It is possible for OBS to receive incomplete frames from the compositor
if the graphics drivers in use do not support implicit synchronization.
The compositors usually try to workaround this issue by waiting all
render operations to complete before sharing frames with OBS. However,
this has performance implications for the compositors. Similarly, OBS
should also make sure that all the rendering operations sourcing the
received buffer are complete before returning the respective pw_buffer
back to the compositor, or it would risk the image it is working on
getting overwritten without some type of synchronization.
This change leverages PipeWire's ability to share DRM syncobj fds to
implement an explicit synchronization solution to solve the problem
described above. The usage of these DRM syncobjs is negotiated with the
compositor that OBS is running on. So OBS can still work even if the
compositor does not support explicit synchronization.
Signed-off-by: Doğukan Korkmaztürk <dkorkmazturk@nvidia.com>
c2b4823075