Suppose I have a sequence of 32-bit (RGBa) PNG files. Is it possible to compress the RGB channel with one codec and the alpha channel with another? For example, if I had the RGB and alpha as separate PNG files (24 and 8 bit, respectively), I would do something like this:
ffmpeg -framerate 60 -i 24_bit_rgb%04d.png -c:v libx264rgb -qp 0 -preset veryslow rgb.mp4
ffmpeg -framerate 60 -i 8_bit_alpha%04d.png -c:v libx265 -x265-params lossless=1 alpha.mp4
But I’m not sure how I’d do this since I don’t have separate RGB and alpha PNG files. Can this be done in ffmpeg?
