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

[Kevin Wells]

From: kevwells at hotmail.co.uk
To: ffmpeg-user at ffmpeg.org
Date: Sun, 10 May 2015 18:23:10 +0000
Subject: Re: [FFmpeg-user] HD > SD Down-Convert Prores Color

> To: ffmpeg-user at ffmpeg.org
> From: cehoyos at ag.or.at
> Date: Sun, 10 May 2015 14:27:29 +0000
> Subject: Re: [FFmpeg-user] HD > SD Down-Convert Prores Color
> 
> Kevin Wells <kevwells <at> hotmail.co.uk> writes:
> 
> > if I emit the format=uyvy422 then the output file 
> > contains tiny green artefacts
> 
> How can I reproduce this?
> 
> Thank you, Carl Eugen
> 
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Hi Carl, Take any HD Prores HQ file and use this command: 

ffmpeg -i HD_Source.mov -map 0:v -map 0:a -vf colormatrix=bt709:bt601,scale=720:576:flags=lanczos -vcodec prores_ks -profile:v 3 -vtag apch -vendor ap10 -pix_fmt yuv422p10le -f mov -c:a pcm_s16le SD_Source.mov 

Take the SD_Source.mov and put it in Final Cut Pro 7, stick it on a sequence and add a Gamma effect (from image control) onto the video track in the sequence. Double click on the video in the sequence and goto the Gamma filter settings and turn the Gamma right up to 5. Now look at any black section of video and you will see it full of ting green artefacts. Adding in the format=uyvy422 gave me an almost perfect file, but not quite sure this is correct. I will attach a tiny video to this email for you to test. Let me know if you need anything else.
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Hi Carl, Is everything OK with my instructions on how to reproduce this issue?

Kind regards.