[FFmpeg-devel] [PATCH v7] lavc/rawdec: Remove monowhite switching code for 1 bpp AVI without a palette

Michael Niedermayer michael at niedermayer.cc
Thu Feb 11 02:14:20 CET 2016


On Thu, Feb 11, 2016 at 01:15:38AM +0100, Mats Peterson wrote:
> On 02/11/2016 01:11 AM, Mats Peterson wrote:
> >On 02/11/2016 12:07 AM, Mats Peterson wrote:
> >>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.
> >>
> >
> >An alternative is to use "-sws_dither none", it seems to work fine. I
> >just don't understand why the fully white color is dithered at all when
> >converting from pal8 to monow.
> >
> 
> Nope, doesn't work. I forgot to use "-pix_fmt monow", and it's the
> same as before.

have you tried updating your git checkout ?
it might be fixed by: 23261e60014908da7446e9b5bc7401dc30fdecd6

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The educated differ from the uneducated as much as the living from the
dead. -- Aristotle 
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