[Spice-devel] [PATCH v1 0/5] dcc: Create a stream for non-gl/remote clients that want to use dmabuf

[Vivek Kasireddy]

For clients that cannot accept a dmabuf fd directly (such as those
running on a remote system), this patch series provides a way for
the Spice server to stream the gl/dmabuf data/buffer instead. This
is mostly done by enabling the creation of Gst memory using a dmabuf
fd as the source. This ability is useful given that dmabuf is the
standard mechanism for sharing buffers between various drivers and
userspace in many Graphics and Media usecases. Currently, this is
only used/tested with Qemu and remote-viewer using the x264enc/dec
codec to stream the Guest/VM desktop but it can be easily extended
to other plugins and applications.

Here is roughly how things work:
- The application (e.g, Qemu) chooses its preferred codec (a Gstreamer
  one) and calls gl_scanout (to update the fd) followed by gl_draw.
- In response, the Spice server checks to see if the client is capable
  of accepting a dmabuf fd directly or not. If yes, the fd is forwarded
  directly to the client; otherwise, a new stream is created.
- The Spice server then sends the dmabuf fd to the Gstreamer encoder
  which uses it as an input for creating an encoded buffer which is then
  sent to the client.
- Once the encoding process is done, an async completion cookie is sent
  to the application.

Here is a link to the previous version that used a drawable to share
the dmabuf fd with the Gstreamer encoder:
https://lists.freedesktop.org/archives/spice-devel/2023-January/052948.html

Cc: Frediano Ziglio <freddy77 at gmail.com>
Cc: Gerd Hoffmann <kraxel at redhat.com>
Cc: Marc-André Lureau <marcandre.lureau at redhat.com>
Cc: Dongwon Kim <dongwon.kim at intel.com>

Vivek Kasireddy (5):
  dcc: Check to see if the client supports multiple codecs
  dcc: Create a stream associated with gl_draw for non-gl clients
  dcc-send: Encode and send gl_draw stream data to the remote client
  gstreamer-encoder: Add an encoder function that takes dmabuf fd as
    input
  video-stream: Don't stop a stream if a gl_draw operation is pending

 meson.build                      |   2 +-
 server/dcc-private.h             |   4 ++
 server/dcc-send.cpp              |  89 ++++++++++++++++++++++-
 server/dcc.cpp                   |  36 +++++++---
 server/display-channel-private.h |   6 ++
 server/gstreamer-encoder.c       | 119 ++++++++++++++++++++++++++++++-
 server/video-encoder.h           |  13 ++++
 server/video-stream.cpp          |  65 ++++++++++++++++-
 server/video-stream.h            |   2 +
 9 files changed, 319 insertions(+), 17 deletions(-)

-- 
2.37.2