What are the WebM (VP9+opus) encoding settings compatible for YouTube import for a video with a still image ?
I tried PAL and NTSC framerates with 48kHz stereo and and image size of 640x360 and kept every other parameters' defaults :
$ ffmpeg -i myOriginialPureAudioFile-CUT.opus -i myAudioFile.png -ac 2 -s 640x360 -strict strict -r pal myAudioFile.webm
But YouTube says :
The video has failed to process. Please make sure you are uploading a supported file type.