Make webm support alpha?
When choosing vp8 or vp9 for video, choose vorbis for sound
Output can choose webm.
But the output webm file does not support transparency
I checked the logs and found pixelFormat=yuv420p
Can you add pixelFormat options of vp8 and vp9?
I know it can be transparent if the pixelFormat is set to yuva420p
I don't want export to ffv1 and manually convert it with ffmpeg.
