meson: add a video codec support option

This allows to turn on/off all hw implementations for a specific video
codec across the tree. Patent encumbered codecs can cause problems for
distributions due to the nature of at least MPEG-LA licensing.

https://jina-liu.medium.com/settle-your-questions-about-h-264-license-cost-once-and-for-all-hopefully-a058c2149256
is probably the best explaination I can find.

From a distro pov, codecs are a jigsaw puzzle, you only seem to become a problem well you fit all the pieces.

This patch will allow disabling the mesa piece of the puzzle.

Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15258>

.gitlab-ci/meson/build.sh

@@ -71,6 +71,7 @@ meson _build --native-file=native.file \
       ${GALLIUM_ST} \
       -D gallium-drivers=${GALLIUM_DRIVERS:-[]} \
       -D vulkan-drivers=${VULKAN_DRIVERS:-[]} \
+      -D video-codecs=h264dec,h264enc,h265dec,h265enc,vc1dec \
       -D werror=true \
       ${EXTRA_OPTION}
 cd _build

meson.build

@@ -320,6 +320,11 @@ if with_vulkan_beta
   pre_args += '-DVK_ENABLE_BETA_EXTENSIONS'
 endif
 
+_codecs = get_option('video-codecs')
+foreach c : ['vc1dec', 'h264dec', 'h264enc', 'h265dec', 'h265enc']
+   pre_args += '-DVIDEO_CODEC_@0@=@1@'.format(c.to_upper(), _codecs.contains(c).to_int())
+endforeach
+
 _platforms = get_option('platforms')
 if _platforms.contains('auto')
   if system_has_kms_drm
@@ -2273,6 +2278,9 @@ if with_gbm
 endif
 
 lines += ''
+lines += 'Video Codecs: ' + ' '.join(_codecs)
+lines += ''
+
 if with_any_vk
   lines += 'Vulkan drivers:  ' + ' '.join(_vulkan_drivers)
   lines += 'Vulkan ICD dir:  ' + with_vulkan_icd_dir

meson_options.txt

@@ -527,3 +527,12 @@ option(
   value : 'disabled',
   description : 'Build the intel-clc compiler (required for ray queries).'
 )
+option(
+  'video-codecs',
+  type : 'array',
+  value : [],
+  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.'
+)