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authorSteinar H. Gunderson <steinar+ffmpeg@gunderson.no>2017-02-18 19:41:02 +0100
committerMichael Niedermayer <michael@niedermayer.cc>2017-02-21 00:40:20 +0100
commite3c14eaa54c87d4d8771bc75cb24b0b537fbcd19 (patch)
treef48d5222c67eb4c93d736483f311246bf80b72cd /libavformat
parented69cb83f8931f6124d74ea4b22114512f5db2e3 (diff)
downloadffmpeg-e3c14eaa54c87d4d8771bc75cb24b0b537fbcd19.tar.gz
speedhq: fix decoding artifacts
The quantization table is stored in the natural order, but when we access it, we use an index that's in zigzag order, causing us to read the wrong value. This causes artifacts, especially in areas with horizontal or vertical edges. The artifacts look a lot like the DCT ringing artifacts you'd expect to see from a low-bitrate file, but when comparing to NewTek's own decoder, it's obvious they're not supposed to be there. Fix by simply storing the scaled quantization table in zigzag order. Performance is unchanged. Reviewed-by: Paul B Mahol <onemda@gmail.com> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Diffstat (limited to 'libavformat')
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