I'm trying to use FFMPEG to create a video with one video overlayed on top another.
I have 2 MP4s. I need to make all BLACK pixels in the overlay video transparent so that I can see the main video undeeath it.
I found two ways to overlay one video on another:
First, the following positions the overlay in the center, and therefore, hides that portion of the main video beneath it:
ffmpeg -i 1.mp4 -vf "movie=2.mp4 [a]; [in][a] overlay=352:0 [b]" combined.mp4 -y
And, this one, places the overlay video on the left, but it's opacity is set to 50% so at least other one beneath it is visible:
ffmpeg -i 1.mp4 -i 2.mp4 -filter_complex "[0:v]setpts=PTS-STARTPTS[top]; [1:v]setpts=PTS-STARTPTS, format=yuva420p,colorchaelmixer=aa=0.5[bottom]; [top][bottom]overlay=shortest=0" -acodec libvo_aacenc -vcodec libx264 out.mp4 -y
My goal is simply to make all black pixels in the overlay (2.mp4) completely transparent. How can this be done.