[FFmpeg-user] Chroma problem converting mp4 to prores

Andy Furniss adf.lists at gmail.com
Fri Mar 3 12:31:52 EET 2017

David Cecco wrote:
> Sorry about the slow response, that has fixed the issue, thanks chronek!
> The file still seems a bit soft in quality though.  I have tried turning the -qscale right down to 1 and adjusting the bits_per_mb up to 2400 and the picture improved but it still wasn’t 100%, but the file grew to 2.5x the size.
> I tried with the prores codec as opposed to the prores_ks codec and it was better, but again not 100% interestingly the file size didn’t grow when using the bits_per_mb with prores.
> Here is an example output:
> $ ffmpeg -y -i "5082197_Soccer Enrique Upd.mp4" -acodec pcm_s16le -vcodec prores_ks -profile:v 1 -vf scale=interl=1 -sws_flags full_chroma_inp+full_chroma_int -copytb -1 "5082197_Soccer Enrique Upd.mov"
> ffmpeg version 3.2.2-tessus Copyright (c) 2000-2016 the FFmpeg developers

Note scale=interl=1 recently changed (hopefully for the better).

You may want to test again with git.

Sometimes adding +accurate_rnd can help, though IIRC it 420 -> 422
8 bit was unaffected, don't know about 10bit.

Interlaced 420 -> rgb really does need it + the other flags.

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