Re: [PATCH] media: hevc: Add sps_max_sub_layers_minus1 to v4l2_ctrl_hevc_sps

[Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>]

Le 27/05/2021 à 09:19, Hans Verkuil a écrit :
> Hi Benjamin,
>
> On 30/04/2021 18:48, John Cox wrote:
> > sps_max_sub_layers_minus1 is needed if the driver wishes to determine
> > whether or not a frame might be used for reference.
> How does this patch from John relate to your "Add HANTRO G2/HEVC decoder
> support for IMX8MQ" patch series?

Hantro hardware doesn't use this information but that could help to optimize
the number of reference frames.

> Can I apply both this patch and your patch series? Does this patch make
> sense for the HEVC stateless API?

Yes it part of the HEVC specification, that will help to move it out of staging.

Regards,
Benjamin

> You have been digging into HEVC, so I hope you can help out.
>
> Regards,
>
> 	Hans
>
> > Signed-off-by: John Cox <jc@xxxxxxxxxxxxx>

Reviewed-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>

> > ---
> > This is useful to the Pi H265 decoder as it allows it to only create
> > and store MV info for frames that need to.
> >
> >   Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 3 +++
> >   include/media/hevc-ctrls.h                                | 3 +--
> >   2 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > index b0de4e6e7ebd..9a891202abbf 100644
> > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> > @@ -2924,6 +2924,9 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
> >       * - __u8
> >         - ``chroma_format_idc``
> >         -
> > +    * - __u8
> > +      - ``sps_max_sub_layers_minus1``
> > +      -
> >       * - __u64
> >         - ``flags``
> >         - See :ref:`Sequence Parameter Set Flags <hevc_sps_flags>`
> > diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
> > index b4cb2ef02f17..b2d296b77653 100644
> > --- a/include/media/hevc-ctrls.h
> > +++ b/include/media/hevc-ctrls.h
> > @@ -75,8 +75,7 @@ struct v4l2_ctrl_hevc_sps {
> >   	__u8	num_short_term_ref_pic_sets;
> >   	__u8	num_long_term_ref_pics_sps;
> >   	__u8	chroma_format_idc;
> > -
> > -	__u8	padding;
> > +	__u8	sps_max_sub_layers_minus1;
> >   
> >   	__u64	flags;
> >   };