We did several things to enable the new memory logic in msdkdec:
(1) We always use video memory for decoder in linux path;
(2) We give negotiated pool to alloc_pool stored in GstMsdkContext which
will be used in callback mfxFrameAllocator:Alloc to alloc surfaces as
MediaSDK needs, and this pool is also available for decoder itself;
(3) We modify decide_allocation process, that is we make pool negotiaion
before gst_msdk_init_decoder to ensure the pool is decided and ready for
use in mfxFrameAllocator:Alloc callback; then we will consider the case
when we need to do the gpu to cpu copy.
(4) In gst_msdkdec_finish_task, we modify the way for copy following the
logic in (3).
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3439>
Rewrite gst_msdk_frame_alloc and name it as xxx_2 before applying it.
It uses negotiated bufferpool stored in GstMsdkContext to allocate buffers
in the callback MfxFrameAllocator:Alloc, then extract VASurface from buffer,
wrap it as mfxMemIDs and pass these IDs to MediaSDK/oneVPL.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3439>
If the buffer is not msdk_buffer, we can try to directly import the
attached memory (i.e. va mem and dmabuf mem) by applying the common
uitl function: import_to_msdk_function ().
Here add a flag "from_qdata" in GstMsdkSurface to handle the cropping case,
we should avoid updating the crop values when msdk_surface is from the
memory's qdata, because the crop info from this surface is the already
updated one.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2498>
