Test renderings, using x265, work fine, except using the 10-bit and
12-bit presets fail indicating that those pixel formats are not
supported by x265 encoder.
Using the multibit appimage (without the new patch), the 12- and
10-bit renderings work, but the vaapi preset does not.
To get 10-bit and 12-bit you have to apply ./thirdparty/compile_multibit_x265.txt and move the 3 patch files WITH the new names (i.e. instead of 3.5, the 17122023) to subdirectory ./thirdparty/src and then do a build. BUT I have not checked to see if the line numbers are still valid in the patchsets. I will try that late today or else tomorrow.
Andrea, I tested and if you have any extra time to run some timings to see if faster, that would be great. I only rendered 1 h265-12bit.mp4 and did not comparisons. However, comparing a build with a multibit appimage may not be useful as appimage might be slower overall. The patch set as described above works as is EXCEPT you will have to edit ./thirdparty/Makefile by hand -- around line 268, delete the x265.cfg lines and substitute this line instead:
x265.cfg_vars?=chmod +x ./configure; chmod +x ./multilib.sh;
So you will see these lines around that area:
twolame.cfg_params?=--enable-shared=no
x264.cfg_params?= --enable-static --enable-pic
x265.cfg_vars?=chmod +x ./configure; chmod +x ./multilib.sh;
libvpx.cfg_params?= --enable-pic --disable-avx512 --enable-vp9-highbitdepth --disable-examples --disable-unit_tests
libdpx.cfg_vars?= libtoolize; aclocal; autoconf; automake -a;