Prores ks in burnin script

[iLLiCiTiT]

Issue

• ffmpeg's output of any prores encoder (prores_ks, prores_aw, prores) is always codec name prores so burnin script can't

Changes

• ffmpeg stores encoder to output metadata tags so we can read them and define which is used
  • this works only if input is created by ffmpeg

Note

• changes should affect only inputs that have codec name prores in metadata

🏴	Pype 3.x PR
pype	#959