Re: [Fwd: Re: USB video driver]

["Jared D. McNeill" <jmcneill%invisible.ca@localhost>]

Donald T Hayford wrote:
> I really must do something about the "netbsd-current%netbsd.org@localhost" that 
> ended up in my address book.
>
> -------- Original Message --------
> Subject:     Re: USB video driver
> Date:     Sat, 07 Feb 2009 15:01:13 -0500
> From:     Donald T Hayford <don%donhayford.com@localhost>
> To:     Jared D. McNeill <jmcneill%invisible.ca@localhost>
> CC:     netbsd-current%netbsd.org@localhost
> References:     <498DCF6A.9010105%donhayford.com@localhost> 
> <498DD121.5060508%invisible.ca@localhost>
>
>
>
> Jared D. McNeill wrote:
> > Donald T Hayford wrote:
> > > I'm trying to get the new USB video drivers to work on an embedded 
> > > (non-GUI) Arm processor (NSLU2).  I built a kernel (20081215), added 
> > > the appropriate drivers (uvideo, video), see the driver when it boots 
> > > up, and can capture video using "cat /dev/video0 >test.avi".  I can 
> > > move the avi file to another machine and play the video.  So the 
> > > basic driver is essentially working.
> > >
> > > But I can't get anything else to work from that point.  I built xawtv 
> > > so I could use webcam, but get the error message:
> > >
> > > -bash-3.2$ 
> > > webcam                                                              
> > > reading config file: 
> > > /home/hayford/.webcamrc                                   no grabber 
> > > device available
> > >
> > > .webcamrc has in it:
> > > device=/dev/video0
> > >
> > >
> > > when I run v4lctl, I get:
> > > -bash-3.2$ v4lctl -c /dev/video0 -v 2 snap 
> > > video/testpic1                      vid-open: trying: 
> > > bktr...                                                      bktr: 
> > > ioctl METEORGSUPPIXFMT: Invalid 
> > > argument                                 vid-open: failed: 
> > > bktr                                                         no 
> > > grabber device available
> > >
> > > The comment about the brooktree device confuses me, since I thought 
> > > the uvideo device was the equivalent.
> > >
> > > This may not be a NetBSD problem, so a referral to a better source of 
> > > info would also be greatly appreciated.
> >
> > Hi Don --
> >
> > I'm not sure that our xawtv package builds the v4l2 support code in; 
> > you might want to give one of the following applications a shot:
> >
> >   graphics/cheese
> >   graphics/ucview
> >   multimedia/mplayer
> >
> > Hope this helps,
> > Jared
> Thanks for the info.  These seem to be either X11 based, or in the case 
> of mplayer, too math-intensive for a little arm processor.  What I was 
> looking for was a simple command-line interface that would grab a few 
> frames (as specified) and store them to a file.  I haven't seen much in 
> the way of command-line stuff other than those that come with xawtv.  
> Sort of ironic, given the recent spate of emails about Desktop NetBSD.
> At any rate, I'll keep looking.

If that's all you need, you can write a simple application to do this 
for you. When you open /dev/video0 the device should be setup in its 
default format; you can query the current format with VIDIOC_G_FMT and 
then read in a single frame's worth of data to a file.

The attached application (totally untested) should help you get started.

Cheers,
Jared

/* $NetBSD$ */

/*
 * 2009 Jared D. McNeill <jmcneill%invisible.ca@localhost>
 * Public domain.
 */

#include <sys/ioctl.h>
#include <sys/videoio.h>

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>

static void
usage(void)
{
        fprintf(stderr, "usage: %s device filename\n", getprogname());
        exit(EXIT_FAILURE);
}

int
main(int argc, char *argv[])
{
        struct v4l2_format fmt;
        uint8_t *buf;
        int ifd, ofd;
        int error;
        size_t frlen;
        ssize_t rdlen, wrlen;

        if (argc != 3)
                usage();
                /* NOTREACHED */

        ifd = open(argv[1], O_RDONLY);
        if (ifd < 0) {
                perror("open camera");
                return EXIT_FAILURE;
        }
        ofd = open(argv[2], O_WRONLY|O_CREAT|O_EXCL, 0644);
        if (ofd < 0) {
                perror("open output");
                return EXIT_FAILURE;
        }

        error = ioctl(ifd, VIDIOC_G_FMT, &fmt);
        if (error) {
                perror("VIDIOC_G_FMT");
                return EXIT_FAILURE;
        }

        frlen = fmt.fmt.pix.width * fmt.fmt.pix.bytesperline;
        buf = malloc(frlen);
        if (buf == NULL) {
                perror("malloc");
                return EXIT_FAILURE;
        }

        rdlen = read(ifd, buf, frlen);
        if (rdlen == -1) {
                perror("read camera");
                return EXIT_FAILURE;
        }

        close(ifd);

        wrlen = write(ofd, buf, rdlen);
        if (wrlen == -1) {
                perror("write output");
                return EXIT_FAILURE;
        }

        close(ofd);

        printf("grabbed %z bytes\n", rdlen);

        return EXIT_SUCCESS;
}