#include <stdio.h>#include <unistd.h>#include <error.h>#include <assert.h>#include <fcntl.h>#include <sys/ioctl.h>#include <sys/types.h>#include <sys/mman.h>#include <linux/videodev.h>#include "v4l.h"//int frame;#define DEFAULT_DEVICE "/dev/video0"//#define DEFAULT_PALETTE VIDEO_PALETTE_RGB24#define VIDEO_MAX_FRAME 32 int v4l_open(char *dev, v4l_device *vd){   if (!dev)      dev = DEFAULT_DEVICE;   if ((vd->fd = open(dev, O_RDWR)) < 0) {      perror("v4l_open:");      return -1;   }   if (v4l_get_capability(vd))      return -1;   if (v4l_get_picture(vd))      return -1;   return 0;}int v4l_get_capability(v4l_device *vd){   if (ioctl(vd->fd, VIDIOCGCAP, &(vd->capability)) < 0) {      perror("v4l_get_capability:");      return -1;   }   return 0;}int v4l_get_channels(v4l_device *vd){   int i;   for (i = 0; i < vd->capability.channels; i++) {      vd->channel[i].channel = i;      if (ioctl(vd->fd, VIDIOCGCHAN, &(vd->channel[i])) < 0) {         perror("v4l_get_channel:");         return -1;      }   }   return 0;}int v4l_get_audios(v4l_device *vd){   int i;   for (i = 0; i < vd->capability.audios; i++) {      vd->audio[i].audio = i;      if (ioctl(vd->fd, VIDIOCGAUDIO, &(vd->audio[i])) < 0) {         perror("v4l_get_audio:");         return -1;      }   }   return 0;}int v4l_get_picture(v4l_device *vd){   if (ioctl(vd->fd, VIDIOCGPICT, &(vd->picture)) < 0) {      perror("v4l_get_picture:");      return -1;   }   return 0;}int v4l_close(v4l_device *vd){   close(vd->fd);   return 0;}int v4l_mmap_init(v4l_device *vd){   if (v4l_get_mbuf(vd) < 0)   return -1;   if ((vd->map = mmap(0, vd->mbuf.size, PROT_READ|PROT_WRITE, MAP_SHARED, vd->fd, 0)) < 0) {      perror("v4l_mmap_init:mmap");      return -1;   }   return 0;}int v4l_switch_channel(v4l_device *vd, int c){   if (ioctl(vd->fd, VIDIOCSCHAN, &(vd->channel[c])) < 0) {      perror("v4l_switch_channel:");      return -1;   }   return 0;}int v4l_set_norm(v4l_device *vd, int norm){   int i;   for (i = 0; i < vd->capability.channels; i++) {      vd->channel[i].norm = norm;   }   if (v4l_get_capability(vd)) {      perror("v4l_set_norm");      return -1;   }   if (v4l_get_picture(vd)) {      perror("v4l_set_norm");   }   return 0;}int v4l_grab_init(v4l_device *vd, int width, int height){   /*full in the mmap structure,and set via VIDIOCMCAPTURE ioctls to   set the image size you wish to use,Having done so it will begin capturing to    the memory mapped buffer   */   vd->mmap.width = width;    vd->mmap.height = height;    vd->mmap.format = vd->picture.palette;    vd->frame_current = 0;   vd->frame_using[0] = 0;   vd->frame_using[1] = 1;   return v4l_grab_frame(vd, 0);}int v4l_grab_frame(v4l_device *vd, int frame){   if (vd->frame_using[frame]) {      fprintf(stderr, "v4l_grab_frame: frame %d is already used.\n", frame);      return -1;   }   vd->mmap.frame = frame;   /*set mmap structure*/   if (ioctl(vd->fd, VIDIOCMCAPTURE, &(vd->mmap)) < 0) {      perror("v4l_grab_frame");      return -1;   }   /*mark frame has been used. and set current frame is the frame.*/   vd->frame_using[frame] = 1;   vd->frame_current = frame;   return 0;}int v4l_grab_sync(v4l_device *vd){   if (ioctl(vd->fd, VIDIOCSYNC, &(vd->frame_current)) < 0) {      perror("v4l_grab_sync");   }   vd->frame_using[vd->frame_current] = 0;   return 0;}int v4l_set_palette(v4l_device* vd, int palette) { vd->picture.palette = palette; if(ioctl(vd->fd, VIDIOCSPICT, &(vd->picture))<0) { perror("v4l_set_palette0:"); return -1; } if(v4l_get_picture(vd)) { perror("v4l_set_palette1:"); return -1; } return 0; } int v4l_get_mbuf(v4l_device* vd) { if(ioctl(vd->fd, VIDIOCGMBUF, &(vd->mbuf)) < 0) { perror("v4l_get_mbuf:"); return -1; } return 0; } int device_grab_frame(v4l_device *vd) {   vd->frame_current = 0;   if (v4l_grab_frame(vd, 0) < 0)      return -1;   return 0; } int device_next_frame(v4l_device *vd) {   vd->frame_current ^= 1;   if (v4l_grab_frame(vd, vd->frame_current) < 0)      return -1;   return 0; } unsigned char* device_get_address(v4l_device* vd) { return (vd->map + vd->mbuf.offsets[vd->frame_current]); }