Take average of chroma samples when subsampling #522
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Taking the average is a form of low-pass filtering. It also puts the subsampled chroma at the center of the 2x2 chroma block. Most YCbCr-to-RGB conversion functions used in image decoding assume the center chroma sample position. A proof of concept for a fix for strukturag#521.
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Thanks @wantehchang. I have implemented this now a bit differently to prevent having conditional branches and divisions by a variable number in the inner loop of the most frequent case. See #521. |
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Taking the average is a form of low-pass filtering. It also puts the
subsampled chroma at the center of the 2x2 chroma block. Most
YCbCr-to-RGB conversion functions used in image decoding assume the
center chroma sample position.
A proof of concept for a fix for
#521.