I made some additions to the manual regarding Vulkan, but only in the general section. I'm not sure if I was always accurate, so please check what I wrote. However, I have not made any changes to the specific sections on decoding [19.1.1] and encoding [19.1.2] because I do not fully understand the subject. Is what is written in these sections still valid? What should we add? I'm sorry, I'm just confused and unable to make corrections.

I am posting my additions here in text format so you can check them.

"NOTE: Hardware acceleration in Linux is constantly evolving and causes numerous prob-
lems (but if it doesn’t work, it automatically reverts to software mode with the CPU). It
depends on the generation and brand of the video card; on proprietary or open source
drivers and on mesa user space drivers. Drivers change constantly, especially with the
succession of new graphics card models, and what worked before may no longer work
afterwards, or vice versa. Furthermore, being able to take advantage of hardware accel-
eration could mean having to compile CINELERRA-GG yourself by activating specific flags
that are necessary (for example: having hardware acceleration in decoding and encoding
the ffv1 codec requires compiling with the libplacebo library). Another case is having to
start the program with environment variables (for example, for older AMD cards, before
RDNA, use RADV_PERFTEST="video_decode,video_encode" to get hardware accel-
eration via Vulkan. Or use ANV_DEBUG="video-decode,
video-encode" for acceleration via Intel, etc.). It should also be noted that, sometimes,
software decoding can be more efficient than hardware acceleration. You need to experi-
ment to see what works best for your use case."

and:

"VULKAN (experimental) Vulkan, like OpenGL and unlike Vdpau and Vaapi, is hardware
agnostic and could work for any type and brand of video card. It appears that OpenGL
will be deprecated in the future and only Vulkan will take its place, emulating OpenGL
functionality. Vulkan requires initialization of its device type. This is done automatically
by CINELERRA-GG for decoding but still needs to be made explicit in the encoding presets.
(CIN_HW_DEV=vulkan)."