Le mercredi 05 mai 2021 à 16:18 +0100, John Cox a écrit :
> > The HEVC HANTRO driver needs to know the number of bits to skip at
> > the beginning of the slice header.
> > That is a hardware specific requirement so create a dedicated control
> > for this purpose.
> >
> > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
> > ---
> > .../userspace-api/media/drivers/hantro.rst | 19 +++++++++++++++++++
> > .../userspace-api/media/drivers/index.rst | 1 +
> > include/media/hevc-ctrls.h | 13 +++++++++++++
> > 3 files changed, 33 insertions(+)
> > create mode 100644 Documentation/userspace-api/media/drivers/hantro.rst
> >
> > diff --git a/Documentation/userspace-api/media/drivers/hantro.rst
> > b/Documentation/userspace-api/media/drivers/hantro.rst
> > new file mode 100644
> > index 000000000000..cd9754b4e005
> > --- /dev/null
> > +++ b/Documentation/userspace-api/media/drivers/hantro.rst
> > @@ -0,0 +1,19 @@
> > +.. SPDX-License-Identifier: GPL-2.0
> > +
> > +Hantro video decoder driver
> > +===========================
> > +
> > +The Hantro video decoder driver implements the following driver-specific
> > controls:
> > +
> > +``V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (integer)``
> > + Specifies to Hantro HEVC video decoder driver the number of data (in
> > bits) to
> > + skip in the slice segment header.
> > + If non-IDR, the bits to be skipped go from syntax element
> > "pic_output_flag"
> > + to before syntax element "slice_temporal_mvp_enabled_flag".
> > + If IDR, the skipped bits are just "pic_output_flag"
> > + (separate_colour_plane_flag is not supported).
>
> What happens if it is a dependant_slice_segement or
> output_flag_present_flag? Those flags are all dependant on
> dependant_slice_segement being false. I'm guessing 0 but it maybe
> should be documented.
Zero indeed.
> Likewise if output_flag_present_flag is false pic_output_flag will not
> be coded, so maybe express it as "after slice_type" rather than "before
> pic_output_flag"?
Should work too.
>
> Regards
>
> John Cox
>
> > +.. note::
> > +
> > + This control is not yet part of the public kernel API and
> > + it is expected to change.
> > diff --git a/Documentation/userspace-api/media/drivers/index.rst
> > b/Documentation/userspace-api/media/drivers/index.rst
> > index 1a9038f5f9fa..12e3c512d718 100644
> > --- a/Documentation/userspace-api/media/drivers/index.rst
> > +++ b/Documentation/userspace-api/media/drivers/index.rst
> > @@ -33,6 +33,7 @@ For more details see the file COPYING in the source
> > distribution of Linux.
> >
> > ccs
> > cx2341x-uapi
> > + hantro
> > imx-uapi
> > max2175
> > meye-uapi
> > diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
> > index 8e0109eea454..b713eeed1915 100644
> > --- a/include/media/hevc-ctrls.h
> > +++ b/include/media/hevc-ctrls.h
> > @@ -224,4 +224,17 @@ struct v4l2_ctrl_hevc_decode_params {
> > __u64 flags;
> > };
> >
> > +/* MPEG-class control IDs specific to the Hantro driver as defined by V4L2
> > */
> > +#define
> > V4L2_CID_CODEC_HANTRO_BASE (V4L2_CTRL_CLASS_CODEC | 0x1200)
> > +/*
> > + * V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP -
> > + * the number of data (in bits) to skip in the
> > + * slice segment header.
> > + * If non-IDR, the bits to be skipped go from syntax element
> > "pic_output_flag"
> > + * to before syntax element "slice_temporal_mvp_enabled_flag".
> > + * If IDR, the skipped bits are just "pic_output_flag"
> > + * (separate_colour_plane_flag is not supported).
> > + */
> > +#define V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (V4L2_CID_CODEC_HANTRO_BASE
> > + 0)
> > +
> > #endif
