Support the wayland zwp_linux_dmabuf_unstable_v1 protocol.
SHM formats and DMABuf formats are exposed differently in caps: the
DMABuf formats are flagged with GST_CAPS_FEATURE_MEMORY_DMABUF.
No buffer pool is proposed for DMABuf buffers, it is the upstream
element responsibility to provide with such buffers.
https://bugzilla.gnome.org/show_bug.cgi?id=711155
This reduces the complexity of having a custom buffer pool, as
we don't really need it. We only need the custom allocation part.
And since the wl_buffer is no longer saved in a GstMeta, we can
create it and add it on the buffers in the sink's render()
function, which removes the reference cycle caused by the pool
holding a reference to the display and also allows more generic
scenarios (the allocator being used in another pool, or buffers
being allocated without a pool [if anything stupid does that]).
This commit also simplifies the propose_allocation() function,
which doesn't really need to do all these complicated checks,
since there is always a correct buffer pool available, created
in set_caps().
The other side effect of this commit is that a new wl_shm_pool
is now created for every GstMemory, which means that we use
as much shm memory as we actually need and no more. Previously,
the created wl_shm_pool would allocate space for 15 buffers, no
matter if they were being used or not.
This also removes the GstWlMeta and adds a wrapper class for wl_buffer
which is saved in the GstBuffer qdata instead of being a GstMeta.
The motivation behind this is mainly to allow attaching wl_buffers on
GstBuffers that have not been allocated inside the GstWaylandBufferPool,
so that if for example an upstream element is sending us a buffer
from a different pool, which however does not need to be copied
to a buffer from our pool because it may be a hardware buffer
(hello dmabuf!), we can create a wl_buffer directly from it and first,
attach it on it so that we don't have to re-create a wl_buffer every
time the same GstBuffer arrives and second, force the whole mechanism
for keeping the buffer out of the pool until there is a wl_buffer::release
on that foreign GstBuffer.
- bump wayland version to 0.95.0 which will lead to stable 1.0 release
- avoid memcopy and use propose_allocation for GstBufferPool allocation
- using WaylandBufferPool
- shm: Allocate shm buffers through new wl_shm_pool interface
(the shm buffer allocation is a two step process now: first
allocate a wl_shm_pool, then allocate a buffer from the pool)
https://bugzilla.gnome.org/show_bug.cgi?id=681453
