I have an alpha.mp4 (alpha matte video) and a color.mp4 (color video). How do I use ffmpeg to make a transparent HVEC (.mov) video?
I can combine with ffmpeg to make a .webm file following the instruction here: https://www.unscreen.com/api under "Convert unpacked Pro Bundle to WEBM video with transparency"
I have a newer mac and should be able to use HVEC_videotoolbox from either these 2 videos or the .webm file created.
The closest I found was this which seems to generate a corrupt video that cannot be viewed in safari. Use FFmpeg to generate a movie with alpha channel from separate video and fill movies? but