With the example from the api specifications I get this output:
root@beagleboard:~# ./capture -d /dev/video0
....................................................................................................
Where can I find the captured images?
----- Original Message -----
From: "Dongsoo, Nathaniel Kim" <dongsoo.kim@xxxxxxxxx>
To: "Rath" <mailings@xxxxxxxxxxxxxxxxxxxxx>
Cc: <linux-media@xxxxxxxxxxxxxxx>
Sent: Saturday, August 15, 2009 11:53 AM
Subject: Re: V4L image grab
On Sat, Aug 15, 2009 at 6:36 AM, Rath<mailings@xxxxxxxxxxxxxxxxxxxxx> wrote:
Hi,
with this code from the internet I only get pictures with some undefined
pixels on the top and black pixels on the bottom.
Where's the problem? I only want a simple example for image captureing.
Here is the code:
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <libv4l1.h>
#include <linux/videodev.h>
#define GES_LAENGE (640*480)
unsigned char bild[GES_LAENGE];
int main()
{
int fd;
long laenge;
struct video_window video_win;
FILE *bilddatei;
if((fd = v4l1_open("/dev/video0", O_RDONLY)) == -1)
{
printf("Fehler beim Oeffnen von /dev/video0\r\n");
return 1;
}
if( v4l1_ioctl( fd, VIDIOCGWIN, &video_win) == -1)
{
printf("Fehler beim setzen der Einstellungen\r\n");
return 1;
}
laenge = video_win.width * video_win.height;
if( laenge > GES_LAENGE)
{
printf("Bild ist groesser als angegeben\r\n");
return 1;
}
if( v4l1_read( fd, bild, laenge) == -1)
{
printf("Auslesen der Kamera nicht möglch\r\n");
return 1;
}
if((bilddatei = fopen( "bild.ppm", "w+b")) == NULL)
{
printf("Konnte die datei zum schreiben nicht öffnen\r\n");
return 1;
}
v4l1_close(fd);
fprintf( bilddatei, "P6\n%d %d\n255\n",video_win.width,
video_win.height);
fwrite( bild, 1, video_win.width*video_win.height,bilddatei);
fclose(bilddatei);
return 0;
}
Hi Joern,
That code seems to be using v4l1 APIs. How about using current version
of video4linux?
You can find a simple example code at following document:
http://www.linuxtv.org/downloads/video4linux/API/V4L2_API/spec-single/v4l2.html#CAPTURE-EXAMPLE
And about the weird image you got from the v4l1 example code, could be
a pixelformat missmatch or just some noise fetched but I can't say any
further without knowing your environment :-)
Cheers,
Nate
Regards, Joern
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--
=
DongSoo, Nathaniel Kim
Engineer
Mobile S/W Platform Lab.
Digital Media & Communications R&D Centre
Samsung Electronics CO., LTD.
e-mail : dongsoo.kim@xxxxxxxxx
dongsoo45.kim@xxxxxxxxxxx
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