Nested entropy encoding

Abstract

Methods and systems for improving coding efficiency of video.

1 . A decoding system for decoding received encoded data, said system comprising:
 (a) a syntax modeler for associating a sequence of first symbols with syntax elements from said data;   (b) at least one buffer for storing a plurality of tables, each nested within a respective one of said sequence of first symbols, and each used to associate a respective one of a sequence of second symbols with encoded data; and   (c) a decoder that decodes said data into a bitstream using a selected respective one of said sequence of second symbols retrieved from a respective one of plurality of tables, where said bitstream is free from including any of said sequence of first symbols.   
     
     
         2 . The decoding system of  claim 1  where said sequence of first symbols is an entropy code. 
     
     
         3 . The decoding system of  claim 2  where said sequence of first symbols is a selected one of a Huffman code or an arithmetic code. 
     
     
         4 . The decoding system of  claim 1  where said sequence of first symbols is a fixed-length code. 
     
     
         5 . The decoding system of  claim 1  where said sequence of second symbols is an entropy code. 
     
     
         6 . The decoding system of  claim 1  where said decoded data is a set of candidate motion vectors. 
     
     
         7 . The decoding system of  claim 1  where said decoder rearranges the association of data with said sequence of second symbols in a respective one of said plurality of tables. 
     
     
         8 . The decoding system of  claim 7  where the rearrangement improves coding efficiency by associating lower bit-length symbols with data coded more frequently in said bitstream. 
     
     
         9 . The decoding system of  claim 1  where the decoded said data is at least one of spatially independent and temporally independent. 
     
     
         10 . The decoding system of  claim 1  where the decoded said data is both spatially independent and temporally independent. 
     
     
         11 . A method for decoding data, said method comprising:
 (a) receiving a candidate set of motion vectors used to decode a block of video, one of said candidate set being encoded in said data;   (b) receiving a value for a flag characterizing said one as belonging to a subset within said candidate set;   (c) using said value to trim said candidate set; and   (e) identifying said one of said candidate motion vectors based on the number of motion vectors remaining in said candidate set.   
     
     
         12 . The method of  claim 11  where said flag is a temporal_mvp_flag. 
     
     
         13 . The method of  claim 12  where said value is used to trim from said candidate set duplicate motion vectors in said subset. 
     
     
         14 . The method of  claim 12  where said value is used to trim from said candidate set motion vectors not belonging to said subset 
     
     
         15 . The method of  claim 11  where said flag preserves at least one of spatial independence and temporal independence in said data. 
     
     
         16 . The method of  claim 11  where said flag is decoded using an entropy coded table nested in a symbol identified from a syntax element of said data. 
     
     
         17 . The method of  claim 11  where said flag is used as a syntax element to decode said one using an entropy coded table nested in a symbol identified from said syntax element. 
     
     
         18 . The method of  claim 11  where said value is selectively set to that of a constrained_intra_pred_flag. 
     
     
         19 . The method of  claim 11  where said flag is nested within a symbol indicating the number of unique motion vectors in said candidate set. 
     
     
         20 . The method of  claim 11  where said subset is a maximized collection of motion vectors for which each member of the subset has an identical motion vector not included in the subset.