Hi Nicolas, On Tue, 14 Jan 2025 11:16:47 -0500, Nicolas Dufresne wrote: > despite Andrzej having left the community, we are not giving up on the encoder > work. In 2025, we aim at working more seriously on the V4L2 spec, as just > writing driver won't cut it. Each class of codecs needs a general workflow spec > similar to what we have already for stateful encoder/decoder and stateless > decoder. > > - https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/dev-decoder.html > - https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/dev-encoder.html > - https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/dev-stateless-decoder.html > > It is on top of this, that for each codec we have to add controls (mostly > compound) specifics and details that suites stateless accelerators. > > From a community stand point, the most important focus is to write and agree on > spec and controls. Once we have that, vendors will be able to slowly move away > from their custom solution, and compete on actual hardware rather then > integration. > > It is also time to start looking toward the future, since Hantro H1 is very > limited and ancient encoder. On same brand, if someone could work on VC8000E > shipped on IMX8M Plus, or Rockchip codecs, that will certainly help progress. Marco Felsch and I recently started to work on stateless encoders, too. Marco is working on a driver for VC8000E and I am working on a driver for the Rockchip VEPU580. As user space, we are currently using the GStreamer element from the draft merge request [0] on both drivers. Michael [0] https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5676 > We > can also get inspiration from many other stateless encoding APIs now, notably > VA, DXVA and Vulkan Video. > > Of course, folks likes to know when this will happen, stateless decoders took 5 > years from start to the first codec being merged, hopefully we don't beat that > record. I personally aim for producing work during the summer, and mostly focus > on the spec. Its obvious for me that testing on H1 with a GStreamer > implementation is the most productive, though I have strong interest in having > an ecosystem of drivers. A second userspace implementation, perhaps ffmpeg ?, > could also be useful. > > If you'd like to take a bite, this is a good thread to discuss forward. Until > the summer, I planned to reach to Paul, who made this great presentation [1] at > FOSDEM last year and start moving the RFC into using these ideas. One of the > biggest discussion is rate control, it is clear to me that modern HW integrated > RC offloading, though some HW specific knobs or even firmware offloading, and > this is what Paul has been putting some thought into. > > If decoders have progressed so much in quality in the last few years, it is > mostly before we have better ways to test them. It is also needed to start > thinking how do we want to test our encoders. The stateful scene is not all > green, with a very organic groth and difficult to unify set of encoders. And we > have no metric of how good or bad they are either.
