Initial support for d3d11 texture so that encoder can copy
upstream d3d11 texture into encoder's own texture pool without
downloading memory.
This implementation requires MFTEnum2() API for creating
MFT (Media Foundation Transform) object for specific GPU but
the API is Windows 10 desktop only. So UWP is not target
of this change.
See also https://docs.microsoft.com/en-us/windows/win32/api/mfapi/nf-mfapi-mftenum2
Note that, for MF plugin to be able to support old OS versions
without breakage, this commit will load MFTEnum2() symbol
by using g_module_open()
Summary of required system environment:
- Needs Windows 10 (probably at least RS 1 update)
- GPU should support ExtendedNV12SharedTextureSupported feature
- Desktop application only (UWP is not supported yet)
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1903>
The behavior for zero AVEncMPVGOPSize value would be
varying depending on GPU vendor implementation and some
GPU will produce keyframe only once at the beginning of encoding.
That's unlikely expected result for users.
To make this property behave consistently among various GPUs,
this commit will change default value of "gop-size" property to -1
which means "auto". When "gop-size" is unspecified, then
mfvideoenc will calculate GOP size based on framerate
like that of our x264enc implementation.
See also
https://docs.microsoft.com/en-us/windows/win32/directshow/avencmpvgopsize-property
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1911>
