[FFmpeg-devel] [PATCH v3] lavc/rawdec: Remove monowhite switching code for 1 bpp AVI without a palette

Mats Peterson matsp888 at yahoo.com
Wed Feb 10 01:32:02 CET 2016


OK Michael, here is a new version of the patch that should be applied 
after your recent PAL8 changes for nut. Please try it out. Description 
follows:

This patch removes the monowhite switching code for 1 bpp raw AVI 
without a palette. I don't see any reason to keep it, since it's 
semantically incorrect to use monowhite for palettized data in my book, 
it adds unnecessary noise to the code, and it's inconsistent with the 
rest of the code in FFmpeg.

For black & white AVI or QuickTime files, in order to produce a 
monochrome nut file, force the pixel format with "-pix_fmt monow" or 
"-pix_fmt monob".

Unfortunately, there is a problem with converting from pal8 to monow, 
and I know what it is now. There seems to be some weird dithering going 
on of the white color, so there will be black pixels here and there in 
the monow output. A better way is to use "ffmpeg -i 1bpp.avi -vcodec 
copy -vtag B1W0 1bpp.nut". The "-vtag" option is currently needed, 
otherwise FFmpeg will use a RGB[15] codec tag for some reason.

I have also updated the 1 bpp FATE test files (once again).

Mats
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