streamer being operable to periodically and continuously provide a stream of media data associated with its corresponding segment on the connection; and

a media client coupled to the streamers to receive the streams of media data, the media client being operable to selectively cause media content from certain of the streams to be downloaded to the media client from the connection in accordance with the fragmentation of the media object and a number of streams that the media client can simultaneously receive for downloading, the media client being operable to cause media content from another stream corresponding to a successive segment in the sequence to be downloaded to the media client from the connection mediately upon the completion of downloading all the data corresponding to a previous segment.

2. An apparatus according to claim 1, wherein each segment comprises a respective number of frames of media content in a respective succession from a first frame to a last frame, the media client being operable to cause media content from the another stream to be downloaded to the media client from the connection at a time corresponding to an interim frame in the succession between the first frame and the last frame.

3. A method of fragmenting a media object into a fragmentation comprising a plurality Km of segments, the segments having a sequence from a first segment to a last segment, the media object having a plurality N_m of frames of media data, the method comprising the steps of:

initializing the fragmentation to K_m=N_m segments, each segment containing one frame;

determining, for each of the K_m segments, a corresponding bandwidth required to download the segment;

combining two successive segments in the sequence into a new segment; and

controlling the combining step so as to minimize a total variance between the corresponding bandwidth for each of the K_m segments.

4. A method according to claim 3, further comprising the step of:

repeating the determining and combining steps until the total variance cannot be reduced.

5. An apparatus for fragmenting a media object comprising a plurality K_m of segments, the segments having a sequence from a first segment to a last segment, the media object having a plurality N_m of frames of media data, the apparatus including:

initialization logic to initialize the fragmentation to K_m=N_m segments, each segment containing one frame;

means for determining a corresponding bandwidth required to download each segment; and

means for combining two successive segments in the sequence into a new segment so as to minimize a total variance between the corresponding bandwidth for each of the K_m segments.