[FFmpeg-user] HD > SD Down-Convert Prores Color

Carl Eugen Hoyos cehoyos at ag.or.at
Wed May 13 13:13:31 CEST 2015

Kevin Wells <kevwells <at> hotmail.co.uk> writes:

> what platform are you using, Windows, Mac?

I suggest one more guess.
(But it doesn't matter: FFmpeg runs fine on Windows 
and Mac, I test regularly myself.)

> In any application if you open the video and turn the
> gamma up you will see big problems.

FFmpeg does contain filter(s) that allow gamma 
correction, how do I reproduce with FFmpeg?

> If you open the resulting video (SD_BARS.mov) up in 
> Photoshop

Sorry, but Photoshop is not a development tool I use 

> ffmpeg -i HD_BARS.mov -map 0:v 
> -vf colormatrix=bt709:bt601,scale=720:576:flags=lanczos 
> -vcodec prores_ks -profile:v 3 -vtag apch -vendor ap10 
> -pix_fmt yuv422p10le -f mov SD_BARS.mov

I already told you that if the issue is reproducible 
with -vcodec prores (you claimed it is), please use it.

Is encoding with prores needed to reproduce the issue, 
or are only seeing a problem with the software scaler?

Why didn't you use the command line I provided and that 
is not bound to some software we don't know much about 
to check the output of FFmpeg?

Please try to fix your mailer, Carl Eugen

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