I can't overlay and center a video on top of an image with ffmpeg. The output is 0 seconds long

Question

I have an mp4 that I want to overlay on top of a jpeg. The command I'm using is:

Ffmpeg -y -i background.jpg -i video.mp4 -filter_complex "overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2" -codec:a copy output.mp4

But for some reason, the output is 0 second long but the thumbnail does show the first frame of the video centred on the image properly.

I have tried using -t 4 to set the output's length to 4 seconds but that does not work.

I am doing this on windows.

Answer 1

You need to loop the image. Since it loops indefinitely you then must use the shortest option in overlay so it ends when video.mp4 ends.

ffmpeg -loop 1 -i background.jpg -i video.mp4 -filter_complex \
"overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2:shortest=1" \
-codec:a copy -movflags +faststart output.mp4

See overlay documentation for more info.

Answer 2

Well you should loop the image until the video duration. So to do the you need to add -loop 1 before the input image. Then the image will have a infinite duration. So to control it specify -shortest before the output file which will trim all the streams to the shortest duration among them. Else you can use -t to trim the image duration to the video length. This will do what you want.

Hope this helps!