v4lapi.c

   1 /*
   2  * v4lapi.c -- api to the video4linux interface
   3  *
   4  * author: hackbard@hackdaworld.dyndns.org
   5  *
   6  */
   7
   8 #include <stdio.h>
   9 #include <sys/types.h>
  10 #include <sys/stat.h>
  11 #include <fcntl.h>
  12 #include <sys/ioctl.h>
  13 #include <string.h>
  14 #include <unistd.h>
  15
  16 #include <linux/videodev.h>
  17
  18 int v4l_init(char *dev) {
  19         int fd,i,res;
  20         unsigned char buf[500*500];
  21         struct video_capability vc;
  22         struct video_buffer vb;
  23         struct video_window vw;
  24         struct video_picture vp;
  25
  26         if((fd=open(dev,O_RDONLY))<0) {
  27                 puts("open failed");
  28                 return -1;
  29         }
  30
  31         if(ioctl(fd,VIDIOCGCAP,&vc)<0) {
  32                 puts("ioctl VIDIOCGCAP failed");
  33                 return -1;
  34         }
  35
  36         printf("video device information:\n");
  37         printf("-------------------------\n\n");
  38         printf("interface name: %s\n\n",vc.name);
  39         printf("type:\n");
  40         printf("capture:\t %c\n",(vc.type&1)?'y':'n');
  41         printf("tuner:\t\t %c\n",((vc.type>>1)&1)?'y':'n');
  42         printf("teletext:\t %c\n",((vc.type>>2)&1)?'y':'n');
  43         printf("overlay:\t %c\n",((vc.type>>3)&1)?'y':'n');
  44         printf("chromakey:\t %c\n",((vc.type>>4)&1)?'y':'n');
  45         printf("clipping:\t %c\n",((vc.type>>5)&1)?'y':'n');
  46         printf("fb memory:\t %c\n",((vc.type>>6)&1)?'y':'n');
  47         printf("scalable:\t %c\n",((vc.type>>7)&1)?'y':'n');
  48         printf("monochrome:\t %c\n",((vc.type>>8)&1)?'y':'n');
  49         printf("subcapture:\t %c\n",((vc.type>>9)&1)?'y':'n');
  50         printf("decode: ");
  51         if((vc.type>>10)&1) printf("mpeg ");
  52         if((vc.type>>12)&1) printf("mjpeg ");
  53         printf("\n");
  54         printf("encode: ");
  55         if((vc.type>>11)&1) printf("mpeg ");
  56         if((vc.type>>13)&1) printf("mjpeg ");
  57         printf("\n\n");
  58         printf("channels:\t %d\n",vc.channels);
  59         printf("audios:\t\t %d\n",vc.audios);
  60         printf("width:\t\t %d - %d\n",vc.minwidth,vc.maxwidth);
  61         printf("height:\t\t %d - %d\n\n",vc.minheight,vc.maxheight);
  62
  63         if(ioctl(fd,VIDIOCGFBUF,&vb)<0) {
  64                 puts("direct framebuffer access unsupported");
  65                 puts("");
  66         }
  67         else {
  68                 printf("\n");
  69                 printf("framebuffer:\n");
  70                 printf("buffer addr:\t %d\n",vb.base);
  71                 printf("h: %d - w: %d - d: %d - bpl: %d\n\n",vb.height,vb.width,vb.depth,vb.bytesperline);
  72         }
  73
  74         memset(&vw,0,sizeof(struct video_window));
  75         vw.x=0;
  76         vw.y=0;
  77         vw.width=vc.maxwidth;
  78         vw.height=vc.maxheight;
  79
  80         if(ioctl(fd,VIDIOCSWIN,&vw)<0) {
  81                 puts("ioctl VIDIOCSWIN failed");
  82                 return -1;
  83         }
  84
  85         if(ioctl(fd,VIDIOCGWIN,&vw)<0) {
  86                 puts("ioctl VIDIOCGWIN failed");
  87                 return -1;
  88         }
  89
  90         printf("real capture area:\n");
  91         printf("x: %u - y: %u\n",vw.x,vw.y);
  92         printf("w: %u - h: %u\n",vw.width,vw.height);
  93         printf("flags: %08x\n",vw.flags);
  94
  95         memset(&vp,0,sizeof(struct video_picture));
  96
  97         if(ioctl(fd,VIDIOCGPICT,&vp)<0) {
  98                 puts("ioctl VIDIOCGPICT failed");
  99                 return -1;
 100         }
 101
 102         printf("picture: b: %04x - h: %04x - c: %04x - c: %04x - w: %04x - d: %04x - p: %04x\n",vp.brightness,vp.hue,vp.colour,vp.contrast,vp.whiteness,vp.depth,vp.palette);
 103
 104         if(ioctl(fd,VIDIOCSPICT,&vp)<0) {
 105                 puts("ioctl VIDIOCSPICT failed");
 106                 return -1;
 107         }
 108
 109         if((res=read(fd,buf,(500*500)))<0) {
 110                 puts("read failed");
 111                 return -1;
 112         }
 113         printf("debug: wrote %d bytes:\n",i);
 114         for(i=0;i<res;i++) printf("%c ",buf[i]);
 115         printf("\n");
 116
 117         return 1;
 118 }