If d3d11window does not convert format internally, shader resource view
is not required. Note that shader resource view is used for
color conversion using shader but when conversion is not required,
we just copy input input texture to backbuffer.
In theory it should not happen but it happened to me
in some cases where it failed to allocate some video
buffers so this was a consequence of a corner case.
Better to be safe than sorry.
The previous implementation had a very high reproducibility race where
if after a track switch, the ex-active track pad completed a buffer
chain (now returning not-linked) the flow combiner had all their pads in
non-linked state, propagating it as an error and stopping the pipeline.
By resetting the flow combiner in response to RECONFIGURE events that
race is made impossible.
Can happen if the oldest frame is the current frame
and if gst_video_decoder_finish_frame failed in which
case the current is unref and then drop instead of
just drop.
This patch also removes some assumptions, it was strange
to call unref and finish_frame in gst_msdkdec_finish_task.
In principle when owning a frame, the code should either
unref, or drop or finish.
It's currently the only sane way we can use MoltenVK functions to
integrate with Metal API.
It also removes the need to specify the VK_ICD_FILENAMES environment
variable pointing to MoltenVK_icd.json.
D3D11 dynamic texture is a special memory type, which is mainly used for
frequent CPU write access to the texture. For now, this texture type
does not support gst_memory_{map,unmap}
* Create staging texture only when the CPU access is requested.
Note that we should avoid the CPU access to d3d11 memory as mush as possible.
Incoming d3d11upload and d3d11download will take this GPU memory upload/download.
* Upload/Download texture memory from/to staging only if it needed, similar to
GstGL PBO implementation.
* Define more dxgi formats for future usage (e.g., color conversion, dxva2 decoder).
Because I420_* formats are not supported formats by dxgi, each plane should
be handled likewise GstGL separately, but NV12/P10 formats might be supported ones.
So we decide the number of d3d11memory per GstBuffer for video memory depending on
OS version and dxgi format. For instance, if NV12 is supported by OS,
only one d3d11memory with DXGI_FORMAT_NV12 texture can be allocated by this commit.
One use case of such texture is DXVA. In case DXVA decoder, it might need to produce decoded data
to one DXGI_FORMAT_NV12 instead of seperate Y and UV planes.
Such behavior will be controlled via configuration of GstD3D11BufferPool and
default configuration is separate resources per plane.
Depending on selected feature level, d3d11 API usage can be different.
Instead of querying the selected feature level by user whenever required,
store it once by d3d11device.
