Converting an existing clean 8k Quicktime Prores 444 file in FFmpeg yields banding. It's a lenflare with a completely smooth gradient from center out to edge of frame (no alpha). If I use AE2020 to convert it to Prores 444, the new file is clean without banding. Am I doing something wrong? Here is the command string:
ffmpeg.exe -i file_8k.mov -map_metadata -1 -c:v prores_ks -profile:v 4 -pix_fmt yuv444p10le -color_primaries 1 -color_trc 1 -colorspace 1 -color_range 2 -y file_6k.mov
In this case I'm converting it down to 6k, however other resolutions show the same problem, plus even converting to the same res.