Re: Very Basic Capture Question, Please Help!!

Hi,

there is a really brain-dead one :-)

8<------------------------ begin---------------------------------------------------

/*
   v4l single frame grabber sample
*/

#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <errno.h>

#include <linux/videodev.h>

const int     mywidth = 640;  // !!!!!!!
const int     myheight = 480; // NTSC-J - pls, put your here

static struct    video_capability  capability;

static int     fd = -1;

static int ret_bytes,vfd;

static char *map = NULL;
static char *dest_buf=NULL;
static char src_buf[691200];


static struct     video_mbuf gb_buffers;
static struct     video_mmap my_buf;

int main(void)
{
   int mymode;
   int no_bytes,i;
   char my_video_dev[100]  = "/dev/video0";

// Open video device


   if (-1 == (fd = open(my_video_dev, O_RDWR)))
   {
       printf("Error opening device: %s\n", my_video_dev);
       goto err;
   }

// Get video device captions


   if (-1 == ioctl(fd,VIDIOCGCAP,&capability))
   {
       printf("Error: ioctl(fd,VIDIOCGCAP,&capability)\n");
       goto err;
   }
   fcntl(fd,F_SETFD,FD_CLOEXEC);

// Get number and size of the internal buffers


   if (-1 == ioctl(fd, VIDIOCGMBUF, &gb_buffers))
   {
       printf("Error: Error getting buffers, I think\n");
       goto err;
   }

   printf("Memory map buffer:\nsize: %d\nframes: %d\n\n",
       gb_buffers.size,
       gb_buffers.frames);

// Mapping internal driver's buffers to the user space

map = mmap(0, mywidth * myheight * 2 + 4096, PROT_READ|PROT_WRITE,MAP_SHARED, fd, 0);

   if (map == NULL)
   {
       printf("Error: mmap returned NULL\n");
       goto err;
   }
   printf("Memory mapped to 0x%08x\n", map);

// set capture dimensions and format


   my_buf.width = mywidth;
   my_buf.height = myheight;
   my_buf.format = VIDEO_PALETTE_RGB565;

   my_buf.frame = 0;

// start capture


   if (-1 == ioctl(fd, VIDIOCMCAPTURE, &my_buf))
   {
       printf("Error: Grabber chip can't sync\n");
       goto err;
   }

// wait for end of the frame capturingif (-1 == ioctl(fd, VIDIOCSYNC, &my_buf.frame))

   {
       printf("Error on sync!\n");
       goto err;
   }

memcpy(src_buf, map, mywidth * myheight * 2);


   {
   int i, j, k;
   char r, g, b;
   unsigned short *ptr = (unsigned short *)src_buf;
   unsigned short  word;
   char *ppm_hdr = "P6\n# CREATOR: anonimous :-) (RGB565)\n640 480\n255\n";

int vfd = open("video-data.ppm",O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);

   k = 0;

write(vfd, ppm_hdr, strlen(ppm_hdr));for(i = 0; i < myheight; i++)

           for(j = 0; j < mywidth; j++)
           {
               word = ptr[k];
               r = (word >> 8) & 0xf8;
               g = (word >> 3) & 0xfc;
               b = (word << 3) & 0xf8;
               write(vfd, &r, 1);
               write(vfd, &g, 1);
               write(vfd, &b, 1);
               k++;
           }
       close(vfd);
   }

   munmap(map, mywidth * myheight * 2 + 4096);

   printf("Press enter to quit\n");

getchar();return 0;


err:
  return -1;
}

8<---------------------------- end------------------------------------------------------------------------------------


Mauricio Henriquez wrote:

Hi:
    My name is Mauricio and I write you from Chili.
I have a Phoebe TV-Master+FM working fine with my redhat 8 system,I like to do some basic test and I need some basic "C" or "C++"example code about how to set and capture a image from the capturecard and saved in some image format in my hard drive. If any of youhave some basic sample code I very appriciate.For advance thanks.Mauricio Henriquez