Video coding with degradation of residuals

Abstract

A method for encoding a video signal using a computing device, the video signal having a plurality of frames, each frame having a plurality of blocks, and each block having a plurality of pixels. The method includes generating a residual block from an original block of a current frame and a prediction block, degrading the residual block to decrease a bit-cost for encoding the residual block, and encoding the residual block into an encoded residual block.

What is claimed is: 
     
         1 . A method for encoding a block of a video frame, the method comprising:
 generating a prediction residual block for the block;   removing high-frequency information from the prediction residual block to produce a degraded residual block; and   encoding the degraded residual block to produce an encoded block,   wherein a header of the encoded block includes data indicative of a block-based post filter available for recovering at least some of the high frequency information.   
     
     
         2 . The method of  claim 1 , wherein the high-frequency information is removed from the prediction residual block by steps of an encoder that are different than steps performed by a transform stage of the encoder and by a quantization stage of the encoder. 
     
     
         3 . The method of  claim 1 , wherein removing the high-frequency information from the prediction residual block to produce the degraded residual block comprises:
 downscaling the prediction residual block to produce a downscaled prediction residual block of pixel values.   
     
     
         4 . The method of  claim 1 , further comprising:
 recovering the high-frequency information by applying the block-based post filter to a reconstructed block produced using the encoded block.   
     
     
         5 . The method of  claim 4 , further comprising:
 subsequent to recovering the high-frequency information, producing a filtered block using the high-frequency information; and   using the filtered block to generate a prediction residual for another block of the video frame or for a block of another video frame.   
     
     
         6 . The method of  claim 4 , further comprising:
 decoding the encoded block to produce a decoded block;   upscaling the decoded block to produce an upscaled block; and   generating the reconstructed block using the upscaled block.   
     
     
         7 . The method of  claim 1 , wherein the data indicative of the block-based post filter includes an identifier corresponding to a predefined filter. 
     
     
         8 . The method of  claim 1 , wherein the data indicative of the block-based post filter includes one or more filter parameters. 
     
     
         9 . A method for encoding a block of a video frame, the method comprising:
 selecting a block-based post filter for recovering high frequency information removed from a prediction residual block; and   encoding data indicative of the block-based post filter to a header of an encoded block produced using the prediction residual block.   
     
     
         10 . The method of  claim 9 , further comprising:
 removing the high-frequency information from the prediction residual block to produce a degraded residual block; and   encoding the degraded residual block to produce the encoded block.   
     
     
         11 . The method of  claim 10 , wherein removing the high-frequency information decreases a bit-cost for encoding the prediction residual block. 
     
     
         12 . The method of  claim 9 , further comprising:
 decoding the encoded block to produce a decoded block;   upscaling the decoded block to produce an upscaled block; and   generating a reconstructed block using the upscaled block.   
     
     
         13 . The method of  claim 12 , further comprising:
 recovering the high-frequency information by applying the block-based post filter to a reconstructed block.   
     
     
         14 . The method of  claim 13 , further comprising:
 using the high-frequency information recovered by applying the block-based post filter for predicting another block of the video frame or for a block of another video frame.   
     
     
         15 . The method of  claim 9 , wherein the high-frequency information is removed from the prediction residual block by steps of an encoder that are different than steps performed by a transform stage of the encoder and by a quantization stage of the encoder. 
     
     
         16 . A method for decoding an encoded block of an encoded video frame, the method comprising:
 applying a block-based post filter to a reconstructed block to recover high-frequency information removed from a prediction residual,   wherein the prediction residual is used to produce the encoded block and the reconstructed block is produced using the encoded block.   
     
     
         17 . The method of  claim 16 , further comprising:
 storing a filtered block produced using the high-frequency information recovered by applying the block-based post filter.   
     
     
         18 . The method of  claim 16 , further comprising:
 decoding the encoded block to produce a decoded block;   upscaling the decoded block to produce an upscaled block; and   generating the reconstructed block using the upscaled block.   
     
     
         19 . The method of  claim 16 , further comprising:
 decoding data indicative of the block-based post filter from a header of the encoded block.   
     
     
         20 . The method of  claim 19 , wherein the data indicative of the block-based post filter includes at least one of an identifier corresponding to a predefined filter or one or more filter parameters.