Apparatus and method for data caching to reduce channel change delay

1. A method for reducing channel change times, comprising:

receiving a channel change command;

immediately initiating caching of an incoming data stream associated with a newly selected channel in response to the channel change command, the cached data stream including packets including decoder synchronization data, and having an associated packet identifier;

finding program specific information included within the incoming data stream, and determining the packet identifier associated with the packets having decoder synchronization data from therein;

finding a first instance of decoder synchronization data, using the determined packet identifier, within the cached data stream including decoder synchronization data received before the program specific information found in the incoming data stream; and

decoding the incoming data stream associated with the newly selected channel in response to the first instance of decoder synchronization data.

2. The method of claim 1 , wherein the program specific information comprises program association table data and program map table data.

3. The method of claim 1 , wherein the step of finding the program specific information includes filtering data from the cached data stream.

4. The method of claim 3 , wherein the data filtered from the cached data stream comprises program map table data.

5. The method of claim 1 , wherein the decoder synchronization data corresponds to sequence headers according to the MPEG standards.

6. The method of claim 1 , wherein the step of finding the program specific information comprises:

finding program association table data within the incoming data stream;

finding program map table data using the program association table data; and

finding at least one of video program identification data and audio program identification data using the program map table data.

7. An apparatus, comprising:

memory means for immediately initiating caching an incoming data stream associated with a newly selected channel responsive to a channel change command, the cached data stream including packets including decoder synchronization data, and having an associated packet identifier;

processing means for finding program specific information included within the incoming data stream, determining the packet identifier associated with the packets of decoder synchronization data, and finding a first instance of decoder synchronization data, using the determined packet identifier, in the cached data stream including decoder synchronization data received before the program specific information; and

decoding means for decoding the cached data stream responsive to the first instance of decoder synchronization data.

8. The apparatus of claim 7 , wherein the program specific information comprises program association table data and program map table data.

9. The apparatus of claim 7 , further comprising transport means for filtering data, and wherein the processing means finds the program specific information by filtering data from the cached data stream via the transport means.

10. The apparatus of claim 9 , wherein the data filtered from the cached data stream by the transport means comprises program map table data.

11. The apparatus of claim 7 , wherein the decoder synchronization data corresponds to sequence headers according to the MPEG standards.

12. The apparatus of claim 7 , wherein the processing means finds the program specific information by finding program association table data within the incoming data stream, finding program map table data using the program association table data, and finding at least one of video program identification data and audio program identification data using the program map table data.

13. The apparatus of claim 7 , wherein the apparatus is a set-top box.

14. A digital communication apparatus having reduced channel change times, comprising:

means for receiving a data stream;

means for receiving a channel change command;

a cache memory operative to initiate storing of a portion of the data stream including packets including decoder synchronization data, and having an associated packet identifier in response to the channel change command;

a decoder operative to process the decoder synchronization data and to decode the data stream;

a processor, coupled to the receiving means, the cache memory, and the decoder, for immediately causing, in response to receipt of the channel change command, the portion of the data stream that follows the receipt including program specific information to be stored in the cache memory, for identifying the program specific information in response to the channel change command, and determining the associated packet identifier for packets having decoder synchronization data from therein, for identifying a first instance of decoder synchronization data, using the determined associated packet identifier, in the cache memory including decoder synchronization data received before the program specific information, and for causing the portion of the data stream stored in the cache memory to the processed by the decoder in response to the first instance of decoder synchronization.

15. The digital communication apparatus of claim 14 , wherein the program specific information comprises program association table data and program map table data.

16. The digital communication apparatus of claim 14 , further comprising a transport operative to filter data, and wherein the processor is operative to find the program specific information by filtering data from the cached data stream via the transport.

17. The digital communication apparatus of claim 16 , wherein the data filtered from the cached data stream by the transport comprises program map table data.

18. The digital communication apparatus of claim 14 , wherein the decoder synchronization data corresponds to sequence headers according to the MPEG standards.

19. The digital communication apparatus of claim 14 , wherein the processor is operative to find the program specific information by finding program association table data within the incoming data stream, finding program map table data using the program association table data, and finding at least one of video program identification data and audio program identification data using the program map table data.

20. The digital communication apparatus of claim 14 , wherein the apparatus is a digital subscriber line set-top box.