From: "Daniel Glöckner" <daniel-gl@gmx.net>
To: Michael PARKER <michael.parker@st.com>
Cc: "linux-media@vger.kernel.org" <linux-media@vger.kernel.org>
Subject: Re: Format of /dev/video0 data for HVR-4000 frame grabber
Date: Tue, 9 Nov 2010 10:10:24 +0100 [thread overview]
Message-ID: <20101109091024.GA15043@minime.bse> (raw)
In-Reply-To: <A3BF01DB4A606149A4C20C4C4C808F6C2A2CACB088@SAFEX1MAIL1.st.com>
On Tue, Nov 09, 2010 at 09:43:29AM +0100, Michael PARKER wrote:
> I'm attempting to capture a single frame from the /dev/video0 output of
> my HVR-4000 card's analogue tuner as a JPEG.
>
> Whilst several resources exist for capturing the output of a card with
> h/w MPEG compression, I'm unable to determine the format of the
> /dev/video0 data for a frame grabber such as the HVR-4000.
According to the sourcecode the cx88 chip can do 8 bit grayscale,
15/16/24/32 bit RGB/BGR, and two variants of 4:2:2 YCbCr.
> Can anyone suggest a means by which I can capture a single frame from a
> frame grabber card? Can I just use "dd if=/dev/video0 of=image.jpg bs=64K"
> or similar or do I have to access the card via the V4L2 drivers?
Yes, dd should work but you need to use a blocksize that can hold a
complete frame and count=1 if you want a single frame. JPEG, as
mentioned above, is not possible with this board.
The resolution and data format can be selected with V4L2 ioctls.
Daniel
next prev parent reply other threads:[~2010-11-09 9:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-09 8:43 Format of /dev/video0 data for HVR-4000 frame grabber Michael PARKER
2010-11-09 9:10 ` Daniel Glöckner [this message]
2010-11-09 9:34 ` Michael PARKER
2010-11-09 12:28 ` Andy Walls
2010-11-09 15:06 ` Michael PARKER
-- strict thread matches above, loose matches on Subject: below --
2010-11-09 17:39 Andy Walls
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