Active stream format for holding multiple media streams

• US 6,041,345 A
• Filed: 03/07/1997
• Issued: 03/21/2000
• 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): Asta, Frank J.
• Assistant Examiner(s): VU, THONG H
• Application Number:
  US08/813,151
• Time in Patent Office: 1,110 Days
• Field of Search: 348/38, 348/441, 370/232, 370/17, 370/94.3, 370/94.1, 370/312, 370/474, 370/329, 375/46, 371/37.4, 371/40, 369/275.3, 386/111, 395/325, 709/217, 380/14, 711/202, 455/4.2, 455/34.1
• 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 operable for connecting to a transport medium, a method of encapsulating multiple streams of data into an aggregated data stream to be transmitted on the transport medium comprising:

determining a packet size for the transport medium;

storing, on a storage device, at least one packet containing information about the aggregated data stream to form a header section in a logical structure that defines the aggregated data stream;

storing, on the storage device, packets containing samples of data from the multiple data streams to form a data section in the logical structure;

designating a portion of at least one packet in the data section for holding error correcting data; and

storing, on the storage device, error correcting data in the designated portion of the at least one packet in the data section, wherein the error correcting data identifies a corresponding error correcting method for each of the encapsulated data streams, and further wherein the aggregated data stream is stored on the storage device prior to receiving a request for transmission of the aggregated data stream on the transport medium from a destination computer.

2. The method of claim 1, further comprising using the error correcting data stored in the designated portion of at the least one packet to correct an error when the aggregated data stream is received by the destination computer on the transport medium.

3. The method of claim 1 wherein the error correcting data is stored in multiple packets in the data section.

5. The method of claim 1 wherein packets containing samples of data from a first of the multiple streams hold a different type of error correcting data than packets containing samples of data from a second of the multiple streams.

6. The method of claim 1 wherein the information in the header section of the logical structure indicates what error correcting methodology is used with the at least one packet in the data section that holds error correcting data.

7. The method of claim 1, further comprising:

transferring the packets from the storage medium as arranged in the logical structure across the transport medium to the destination computer.

8. The method of claim 1 wherein at least two of the multiple streams of data are of different media.

4. The method of claim I wherein the error correcting data holds parity bits.

9. In a computer system operable for connecting to a transport medium, a method of building an aggregated data stream in a logical structure on a storage medium in the computer system comprising:

determining a packet size for the transport medium;

storing data from multiple streams of data into packets;

storing error correcting data in at least some of the packets;

encapsulating the packets into the logical structure for the aggregated data stream; and

storing information regarding a plurality of error correcting methods that are employed for the packets in the aggregated data stream into the logical structure,

wherein the aggregated data stream is built prior to receiving a request for transmission of the aggregated data stream on the transport medium from a destination computer.

10. The method of claim 9 wherein the logical structure for the aggregated stream includes a header section and the information regarding the error correcting methods that are employed is stored in the header section.

11. The method of claim 10 wherein multiple error correcting methods are employed.

12. The method of claim 11 wherein a separate object is stored in the header section for each error correcting method to encapsulate the information regarding the error correcting method.

13. In a computer operable for connecting to a transport medium, a computer-readable storage medium holding instructions for encapsulating multiple streams of data into an aggregated data stream to be transmitted on the transport medium:

determining a packet size for the transport medium;

storing, on a storage device, at least one packet containing information about the aggregated data stream to form a header section in a logical structure that defines the aggregated data stream;

storing, on the storage device, packets containing samples of data from the multiple data streams to form a data section in the logical structure;

designating a portion of at least one packet in the data section for holding error correcting data; and

storing, on the storage device, error correcting data in the designated portion of the at least one packet in the data section, wherein the error correcting data identifies a corresponding error correcting method for each of the encapsulated data streams, and further wherein the instructions are executed prior to receiving a request for transmission of the aggregated data stream on the transport medium from a destination computer.

14. The computer-readable storage medium of claim 13 further holding instructions that store the error correcting data in multiple packets in the data section of the logical structure.

15. The computer-readable storage medium of claim 13 wherein the medium holds instructions for encapsulating a first type of error correcting data for packets that contain samples from a first of the streams of data and encapsulating a second type of error correcting data for packets that contain samples from a second of the streams of data.

16. In a computer system, a computer-readable storage medium holding a logical structure that encapsulates multiple streams of data, the logical structure comprising:

packets of data from the multiple streams of data forming a data section of the logical structure and stored on mass storage for subsequent transmission over a transport medium when requested by a destination computer; and

error correcting data within at least some of the packets at designated locations, wherein the error correcting data identifies a plurality of error correcting methods.

17. The computer-readable storage medium of claim 16 wherein the logical structure further comprises a header section in which information regarding an error correcting method that uses the error correcting data is stored.

18. The computer-readable storage medium of claim 17 wherein the header section holds information regarding multiple error correcting methods.

19. The computer-readable storage medium of claim 16 wherein the multiple streams of data include at least two streams of different media.

20. In a computer system, a computer-readable storage medium holding instructions for:

receiving a logical structure that holds multiple streams of data, wherein the streams of data include samples that are stored in packets in the logical structure and wherein at least some of the packets include error correcting data that was stored in the packets prior to a request being transmitted by the computer system that caused the logical structure to be received, wherein the error correcting data identifies a plurality of error correcting methods; and

extracting the error correcting data from at least some of the packets as needed to correct errors according to the identified error correcting methods.

21. A data processing system having:

a source computer with a storage;

a logical structure stored in the storage for encapsulating multiple data streams into an aggregated data stream defined by the logical structure, data from the data streams being incorporated in packets prior to a request being received by the source computer to transmit the aggregated data stream to a destination computer; and

error correcting data encapsulated in the packets, wherein the error correcting data identifies a corresponding error correcting method for each of the encapsulated data streams.