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From:   Jernej =?utf-8?B?xaBrcmFiZWM=?= <jernej.skrabec@gmail.com>
To:     Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>,
        Benjamin Gaignard <benjamin.gaignard@collabora.com>
Cc:     mchehab@kernel.org, hverkuil@xs4all.nl, p.zabel@pengutronix.de,
        gregkh@linuxfoundation.org, mripard@kernel.org,
        paul.kocialkowski@bootlin.com, wens@csie.org, samuel@sholland.org,
        nicolas.dufresne@collabora.com, andrzej.p@collabora.com,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev,
        kernel@collabora.com
Subject: Re: Re: [PATCH v10 11/17] media: uapi: Add V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS control
Date:   Tue, 05 Jul 2022 18:11:09 +0200
Message-ID: <4408380.LvFx2qVVIh@kista>
In-Reply-To: <6ae43dcd-9b1d-ce30-8c3e-a8c313ef5b0a@collabora.com>
References: <20220705085420.272912-1-benjamin.gaignard@collabora.com> <YsRclobW7gL/Dtlr@eze-laptop> <6ae43dcd-9b1d-ce30-8c3e-a8c313ef5b0a@collabora.com>
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Dne torek, 05. julij 2022 ob 18:03:28 CEST je Benjamin Gaignard napisal(a):
> Le 05/07/2022 =E0 17:45, Ezequiel Garcia a =E9crit :
> > Hi guys,
> >=20
> > On Tue, Jul 05, 2022 at 10:54:14AM +0200, Benjamin Gaignard wrote:
> >> The number of 'entry point offset' can be very variable.
> >> Instead of using a large static array define a v4l2 dynamic array
> >> of U32 (V4L2_CTRL_TYPE_U32).
> >> The number of entry point offsets is reported by the elems field
> >> and in struct v4l2_ctrl_hevc_slice_params.num_entry_point_offsets
> >> field.
> >>=20
> >> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> >> Acked-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
> >> Tested-by: Jernej Skrabec <jernej.skrabec@gmail.com>
> >> ---
> >>=20
> >>   .../userspace-api/media/v4l/ext-ctrls-codec.rst       | 11 +++++++++=
++
> >>   drivers/media/v4l2-core/v4l2-ctrls-defs.c             |  5 +++++
> >>   include/media/hevc-ctrls.h                            |  5 ++++-
> >>   3 files changed, 20 insertions(+), 1 deletion(-)
> >>=20
> >> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> >> b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst index
> >> db0df7d9f27c..8df8d7fdfe70 100644
> >> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> >> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
> >> @@ -3010,6 +3010,9 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
> >>=20
> >>       * - __u32
> >>      =20
> >>         - ``data_bit_offset``
> >>         - Offset (in bits) to the video data in the current slice data.
> >>=20
> >> +    * - __u32
> >> +      - ``num_entry_point_offsets``
> >> +      - Specifies the number of entry point offset syntax elements in
> >> the slice header.>=20
> > This looks underdocumented. Somewhere in the docs it should be mentioned
> > that the field 'num_entry_point_offsets' is linked to the control
> > V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS.
>=20
> This field is here because some drivers would like know the number of
> entry point offsets without getting the entry point offsets data itself.

Yeah, this field must be set even when entry points offset control isn't us=
ed.=20
Additionally, if entry point offsets control is needed and if submitting=20
multiple slices at once, length of entry point offsets array must be sum of=
=20
num_entry_point_offsets of all slices in that job. Not sure where to put th=
is=20
explanation.

Best regards,
Jernej

>=20
> Benjamin
>=20
> > Thanks,
> > Ezequiel
> >=20
> >>       * - __u8
> >>      =20
> >>         - ``nal_unit_type``
> >>         - Specifies the coding type of the slice (B, P or I).
> >>=20
> >> @@ -3150,6 +3153,14 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
> >>=20
> >>       \normalsize
> >>=20
> >> +``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (integer)``
> >> +    Specifies entry point offsets in bytes.
> >> +    This control is a dynamically sized array. The number of entry po=
int
> >> +    offsets is reported by the ``elems`` field.
> >> +    This bitstream parameter is defined according to :ref:`hevc`.
> >> +    They are described in section 7.4.7.1 "General slice segment head=
er
> >> +    semantics" of the specification.
> >> +
> >>=20
> >>   ``V4L2_CID_STATELESS_HEVC_SCALING_MATRIX (struct)``
> >>  =20
> >>       Specifies the HEVC scaling matrix parameters used for the scaling
> >>       process
> >>       for transform coefficients.
> >>=20
> >> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> >> b/drivers/media/v4l2-core/v4l2-ctrls-defs.c index
> >> d594efbcbb93..e22921e7ea61 100644
> >> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> >> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
> >> @@ -1188,6 +1188,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> >>=20
> >>   	case V4L2_CID_STATELESS_HEVC_DECODE_PARAMS:		return=20
"HEVC Decode
> >>   	Parameters"; case V4L2_CID_STATELESS_HEVC_DECODE_MODE:	=09
return "HEVC
> >>   	Decode Mode"; case V4L2_CID_STATELESS_HEVC_START_CODE:	=09
return "HEVC
> >>   	Start Code";>>=20
> >> +	case V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS:	return=20
"HEVC Entry
> >> Point Offsets";>>=20
> >>   	/* Colorimetry controls */
> >>   	/* Keep the order of the 'case's the same as in v4l2-controls.h!=20
*/
> >>=20
> >> @@ -1518,6 +1519,10 @@ void v4l2_ctrl_fill(u32 id, const char **name,
> >> enum v4l2_ctrl_type *type,>>=20
> >>   	case V4L2_CID_STATELESS_HEVC_DECODE_PARAMS:
> >>   		*type =3D V4L2_CTRL_TYPE_HEVC_DECODE_PARAMS;
> >>   		break;
> >>=20
> >> +	case V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS:
> >> +		*type =3D V4L2_CTRL_TYPE_U32;
> >> +		*flags |=3D V4L2_CTRL_FLAG_DYNAMIC_ARRAY;
> >> +		break;
> >>=20
> >>   	case V4L2_CID_STATELESS_VP9_COMPRESSED_HDR:
> >>   		*type =3D V4L2_CTRL_TYPE_VP9_COMPRESSED_HDR;
> >>   		break;
> >>=20
> >> diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
> >> index a372c184689e..3a6601a46ced 100644
> >> --- a/include/media/hevc-ctrls.h
> >> +++ b/include/media/hevc-ctrls.h
> >> @@ -20,6 +20,7 @@
> >>=20
> >>   #define V4L2_CID_STATELESS_HEVC_DECODE_PARAMS=09
(V4L2_CID_CODEC_BASE +
> >>   1012)
> >>   #define V4L2_CID_STATELESS_HEVC_DECODE_MODE	(V4L2_CID_CODEC_BASE=20
+
> >>   1015)
> >>   #define V4L2_CID_STATELESS_HEVC_START_CODE	(V4L2_CID_CODEC_BASE + 10=
16)
> >>=20
> >> +#define V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (V4L2_CID_CODEC_B=
ASE
> >> + 1017)>>=20
> >>   /* enum v4l2_ctrl_type type values */
> >>   #define V4L2_CTRL_TYPE_HEVC_SPS 0x0120
> >>=20
> >> @@ -316,6 +317,8 @@ struct v4l2_hevc_pred_weight_table {
> >>=20
> >>    *
> >>    * @bit_size: size (in bits) of the current slice data
> >>    * @data_bit_offset: offset (in bits) to the video data in the curre=
nt
> >>    slice data>>=20
> >> + * @num_entry_point_offsets: specifies the number of entry point offs=
et
> >> syntax + *			     elements in the slice=20
header.
> >>=20
> >>    * @nal_unit_type: specifies the coding type of the slice (B, P or I)
> >>    * @nuh_temporal_id_plus1: minus 1 specifies a temporal identifier f=
or
> >>    the NAL unit * @slice_type: see V4L2_HEVC_SLICE_TYPE_{}
> >>=20
> >> @@ -358,7 +361,7 @@ struct v4l2_hevc_pred_weight_table {
> >>=20
> >>   struct v4l2_ctrl_hevc_slice_params {
> >>  =20
> >>   	__u32	bit_size;
> >>   	__u32	data_bit_offset;
> >>=20
> >> -
> >> +	__u32	num_entry_point_offsets;
> >>=20
> >>   	/* ISO/IEC 23008-2, ITU-T Rec. H.265: NAL unit header */
> >>   	__u8	nal_unit_type;
> >>   	__u8	nuh_temporal_id_plus1;
> >>=20
> >> --
> >> 2.32.0