I can confirm that making the following modification to meson_options.txt fixes the issue:
option( 'video-codecs',
type : 'array',
value : ['vc1dec', 'h264dec', 'h264enc', 'h265dec', 'h265enc'],
choices: [
'vc1dec', 'h264dec', 'h264enc', 'h265dec', 'h265enc'
],
description : 'List of patent encumbered codecs to build support for. Distros might want to consult their legal department before enabling these. This is used for all video APIs (vaapi, vdpau, vulkan). Non-patent encumbered codecs will be enabled by default.'
)
Basically copy the contents of the 'choices' field to the 'value' field. Here's my vainfo output with a self-compiled mesa package including these modifications:
libva info: VA-API version 1.15.0libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so
libva info: Found init function __vaDriverInit_1_15
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.15 (libva 2.12.0)
vainfo: Driver version: Mesa Gallium driver 22.2.0-rc1 for AMD Radeon RX 6900 XT (navi21, LLVM 14.0.6, DRM 3.46, 5.18.0-3-amd64)
vainfo: Supported profile and entrypoints
VAProfileMPEG2Simple : VAEntrypointVLD
VAProfileMPEG2Main : VAEntrypointVLD
VAProfileVC1Simple : VAEntrypointVLD
VAProfileVC1Main : VAEntrypointVLD
VAProfileVC1Advanced : VAEntrypointVLD
VAProfileH264ConstrainedBaseline: VAEntrypointVLD
VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice
VAProfileH264Main : VAEntrypointVLD
VAProfileH264Main : VAEntrypointEncSlice
VAProfileH264High : VAEntrypointVLD
VAProfileH264High : VAEntrypointEncSlice
VAProfileHEVCMain : VAEntrypointVLD
VAProfileHEVCMain : VAEntrypointEncSlice
VAProfileHEVCMain10 : VAEntrypointVLD
VAProfileHEVCMain10 : VAEntrypointEncSlice
VAProfileJPEGBaseline : VAEntrypointVLD
VAProfileVP9Profile0 : VAEntrypointVLD
VAProfileVP9Profile2 : VAEntrypointVLD
VAProfileAV1Profile0 : VAEntrypointVLD
VAProfileNone : VAEntrypointVideoProc
====