From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
To: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Chen-Yu Tsai <wens@csie.org>, Tomasz Figa <tfiga@chromium.org>,
Hans Verkuil <hans.verkuil@cisco.com>,
Alexandre Courbot <acourbot@chromium.org>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Pawel Osciak <posciak@chromium.org>,
Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
Joerg " "Roedel <joro@8bytes.org>,"
<linux-arm-kernel@lists.infradead.org>,
Linux Media Mailing List <linux-media@vger.kernel.org>,
Jens Kuske <jenskuske@gmail.com>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
Jonas Karlman <jonas@kwiboo.se>,
Ezequiel Garcia <ezequiel@collabora.com>,
linux-sunxi <linux-sunxi@googlegroups.com>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
Guenter Roeck <groeck@chromium.org>
Subject: Re: [PATCH RESEND v7 1/2] media: uapi: Add H264 low-level decoder API compound controls.
Date: Fri, 05 Apr 2019 12:27:48 -0400 [thread overview]
Message-ID: <05078223a4098c96f6260f77e9ef2a01b966daa6.camel@collabora.com> (raw)
In-Reply-To: <20190405151552.biesirbs35uivk7d@flea>
[-- Attachment #1: Type: text/plain, Size: 2806 bytes --]
Le vendredi 05 avril 2019 à 17:15 +0200, Maxime Ripard a écrit :
> Hi Nicolas,
>
> On Thu, Apr 04, 2019 at 11:41:13AM -0400, Nicolas Dufresne wrote:
> > > > > + * - __u16
> > > > > + - ``pic_width_in_mbs_minus1``
> > > > > + -
> > > > > + * - __u16
> > > > > + - ``pic_height_in_map_units_minus1``
> > > > > + -
> > > >
> > > > We recently had some reflection with Alex that this is redundant with
> > > > the width and height in the OUTPUT format. It may also apply to some
> > > > other fields in these structs. I feel like they should be removed and
> > > > passed via corresponding generic V4L2 properties - format, selection,
> > > > etc.
> > > >
> > > > The same problem is also present in the MPEG2 controls. In fact, there
> > > > was a patch already which used some fields from the controls to
> > > > calculate the destination buffer strides, rather than bytesperline in
> > > > the format.
> > > >
> > > > Since we're in staging, it could be done with a follow-up patch, though.
> > >
> > > Just my two cents. I played with some codecs a while back. IIRC some
> > > specify a "codec" size in addition to the actual picture size, like
> > > when the encoder does padding to fit the requirements of the codec
> > > (spec). Is this needed anywhere?
> >
> > With state-less encoders, the headers, which contains the crop
> > information is created by userspace and for state less decoder, the
> > headers that contains this information is parsed by userspace. So I
> > believe that in theory, the accelerator does not strictly need to be
> > aware of the cropped dimensions.
> >
> > Another thing, is that there is not guarantied matches between e.g.
> > depth of the chrome/luma and the final image buffers. Some hardware may
> > have bandwidth limitation or internal converter and could possibly
> > decode 10bit data into 8bit buffers.
> >
> > A third reason why I would not try and encode this header information
> > is that there can be multiple PPS/SPS at the same time, and I think
> > it's confusing if the relevant information to differentiate them is
> > removed.
>
> Sorry if that sounds a bit dumb, but it's not really clear to me if
> you're arguing for the removal of the data as Tomasz suggests, or if
> you want to keep them.
>
> The first paragrah seems to advocate for the former, but the two
> others for the latter.
I think the data should stay. As I said, there can be multiple SPS/PPS,
while there is only one format. That being said, how does SPS/PPS
activation works ? How do you tell the driver about all the SPS/PPS and
which one is being activated ?
>
> Thanks!
> Maxime
>
> --
> Maxime Ripard, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 195 bytes --]
next prev parent reply other threads:[~2019-04-05 16:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-04 12:26 [PATCH RESEND v7 0/2] media: cedrus: Add H264 decoding support Maxime Ripard
2019-04-04 12:26 ` [PATCH RESEND v7 1/2] media: uapi: Add H264 low-level decoder API compound controls Maxime Ripard
2019-04-04 12:31 ` Hans Verkuil (hansverk)
2019-04-04 12:36 ` Hans Verkuil
2019-04-04 12:54 ` Tomasz Figa
2019-04-04 14:42 ` Chen-Yu Tsai
2019-04-04 15:41 ` Nicolas Dufresne
2019-04-05 15:15 ` Maxime Ripard
2019-04-05 16:27 ` Nicolas Dufresne [this message]
2019-04-11 15:57 ` Maxime Ripard
2019-04-16 7:16 ` Tomasz Figa
2019-04-16 11:54 ` Nicolas Dufresne
2019-04-04 12:26 ` [PATCH RESEND v7 2/2] media: cedrus: Add H264 decoding support Maxime Ripard
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=05078223a4098c96f6260f77e9ef2a01b966daa6.camel@collabora.com \
--to=nicolas.dufresne@collabora.com \
--cc=acourbot@chromium.org \
--cc=ezequiel@collabora.com \
--cc=groeck@chromium.org \
--cc=hans.verkuil@cisco.com \
--cc=jenskuske@gmail.com \
--cc=jernej.skrabec@gmail.com \
--cc=jonas@kwiboo.se \
--cc=laurent.pinchart@ideasonboard.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=linux-sunxi@googlegroups.com \
--cc=maxime.ripard@bootlin.com \
--cc=paul.kocialkowski@bootlin.com \
--cc=posciak@chromium.org \
--cc=sakari.ailus@linux.intel.com \
--cc=tfiga@chromium.org \
--cc=thomas.petazzoni@bootlin.com \
--cc=wens@csie.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).