Creating transparent video from transparent png files using ffmpeg I have a set of 300 transparent png files and I would like to create a transparent video file from them. I'm using the ffmpeg command as follows:
ffmpeg -f image2 -i anim.%04d.png -r 30 -vcodec png video.webm

I know webm has an alpha channel according to this answer. The command creates the video but the transparency is completely lost. What am I doing wrong? Is it possible to create a transparent .mp4 with ffmpeg?
You have to specify the pixel format, to force it to include the alpha channel, using the -pix_fmt option. You don't need to use png as your video codec either.
ffmpeg -i anim.%04d.png -r 30  -pix_fmt yuva420p video.webm