In gst-msdk, a mfx session may be shared between different gst
elements, each element tries to set the frame allocator. However, per
the MSDK documation[1], the behavior is undefined if reset the frame
allocator while the previous allocator is in use. Fortunately all
elements use the same frame allocator, so we can avoid to call
MFXVideoCORE_SetFrameAllocator again.
[1]: https://software.intel.com/en-us/node/628430#MFXVideoCORE3
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
In case that pipeline is like ".. ! decoder ! encoder ! ..." with using
video memory,
decoder needs to know the async depth of the following msdk element so
that it could
allocate the correct number of video memory.
Otherwise, decoder's memory is exhausted while processing.
https://bugzilla.gnome.org/show_bug.cgi?id=790752
According to the driver's instruction, if there are two or more encoders
or decoders in a process, the session should be joined by
MFXJoinSession.
To achieve this successfully by GstContext, this patch adds job type
specified if it's encoder, decoder or vpp.
If a msdk element gets to know if joining session is needed by the
shared context,
it should create another instance of GstContext with joined session,
which
is not shared.
https://bugzilla.gnome.org/show_bug.cgi?id=790752
Implements msdk frame allocator which is required from the driver.
Also makes these functions global so that GstMsdkAllocator could use
the allocated video memory later and couple with GstMsdkMemory.
GstMsdkContext keeps allocation information such as mfxFrameAllocRequest
and mfxFrameAllocResponse after allocation.
https://bugzilla.gnome.org/show_bug.cgi?id=790752
Makes GstMsdkContext to be a descendant of GstObject so that
we could track the life-cycle of the session of the driver.
Also replaces MsdkContext with this one.
Keeps msdk_d3d.c alive for the future.
https://bugzilla.gnome.org/show_bug.cgi?id=790752
