REDUCING CHANNEL-CHANGE TIME

• US 20080109692A1
• Filed: 10/18/2006
• Published: 05/08/2008
• Est. Priority Date: 10/18/2006
• Status: Active Grant

• Current Assignee: Synamedia Limited
• Original Assignee: Scientific-Atlanta LLC (Cisco Systems, Inc.)
• Inventors: VerSteeg, William C.
• Granted Patent: US 7,870,465 B2
• Time in Patent Office: Days
• US Class Current: 714/746
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• 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 21/44016 involving splicing one content stream with another content stream, e.g. for substituting a video clip
• CPC Class Codes: H04N 21/64315 DVB-H

Abstract

Systems and methods are disclosed herein for utilizing forward error correction (FEC) during a channel-change event. In one embodiment, among others, a method for executing a change from one communication channel to another includes receiving a channel-change indication and obtaining data and FEC that corresponds to the data. The data and FEC are related to a new channel, and the data includes a portion of data within a data packet. By utilizing the FEC, the method further includes recreating portions of data of the data packet that were missed due to the channel-change indication occurring in the middle of the transmission of the data packet. As an example, the data packet can be associated with video data arranged in a group of pictures (GOP) structure.

Claims

1. An apparatus for processing image data, the apparatus comprising:

a buffer configured to receive image signals from one or more sources;

a processor configured to encode the image signals to create a group of pictures (GOP) structure, the GOP structure including a header, a data portion, and a trailer, wherein the processor is further configured to encode the image signals to create forward error correction (FEC) capable of correcting errors in the GOP structure; and

a driver configured to transmit the GOP structure and FEC, wherein the FEC lags the GOP structure by an amount that allows a device receiving the GOP structure and FEC to utilize both the GOP structure and FEC during a channel-change event in order to decrease a channel-change time.

2. The apparatus of claim 1, wherein the apparatus is embodied within a head-end facility.

3. The apparatus of claim 1, wherein the processor is configured to encode the header to include information pertaining to the relationship between the GOP structure and the FEC.

4. The apparatus of claim 1, wherein the GOP structure includes between 12 and 30 frames.

5. The apparatus of claim 1, wherein the driver is configured to transmit the FEC with a lag time that lags the GOP structure by an amount depending on the protection period of the GOP structure.

6. The apparatus of claim 5, wherein the lag time is equal to about one-half of the protection period of the GOP structure.

7. The apparatus of claim 5, wherein the lag time is further dependent on a time to process the FEC.

8. A set-top box comprising:

an input device for receiving a group of pictures (GOP) structure and forward error correction (FEC) code, wherein the FEC code is offset, with respect to time, from the GOP structure; and

a processor configured to decode the GOP structure and FEC during a channel-change event.

9. The set-top box of claim 8, wherein the processor uses the FEC to assist in recreating a quanta of the GOP.

10. The set-top box of claim 9, whereby the quanta of the GOP is recreated in about a half of a protection period of the quanta during the change-change event.

11. The set-top box of claim 8, further comprising a buffer for storing frames to be displayed on a display device.

12. The set-top box of claim 8, wherein the processor performs an algorithm to determine which portions of the GOP structure and FEC to use to calculate an I-frame of a GOP tuned to during the channel-change event.

13. A method for executing a change from one communication channel to another, the method comprising:

receiving a channel-change indication;

obtaining data and obtaining forward error correction (FEC) that corresponds to the data, wherein the data and FEC are related to a new channel, and the data includes a portion of data within a data packet; and

utilizing the FEC to recreate portions of data of the data packet that were missed due to the channel-change indication occurring in the middle of the transmission of the data packet.

14. The method of claim 13, wherein the data packet is associated with video data arranged in a group of pictures (GOP) structure.

15. The method of claim 14, wherein utilizing the FEC to recreate portions of the data further comprises recreating frames for display on a display device.

16. The method of claim 15, further comprising:

storing the frames in a frame buffer.

17. The method of claim 14, further comprising:

utilizing the obtained data and FEC until a quanta of data of the GOP is created.

18. The method of claim 17, further comprising:

determining which portions of the data and FEC to utilize to reduce a channel-change time.

19. The method of claim 13, wherein obtaining the FEC includes obtaining the FEC at a time that lags the time that the data is obtained by about one-half of the period of the data packet.

20. The method of claim 13, further comprising:

determining whether or not errors exist in the data packet; and

utilizing the FEC to correct errors in the data packet when it is determined that errors exist.