EXPEDITED DIGITIAL SIGNAL DECODING

• US 20070130393A1
• Filed: 11/11/2005
• Published: 06/07/2007
• Est. Priority Date: 11/11/2005
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: Scientific-Atlanta Incorporated (Cisco Systems, Inc.)
• Inventors: Versteeg, William
• Granted Patent: US 7,873,760 B2
• Time in Patent Office: Days
• US Class Current: 710/57
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/22 Traffic shaping
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04N 21/2221 being a cable television head-end CATV in broadcast systems H04H20/78
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/4384 involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/6405 Multicasting data broadcast and multicast in packet switching networks H04L12/18
• CPC Class Codes: H04N 21/6408 Unicasting

Abstract

Expedited digital signal decoding. A multicast or unicast data stream is sent from a headend to a set-top box at a natural rate. A decoder buffer in the set-top box begins to fill. Once the buffer is partially full, a decoder begins to decode the data at a rate lower than the natural rate. Images are displayed to the user before the buffer is full, allowing for a faster channel change.

Claims

1. A method for buffering digital signals, the method comprising the steps of:

reading data into a buffer at a first data rate;

obtaining a first occupancy level in said buffer;

outputting data from said buffer at a second data rate, wherein said second data rate is less than said first data rate;

obtaining a second occupancy level in said buffer; and

outputting data from said buffer at a third data rate wherein said third data rate is greater than said second data rate.

2. The method of claim 1, wherein said third data rate is equal to said first data rate.

3. The method of claim 1, wherein said first data rate is a natural rate.

4. The method of claim 1, wherein said step of obtaining said second occupancy level comprises the step of allowing said buffer to fill.

5. The method of claim 1, wherein said step of obtaining said second occupancy level comprises the step of obtaining a full buffer.

6. The method of claim 1, further comprising the step of a channel alteration occurring prior to said buffer being full.

7. The method of claim 6, further comprising the step of a channel alteration as a result of outputting data from said buffer at said second data rate.

8. The method of claim 1, further comprising the step of a channel alteration occurring prior to obtaining said second occupancy level.

9. The method of claim 1, further comprising the step of a home communications terminal tuning to a multicast data stream and said buffer reading from said multicast data stream.

10. The method of claim 1, further comprising the step of reading a key frame into said buffer prior to outputting data from said buffer at said second data rate.

11. The method of claim 1, further comprising the step of a home communications terminal tuning to a unicast data stream and said buffer reading from said unicast data stream.

12. The method of claim 11, further comprising the steps of closing said unicast data stream upon reaching a second occupancy level of said buffer and tuning to a multicast data stream to be read into said buffer.

13. A method for buffering digital signals, the method comprising the steps of:

tuning to a unicast data stream;

reading said unicast data stream into a buffer at a first data rate;

obtaining a first occupancy level in said buffer;

outputting data from said buffer at a second data rate, wherein said second data rate is less than said first data rate;

obtaining a second occupancy level in said buffer, wherein said second occupancy level is greater than said first occupancy level;

closing said unicast data stream;

tuning to a multicast data stream;

reading said multicast data stream into said buffer;

obtaining a third occupancy level in said buffer;

wherein said third occupancy level is greater than said second occupancy level; and

outputting data from said buffer at a third data rate wherein said third data rate is greater than said second data rate.

14. The method of claim 13, wherein said third occupancy level is substantially full.

15. The method of claim 13, wherein said third data rate is equal to said first data rate.

16. The method of claim 13, wherein said first data rate is a natural rate.

17. The method of claim 13, further comprising the step of a channel alteration occurring prior to said buffer being full.

18. The method of claim 17, further comprising the step of a channel alteration as a result of outputting data from said buffer at said second data rate.

19. The method of claim 13, further comprising the step of a channel alteration occurring prior to obtaining said third occupancy level.

20. The method of claim 13, further comprising the step of reading a key frame into said buffer prior to outputting data from said buffer at said second data rate.

21. A decoder buffer for receiving digital signals at a first data rate to obtain a first occupancy level, outputting said data at a second data rate which is less than said first data rate, and obtaining a second occupancy level wherein said second occupancy level is greater than said first occupancy level in order to output said data at a third data rate that is greater than said second data rate.

22. The decoder buffer of claim 21, wherein said third data rate is equal to said first data rate.

23. The decoder buffer of claim 21, wherein said first data rate is a natural rate.

24. The decoder buffer of claim 21, wherein said second occupancy level is a full buffer.

25. The decoder buffer of claim 21, wherein channel alterations may occur prior to said buffer being full.

26. The decoder buffer of claim 21, wherein said data stream is a multicast data stream.

27. The decoder buffer of claim 21, wherein said data stream is a unicast data stream.