> Interesting.  One issue I would anticipate is that H.264 is typically 

> 4:2:0, so if you save in another YUV format, FFmpeg would have 

> to convert it, possibly by converting back to RGB.  I would hope 

> there was some 4:2:0 YUV format that wouldn't involve those issues, 

> but I don't know.

>

> Brendan

Doesnt an encoder need to full decode the file and get an RGB image before re-encoding it again? That is what i was thinking and caused the colorshift i was seeing, that FFmpeg did a "wrong" YUV -> RGB conversion. Maybe it is possible to keep it in keep it in YUV space without the color conversion, it should be when i think about it.

It has been a while since i tested this, and some things might have been improved with newer versions of FFmpeg. But i did test Uncompressed YUV, ProRes HQ and DNxHD 185, and they are all in YUV 4:2:2 and all showed colorshifts. FFmpeg wouldnt read DNxHD 444 or ProRes 444 so i couln't check those, but it might be able to now, dont know.

I think DNxHD444 is RGB, but ProRes444 is still YUV??? So it could be interesting to test those again if they are read now.

Robert