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w3v4l.c

/*
 * w3v4l.c
 *
 * Copyright (C) 1998 - 2000 Rasca, Berlin
 * EMail: thron@gmx.de
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/types.h>
#include <linux/videodev.h>
#include "w3v4l.h"

/*
 */
video_t *
v4l_init (char *dev, int input, int width, int height)
{
      int fd;
      struct video_capability vid_caps;
      struct video_mbuf vid_mbuf;
      struct video_channel vid_chnl;
      video_t *vid;

      fd = open (dev, O_RDWR);
      if (fd == -1) {
            perror (dev);
            return (NULL);
      }
      if (ioctl (fd, VIDIOCGCAP, &vid_caps) == -1) {
            perror ("ioctl (VIDIOCGCAP)");
            return (NULL);
      }

      vid = malloc (sizeof (video_t));
      vid->fd = fd;
      if (ioctl (fd, VIDIOCGMBUF, &vid_mbuf) == -1) {
            struct video_window vid_win;
            vid->map_size = 0;
            if (ioctl(fd, VIDIOCGWIN, &vid_win) != -1) {
                  vid_win.width = width;
                  vid_win.height= height;
                  ioctl (fd, VIDIOCSWIN, &vid_win);
            }
      } else {
            vid->map_size = vid_mbuf.size;
      }
#ifdef DEBUG
      printf ("%s: mbuf.size=%d\n", __FILE__, vid_mbuf.size);
#endif

      if (input > -1) {
            vid_chnl.channel = input;
            if (ioctl (fd, VIDIOCGCHAN, &vid_chnl) == -1) {
                  perror ("ioctl (VIDIOCGCHAN)");
            } else {
                  vid_chnl.channel = input;
                  if (ioctl (fd, VIDIOCSCHAN, &vid_chnl) == -1) {
                        perror ("ioctl (VIDIOCSCHAN)");
                  }
            }
      }
      if (vid->map_size > 0) {
            vid->mem = mmap (0,vid->map_size, PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);
            if ((unsigned char *) -1 == (unsigned char *)vid->mem) {
                  perror ("mmap()");
                  close (fd);
                  free (vid);
                  return (NULL);
            }
      } else {
            vid->mem = malloc (width * height * 3);
      }
      vid->width = width;
      vid->height= height;
      return (vid);
}

/*
 */
void
v4l_fini (video_t *vid)
{
      if (vid->fd >= 0) {
            if (vid->map_size == 0)
                  free (vid->mem);
            else
                  munmap (vid->mem, vid->map_size);
            close (vid->fd);
      }
      free (vid);
}

/*
 * return a new image
 */
int
v4l_image (video_t *vid)
{
      struct video_mmap vid_mmap;

      if (vid->map_size == 0) {
            printf ("%s: reading image .. \n", __FILE__);
            if (read (vid->fd, vid->mem, vid->width * vid->height * 3) <= 0) {
                  free (vid->mem);
                  return (0);
            }
      } else {
            vid_mmap.format = VIDEO_PALETTE_RGB24;
            vid_mmap.frame = 0;
            vid_mmap.width = vid->width;
            vid_mmap.height= vid->height;
            if (ioctl (vid->fd, VIDIOCMCAPTURE, &vid_mmap) == -1) {
                  perror ("ioctl (VIDIOCMCAPTURE)");
                  return (0);
            }
            if (ioctl (vid->fd, VIDIOCSYNC, &vid_mmap) == -1) {
                  perror ("ioctl (VIDIOCSYNC)");
                  return (0);
            }
      }
      printf ("%s: done\n", __FILE__);
      return (1);
}


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