Refined block-based predictive coding and decoding of a picture
An apparatus for block-based predictive decoding of a picture comprises a combiner configured to combine a residual signal a predetermined block of the picture and a reference signal for the predetermined block so as to obtain a first spectrum, the residual signal correcting a prediction error of a prediction of the predetermined block of the picture; a reducer configured to perform thresholding on the first spectrum to obtain a second spectrum so that coefficients below a threshold value are set to a predefined value; an extractor configured to obtain from the second spectrum a modified version of the residual signal; and a reconstructor block configured to decode the predetermined block of the picture from the data stream on the basis of the modified version of the residual signal.
1 . An apparatus for decoding a picture, the apparatus comprising a processor configured to:
combine a residual signal of a block of the picture and a reference signal for the block to obtain a first set of coefficients;
generate a second set of coefficients by setting select coefficients from the first set of coefficients to a predefined value;
obtain a modified version of the residual signal based on the second set of coefficients; and
reconstruct the block of the picture using the modified version of the residual signal.
2 . The apparatus of claim 1 , wherein to generate the second set of coefficients, the processor is configured to:
compare each coefficient of the first set of coefficients to a threshold value;
select each coefficient that is below the threshold value based on a result of the comparison; and
set each of the selected coefficients to the predefined value to generate the second set of coefficients.
3 . The apparatus of claim 2 , wherein to set each of the selected coefficients to the predefined value, the processor is configured to quantize each coefficient associated with the predefined value.
4 . The apparatus of claim 1 , wherein:
the reference signal comprises previous residual signals of a neighborhood of the block,
the block of the picture is an inter-predicted block, and
the reference signal comprises a previously decoded version of the neighborhood of the block.
5 . The apparatus of claim 4 , wherein the neighborhood of the block comprises:
a spatial area surrounding one or more sides of the block,
a spatial area offset relative to the block, or
a spatial area surrounding one or more sides of a reference block.
6 . The apparatus of claim 5 , wherein the spatial area surrounding one or more sides of the block comprises a leftward extension of the block so that an overall width is N and above the block so that an overall height is M, wherein N is equal to M.
7 . A method for decoding a picture, the method comprising:
combining a residual signal of a block of the picture and a reference signal for the block to obtain a first set of coefficients;
generating a second set of coefficients by setting select coefficients from the first set of coefficients to a predefined value;
obtaining a modified version of the residual signal based on the second set of coefficients; and
reconstructing the block of the picture using the modified version of the residual signal.
8 . The method of claim 7 , wherein generating the second set of coefficients, comprises:
comparing each coefficient of the first set of coefficients to a threshold value;
selecting each coefficient that is below the threshold value based on a result of the comparison; and
setting each of the selected coefficients to the predefined value to generate the second set of coefficients.
9 . The method of claim 8 , wherein setting each of the selected coefficients to the predefined value, comprises quantizing each coefficient associated with the predefined value.
10 . The method of claim 7 , wherein:
the reference signal comprises previous residual signals of a neighborhood of the block,
the block of the picture is an inter-predicted block, and
the reference signal comprises a previously decoded version of the neighborhood of the block.
11 . The method of claim 10 , wherein the neighborhood of the block comprises:
a spatial area surrounding one or more sides of the block,
a spatial area offset relative to the block, or
a spatial area surrounding one or more sides of a reference block.
12 . The method of claim 11 , wherein the spatial area surrounding one or more sides of the block comprises a leftward extension of the block so that an overall width is N and above the block so that an overall height is M, wherein N is equal to M.
13 . A non-transitory computer readable medium containing instructions that when executed cause at least one processor to:
combine a residual signal of a block of a picture and a reference signal for the block to obtain a first set of coefficients;
generate a second set of coefficients by setting select coefficients from the first set of coefficients to a predefined value;
obtain a modified version of the residual signal based on the second set of coefficients; and
reconstruct the block of the picture using the modified version of the residual signal.
14 . The non-transitory computer readable medium of claim 13 , wherein the instructions that when executed cause the at least one processor to generate the second set of coefficients, comprise further instructions that when executed cause the at least one processor to:
compare each coefficient of the first set of coefficients to a threshold value;
select each coefficient that is below the threshold value based on a result of the comparison; and
set each of the selected coefficients to the predefined value to generate the second set of coefficients.
15 . The non-transitory computer readable medium of claim 14 , wherein the instructions that when executed cause the at least one processor to set each of the selected coefficients to the predefined value, comprise further instructions that when executed cause the at least one processor to quantize each coefficient associated with the predefined value.
16 . The non-transitory computer readable medium of claim 13 , wherein:
the reference signal comprises previous residual signals of a neighborhood of the block,
the block of the picture is an inter-predicted block, and
the reference signal comprises a previously decoded version of the neighborhood of the block.
17 . The non-transitory computer readable medium of claim 16 , wherein the neighborhood of the block comprises:
a spatial area surrounding one or more sides of the block,
a spatial area offset relative to the block, or
a spatial area surrounding one or more sides of a reference block.
18 . The non-transitory computer readable medium of claim 17 , wherein the spatial area surrounding one or more sides of the block comprises a leftward extension of the block so that an overall width is N and above the block so that an overall height is M, wherein N is equal to M.