[RFC 0/2] VP8 stateless V4L2 encoding uAPI + driver

[Nicolas Frattaroli]

On Thursday, 9 March 2023 13:56:49 CET Andrzej Pietrasiewicz wrote:
> Dear All,
> 
> This two-patch series adds uAPI for stateless VP8 encoding
> and an accompanying driver using it.
> 
> It has been tested on an rk3399 board and there exists
> a gstreamer user:
> 
> https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3736
> 
> example pipeline:
> 
> gst-launch-1.0 videotestsrc num-buffers=500 !
> video/x-raw,width=640,height=480 \ ! v4l2slvp8enc ! queue ! matroskamux !
> filesink location=test_vp8.mkv
> 
> I kindly ask for comments.
> 
> Notably, the documentation for the added uAPI is missing,
> that is to be addressed when sending a patch series proper (not RFC).
> 
> For the RFC I also did not care to replace a BUG_ON() in the boolean
> encoder.
> 
> Rebased onto v6.2.
> 
> Regards,
> 
> Andrzej

Hello,

I can't offer much in terms on technical comments on the implementation,
but thank you for your work on this. A more general question: Is the
rate control done by the userspace component or the kernel or even the
hardware?

I tried this patchset (and the gstreamer merge request) out last night
and ran into quite noticable i-frame pulsing, and am wondering who the
culprit of that is. Looking at the vp8 encode params in the uAPI, it
looks like it'll be userspace in charge of rate control?

On a related side note, since I let this run all night with different
parameters I can happily report that it seems to be quite stable, no
problems encountered at all.

Kind regards,
Nicolas Frattaroli