Mitigating Impairments in Redundant Streams

1 . A method comprising:

receiving a primary stream of encoded frames and a separate stream of frames selected from frames in the primary stream based on a combination of: 1) a minimum number of other frames depending on each frame in relation to reference frames, 2) a level of information propagation via indirect dependence, and 3) a longevity of the information propagation.

2 . The method of claim 1 , further comprising:

decoding and reconstructing in parallel the frames in the primary stream and the separate stream of redundant frames.

3 . The method of claim 2 , wherein decoding and reconstruction in parallel occurs on a real-time basis, in accordance with a specified common clock reference:

4 . The method of claim 2 , further comprising: determining that a frame in the primary stream exhibits an error or impairment.

5 . The method of claim 4 , further comprising: determining a decoded redundant frame in the separate stream that corresponds to the determined frame in the primary stream exhibiting an error or impairment.

6 . The method of claim 5 , further comprising: substituting at least a portion of the decoded redundant frame for a corresponding decoded version of the impaired frame.

7 . The method of claim 6 , further comprising: determining whether a forward error correction (FEC) frame associated with the frame in the primary stream has been received; and if the FEC frame has been received, using the FEC frame to correct the frame in the primary stream.

8 . The method of claim 6 , further comprising:

determining whether a forward error correction (FEC) frame associated with the frame in the primary stream has been received;

if the FEC frame has not been received, evaluating whether decoding with the frame in the primary stream will produce a picture of acceptable quality; and

if the evaluation determines that the decoding will produce unacceptable quality, requesting retransmission of the frame in the primary stream.

9 . The method of claim 6 , further comprising:

determining whether a forward error correction (FEC) frame associated with the frame in the primary stream has been received;

if the FEC frame has not been received, evaluating whether decoding with the frame in the primary stream will produce a picture of acceptable quality; and

if the evaluation determines decoding will produce acceptable quality, supplying the frame in the primary stream for decoding.

10 . A system comprising:

means for receiving a primary stream of encoded frames and a separate stream of frames redundant of frames in the primary stream, wherein frames are selected for the separate stream based on a combination of: 1) a minimum number of other frames depending on each frame in relation to reference frames, 2) a level of information propagation via indirect dependence, and 3) a longevity of the information propagation.

11 . The system of claim 10 , further comprising:

means for determining if a frame in the primary stream exceeds an error criterion.

12 . The system of claim 11 , further comprising:

means for determining a decoded corresponding frame in the separate stream corresponds to a frame in the primary stream.

13 . The system of claim 12 , further comprising:

means for supplying the corresponding frame responsive to the frame in the primary stream exceeding the error criterion.

14 . The system of claim 12 , further comprising:

means for determining the decoded corresponding frame in the separate stream based on a picture or slice type.

15 . The system of claim 12 , further comprising:

means for determining the decoded corresponding frame in the separate stream based on a frame number that is relative to a sequence parameter set.

16 . The system of claim 12 , further comprising:

means for determining the decoded corresponding frame in the separate stream based on matching a presentation time stamp in a frame in the primary stream with a presentation time stamp in the frame in the separate stream.

17 . The system of claim 11 , further comprising:

means for determining whether a forward error correction (FEC) frame associated with the frame in the primary stream has been received, responsive to the frame in the primary stream exceeding the error criterion; and

means for using the FEC frame to correct the frame in the primary stream, responsive to determining the FEC frame has been received.

18 . The system of claim 11 , further comprising:

means for determining whether a forward error correction (FEC) frame associated with the frame in the primary stream has been received, responsive to the frame in the primary stream exceeding the error criterion; and

means for requesting retransmission of the frame in the primary stream, responsive to determining the FEC frame has not been received.

19 . The system of claim 11 , further comprising:

means for determining whether a forward error correction (FEC) frame associated with the frame in the primary stream has been received, responsive to the frame in the primary stream exceeding the error criterion;

means for evaluating whether decoding with the frame in the primary stream will produce a picture of acceptable quality, responsive to determining that the FEC frame has not been received; and

means for requesting retransmission of the frame in the primary stream, responsive to the evaluation that decoding will produce unacceptable quality.

20 . An apparatus comprising:

an encoder; and

a multiplexer configured to combine a primary stream of encoded frames and a separate stream of frames redundant of frames in the primary stream, wherein frames are selected for the separate stream based on a combination of: 1) a minimum number of other frames depending on each frame in relation to reference frames, 2) a level of information propagation via indirect dependence, and 3) a longevity of the information propagation.