Signal compressing signal

Abstract

A multi-scanner scans a signal according to several different patterns. A scanning pattern selector determines which scanning pattern produced the most efficient coding result, for example, for runlength coding, and outputs a coded signal, coded most efficiently, and a selection signal which identifies the scanning pattern found to be most efficient.

1 . A decoder for decompressing a compressed video signal, the compressed video signal containing entropy encoded data representing a set of video spatial frequency coefficients of an individual sub-block which have been scanned using a selected one of a plurality of different scanning patterns to produce a set of reordered coefficients and also containing a scanning mode signal indicating the selected one of the plurality of different scanning patterns, the decoder comprising: 
 an entropy decoder operative to decode the entropy encoded data and to output entropy decoded data; and    a scanner operative to scan the entropy decoded data according to the selected one of the plurality of different scanning patterns as indicated by the scanning mode signal,    wherein the plurality of different scanning patterns includes  FIG. 3H .    
   
   
       2 . The decoder according to  claim 1  wherein the entropy encoded data and the scanning mode signal are multiplexed together as part of coded data signal.  
   
   
       3 . The decoder according to  claim 1 , wherein the entropy encoded data, the scanning mode signal and the additional information are multiplexed together as part of coded data signal, and wherein said decoder further includes a demultiplexer which demultiplexes the entropy encoded data, the scanning mode signal and the additional information.  
   
   
       4 . The decoder according to  claim 1 , wherein the entropy encoded data is encoded according to a variable length encoding regime.  
   
   
       5 . The decoder according to  claim 1 , wherein the scanner scans the entropy decoded data according to a runlength decoding regime.  
   
   
       6 . The decoder of  claim 1 , further comprising a dequantizer which dequantizes the scanned data output by said scanner and outputs dequantized data.  
   
   
       7 . The decoder of  claim 6 , further comprising an inverse discrete cosine transformer which inverse discrete cosine transforms the dequantized data output by said dequantizer.