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

Carl Eugen Hoyos cehoyos at ag.or.at
Mon May 28 16:07:49 CEST 2012

 <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. .

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.

> 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.)

Carl Eugen

More information about the Libav-user mailing list