VP9 on Android Exoplayer transcoding

[tbjf]

I tried converting to mkv ("ffmpeg -i input_vp9.mp4 -c copy output_vp9.mkv") and Exoplayer on Android accepts it.

But, another piece of the puzzle:

(With Web Player on Android)
DirectPlayProfile { Container: "webm", AudioCodec: "vorbis,opus", VideoCodec: "vp8,vp9,av1", Type: Video },
DirectPlayProfile { Container: "mp4,m4v", AudioCodec: "aac,mp3,opus,flac,vorbis", VideoCodec: "h264,hevc,vp9,av1", Type: Video }


So the webplayer accepts vp9 in mp4 without problem.

I remember Googling this a while ago, and there was something that Exoplayer were very strict with what is "officially" supported.

But it doesn't make sense if that the webplayer can accept it, but Exoplayer can't. (I don't have access to the Exoplayer on the TV at the moment, but I'm sure this is accepting VP9 MP4 without transcoding.)