Linux-ARM-Kernel Archive on lore.kernel.org
 help / color / Atom feed
From: Ezequiel Garcia <ezequiel@collabora.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>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Alexandre Courbot <acourbot@chromium.org>,
	Jonas Karlman <jonas@kwiboo.se>,
	Maxime Ripard <maxime.ripard@bootlin.com>,
	jenskuske@gmail.com, linux-sunxi@googlegroups.com,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
	Chen-Yu Tsai <wens@csie.org>,
	Hans Verkuil <hans.verkuil@cisco.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Nicolas Dufresne <nicolas.dufresne@collabora.com>,
	Pawel Osciak <posciak@chromium.org>,
	Linux Media Mailing List <linux-media@vger.kernel.org>
Subject: Re: [PATCH v3 0/2] media: cedrus: Add H264 decoding support
Date: Wed, 13 Feb 2019 13:28:34 -0300
Message-ID: <2e468fd22b577f1a5fd5d3186d6cc88e442e07ec.camel@collabora.com> (raw)
In-Reply-To: <CAAFQd5DE+T6KJ0TXcQUxLSnog5enQf5G0SVM+5t6f60VjcovFw@mail.gmail.com>

On Wed, 2019-02-13 at 12:02 +0900, Tomasz Figa wrote:
> On Wed, Feb 13, 2019 at 6:22 AM Ezequiel Garcia <ezequiel@collabora.com> wrote:
> > Hey Tomasz,
> > 
> > On Tue, 2019-02-12 at 21:50 +0900, Tomasz Figa wrote:
> > > Hi Maxime,
> > > 
> > > On Mon, Feb 11, 2019 at 11:39 PM Maxime Ripard
> > > <maxime.ripard@bootlin.com> wrote:
> > > > Hi,
> > > > 
> > > > Here is a new version of the H264 decoding support in the cedrus
> > > > driver.
> > > 
> > > Thanks for working on this. Please see my comments below.
> > > 
> > > > As you might already know, the cedrus driver relies on the Request
> > > > API, and is a reverse engineered driver for the video decoding engine
> > > > found on the Allwinner SoCs.
> > > > 
> > > > This work has been possible thanks to the work done by the people
> > > > behind libvdpau-sunxi found here:
> > > > https://github.com/linux-sunxi/libvdpau-sunxi/
> > > > 
> > > > I've tested the various ABI using this gdb script:
> > > > http://code.bulix.org/jl4se4-505620?raw
> > > > 
> > > > And this test script:
> > > > http://code.bulix.org/8zle4s-505623?raw
> > > > 
> > > > The application compiled is quite trivial:
> > > > http://code.bulix.org/e34zp8-505624?raw
> > > > 
> > > > The output is:
> > > > arm:    builds/arm-test-v4l2-h264-structures
> > > >         SHA1: 88cbf7485ba81831fc3b93772b215599b3b38318
> > > > x86:    builds/x86-test-v4l2-h264-structures
> > > >         SHA1: 88cbf7485ba81831fc3b93772b215599b3b38318
> > > > x64:    builds/x64-test-v4l2-h264-structures
> > > >         SHA1: 88cbf7485ba81831fc3b93772b215599b3b38318
> > > > arm64:  builds/arm64-test-v4l2-h264-structures
> > > >         SHA1: 88cbf7485ba81831fc3b93772b215599b3b38318
> > > > 
> > > > Let me know if there's any flaw using that test setup, or if you have
> > > > any comments on the patches.
> > > > 
> > > > Maxime
> > > > 
> > > > Changes from v2:
> > > >   - Simplified _cedrus_write_ref_list as suggested by Jernej
> > > >   - Set whether the frame is used as reference using nal_ref_idc
> > > >   - Respect chroma_format_idc
> > > >   - Fixes for the scaling list and prediction tables
> > > >   - Wrote the documentation for the flags
> > > >   - Added a bunch of defines to the driver bit fields
> > > >   - Reworded the controls and data format descriptions as suggested
> > > >     by Hans
> > > >   - Reworked the controls' structure field size to avoid padding
> > > >   - Removed the long term reference flag
> > > 
> > > This and...
> > > 
> > 
> > Maxime has dropped this because of Ayaka's mail about long term references
> > not making much sense in stateless decoders.
> 
> I haven't seen any argument confirming that thesis, though. I should
> have kicked in earlier, sorry.
> 

OK, in that case, we need to have this flag back.

> > I noticed that RK3399 TRM has a field to specify long term refs and
> > so was wondering about this item as well.
> > 
> > > >   - Reintroduced the neighbor info buffer
> > > >   - Removed the ref_pic_list_p0/b0/b1 arrays that are redundant with the
> > > >     one in the DPB
> > > 
> > > these are used in our Rockchip VDEC driver.
> > > 
> > > Could you elaborate on the reasons why they got removed?
> > > 
> > 
> > If I understood correctly, there are two reference picture lists.
> > P-frames will populate ref_pic_list0 and B-frames will populate both.
> > 
> > According to this, v4l2_ctrl_h264_slice_param.ref_pic_list0 and .ref_pic_list1
> > should be enough and ref_pic_list_p0/b0/b1 are not needed.
> > 
> > What do you think?
> 
> The lists in v4l2_ctrl_h264_slice_param are expected to be past the
> per-slice modification stage (which is quite complicated and better
> done in userspace),

The fact that these are RefPicList0 and RefPicList1, after
the reordering stage should be better documented.

> while the ones in v4l2_ctrl_h264_decode_param just
> in the original order. Rockchip VPU expects them in the original order
> and does the modification in the hardware.
> 

OK, I see.

So, we have RefPicList0 and RefPicList1, and there is an initialization
stage and a modification/reordering process.

One could argue that it's more generic to just pass the initial list,
but that would mean doing in the kernel something that is easier
done in userspace (and parsers doing this are already available).

The question would be what is the most generic way of passing
the RefPicList0 and RefPicList1 in its initial state.

1/ We create additional controls for these.

2/ We put them on some of the other controls. Putting them on
v4l2_ctrl_h264_decode_param didn't seem too wrong.

Any objections to put them back in there?

Regards,
Ezequiel


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-11 14:39 Maxime Ripard
2019-02-11 14:39 ` [PATCH v3 1/2] media: uapi: Add H264 low-level decoder API compound controls Maxime Ripard
2019-02-11 15:16   ` Hans Verkuil
2019-02-11 15:21     ` Hans Verkuil
2019-02-12 13:05       ` Maxime Ripard
2019-02-12 21:17         ` Ezequiel Garcia
2019-02-11 17:16     ` Nicolas Dufresne
2019-02-11 17:12   ` Ezequiel Garcia
2019-02-12 10:23     ` Maxime Ripard
2019-02-11 19:53   ` Ezequiel Garcia
2019-02-11 14:39 ` [PATCH v3 2/2] media: cedrus: Add H264 decoding support Maxime Ripard
2019-02-11 19:21   ` [linux-sunxi] " Jernej Škrabec
2019-02-12 10:43     ` Maxime Ripard
2019-02-12 17:46       ` Jernej Škrabec
2019-02-11 19:48   ` Ezequiel Garcia
2019-02-12 12:47     ` Maxime Ripard
2019-02-12 17:40       ` Jernej Škrabec
2019-02-14 20:42   ` Jernej Škrabec
2019-02-14 21:27   ` Jernej Škrabec
2019-02-12 12:50 ` [PATCH v3 0/2] " Tomasz Figa
2019-02-12 21:22   ` Ezequiel Garcia
2019-02-13  3:02     ` Tomasz Figa
2019-02-13 16:28       ` Ezequiel Garcia [this message]
2019-02-14 15:47         ` Maxime Ripard

Reply instructions:

You may reply publically 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=2e468fd22b577f1a5fd5d3186d6cc88e442e07ec.camel@collabora.com \
    --to=ezequiel@collabora.com \
    --cc=acourbot@chromium.org \
    --cc=hans.verkuil@cisco.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jenskuske@gmail.com \
    --cc=jernej.skrabec@gmail.com \
    --cc=jonas@kwiboo.se \
    --cc=joro@8bytes.org \
    --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=nicolas.dufresne@collabora.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

Linux-ARM-Kernel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/0 linux-arm-kernel/git/0.git
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/1 linux-arm-kernel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-kernel linux-arm-kernel/ https://lore.kernel.org/linux-arm-kernel \
		linux-arm-kernel@lists.infradead.org infradead-linux-arm-kernel@archiver.kernel.org
	public-inbox-index linux-arm-kernel


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-arm-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox