Allow FFmpeg to hardcode subtitles to Dolby Vision video track to be muxed with tsMuxeR

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I have not verified that FFmpeg supports this yet so this is pending testing

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This is difficult because FFmpeg does not automatically output the same format metadata as the input file, so we need to detect and add a lot of flags like:

-pix_fmt yuv420p10le 
-x265-params colorprim=bt2020:transfer=smpte2084:colormatrix=bt2020nc:range=limited:master-display="G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,50)"
-bsf:v hevc_metadata=colour_primaries=9:transfer_characteristics=16:matrix_coefficients=9

and that is just for HDR, not even Dolby Vision yet.
I hope FFmpeg make it more simple but there is a big arguing thread that makes it seem like they won't do it https://trac.ffmpeg.org/ticket/7037 :(

I also started a Q&A at this link https://superuser.com/questions/1835560/how-can-i-transcode-a-dolby-vision-video