VAAPI is broken in Wayland
Since maybe september/october VAAPI (can't pinpoint exact versions, sorry) is broken for me on wayland (KDE).
I have a Sandy Bridge gen CPU therefore I'm using libva-intel-driver, with LIBVA_DRIVER_NAME set to 'i965' as it should.
mpv gives the following error:
error: failed to resolve wl_drm_interface(): /usr/lib/libEGL_mesa.so.0: undefined symbol: wl_drm_interface
[vaapi] libva: /usr/lib/dri/i965_drv_video.so init failed
and vainfo:
Trying display: wayland
error: failed to resolve wl_drm_interface(): /usr/lib/libEGL_mesa.so.0: undefined symbol: wl_drm_interface
libva error: /usr/lib/dri/i965_drv_video.so init failed
vaInitialize failed with error code -1 (unknown libva error),exit
I haven't tried in other wayland compositors, but I can certainly be sure that error will still be there.
Of course in Xorg it Just Works™.