so I played around with vp9 enciding a bit more.apoarently there is vp9 lossless mode, and additionally libvpx can support high bit depth if configured so.
Tested on my laptop and the lossless file is, as expected, 15 times larger but looks better. Thank you Andrew.
Will compiling with vp9 multibit affect any loading or rendering of vp8/vp9? I will try to check this and test it too.
I also tried to remove (currently unused?) libavdevice build from ffmpeg, and fix termux breakage (libandroid-shmem lib was missing)
This I did not check in yet because my early morning tests were flawed -- I only had the configure.ac patch portion in and not the thirdparty/Makefile patch because I was testing the vp9 multibit. So I have to start over with that and right now am at least compiling on Debian 9.1 32-bit just to make sure it compiles.
try attached patches and check if vdpau/vaapi still works?
Got to redo my tests. I am concerned about potential impact, not to vdpau/vaapi, but rather to v4linux2 and alsa and captures from devices.