Requirements: ffmpeg 4.3+ for crossfade. All commands tested on
I think that it is required that all videos(maybe audios) need to be the same resolution, framerate and all that. For my use case this is solved by pixabay
My specific goal here is to be able to use a site such as https://pixabay.com videos and mp3s to make long form videos with multiple songs
Obviously, you don't have to use pixabay. You probably don't have to use mp4s or mp3s, untested but ffmpeg should be able to figure it out, the commands do not use any codec specific flags.