[FFmpeg-user] dpx to prores & h.264 - color shift

[Andy Furniss]

Kevin Wheatley wrote:
> Andreas,
>
> instead of using the -colormatrix option try instead using
>
> -vf scale=in_range=full:in_color_matrix=bt709:out_range=tv:out_color_matrix=bt709
>
> assuming your DPX files are utilising full range encoding

also scale has flags which may or may not affect quality in this case.

IIRC getting them to work can be a bit variable, historically

-sws-flags flag1+flag2 ... used to work, but not last time I tested so

-vf scale=........:flags=flag1+flag2..... was what I last used - best

to double check with -loglevel verbose + check output to be sure.

https://www.ffmpeg.org/ffmpeg-scaler.html#scaler_005foptions

I am thinking of trying accurate_rnd full_chroma_int full_chroma_inp 
bitexact

not that I know what's best or relevant, so trial and error really.