Re: [PATCH v5 1/2] media: uapi: Add H264 low-level decoder API compound controls.

From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Tomasz Figa <tfiga@chromium.org>
Cc: "list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
	Joerg Roedel <joro@8bytes.org>,
	" <linux-arm-kernel@lists.infradead.org>,
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	Alexandre Courbot <acourbot@chromium.org>,
	Jonas Karlman <jonas@kwiboo.se>,
	jenskuske@gmail.com, linux-sunxi@googlegroups.com,
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	Jernej Skrabec <jernej.skrabec@gmail.com>,
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	Hans Verkuil <hans.verkuil@cisco.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Guenter Roeck <groeck@chromium.org>,
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	Ezequiel Garcia <ezequiel@collabora.com>,
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	Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: [PATCH v5 1/2] media: uapi: Add H264 low-level decoder API compound controls.
Date: Mon, 18 Mar 2019 16:47:00 +0100	[thread overview]
Message-ID: <20190318154700.4qks2qfxown2frgk@flea> (raw)
In-Reply-To: <CAAFQd5BeiGVvDcZTFVYg_Qbw1NxRcWFybW2FcDGE=ohFWHFbYA@mail.gmail.com>

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On Thu, Mar 14, 2019 at 01:13:33PM +0900, Tomasz Figa wrote:
> On Thu, Mar 14, 2019 at 12:31 AM Maxime Ripard
> <maxime.ripard@bootlin.com> wrote:
> >
> > Hi Tomasz,
> >
> > On Fri, Mar 08, 2019 at 03:12:18PM +0900, Tomasz Figa wrote:
> > > > +.. _v4l2-mpeg-h264:
> > > > +
> > > > +``V4L2_CID_MPEG_VIDEO_H264_SPS (struct)``
> > > > +    Specifies the sequence parameter set (as extracted from the
> > > > +    bitstream) for the associated H264 slice data. This includes the
> > > > +    necessary parameters for configuring a stateless hardware decoding
> > > > +    pipeline for H264.  The bitstream parameters are defined according
> > > > +    to :ref:`h264`. Unless there's a specific comment, refer to the
> > > > +    specification for the documentation of these fields, section 7.4.2.1.1
> > > > +    "Sequence Parameter Set Data Semantics".
> > >
> > > I don't see this section being added by this patch. Where does it come from?
> >
> > This is referring to the the H264 spec itself, as I was trying to
> > point out with the reference in that paragraph. How would you write
> > this down to make it more obvious?
> >
>
> Aha, somehow it didn't come to my mind when reading it. How about
> something like below?
>
> Unless there is a specific comment, refer to the ITU-T Rec. H.264
> specification, section "7.4.2.1.1 Sequence parameter set data semantics"
> (as of the 04/2017 edition).

The :ref:`h264` currently expands to "ITU H.264", which means in the
documentation, in the case above, it ends up as

 The bitstream parameters are defined according to ITU H.264. Unless
 there’s a specific comment, refer to the specification for the
 documentation of these fields, section 7.4.2.1.1 “Sequence Parameter
 Set Data Semantics”.

I could change the reference to have "ITU-T Rec. H.264 Specification
(04/2017 Edition)". Would that work for you?

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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