[Libav-user] Lossless encoding - red color sharpness defect

koli at koli.sk koli at koli.sk
Mon May 28 16:23:51 CEST 2012

On 28.05.2012 16:07, Carl Eugen Hoyos wrote:
> <koli at ...> writes:
>> > (Note that ffmpeg natively supports screen capture input,
>> > no need to use png's.)
>> I know, but the PNG images was meant as kind of etalon. If someone 
>> can
>> download those pictures and with some command (option), create a 
>> H264
>> encoded video with sharp red colored text that is possible to play 
>> via
>> ffplay, mplayer (ffmpeg). I don't know a way how to share my desktop 
>> for
>> everybody anytime someone wants to play with it. .
Ok next time I won't forget.

> You are right and thank you for clarifying it (it it true that
> unreproducible problems often cannot be fixed), but in your
> case, complete, uncut console output would have been sufficient
> (and is needed for every report on this list).
>> I am not suffering with color degradation.
> Yes, you are, this is what you reported and it is not a known
> "problem", but a known limitation of the usual (in the sense
> of "MPEG usual") way of storing pixel information.

Ok you are right.

>> Anyway what kind of option (switch.value) and how should I use when 
>> I
>> want to encode in yuv444 and not the default yuv420.
> You need to recompile x264 with support for yuv444p encoding.
> (I may absolutely be wrong with this recommendation:
> Try ffmpeg -i input.png -pix_fmt yuv444p -vcodec libx264 out.mov
> to know for sure.)

Perfect. Recompile was not needed, -pic_fmt option solved it and it is 
nice sharp and has only 0,7MB

Thanks for help

> Carl Eugen
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> Libav-user at ffmpeg.org
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