[FFmpeg-user] RGB-YUV color shift

[Francois Visagie]

> -----Original Message-----
> From: ffmpeg-user-bounces at ffmpeg.org [mailto:ffmpeg-user-
> bounces at ffmpeg.org] On Behalf Of George L.P. Fitz
> Sent: 18 October 2012 01:03
> To: ffmpeg-user at ffmpeg.org
> Subject: [FFmpeg-user] RGB-YUV color shift
> 
> Hello,
> 
> I am seeing a slight color shift when using ffmpeg to encode to yuv based
> codecs like prores and v210 from an rgb source.  The resulting file has
slightly
> more saturation and gamma than the original- it doesn't look way
different,
> but there is enough of a difference to be noticed.  I'm assuming this has
to do
> with the rgb->yuv colorspace conversion, since encoding from a yuv source
> to a yuv codec shows no perceivable color difference. 

Correct.

> Has anyone run across
> this and if so, found a way to keep the color shift negligible?

I'm not sure which of these might work for you, but in principle:
*	avoid colourspace conversion (I think not possible for you?)
*	try to specify different conversion mapping, i.e. [0..255] ->
[0..255] instead of the [0..255] -> [16..255] which might be the case
currently.

Unfortunately this is the extent of my knowledge on the subject but
hopefully enough to point you towards something to investigate. Or enough to
keep you busy until the experts arrive ;-).

> Here's a sample command:
> 
> ffmpeg -f rawvideo -pix_fmt rgb24 -s 1920x1080 -r 23.976 -i
> c3yoz4vuuy.video.raw -vcodec prores -profile 3 test.mov
> 
> Thanks for any help you can provide
> 
> -George
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