Apparatus and method for segmentation and time synchronization of the transmission of multimedia data

• US 5,533,021 A
• Filed: 02/03/1995
• Issued: 07/02/1996
• Est. Priority Date: 02/03/1995
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Sendelbach, Lee A., Lynch, Jeffrey J., Branstad, Mark W., Byrn, Jonathan W., Delp, Gary S., Plotz, Kevin G., Slane, Albert A., Leichty, Philip L.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): BLUM, RUSSELL
• Application Number:
  US08/382,905
• Time in Patent Office: 515 Days
• Field of Search: 370/60, 370/60.1, 370/79, 370/85.6, 370/94.1, 370/94.2, 370/100.1, 370/108, 379/93, 379/94, 379/96, 348/13, 348/17, 348/461, 348/464, 348/467, 348/473, 348/500, 348/512, 348/518
• US Class Current: 370/396
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04L 2012/5616 Terminal equipment, e.g. codecs, synch.
• CPC Class Codes: H04L 2012/565 Sequence integrity
• CPC Class Codes: H04L 2012/5652 Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
• CPC Class Codes: H04L 2012/5664 Support of Video, e.g. MPEG
• CPC Class Codes: H04L 2012/5674 Synchronisation, timing recovery or alignment
• CPC Class Codes: H04L 2012/5679 Arbitration or scheduling
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 21/234318 by decomposing into objects, e.g. MPEG-4 objects
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/2381 Adapting the multiplex stream to a specific network, e.g. an Internet Protocol [IP] network transmission of MPEG streams over ATM H04L12/5601
• CPC Class Codes: H04N 21/242 Synchronization processes, e.g. processing of PCR [Program Clock References] arrangements for synchronising broadcast or distribution via plural systems in broadcast distribution systems H04H20/18
• CPC Class Codes: H04N 21/2543 Billing , e.g. for subscription services payment schemes, architectures or protocols G06Q20/00; e-commerce G06Q30/00; arrangements for billing for the use of broadcast information or broadcast-related information H04H60/21
• CPC Class Codes: H04N 21/262 Content or additional data distribution scheduling, e.g. sending additional data at off-peak times, updating software modules, calculating the carousel transmission frequency, delaying a video stream transmission, generating play-lists scheduling strategies for dispatcher in multiprogramming arrangements G06F9/4881; arrangements for scheduling broadcast services or broadcast-related services H04H60/06; flow control in packet networks H04L47/10; establishing a time schedule or organising the servicing of application requests H04L67/62
• CPC Class Codes: H04N 21/26208 the scheduling operation being performed under constraints
• CPC Class Codes: H04N 21/43072 of multiple content streams on the same device
• CPC Class Codes: H04N 21/4341 : Demultiplexing of audio and video streams
• CPC Class Codes: H04N 21/4363 : Adapting the video stream to a specific local network, e.g. a Bluetooth® network
• CPC Class Codes: H04N 21/4381 : Recovering the multiplex stream from a specific network, e.g. recovering MPEG packets from ATM cells transmission of MPEG streams over ATM H04L12/5601
• CPC Class Codes: H04N 21/47202 : for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/64307 : ATM
• CPC Class Codes: H04N 21/8456 : by decomposing the content in the time domain, e.g. in time segments
• CPC Class Codes: H04N 21/8547 : involving timestamps for synchronizing content
• CPC Class Codes: H04Q 11/0478 : Provisions for broadband connections

Abstract

Method and apparatus are provided for transmitting a stream of multimedia digital data over a distribution communications network. A multimedia stream server segments the multimedia digital data stream into data blocks on a first boundary and a second boundary. The first boundary is a set number of transport system data packets and the second boundary is a transport system data packet including a timestamp. A scheduler schedules the segmented data blocks for transmission. The multimedia stream server decodes the segmented data blocks to locate the timestamps and matches the transmission of the located timestamp data block with a time value indicated by the timestamp. The set number of transport system data packets can be determined at connection setup and is not a predetermined value for all sessions. At the receiver, batch processing of received multimedia data can be provided.

Claims

1. Apparatus for transmitting a stream of multimedia digital data over a distribution communications network comprising:

means for receiving and for segmenting the multimedia digital data stream into data blocks on a first boundary and a second boundary;

said first boundary being a set number of transport system data packets and said second boundary being a transport system data packet including a timestamp;

means for scheduling said segmented data blocks for transmission;

means for decoding said segmented data blocks to locate said timestamp; and

means for matching the transmission of said located timestamp data block with a time value indicated by said timestamp.

2. Apparatus as recited in claim 1 further includes receiver means for receiving said segmented data blocks, said receiver means including timer means for identifying a predefined time interval, queue means for enqueuing a predetermined number of said segmented data blocks and interrupt means responsive to said timer means and said queue means for raising an interrupt.

3. Apparatus as recited in claim 1 wherein said means for receiving and for segmenting the multimedia digital data stream into data blocks on said first boundary and said second boundary;

said means for scheduling said segmented data blocks for transmission;

said means for decoding said segmented data blocks to locate said timestamp; and

said means for matching the transmission of said located timestamp data block with a time value indicated by said timestamp comprise a multimedia stream server.

4. Apparatus as recited in claim 3 wherein said means for receiving and segmenting include notification means for requesting data from said data supply processor.

5. Apparatus as recited in claim 3 wherein said means for scheduling include notification means for requesting data from said data supply processor.

6. Apparatus as recited in claim 3 wherein said means for receiving and segmenting and said means for decoding said segmented data blocks to locate said timestamp includes means for delaying transmission of said data block containing said located timestamp until said time value is reached.

7. Apparatus as recited in claim 6 wherein each of said data blocks contains multiple enqueued fixed size data cells and wherein said transmission delay is based on a first cell of said transport system data packet containing said timestamp.

8. Apparatus as recited in claim 6 wherein each of said data blocks contain multiple enqueued fixed size data cells and wherein said transmission delay is based on a last cell of said transport system data packet containing said timestamp.

9. Apparatus as recited in claim 3 wherein said means for receiving and segmenting and said means for decoding said segmented data blocks to locate said timestamp includes means for requesting rescheduled transmission of said data block containing said located timestamp until said time value is reached.

10. Apparatus as recited in claim 9 wherein each of said data blocks contain multiple enqueued fixed size data cells, said means for scheduling include includes a first time wheel and a second higher priority time wheel and wherein rescheduling of said data block containing said located timestamp uses said second higher priority time wheel to reschedule a data cell containing said timestamp.

11. A method for transmitting a stream of multimedia digital data over a distribution communications network comprising the steps of:

receiving the multimedia digital data stream;

enqueuing the received multimedia digital data stream in data blocks;

decoding said enqueued data blocks to identify a program clock reference (PCR);

transmitting enqueued data blocks at a selected rate; and

responsive to identifying said PCR, delaying the transmission of said data block containing said identified PCR to match a time value indicated by said PCR.

12. A method for transmitting a stream of multimedia digital data as recited in claim 11 wherein said step transmitting enqueued data blocks at said selected rate includes the step of transmitting enqueued data blocks at a higher data rate than an encoded rate of the multimedia digital data stream.

13. A method for transmitting a stream of multimedia digital data as recited in claim 12 wherein said step of delaying the transmission of said data block containing said identified PCR to match said time value indicated by said PCR includes the steps of utilizing a cell segmenter function for comparing said indicated time value of said PCR with a clock value and delaying transmission of said PCR containing data block responsive to said compared values.

14. A method for transmitting a stream of multimedia digital data as recited in claim 11 wherein said step of delaying the transmission of said PCR containing data block to match said time value indicated by said PCR includes the steps of utilizing a cell segmenter function for requesting a scheduler function to defer scheduling of said PCR containing data block.

15. A method for transmitting a stream of multimedia digital data as recited in claim 14 wherein said scheduler function provides rescheduling to a higher priority time wheel for said PCR containing data block.

16. Apparatus for transmitting a stream of multimedia digital data over a distribution communications network comprising:

means for receiving and for segmenting the multimedia digital data stream into enqueued data blocks;

means for scheduling said enqueued data blocks for transmission;

means for decoding said enqueued data blocks to locate a timestamp;

means for transmitting enqueued data blocks at a selected rate; and

means responsive to each said located timestamp for matching the transmission of said located timestamp containing data block with a time value indicated by said timestamp.

17. Apparatus for transmitting a stream of multimedia digital data as recited in claim 16 wherein said means responsive to said located timestamp for matching the transmission of said located timestamp containing data block with said time value indicated by said timestamp include means for rescheduling said located timestamp containing data block for transmission at said indicated time value.

18. Apparatus for transmitting a stream of multimedia digital data as recited in claim 16 wherein said means responsive to said located timestamp for matching the transmission of said located timestamp containing data block with said time value indicated by said timestamp include means for delaying transmission of said located timestamp containing data block until said indicated time value.

19. Apparatus for processing multimedia digital data in a receiver comprising:

means for receiving fixed size Asynchronous Transfer Mode (ATM) cells;

means for reassemblying said received fixed size Asynchronous Transfer Mode (ATM) cells into multimedia data stream frames;

means for decoding said reassembled multimedia data stream frames;

said decoding means include data queue means for receiving and enqueuing at least a predefined number of mutlimedia digital data stream frames;

timer means responsive to a first frame arrival at said data queue means for identifying a predefined time interval; and

interrupt means responsive to both said data queue means and said timer means for raising an interrupt for processing said enqueued frames;

said interrupt being raised after said predefined number of frames are enqueued or after said predefined time interval has elapsed; and

said timer means being reset responsive to said interrupt being raised.

20. Apparatus for processing multimedia digital data in a receiver as recited in claim 19 further includes a processor responsive to said interrupt means for processing said enqueued mutlimedia digital data stream frames.

21. A system for communicating a stream of multimedia digital data comprising:

a distribution communications network;

multimedia server means for receiving and segmenting the multimedia digital data stream into data blocks and for transmitting said segmented data blocks over said distribution communications network;

said multimedia server means including means for decoding the multimedia digital data stream to identify a program clock reference (PCR) and means for delaying transmission of PCR containing data block responsive to said identified PCR; and

receiver means coupled to said distribution communications network for receiving the multimedia digital data stream.

22. A system as recited in claim 21 wherein said receiver means includes queue means for enqueuing a predefined number of received multimedia digital data stream frames;

timer means for identifying a predetermined time interval responsive to enqueuing a first one of said received multimedia digital data stream frames; and

interrupt means for raising an interrupt responsive to said queue means and said timer means.

23. A communications system comprising:

segmenter means for receiving and segmenting a multimedia digital data stream into data blocks;

said segmenter means including means for decoding the multimedia digital data stream to identify a program clock reference (PCR);

means for transmitting said segmented data blocks and means for delaying transmission of each PCR containing data block responsive to each identified PCR; and

receiver means for receiving and decoding the transmitted multimedia digital data blocks.

24. A communications system as recited in claim 23 wherein said receiver means includes means for batch processing a plurality of said received transmitted multimedia digital data blocks.