Generate a SD version of a normal video

See https://www.youtube.com/watch?v=PddIlnAdv68

Convert video into a .jpg sequence

ffmpeg -i video.mp4 -r 25 -qscale:v 2 -s 1920x1080 frames/frame-%05d.jpg

Use Stable Diffusion and img2img in batch

set the correct width & height, select a fixed seed, e.g. 234719090

Convert .jpg sequence back into video (with interpolation)

ffmpeg -y -r 25 -i output/frame-%05d.jpg -s 1920x1080 -b:v 12M -vcodec h264_nvenc -pix_fmt yuv420p -strict -2 -filter:v minterpolate='mi_mode=mci:me_mode=bidir:mc_mode=aobmc:vsbmc=1:fps=30',deflicker output_video.mp4

As above, with a specific starting frame

ffmpeg -y -r 25 -start_number 00090 -i output/frame-%05d.jpg -s 1920x1080 -b:v 12M -vcodec h264_nvenc -pix_fmt yuv420p -strict -2 -filter:v minterpolate='mi_mode=mci:me_mode=bidir:mc_mode=aobmc:vsbmc=1:fps=30',deflicker output_video.mp4

example

ffmpeg -i IMG_4338.MOV -r 25 -qscale:v 2 -s 1920x1080 frames/frame-%05d.jpg

Convert .mov to .mp4

ffmpeg -i output_video.mov -q:v 0 output_video.mp4