[FFmpeg-devel] [PATCH 1/2] libavcodec/zmbvenc: block scoring improvements/bug fixes

Michael Niedermayer michael at niedermayer.cc
Wed Feb 20 23:12:58 EET 2019

On Sat, Feb 09, 2019 at 01:10:20PM +0000, Matthew Fearnley wrote:
> - Improve block choices by counting 0-bytes in the entropy score
> - Make histogram use uint16_t type, to allow byte counts from 16*16
> (current block size) up to 255*255 (maximum allowed 8bpp block size)
> - Make sure score table is big enough for a full block's worth of bytes
> - Calculate *xored without using code in inner loop

This should have been split into multiple changes

compression seems to become slightly worse from this change

./ffmpeg -i matrixbench_mpeg2.mpg -vframes 30 -vcodec zmbv -an -y test-old.avi
./ffmpeg -i matrixbench_mpeg2.mpg -vframes 30 -vcodec zmbv -an -y test-new.avi

-rw-r----- 1 michael michael 1175466 Feb 20 22:06 test-new.avi
-rw-r----- 1 michael michael 1174832 Feb 20 22:07 test-old.avi

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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