Video coder providing implicit coefficient prediction and scan adaptation for image coding and intra coding of video

Abstract

A predictive video coder performs gradient prediction based on previous blocks of image data. For a new block of image data, the prediction determines a horizontal gradient and a vertical gradient from a block diagonally above the new block (vertically above a previous horizontally adjacent block). Based on these gradients, the encoder predicts image information based on image information of either the horizontally adjacent block or a block vertically adjacent to the new block. The encoder determines a residual that is transmitted in an output bitstream. The decoder performs the identical gradient prediction and predicts image information without need for overhead information. The decoder computes the actual information based on the predicted information and the residual from the bitstream.

What is claimed: 
     
         1 . A method comprising:
 receiving, by a processor, a plurality of decoded blocks of image data adjacent to a current block X of image data, the plurality of decoded blocks of image data being blocks in a row above or in a column to the left of the current block X of image data;   receiving, by the processor, a first parameter associated with one of a plurality of prediction modes;   generating, by the processor, a second parameter associated with a direction of prediction; and   decoding, by the processor, the current block X of image data predicted from one of the plurality of decoded adjacent blocks of image data according to the direction associated with the second parameter.   
     
     
         2 . The method of  claim 1 , wherein the first parameter comprises a flag. 
     
     
         3 . The method of  claim 2 , wherein the flag indicates that the one of the plurality of prediction modes comprises predicting the current block X from one of the decoded blocks adjacent to the current block X. 
     
     
         4 . The method of  claim 3 , wherein the current block X comprises an 8 pixel by 8 pixel array. 
     
     
         5 . The method of  claim 1 , wherein the plurality of decoded blocks is inside a boundary of a video object plane containing the current block X. 
     
     
         6 . A decoder comprising:
 a processor;   a module configured to control the processor to receive a plurality of decoded blocks of image data adjacent to a current block X of image data, the plurality of decoded blocks of image data being blocks in a row above or in a column to the left of the current block X of image data;   a module configured to control the processor to receive a first parameter associated with one of a plurality of prediction modes;   a module configured to control the processor to generate a second parameter associated with a direction of prediction; and   a module configured to control the processor to decode the current block X of image data predicted from one of the plurality of decoded adjacent blocks of image data according to the direction associated with the second parameter.   
     
     
         7 . The decoder of  claim 6 , wherein the first parameter comprises a flag. 
     
     
         8 . The decoder of  claim 7 , wherein the flag indicates that the one of the plurality of prediction modes comprises predicting the current block X from one of the decoded blocks adjacent to the current block X. 
     
     
         9 . The decoder of  claim 8 , wherein the current block X comprises an 8 pixel by 8 pixel array. 
     
     
         10 . The decoder of  claim 6 , wherein the plurality of decoded blocks is inside a boundary of a video object plane containing the current block X. 
     
     
         11 . A decoder that decodes according to stored operations, the operations comprising:
 receiving a plurality of decoded blocks of image data adjacent to a current block X of image data, the plurality of decoded blocks of image data being blocks in a row above or in a column to the left of the current block X of image data;   receiving a first parameter associated with one of a plurality of prediction modes;   generating a second parameter associated with a direction of prediction the second parameter being associated with the first parameter; and   decoding the current block X of image data predicted from one of the plurality of decoded adjacent blocks of image data according to the direction associated with the second parameter.   
     
     
         12 . The decoder of  claim 11 , wherein the first parameter comprises a flag. 
     
     
         13 . The decoder of  claim 12 , wherein the flag indicates that the one of the plurality of prediction modes comprises predicting the current block X from one of the decoded blocks adjacent to the current block X. 
     
     
         14 . The decoder of  claim 13 , wherein the current block X comprises an 8 pixel by 8 pixel array. 
     
     
         15 . The decoder of  claim 11 , wherein the plurality of decoded blocks is inside a boundary of a video object plane containing the current block X.