I am trying to use FFmpeg to overlay one video on top of the other using an additive blend. One video is the actual video I want to transcode, the other is a ~10 second long video I want to put into one corner, sort of an animated watermark. The watermark video is some white animated stuff with a black background.
So far, I have tried something along these lines:
$ /d/ffmpeg/ffmpeg.exe -i actualvideo.mkv -i myoverlay.mp4 \ -filter_complex "[1:0] setsar=sar=1 [1sared]; [0:0][1sared] blend=all_mode='addition':repeatlast=1" \ test.mkv
setsar seemed necessary as otherwise it would complain:
[Parsed_blend_0 @ 00000000043e0e40] First input link top parameters (size 1280x720, SAR 1:1) do not match the corresponding second input link bottom parameters (1280x720, SAR 0:1)
setsar there's no complaint, but the output video looks.. mostly pink. Both videos look fine when viewed on their own before I feed them into FFmpeg.
Any ideas? Am I doing something wrong?