Adapt GstVaapiVideoMemory allocator to support creation of VA surfaces
with an explicit pixel format. This allows for direct rendering to
VA surface memory from a software decoder.
Allow plain gst_buffer_map() interface to work with gstreamer-vaapi
video buffers, i.e. expose the underlying GstVaapiSurfaceProxy to the
caller. This is the only sensible enough thing to do in this mode as
the underlying surface pixels need to be extracted through an explicit
call to the gst_video_frame_map() function instead.
A possible use-case of this is to implement a "handoff" signal handler
to fakesink or identity element for further processing.
Fix gst_vaapi_video_allocator_new() to silently check for direct-rendering
mode support, and not trigger fatal-criticals if either test surface or
image could not be created. Typical case: pixel format mismatch, e.g. NV12
supported by most hardware vs. I420 supported by most software decoders.
On map, ensure we have GST_MAP_WRITE flags since this is only what we
support for now. Likewise, on unmap, make sure that the VA image is
unmapped for either read or write, while still committing it to the
VA surface if write was requested.
Implement GstVideoMeta::{,un}map() to support raw YUV buffer upload when
the last component is unmapped. Downloads are not supported yet. The aim
was to first support SW decoding + HW accelerated rendering (vaapisink).
e.g. for Wayland.
Add initial support for GstVaapiVideoMemory backed buffer pool. The memory
object currently holds a reference to GstVaapiVideoMeta.
Signed-off-by: Gwenole Beauchesne <gwenole.beauchesne@intel.com>