Active stream format for holding multiple media streams

• US 6,763,374 B1
• Filed: 02/22/2000
• Issued: 07/13/2004
• Est. Priority Date: 03/08/1996
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Knowlton, Chadd B., VanAntwerp, Mark D., Levi, Steven P., Dowell, Craig M.
• Primary Examiner(s): Powell, Mark
• Assistant Examiner(s): VU, THONG H
• Application Number:
  US09/510,023
• Time in Patent Office: 1,603 Days
• Field of Search: 709/203, 709/231, 709/247, 709/215, 709/217, 348/605, 375/152, 370/477, 370/40.395, 370/60.1, 370/60, 370/352, 370/474, 370/253, 707/7, 386/98, 714/769
• US Class Current: 709/217
• 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 7/52 Systems for transmission of a pulse code modulated video signal with one or more other pulse code modulated signals, e.g. an audio signal or a synchronizing signal assembling of a multiplex stream by combining a video stream with other content or additional data, remultiplexing of multiplex streams, insertion of stuffing bits into the multiplex stream, assembling of a packetised elementary stream at server side H04N21/236; disassembling of a multiplex stream, remultiplexing of multiplex streams, extraction or processing of Service Information, disassembling of packetised elementary stream at client side H04N21/434

Abstract

An active stream format is defined and adopted for a logical structure that encapsulates multiple data streams. The data streams may be of different media. The data of the data streams is partitioned into packets that are suitable for transmission over a transport medium. The packets may include error correcting information. The packets may also include clock licenses for dictating the advancement of a clock when the data streams are rendered. The format of ASF facilitates flexibility and choice of packet size and in specifying maximum bit rate at which data may be rendered. Error concealment strategies may be employed in the packetization of data to distribute portions of samples to multiple packets. Property information may be replicated and stored in separate packets to enhance its error tolerance. The format facilitates dynamic definition of media types and the packetization of data in such dynamically defined data types within the format.

Claims

1. In a computer system that is coupled to a destination, a method comprising the steps of:

storing samples of data from multiple data streams in packets;

storing replicas of information in at least some of the packets;

storing error correcting data in the at least some of the packets, wherein the error correcting data identifies an error correcting method for the at least some of the packets;

setting a flag in the packets that hold the replicas to indicate that the packets hold replicas;

encapsulating the packets into a larger logical structure, wherein at least some of the packets hold the replicas; and

transmitting the packets of the logical structure on a packet-by-packet basis over a packet switched network to the destination.

2. The method of claim 1 wherein the replicas of information hold property information regarding the samples of data.

3. The method of claim 1 wherein portions of a sample are stored in selected packets and a replica of property information regarding the sample is stored in each packet in which a portion of the sample is stored.

4. The method of claim 1, further comprising the step of examining one of the replicas of information at the destination when one of the packets is lost during the transmitting.

5. The method of claim 1, further comprising using the error correcting data in the at least some of the packets to correct an error when the transmitted logical structure is received at the destination.

6. The method of claim 1, wherein:

the logical structure includes;

a header section; and

a data section;

the error correcting data is stored in multiple packets in the data section.

7. The method of claim 6, wherein the information in the header section of the logical structure indicates what error correcting methodology is used with the error correcting data stored in the multiple packets in the data section.

8. The method of claim 6, wherein the header section holds information regarding multiple error correcting methods.

9. The method of claim 6, wherein the error correcting data identifies a plurality of error correcting methods.

10. The method of claim 1, wherein the error correcting data holds parity bits.

11. In a computer system, a computer-readable storage medium holding a logical structure that includes:

samples of data from multiple data streams in packets for transmission on a packet-by-packet basis over a packet switched network;

replicas of information in at least some of the packets;

error correcting data in the at least some of the packets, wherein the error correcting data identifies an error correcting method for the at least some of the packets; and

a flag in the packets that hold the replicas to indicate that the packets hold replicas.

12. The computer-readable storage medium of claim 11 wherein portions of a sample are stored in selected packets and a replica of property information regarding the sample is stored in each packet in which a portion of the sample is stored.

13. The computer-readable storage medium holding the logical structure recited in claim 11, wherein:

the logical structure includes a header section and a data section, and

the error correcting data is stored in multiple packets in the data section.

14. The computer-readable storage medium holding the logical structure recited in claim 13, wherein the information in the header section of the logical structure indicates what error correcting methodology is used with the error correcting data stored in the multiple packets in the data section.

15. The computer-readable storage medium holding the logical structure recited in claim 14, wherein the header section holds information regarding multiple error correcting methods.

16. The computer-readable storage medium holding the logical structure recited in claim 11, wherein the error correcting data identifies a plurality of error correcting methods.

17. The computer-readable storage medium holding the logical structure recited in claim 11, wherein the error correcting data holds parity bits.

18. The method of claim 17, wherein the multiple streams of data in the logical structure are Active Stream Format (ASF) data streams.

19. A method comprising packetizing samples of data from multiple data streams for transmission of the packets, with an identifier that identifies one of a plurality of error correcting methods, on a packet-by-packet basis over a packet switched network such that at least some of the packets include:

error correcting data;

a replica of the data from multiple data streams; and

a flag to indicate each said packet that holds the replica of the data from multiple data streams.

20. The method of claim 19, further comprising transmitting the packets on the packet-by-packet basis over the packet switched network.

21. The method of claim 20, further comprising:

receiving the packets at a destination in communication with the packet switched network; and

extracting the error correcting data from at least some of the packets as needed to correct errors, wherein;

the received packets are included in a logical structure that holds multiple streams of data;

the multiple streams of data include samples that are stored in the packets; and

at least some of the received packets include the error correcting data.

22. The method of claim 21, further comprising:

receiving at the destination a transmission of the identifier that identifies the one error correcting method; and

performing the one error correcting method at the destination upon data in the received packets.

23. The method of claim 22, wherein the one error correcting method can be employed in the ASF data streams.

24. The method of claim 21, wherein the logical structure holds:

a field for a maximum packet size of the received packets; and

a field for a minimum packet size of the received packets.

25. The method of claim 21 wherein at least two of the multiple streams of data hold data of different media.

26. The method of claim 21, wherein the packetizing samples of data from multiple data streams into packets further comprises:

taking a plurality of samples from data streams; and

incorporating each said sample into one or more said packets in accordance with the Active Stream Format (ASF).

27. The method of claim 21, further comprising rendering the multiple streams of data at the destination with a renderer, wherein the logical structure includes an identification of the renderer.