gst_buffer_make_writable() requires exclusive reference to the
GstMemory so the _make_writable() for the msdk buffer will result
to fallback system memory copy, because the msdk memory were initialized
with GST_MEMORY_FLAG_NO_SHARE flag.
Note that, disable sharing GstMemory brings high overhead but actually
the msdk memory objects can be shared over multiple buffers.
If the memory is not shareable, newly added GstAllocator::mem_copy will
create copied msdk memory.
This patch includes:
1\ Implements MsdkDmaBufAllocator and allocation of msdk dmabuf memroy.
2\ Each msdk dmabuf memory include its own msdk surface kept by GQuark.
3\ Adds new option GST_BUFFER_POOL_OPTION_MSDK_USE_DMABUF
https://bugzilla.gnome.org/show_bug.cgi?id=793707
There needs to be generalized for the parameter from
GstVideoMsdkVideoMemory to GstMemory.
Thus we can call these functions if using DMABuf memory.
https://bugzilla.gnome.org/show_bug.cgi?id=793707
Currently a gst buffer has one mfxFrameSurface when it's allocated and
can't be changed.
This is based on that the life of gst buffer and mfxFrameSurface would
be same.
But it's not true. Sometimes even if a gst buffer of a frame is finished
on downstream,
mfxFramesurface coupled with the gst buffer is still locked, which means
it's still being used in the driver.
So this patch does this.
Every time a gst buffer is acquired from the pool, it confirms if the
surface coupled with the buffer is unlocked.
If not, replace it with new unlocked one.
In this way, user(decoder or encoder) doesn't need to manage gst buffers
including locked surface.
To do that, this patch includes the following:
1. GstMsdkContext
- Manages MSDK surfaces available, used, locked respectively as the
following:
1\ surfaces_avail : surfaces which are free and unused anywhere
2\ surfaces_used : surfaces coupled with a gst buffer and being used
now.
3\ surfaces_locked : surfaces still locked even after the gst buffer
is released.
- Provide an api to get MSDK surface available.
- Provide an api to release MSDK surface.
2. GstMsdkVideoMemory
- Gets a surface available when it's allocated.
- Provide an api to get an available surface with new unlocked one.
- Provide an api to release surface in the msdk video memory.
3. GstMsdkBufferPool
- In acquire_buffer, every time a gst buffer is acquired, get new
available surface from the list.
- In release_buffer, it confirms if the buffer's surface is unlocked or
not.
- If unlocked, it is put to the available list.
- If still locked, it is put to the locked list.
This also fixes bug #793525.
https://bugzilla.gnome.org/show_bug.cgi?id=793413https://bugzilla.gnome.org/show_bug.cgi?id=793525
Implements 2 memory allocators:
1\ GstMsdkSystemAllocator: This will allocate system memory.
2\ GstMsdkVideoAllocator: This will allocate device memory depending
on the platform. (eg. VASurface)
Currently GstMsdkBufferPool uses video allocator currently by default
only on linux. On Windows, we should use system memory until d3d
allocator
is implemented.
https://bugzilla.gnome.org/show_bug.cgi?id=790752
