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From:   Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Date:   Tue, 27 Jul 2021 15:03:49 -0300
Message-ID: <CAAEAJfBTPFp4YX-yy6==w15OdKEj=Qy-epUEsdqqWsQ1DWJNrA@mail.gmail.com>
Subject: Re: [PATCH v5 02/14] media:Add nt8 and nt10 video format.
To:     Nicolas Dufresne <nicolas@ndufresne.ca>
Cc:     Ming Qian <ming.qian@nxp.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>, aisheng.dong@nxp.com,
        linux-media <linux-media@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
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On Tue, 27 Jul 2021 at 14:58, Nicolas Dufresne <nicolas@ndufresne.ca> wrote=
:
>
> Le mardi 27 juillet 2021 =C3=A0 11:20 +0800, Ming Qian a =C3=A9crit :
> > NT8 is 8-bit tiled nv12 format used by amphion decoder.
> > NT10 is 10-bit tiled format used by amphion decoder.
> > The tile size is 8x128
> >
> > Signed-off-by: Ming Qian <ming.qian@nxp.com>
> > Signed-off-by: Shijie Qin <shijie.qin@nxp.com>
> > Signed-off-by: Zhou Peng <eagle.zhou@nxp.com>
> > ---
> >  .../userspace-api/media/v4l/pixfmt-reserved.rst   | 15 +++++++++++++++
> >  drivers/media/v4l2-core/v4l2-ioctl.c              |  2 ++
> >  include/uapi/linux/videodev2.h                    |  2 ++
> >  3 files changed, 19 insertions(+)
> >
> > diff --git a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst =
b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
> > index c9231e18859b..2deae49210a7 100644
> > --- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
> > +++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
> > @@ -256,3 +256,18 @@ please make a proposal on the linux-media mailing =
list.
> >       of tiles, resulting in 32-aligned resolutions for the luminance p=
lane
> >       and 16-aligned resolutions for the chrominance plane (with 2x2
> >       subsampling).
> > +    * .. _V4L2-PIX-FMT-NT8:
> > +
> > +      - ``V4L2_PIX_FMT_NT8``
> > +      - 'NA12'
> > +      - Two-planar NV12-based format used by the video engine found on=
 Amphion decoder,
> > +    with 8x128 tiles for the luminance plane and chrominance plane.
> > +    The number of bytes in one luminance or chrominance row must be di=
visible by 256.
> > +    * .. _V4L2-PIX-FMT-NT10:
>
> There is a large spread of "vendor specific" format that aren't really sp=
ecific,
> or complex enough to be worth being marked as vendor format. As per my re=
ading
> of this description, this is linearly layout 8x128 tiled format, with no
> compression or anything (well unless you forgot to mention). As a side ef=
fect,
> we should give that format an explicit name (NT8 is cryptic). What about
> V4L2_PIX_FMT_NV12_8L128, my colleague is about to send a proposal in that
> direction. That would be NV12 with plane tiled 8x128 bytes and layout lin=
early,
> row by row, left to right. We already have cryptic formats like SUNXI, HM=
12 that
> are literally just that, simple tiling, and we endup having to use obscur=
e
> vendor name whenever other HW uses the same.
>
> (this comment extends to the other formats here)
>

Here's the proposal Nicolas is talking about:

https://lore.kernel.org/linux-media/20210727145745.25203-1-ezequiel@collabo=
ra.com/T/#t

V4L2_PIX_FMT_NV12_8L128 makes sense, please also add support for this
format in GStreamer. I think that makes it easier to confirm the
layout of the format.

Thanks!
Ezequiel