From: "Daniel Glöckner" <daniel-gl@gmx.net>
To: Linos <info@linos.es>
Cc: video4linux-list@redhat.com
Subject: Re: bttv 2.6.26 problem
Date: Mon, 20 Oct 2008 18:14:36 +0200 [thread overview]
Message-ID: <20081020161436.GB1298@daniel.bse> (raw)
In-Reply-To: <48FC8DF1.8010807@linos.es>
On Mon, Oct 20, 2008 at 03:56:01PM +0200, Linos wrote:
> Error: Could not set image size to 352x288 for color format I420 (15)
> (VIDIOCMCAPTURE: buffer 0)
The problem is that the v4l1-compat code for VIDIOCMCAPTURE calls
VIDIOC_S_FMT. At the beginning of bttv_s_fmt_vid_cap the call to
bttv_switch_type fails because the buffers have already been mmap'ed
by the application. I'd say this is a bug in bttv.
In which case does the videobuf_queue_is_busy test prevent bad things
from happening?
A workaround is to set the resolution and image format before the
buffers are mapped, f.ex. with this small program:
--------------
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <linux/videodev.h>
void main()
{
struct video_mmap vmm;
vmm.height=352;
vmm.width=288;
vmm.format=VIDEO_PALETTE_YUV420P;
vmm.frame=0;
ioctl(open("/dev/video",O_RDWR),VIDIOCMCAPTURE,&vmm);
}
--------------
Daniel
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next prev parent reply other threads:[~2008-10-20 16:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-20 13:56 bttv 2.6.26 problem Linos
2008-10-20 16:14 ` Daniel Glöckner [this message]
2008-10-20 17:01 ` Linos
2008-10-20 17:23 ` David Ellingsworth
2008-10-20 18:25 ` Daniel Glöckner
2008-10-20 18:42 ` Linos
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