Method and apparatus for storing and accessing multiple constant bit rate data

• US 6,282,207 B1
• Filed: 12/10/1999
• Issued: 08/28/2001
• Est. Priority Date: 03/30/1999
• Status: Expired due to Term

• Current Assignee: Cox Communications Incorporated (Cox Enterprises Incorporated)
• Original Assignee: DIVA Systems Corporation
• Inventors: Lerman, Jesse S., Chin, Danny
• Primary Examiner(s): TON, DANG T
• Application Number:
  US09/458,337
• Time in Patent Office: 627 Days
• Field of Search: 370/470, 370/465, 370/503, 370/389, 370/261, 370/264, 370/229, 370/428, 370/442, 370/347, 370/537, 370/535, 370/528, 370/524, 370/523, 370/508, 370/506, 370/502, 370/476, 710/260, 709/204, 709/247, 709/202, 709/227, 348/348.1, 348/390.1, 348/441
• US Class Current: 370/470
• CPC Class Codes: H04N 21/2312 Data placement on disk arrays data placement in general G06F3/0604
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/23611 Insertion of stuffing data into a multiplex stream, e.g. to obtain a constant bitrate synchronisation arrangements in time-division multiplex systems using bit stuffing for systems with different or fluctuating information rates H04J3/073

Abstract

A method of defining extent for storing a plurality data streams having different bit rates. The method calculates the size of the extent for a given data stream then periodically inserts at least one null packet into the extents to enable any bit rate to be able to be stored using a fixed extent size for the stream.

Claims

1. A method for storing data in a memory comprising the steps of:

computing an extent size from a bit rate of a data stream;

rounding the computed extent size up to the next whole packet of data;

identifying extents that require a null packet to be added to the extent;

inserting the null packet into the identified extents; and

storing each extent in said memory.

2. The method of claim 1 wherein said memory is a disk drive array comprising a plurality of disk drives.

3. The method of claim 2 wherein said storing step further comprises the step of:

striping the extents across said disk drive array.

4. The method of claim 1 wherein the memory stores a plurality of packetized data streams where each data stream has a different bit rate.

5. The method of claim 1 wherein the packetized data stream comprising packets of encoded video information.

6. The method of claim 1 wherein said computing step comprises the step of:

computing the extent size by multiplying a bit rate times a service interval.

7. A method for storing and accessing data in a memory comprising the steps of:

determining a bit rate for a packetized data stream;

computing, in response to the bit rate, an extent size;

selecting groups of packets within said packetized data stream and a null packet, when needed, to define each extent;

storing each extent in said memory;

retrieving, upon request for a packetized data stream, an extent from said requested stream;

storing a retrieved extent in a buffer memory;

retrieving packets of data, as needed, from said buffer to create a transport stream.

8. The method of claim 7 further comprising the step of timing said retrieval of each packet to ensure that a user receives a steady flow of packets from said packetized data stream.

9. The method of claim 7 further comprising the step of analyzing each extent to identify null packets.

10. The method of claim 9 further comprising the step of skipping retrieving said identified null packets as said packets of data are retrieved from said buffer.

11. The method of claim 7 wherein said memory is a disk drive array comprising a plurality of disk drives.

12. The method of claim 11 wherein said storing step further comprises the step of:

striping the extents across said disk drive array.

13. The method of claim 7 wherein the memory stores a plurality of packetized data streams where each data stream has a different bit rate.

14. The method of claim 7 wherein the packetized data stream comprising packets of encoded video information.

15. The method of claim 7 wherein each data stream comprises an encoded bitstream video.

16. The method of claim 7 wherein said portion retrieval step removes any null packets from said portion of the extent.

17. Apparatus for storing data in a memory comprising:

means for determining a bit rate for a packetized data stream;

means for computing, in response to the bit rate, an extent size;

means for selecting groups of packets within said packetized data stream and at least one null packet, when needed, to define each extent; and

a memory for storing each extent.

18. The apparatus of claim 17 wherein said memory is a disk drive array comprising a plurality of disk drives.

19. The apparatus of claim 18 wherein the extents are striped across said disk drive array.

20. The apparatus of claim 17 wherein the memory stores a plurality of packetized data streams where each data stream has a different bit rate.

21. The apparatus of claim 17 wherein the packetized data stream comprising packets of encoded video information.