ProRes only supports RGB and I444 and requires next to no additional setup, all you need to do is adjust the profile setting according to the table below. Due to there being no further profiles to support 4:4:4 at lower quality, 4:2:2 subsampling is used. This halves the horizontal chroma samples, while keeping the vertical chroma samples in tact – not exactly ideal for text and other high contrast content.
|Option||Effective Lossless||Visually Lossless||High Quality||Acceptable Quality|
|Profile||4444 Extreme Quality (AP4X)||4444 High Quality (AP4H)||422 High Quality (APCH)||422 Standard (APCN)|