Tested hardware: Geforce 9300 mGPU (NVAC), GT730-GK208B (NV106)
VA-API apps: gstreamer-vaapi, Chromium-vaapi-bin(AUR)
OS: ArchLinux x86_64 kernel 5.2.2-arch1-1-ARCH
GUI: GNOME/Wayland using nouveau

- vainfo & vdpauinfo SIGSEV due to NULL pointer
ArchLinux discussion thread
https://bbs.archlinux.org/viewtopic.php?id=247466

- h264 video decode failed with assertion and tendency to crash GNOME/GUI
Test h264 clip:
$ youtube-dl -f mp4 https://www.youtube.com/watch?v=azvR__GRQic
Gstreamer command line
$ gst-launch-1.0 playbin uri=file:///path/to/MP4
or
$ gst-launch-1.0 filesrc location=/path/to/MP4 ! qtdemux ! vaapidecodebin !
vaapisink

Use enhanced-h264ify plugin on Chromium to playback the same h264 video clip
from YouTube.com
Geforce 9300 mGPU - video played as garbage, browser may crash
GT730 - fallback to FFmpegVideoDecoder after asserts
ve4_set_surface_info:969 - unsupported surface format, try
is_format_supported() !
romium/chromium --type=gpu-process
--field-trial-handle=7734813049068668419,17986421265460211344,131072
--disable-breakpad
--gpu-preferences=KAAAAAAAAAAgAACgAQAAAAAAAAAAAGAAAAAAAAAAAAAIAAAAAAAAAAgAAAAAAAAA
--service-request-channel-token=7551475798706255496:
../mesa-19.1.3/src/gallium/drivers/nouveau/nvc0/nve4_compute.c:396:
nve4_compute_validate_constbufs: Assertion `i > 0' failed.