Can anyone recommend a tool/library to output at least full HD image fades to a video with correct gamma? Preferably even with dithering for finer steps when fa

Can anyone recommend a tool/library to output at least full HD image fades to a video with correct gamma? Preferably even with dithering for finer steps when fading slowly. My main problem is that I'm not good at on-the-fly encoding and outputting frame by frame feels a bit excessive.