Systems and methods for enhanced error concealment in a video decoder

Abstract

The invention is related to methods and apparatus that conceal errors in images of a corrupted video bitstream. One embodiment conceals errors in a missing or corrupted intra-coded macroblock by linearly interpolating data from other macroblocks that correspond to portions of the image above and below the missing or corrupted macroblock. One embodiment can utilize substitute motion vectors for a missing or corrupted predictive-coded macroblock. Another embodiment doubles the received motion vectors and references the doubled motion vectors to a previous-previous frame. Another embodiment adaptively selects which concealment or reconstruction technique is applied according to projected error estimates. Another embodiment conceals errors by replacing corrupted or missing data by combining concealment data in a weighted sum to reduce an estimated error.

1 . A video decoder that conceals errors received in a video bitstream, the video decoder comprising: 
 an error detection circuit adapted to detect errors in the video bitstream;    a memory device configured to provide an indication of an error in a portion of a video bitstream corresponding to a portion in an image;    a control circuit configured to be responsive to an indication of the error in a first portion of the image, where the control circuit is further configured to detect if a second portion above the first portion in the image and if a third portion below the first portion in the image are error-free, where the control circuit is further configured to interpolate between corresponding data in the second portion of the image and corresponding data in the third portion of the data to conceal the error.    
     
     
         2 . The video decoder as defined in  claim 1 , wherein the control circuit is further configured to determine when the first portion is at an upper boundary of the image and to copy corresponding data from the third portion of the data to the first portion to conceal the error.  
     
     
         3 . The video decoder as defined in  claim 1 , wherein the control circuit is further configured to conceal the error by setting pixels in the first portion to gray.  
     
     
         4 . A video decoder that adaptively conceals errors received in a video bitstream, the video decoder comprising: 
 a memory module adapted to maintain error values for selected portions of an image;    a plurality of error resilience modules that generate images in response to errors;    a prediction module adapted to generate a plurality of predictions of error values corresponding to the plurality of error resilience modules;    a control module adapted receive an indication of an error in the video bitstream and, in response, to select an error resilience module from the error resilience module based on a comparison of the predictions of error values.    
     
     
         5 . The video decoder as defined in  claim 4 , further comprising a lookup table that stores predetermined error values corresponding to error resilience techniques, where the lookup table is coupled to the prediction module.  
     
     
         6 . A video decoder that conceals errors received in a video bitstream, the video decoder comprising: 
 a memory module adapted to maintain error variances for selected portions of an image;    a plurality of error resilience modules that generate images in response to errors;    a prediction module adapted to generate a plurality of weights corresponding to the plurality of error resilience modules;    a control module adapted receive an indication of an error in the video bitstream and, in response, to combine outputs of selected error resilience modules with the weights from the prediction module to conceal the error.    
     
     
         7 . The video decoder as defined in  claim 6 , wherein the prediction module provides a weight that is related to an inverse of an expected error.  
     
     
         8 . The video decoder as defined in  claim 6 , wherein the prediction module provides a weight that provides a minimal mean squared error.  
     
     
         9 . An optimizer circuit that selectively applies an error concealment technique from among a plurality of error concealment techniques comprising: 
 means for maintaining an estimated error relating to at least a portion of an image;    means for using the estimated error to generate a plurality of projected error estimates corresponding to application of an error concealment technique; and    means for selecting the error concealment technique that provides the lowest projected error estimate.    
     
     
         10 - 50 . (canceled)