Video compression and decompression system with postfilter to filter coding artifacts

Abstract

A video compression and decompression system has an input to receive an encoded video sequence and an output for a decoded video sequence. A video decoder is coupled to the input and decode the received encoded video sequence. A filter module is coupled to the video decoder and the output and filters the decoded video sequence from the video decoder. The filter module has a variable filter strength that is a function of detected motion activity within the video sequence. The filter module filters coding artifacts, such as mosquito artifacts and blocking artifacts from the decoded video sequence so that the displayed video is more pleasing for a viewer's eyes.

1 . A method comprising: 
 receiving an encoded video sequence;    decoding the received encoded video sequence into a decoded video sequence that contains compression artifacts;    categorizing each frame of the decoded video sequence as a first activity frame or as a second activity frame; and    removing with a filter module the compression artifacts in the decoded video sequence, the filter module having a variable filter strength being a function of the motion activity within the decoded video sequence.    
   
   
       2 . The method of  claim 1 , wherein the category of the first activity frame is a high activity frame and the category of the second activity frame is a low activity frame.  
   
   
       3 . The method of  claim 1 , additionally comprising selectively adjusting the filter strength to one of a high level, a medium level and a weak level.  
   
   
       4 . The method of  claim 3 , wherein medium level is a default level.  
   
   
       5 . An apparatus, comprising: 
 a video decoder coupled configured to decode a received encoded video sequence into a decoded video sequence that contains compression artifacts; and    a filter module coupled with the video decoder, said filter module configured to filter the compression artifacts in the decoded video sequence, the filter module being configured to remove compression artifacts and having a variable filter strength that is a function of the motion activity within the video sequence.    
   
   
       6 . The apparatus of  claim 5 , wherein the filter module includes a threshold detector configured to generate a control signal to adjust the filter strength.  
   
   
       7 . The apparatus of  claim 6 , wherein the control signal adjusts the filter strength to one of a high level, a medium level and a weak level.  
   
   
       8 . The apparatus of  claim 7 , wherein the medium level is a default level.  
   
   
       9 . A method comprising: 
 receiving an encoded video sequence;    decoding the received encoded video sequence into a decoded video sequence that contains compression artifacts; and    removing with a filter module the compression artifacts in the decoded video sequence, the filter module having a variable filter strength being a function of the motion activity within the decoded video sequence.    
   
   
       10 . The method of  claim 9 , wherein the category of the first activity frame is a high activity frame and the category of the second activity frame is a low activity frame.  
   
   
       11 . The method of  claim 9 , additionally comprising selectively adjusting the filter strength to one of a high level, a medium level and a weak level.  
   
   
       12 . The method of  claim 11 , wherein medium level is a default level.  
   
   
       13 . A program storage device storing instructions that when executed performs the steps comprising: 
 receiving an encoded video sequence;    decoding the received encoded video sequence into a decoded video sequence that contains compression artifacts;    categorizing each frame of the decoded video sequence as a first activity frame or as a second activity frame; and    removing with a filter module the compression artifacts in the decoded video sequence, the filter module having a variable filter strength being a function of the motion activity within the decoded video sequence.    
   
   
       14 . The program storage device of  claim 13 , wherein the category of the first activity frame is a high activity frame and the category of the second activity frame is a low activity frame.  
   
   
       15 . The program storage device of of  claim 13 , wherein adjusting the filter strength includes selectively adjusting the filter strength to one of a high level, a medium level and a weak level.  
   
   
       16 . The method of  claim 15 , wherein adjusting the filter strength includes adjusting the filter strength to the medium level is a default level.  
   
   
       17 . An apparatus comprising: 
 means for receiving an encoded video sequence;    means for decoding the received encoded video sequence into a decoded video sequence that contains compression artifacts;    means for categorizing each frame of the decoded video sequence as a first activity frame or as a second activity frame; and    means for removing with a filter module the compression artifacts in the decoded video sequence, the filter module having a variable filter strength being a function of the motion activity within the decoded video sequence.    
   
   
       18 . The apparatus of  claim 17 , wherein the category of the first activity frame is a high activity frame and the category of the second activity frame is a low activity frame.  
   
   
       19 . The apparatus of  claim 17 , additionally comprising selectively adjusting the filter strength to one of a high level, a medium level and a weak level.  
   
   
       20 . The apparatus of  claim 20 , wherein medium level is a default level.