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From: Philipp Zabel <p.zabel@pengutronix.de>
To: Ezequiel Garcia <ezequiel@collabora.com>, linux-media@vger.kernel.org
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Mikhail Ulyanov <mikhail.ulyanov@cogentembedded.com>,
	Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>,
	Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	Sylwester Nawrocki <s.nawrocki@samsung.com>,
	Rick Chang <rick.chang@mediatek.com>,
	Bin Liu <bin.liu@mediatek.com>,
	Mirela Rabulea <mirela.rabulea@nxp.com>,
	kernel@pengutronix.de
Subject: Re: [PATCH 0/5] v4l2 JPEG helpers and CODA960 JPEG decoder
Date: Thu, 14 Nov 2019 11:00:31 +0100	[thread overview]
Message-ID: <e33cbcc4a95e025563059a121a4472eb6fb1d269.camel@pengutronix.de> (raw)
In-Reply-To: <e65ca03c095c99dc8482e9c36dcd099b6c69fc38.camel@collabora.com>

Hi Ezequiel,

On Wed, 2019-11-13 at 16:42 -0300, Ezequiel Garcia wrote:
> Hi Philipp,
> 
> Thanks a lot for working on this. I'm so glad about
> both efforts: the CODA JPEG support and the JPEG
> helpers.
> 
> On Wed, 2019-11-13 at 16:05 +0100, Philipp Zabel wrote:
> > Hi,
> > 
> > as far as I can tell we currently have three JPEG header parsers in the
> > media tree (in the rcar_jpu, s5p-jpeg, and mtk-jpeg drivers). I would
> > like to add support for the CODA960 JPEG decoder to the coda-vpu driver
> > without adding yet another.
> > 
> > To this end, this patch series adds some common JPEG code to v4l2-core.
> > For now this just contains header parsing helpers (I have tried to keep
> > the terminology close to JPEG ITU-T.81) that should be usable for all of
> > the current drivers. In the future we might want to move JPEG header
> > generation for encoders and common quantization tables in there as well.
> > 
> 
> Indeed, moving encoders to use these helpers sounds like the right thing
> to do. IIRC, quantization tables are implementation defined, and not imposed
> by anything. I believe gspca drivers use some tables that don't follow
> any recomendation.

Right. I was just thinking of the default tables from Annex K.3. I'll
have to recheck what's up with the CODA q tables, but the Huffman tables
are identical between hantro_jpeg and coda-jpeg. I suppose we could make
the tables userspace controlled for those drivers that support arbitrary
ones.

> I guess it's fine to leave some drivers unconverted, without using any helpers,
> and move others to use a helper-derived quantization table.  

Agreed.

regards
Philipp


  parent reply	other threads:[~2019-11-14 10:00 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-13 15:05 [PATCH 0/5] v4l2 JPEG helpers and CODA960 JPEG decoder Philipp Zabel
2019-11-13 15:05 ` [PATCH 1/5] media: add v4l2 JPEG helpers Philipp Zabel
2019-11-25 11:36   ` [EXT] " Mirela Rabulea
2019-11-25 16:36     ` Philipp Zabel
2019-11-26  9:07       ` Mirela Rabulea
2019-11-13 15:05 ` [PATCH 2/5] media: coda: jpeg: add CODA960 JPEG decoder support Philipp Zabel
2020-03-06 20:31   ` Tim Harvey
2020-03-06 21:01     ` Adrian Ratiu
2020-03-06 21:57       ` Tim Harvey
2020-03-07 12:14         ` Ezequiel Garcia
2020-03-11 17:06           ` Adrian Ratiu
2019-11-13 15:05 ` [PATCH 3/5] media: rcar_jpu: use V4L2 JPEG helpers Philipp Zabel
2019-11-13 15:05 ` [PATCH 4/5] media: s5p-jpeg: use v4l2 " Philipp Zabel
2019-11-13 15:05 ` [PATCH 5/5] media: mtk-jpeg: use V4L2 " Philipp Zabel
2019-11-13 19:42 ` [PATCH 0/5] v4l2 JPEG helpers and CODA960 JPEG decoder Ezequiel Garcia
2019-11-13 20:36   ` Jacek Anaszewski
2019-11-13 21:25     ` Nicolas Dufresne
2019-11-14 10:00   ` Philipp Zabel [this message]
2019-11-25 11:36 ` [EXT] " Mirela Rabulea
2019-12-04 10:30 ` Adrian Ratiu
2019-12-13  9:18 ` Hans Verkuil
2020-03-18 10:41 ` Adrian Ratiu
2020-03-18 12:15   ` Andrzej Pietrasiewicz
2020-03-18 12:42     ` Adrian Ratiu

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