Re: [PATCH v5 0/3] media: rkvdec: Add a VP9 backend

Adrian Ratiu <adrian.ratiu@xxxxxxxxxxxxx> · Wed, 11 Nov 2020 02:11:30 +0200

On Tue, 10 Nov 2020, Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx> 
wrote:
On Wed, 2020-11-11 at 00:28 +0200, Adrian Ratiu wrote: 
Hi Ezequiel, 

On Tue, 10 Nov 2020, Ezequiel Garcia 
<ezequiel@xxxxxxxxxxxxxxxxxxxx> wrote: 
> On Mon, 2 Nov 2020 at 16:04, Adrian Ratiu 
> <adrian.ratiu@xxxxxxxxxxxxx> wrote:  
> > Dear all,   This is v5 of the series adding VP9 profile 0 
> > decoding to  rkvdec.    All feedback from v4 should be 
> > addressed, there's just one  thing I did not address: 
> > ref_frame_sign_biases in the uAPI. The  userspace tool I'm  
>  I believe that Hantro G2 VP9 needs ref_frame_sign_biases. 
> I think that it's also needed for the MTK decoder.  Might be 
> worth checking that as well, if the code is publicly 
> available  somewhere. 
 I consulted the imx8m app ref manual for the Hantro G2 core 
and  indeed there's not one, but three fields at SWREG11 and 13 
(last,  gold, alt) to signify sign biases for ref 
frames. Thanks for the  hint! 

> Coming to think about it, I think we are really close to 
> having  this uAPI directly upstream.    Let's take a step 
> back on why we have these uAPIs in the staging  area. Couple 
> years ago, there were some doubts in the media  community 
> about these uAPIs, and we wanted to wait a bit for  more 
> users before moving to public land.    The uAPIs were meant 
> to be in staging until enough users  appeared and we were 
> confident enough to move to stable.    For VP9, given the 
> feedback received through the year was  already addressed, I 
> think all that's left is to check the  interface and make 
> sure it can support Rockchip (RK3399, RK3326,  etc), Hantro 
> G2 and Mediatek,   We will be very close to having a public 
> API, and we could even  merge it directly there. 
 Thank you very much for this background. I understand that the 
uAPI is independent from the driver implementations, so having 
a  good stable uAPI is beneficial when (for example) adding 
support  for VP9 on G2 in  hantro or for upstream adoption of 
these  drivers.   Given this rkvdec driver implementation is 
also adding the VP9  uAPI and it's very close to stability 
(maybe only missing ref  frame sign bias, but who knows?) would 
you like to block its  submission until the uAPI is finalized 
or would it make sense to  treat the uAPI de-staging process 
separately because the uAPI is  independent from the driver?   

I don't mean to block it, quite the opposite, to make sure we 
take this opportunity to go through Rockchip, Hantro and 
Mediatek, double-check the uAPI is covering all the VP9 syntax, 
and then target for public API.

That makes sense. I'm just cautious to not directly botch the 
public API, but that's what reviews are for, right? :) Thanks 
again for helping with background & direction.

Cheers,
Ezequiel

Thanks,
Adrian

> Thanks,
> Ezequiel
> 
> > using [1] apparently doesn't need it or the default hwreg value for it
> > is capable of decoding the bitstreams I used on the driver, so I don't
> > really have a use-case to change and test that. :)
> > 
> > Considering the uAPI is a work in progress and expected to be modified,
> > ref_frame_sign_biases can be added later with others which might be
> > required to enable more functionality (for eg profiles >= 1).
> > 
> > Series tested on rk3399 and applies on next-20201030.
> > 
> > [1] https://github.com/Kwiboo/FFmpeg/tree/v4l2-request-hwaccel-4.2.2-rkvdec
> > 
> > Changelog
> > ---------
> > 
> > v5:
> > 
> > * Drop unnecessary OUTPUT buffer payload set in .buf_prepare.
> > * Drop obsolete .per_request ctrl flag
> > * Added new vp9 ctrls to v4l2_ctrl_ptr
> > * Fix pahole detected padding issues
> > * Send userspace an error if it tries to reconfigure decode resolution
> >   as v4l2 or rkvdec-vp9 backend do not support dynamic res changes yet
> > * Allow frame ctx probability tables to be non-mandatory so users can
> >   set them directly during frame decoding in cases where no defaults
> >   have been set previously (eg. ffmpeg vp9 backend)
> > * Some comments and documentation clarifications
> > * Minor checkpatch fixes
> > 
> > v4:
> > 
> > * Drop color_space field from the VP9 interface.
> >   V4L2 API should be used for it.
> > * Clarified Segment-ID comments.
> > * Moved motion vector probabilities to a separate
> >   struct.
> > 
> > v3:
> > 
> > * Fix documentation issues found by Hans.
> > * Fix smatch detected issues as pointed out by Hans.
> > * Added patch to fix wrong bytesused set on .buf_prepare.
> > 
> > v2:
> > 
> > * Documentation style issues pointed out by Nicolas internally.
> > * s/VP9_PROFILE_MAX/V4L2_VP9_PROFILE_MAX/
> > * Fix wrong kfree(ctx).
> > * constify a couple structs on rkvdec-vp9.c
> > 
> > 
> > Boris Brezillon (2):
> >   media: uapi: Add VP9 stateless decoder controls
> >   media: rkvdec: Add the VP9 backend
> > 
> > Ezequiel Garcia (1):
> >   media: rkvdec: Fix .buf_prepare
> > 
> >  .../userspace-api/media/v4l/biblio.rst        |   10 +
> >  .../media/v4l/ext-ctrls-codec.rst             |  550 ++++++
> >  drivers/media/v4l2-core/v4l2-ctrls.c          |  239 +++
> >  drivers/media/v4l2-core/v4l2-ioctl.c          |    1 +
> >  drivers/staging/media/rkvdec/Makefile         |    2 +-
> >  drivers/staging/media/rkvdec/rkvdec-vp9.c     | 1577 +++++++++++++++++
> >  drivers/staging/media/rkvdec/rkvdec.c         |   72 +-
> >  drivers/staging/media/rkvdec/rkvdec.h         |    6 +
> >  include/media/v4l2-ctrls.h                    |    5 +
> >  include/media/vp9-ctrls.h                     |  486 +++++
> >  10 files changed, 2942 insertions(+), 6 deletions(-)
> >  create mode 100644 drivers/staging/media/rkvdec/rkvdec-vp9.c
> >  create mode 100644 include/media/vp9-ctrls.h
> > 
> > --
> > 2.29.0
> > 