This affects vo_opengl_cb in particular: it'll most likely auto-load
VDA, and then the VideoToolbox decoder won't work. And everything fails.
This is mainly caused by FFmpeg using separate pixfmts for the _same_
thing (CVPixelBuffers), simply because libavcodec's architecture demands
that hwaccel backends are selected by pixfmts. (Which makes no sense,
but now we have the mess.)
So instead of duplicating FFmpeg's misdesign, just change the format to
our own canonical one on the image output by the decoder. Now the GL
interop code is exactly the same for VDA and VT, and we use the VT name
only.
wm4
6894858bf2