Comment 16 for bug 1698287

Doug,

A couple of my fixes have landed today, as well as ffmpeg 3.3 which fixes most of mpv's acceleration problems. However your comment reminds me there's another bug with mpv I need to open and fix... mpv will by default try to use the X11 display provided by Xwayland and ends up with vaapi-copy. You can work around that trivially and get hwdec=vaapi proper working again by hiding Xwayland:

   env -uDISPLAY mpv --hwdec myvideo.mp4