The support for buffer exports in VA-API was added in version 0.36. These
interfaces are for interop with EGL, OpenCL, etc.
GStreamer-VAAPI uses it for a dmabuf memory allocator. Though, gstreamer-vaapi
has to support VA-API versions ranging from 0.30.4, which doesn't support it.
This patch guards all the buffer exports handling (and dmabuf allocator) if
the detected VA-API version is below 0.36.
https://bugzilla.gnome.org/show_bug.cgi?id=746405
Add support for GEM buffer exports. This will only work with VA drivers
based off libdrm, e.g. the Intel HD Graphics VA driver. This is needed
to support interop with EGL and the "Desktop" GL specification. Indeed,
the EXT_image_dma_buf_import extension is not going to be supported in
Desktop GL, due to the lack of support for GL_TEXTURE_EXTERNAL_OES targets
there.
This is useful for implementing VA/EGL interop with legacy Mesa stacks,
in Desktop OpenGL context.
https://bugzilla.gnome.org/show_bug.cgi?id=736717
Use the new VA buffer export APIs to allow for a VA surface to be
exposed as a plain PRIME fd. This is in view to simplifying interop
with EGL or OpenCL for instance.
https://bugzilla.gnome.org/show_bug.cgi?id=735364
The VA buffer export APIs work for a particular lifetime starting from
vaAcquireBufferHandle() and ending with vaReleaseBufferHandle(). As such,
it could be much more convenient to support implicit releases by simply
having a refcount reaching zero.
https://bugzilla.gnome.org/show_bug.cgi?id=736721
