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Message-ID: <49a15300a5db8b4c61115c4a89eac1762dc3f31a.camel@collabora.com>
Subject: Re: [PATCH v3 2/3] media: uapi: Add VP9 stateless decoder controls
From:   Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reply-To: Nicolas Dufresne <nicolas.dufresne@collabora.com>
To:     Hans Verkuil <hverkuil@xs4all.nl>,
        Ezequiel Garcia <ezequiel@collabora.com>,
        linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org,
        linux-kernel@vger.kernel.org
Cc:     Tomasz Figa <tfiga@chromium.org>, kernel@collabora.com,
        Jonas Karlman <jonas@kwiboo.se>,
        Heiko Stuebner <heiko@sntech.de>,
        Alexandre Courbot <acourbot@chromium.org>,
        Jeffrey Kardatzke <jkardatzke@chromium.org>,
        gustavo.padovan@collabora.com,
        Boris Brezillon <boris.brezillon@collabora.com>
Date:   Mon, 11 May 2020 08:17:06 -0400
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Le vendredi 08 mai 2020 =C3=A0 15:16 +0200, Hans Verkuil a =C3=A9crit :
> > I think this comes directly from the spec. The Rockchip VDEC doesn't
> > seem to use it.
> > Do you think we can drop it from here, and rely on the V4L2 colorspace
> > passed in the format negotiation?
>=20
>=20
> That would be preferred, yes. Otherwise you would have two places where y=
ou can
> define colorspaces, and that's confusing.

This is indeed redundant with the color information in the format. In
VP8/9 there is only 1 header for everything, so it's harder to figure-
out what to filter. While in H.264/HEVC this information is usually set
an an extension header.

Though this do re-open the discussion about SPS in H.264/HEVC. In there
you will find the coded size and the crop window and the sub-sampling.
I don't remember exactly what was the conclusion, but I think it was
kept to allow allow bitstream reconstruction. But it will effectively
overlap directly (or indirectly) with some V4L2 generic API.

regards,
Nicolas

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