Method for encoding and decoding video signal

Abstract

Disclosed is a method for encoding a decoding a video signal. In the procedure of encoding the video signal, when a frame temporarily simultaneous with a frame including a macro block of an enhanced layer which will obtain a prediction video does not exist in a base layer, the macro block is encoded based on difference values of residual data using corresponding residual blocks in a past frame and a future frame of the base layer which are residual data corresponding to image difference values and using a residual block for the macro block of the enhanced layer. In another embodiment, the macro block is encoded based on difference values of residual data using corresponding residual blocks in a past frame and a future frame of the enhanced layer and the residual block for the macro block. Accordingly, a residual prediction mode is applied for a macro block of an enhanced layer even if a frame temporally simultaneous with a frame of the enhanced layer does not exist in a base layer, thereby improve coding efficiency.

1 . A method for encoding a video signal, the method comprising the steps of: 
 generating a bit stream of a first layer by encoding the video signal through a first predetermined scalable scheme; and    generating a bit stream of a second layer by encoding the video signal through a second predetermined scheme,    wherein the step of generating the bit stream of the first layer includes a first step of generating a prediction video of a video block using frames selected from frames of the second layer, in which the frames consist of blocks encoded in such a manner that the blocks have residual data corresponding to difference values of pixels between the reference block and the encoded blocks and include a past frame and a future frame with respect to a predetermined frame of the first layer having the video block encoded using residual blocks having the residual data.    
   
   
       2 . The method as claimed in  claim 1 , wherein the first step includes the sub-steps of: 
 generating an insert block temporally simultaneous with the predetermined frame by using corresponding blocks, which are included in the past frame and the future frame of the second layer and have relative positions identical to a relative position of the video block in a frame, and enlarging a size of the insert block corresponding to a size of the video block if there is no frame in the second layer temporally simultaneous with the predetermined frame; and    finding difference values of residual data for the video block by subtracting pixel values of the enlarged insert block from pixel values of the residual block.    
   
   
       3 . The method as claimed in  claim 2 , wherein the insert block is generated by weighting a first corresponding block in the past frame of the second layer and a second corresponding bock in the future frame of the second layer, respectively.  
   
   
       4 . The method as claimed in  claim 1 , further comprising a step of recording first information on a header of the video block indicating that the video block is encoded using difference values of residual data based on the past frame and the future frame of the second layer.  
   
   
       5 . The method as claimed in  claim 4 , wherein the first information includes second information and third information, the second information indicating that the video block is encoded by using difference values of residual data, the third information indicating that the past frame and the future frame of the second layer are used in order to calculate the difference values corresponding to the residual data.  
   
   
       6 . The method as claimed in  claim 4 , further comprising a step of recording fourth information on the header of the video block, the fourth information relating to a value used for weighting the corresponding block when the insert block is generated.  
   
   
       7 . A method for encoding a video signal, the method comprising the steps of: 
 (1) generating a residual block having residual data, which are difference values of pixels between a video block included in a predetermined frame of the video signal and a reference block for the video block; and    (2) generating a prediction video for the video block using a past frame and a future frame of the predetermined frame, the prediction video including blocks encoded in such a manner that the blocks have the residual data.    
   
   
       8 . The method as claimed in  claim 7 , wherein step ( 2 ) includes the steps of: 
 (2-1) generating an insert block temporally simultaneous with the predetermined frame by using corresponding blocks, which are included in the past frame and the future frame of the second layer and have relative positions identical to a position of the video block in a frame; and    (2-2) finding difference values of residual data for the video block by subtracting pixel values of the insert block from pixel values of the residual block.    
   
   
       9 . The method as claimed in  claim 7 , wherein step (2) is performed if a frame temporally simultaneous with the predetermined frame including the video block does not exist in a bit stream generated by encoding the video signal through another scheme.  
   
   
       10 . The method as claimed in  claim 7 , further comprising a step of recording a first information on a header of the video bock, the first information indicating that the video block is encoded using difference values of residual data based on the past frame and the future frame.  
   
   
       11 . A method for decoding an encoded video bit stream, the method comprising the steps of: 
 decoding a bit stream of a second layer scalably encoded through a second predetermined scheme; and    decoding a bit stream of a first layer encoded through the second predetermined scheme using decoding information extracted from the bit stream of the second layer,    wherein the step of decoding the bit stream of the first layer includes a first step of restoring a video block, which is included in a predetermined frame of the first layer and encoded using difference values of residual data, such that the video block has original pixel values by using frames, which are a past frame and a future frame with respect to the predetermined frame of the first layer, selected from frames of the second layer and consisting of blocks encoded to have residual data, or by using frames, which are a past frame and a future frame with respect to the predetermined frame of the first layer, selected from frames of the first layer and consisting of blocks encoded to have residual data.    
   
   
       12 . The method as claimed in  claim 11 , wherein it is determined if the video block is encoded using the difference values of the residual data based on information included in a header of the video block.  
   
   
       13 . The method as claimed in  claim 11 , wherein the first step includes the sub-steps of: 
 determining based on the information included in the header of the video block if the past frame and the future frame on the second layer are used in order to calculate difference values of the residual data for the video block;    generating an insert block temporally simultaneous with the predetermined frame by using corresponding blocks, which are included in the past frame and the future frame on the second layer and have relative positions identical to a position of the video block in the past frame and the future frame, and enlarging a size of the insert block to a size of the video block if the past frame and the future frame on the second layer are used in order to calculate difference values of the residual data for the video block; and    adding pixel values of the enlarged insert block to pixel values of the video block encoded using the difference values of the residual data so as to generate residual data for the video block.    
   
   
       14 . The method as claimed in  claim 11 , wherein first step includes the sub-steps of: 
 determining based on the information included in the header of the video block if the past frame and the future frame on the second layer are used in order to calculate the difference values of the residual data for the video block when there are no frames on the second layer temporally simultaneous with the predetermined frame;    generating an insert block temporally simultaneous with the predetermined frame using corresponding blocks included in the past frame and the future frame on the first layer and having relative positions identical to a position of the video block in the frames if the past frame and the future frame on the second layer are not used in order to calculate the difference values of the residual data for the video block; and    adding pixel values of the insert block to pixel values of the video block encoded using the difference values of the residual data so as to generate residual data for the video block.    
   
   
       15 . A method for decoding an encoded video bit stream, the method comprising the steps of: 
 (1) determining if a video block included in a predetermined frame of the bit stream scalably encoded through a predetermined scheme is encoded using difference values of residual data; and    (2) restoring the video block to a block having original pixel values by using a past frame and a future frame of the predetermined frame, the past frame and the future frame including blocks encoded in such a manner that the blocks have residual data when the video block is encoded using difference values of residual data.    
   
   
       16 . The method as claimed in  claim 15 , wherein it is determined based on information included in a header of the video block if the video block is encoded using the difference values of the residual data.  
   
   
       17 . The method as claimed in  claim 15 , wherein step (2) includes the steps of: 
 (2-1) determining based on the information included in the header of the video block if the difference values of the residual data for the video block are calculated by using the past frame and the future frame when the video block is encoded using the difference values of the residual data;    (2-2) generating an insert block temporally simultaneous with the predetermined frame using corresponding blocks included in the past frame and the future frame and having relative positions identical to a position of the video block in the frames when the difference values of the residual data for the video block are calculated by using the past frame and the future frame; and    (2-3) adding pixel values of the insert block to pixel values of the video block encoded using the difference values of the residual data so as to generate residual data for the video block.    
   
   
       18 . The method as claimed in  claim 2 , further comprising a step of recording first information on a header of the video block indicating that the video block is encoded using difference values of residual data based on the past frame and the future frame of the second layer.  
   
   
       19 . The method as claimed in  claim 5 , further comprising a step of recording fourth information on the header of the video block, the fourth information relating to a value used for weighting the corresponding block when the insert block is generated.  
   
   
       20 . The method as claimed in  claim 8 , wherein step (2) is performed if a frame temporally simultaneous with the predetermined frame including the video block does not exist in a bit stream generated by encoding the video signal through another scheme.  
   
   
       21 . The method as claimed in  claim 8 , further comprising a step of recording a first information on a header of the video bock, the first information indicating that the video block is encoded using difference values of residual data based on the past frame and the future frame.