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Date: Thu, 15 Sep 2011 10:49:10 +0200
From: Sylwester Nawrocki <s.nawrocki@samsung.com>
Subject: Re: [PATCH 4/4] v4l2: add blackfin capture bridge driver
In-reply-to: <CAHG8p1AM9HxRSfEOEc8_cuvSkRO8LvUw0DCAfcK+_SHD8yr=cg@mail.gmail.com>
To: Scott Jiang <scott.jiang.linux@gmail.com>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>,
	Mauro Carvalho Chehab <mchehab@infradead.org>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Hans Verkuil <hverkuil@xs4all.nl>, linux-media@vger.kernel.org,
	uclinux-dist-devel@blackfin.uclinux.org
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On 09/15/2011 08:37 AM, Scott Jiang wrote:
>>
>>> +
>>> +#define CAPTURE_DRV_NAME        "bfin_capture"
>>> +#define BCAP_MIN_NUM_BUF        2
>>> +
>>> +struct bcap_format {
>>> +     u8 *desc;
>>> +     u32 pixelformat;
>>> +     enum v4l2_mbus_pixelcode mbus_code;
>>> +     int bpp; /* bytes per pixel */
>>
>> Don't you think you might have to process 12 bpp formats at some point,
>> like YUV 4:2:0, or NV12? Maybe better calculate in bits from the beginning?
>>
> I have a question here. How to calculate bytesperline for planar format?
> According to v4l2 specification  width, height and bytesperline apply
> to largest plane.
> Does it mean bytesperline equal to Y plane distance between two line?

For planar formats - I think so.

> And so you can't use bytesperline x height to calculate sizeimage?

No, you can't. Please see this thread:
http://www.mail-archive.com/linux-media@vger.kernel.org/msg28957.html


Regards,
-- 
Sylwester Nawrocki
Samsung Poland R&D Center