[TCP] FRTO: Use of existing funcs make code more obvious & robust
[linux-2.6] / Documentation / video4linux / v4lgrab.c
1 /* Simple Video4Linux image grabber. */
2 /*
3  *      Video4Linux Driver Test/Example Framegrabbing Program
4  *
5  *      Compile with:
6  *              gcc -s -Wall -Wstrict-prototypes v4lgrab.c -o v4lgrab
7  *      Use as:
8  *              v4lgrab >image.ppm
9  *
10  *      Copyright (C) 1998-05-03, Phil Blundell <philb@gnu.org>
11  *      Copied from http://www.tazenda.demon.co.uk/phil/vgrabber.c
12  *      with minor modifications (Dave Forrest, drf5n@virginia.edu).
13  *
14  */
15
16 #include <unistd.h>
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <fcntl.h>
20 #include <stdio.h>
21 #include <sys/ioctl.h>
22 #include <stdlib.h>
23
24 #include <linux/types.h>
25 #include <linux/videodev.h>
26
27 #define FILE "/dev/video0"
28
29 /* Stole this from tvset.c */
30
31 #define READ_VIDEO_PIXEL(buf, format, depth, r, g, b)                   \
32 {                                                                       \
33         switch (format)                                                 \
34         {                                                               \
35                 case VIDEO_PALETTE_GREY:                                \
36                         switch (depth)                                  \
37                         {                                               \
38                                 case 4:                                 \
39                                 case 6:                                 \
40                                 case 8:                                 \
41                                         (r) = (g) = (b) = (*buf++ << 8);\
42                                         break;                          \
43                                                                         \
44                                 case 16:                                \
45                                         (r) = (g) = (b) =               \
46                                                 *((unsigned short *) buf);      \
47                                         buf += 2;                       \
48                                         break;                          \
49                         }                                               \
50                         break;                                          \
51                                                                         \
52                                                                         \
53                 case VIDEO_PALETTE_RGB565:                              \
54                 {                                                       \
55                         unsigned short tmp = *(unsigned short *)buf;    \
56                         (r) = tmp&0xF800;                               \
57                         (g) = (tmp<<5)&0xFC00;                          \
58                         (b) = (tmp<<11)&0xF800;                         \
59                         buf += 2;                                       \
60                 }                                                       \
61                 break;                                                  \
62                                                                         \
63                 case VIDEO_PALETTE_RGB555:                              \
64                         (r) = (buf[0]&0xF8)<<8;                         \
65                         (g) = ((buf[0] << 5 | buf[1] >> 3)&0xF8)<<8;    \
66                         (b) = ((buf[1] << 2 ) & 0xF8)<<8;               \
67                         buf += 2;                                       \
68                         break;                                          \
69                                                                         \
70                 case VIDEO_PALETTE_RGB24:                               \
71                         (r) = buf[0] << 8; (g) = buf[1] << 8;           \
72                         (b) = buf[2] << 8;                              \
73                         buf += 3;                                       \
74                         break;                                          \
75                                                                         \
76                 default:                                                \
77                         fprintf(stderr,                                 \
78                                 "Format %d not yet supported\n",        \
79                                 format);                                \
80         }                                                               \
81 }
82
83 int get_brightness_adj(unsigned char *image, long size, int *brightness) {
84   long i, tot = 0;
85   for (i=0;i<size*3;i++)
86     tot += image[i];
87   *brightness = (128 - tot/(size*3))/3;
88   return !((tot/(size*3)) >= 126 && (tot/(size*3)) <= 130);
89 }
90
91 int main(int argc, char ** argv)
92 {
93   int fd = open(FILE, O_RDONLY), f;
94   struct video_capability cap;
95   struct video_window win;
96   struct video_picture vpic;
97
98   unsigned char *buffer, *src;
99   int bpp = 24, r, g, b;
100   unsigned int i, src_depth;
101
102   if (fd < 0) {
103     perror(FILE);
104     exit(1);
105   }
106
107   if (ioctl(fd, VIDIOCGCAP, &cap) < 0) {
108     perror("VIDIOGCAP");
109     fprintf(stderr, "(" FILE " not a video4linux device?)\n");
110     close(fd);
111     exit(1);
112   }
113
114   if (ioctl(fd, VIDIOCGWIN, &win) < 0) {
115     perror("VIDIOCGWIN");
116     close(fd);
117     exit(1);
118   }
119
120   if (ioctl(fd, VIDIOCGPICT, &vpic) < 0) {
121     perror("VIDIOCGPICT");
122     close(fd);
123     exit(1);
124   }
125
126   if (cap.type & VID_TYPE_MONOCHROME) {
127     vpic.depth=8;
128     vpic.palette=VIDEO_PALETTE_GREY;    /* 8bit grey */
129     if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
130       vpic.depth=6;
131       if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
132         vpic.depth=4;
133         if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
134           fprintf(stderr, "Unable to find a supported capture format.\n");
135           close(fd);
136           exit(1);
137         }
138       }
139     }
140   } else {
141     vpic.depth=24;
142     vpic.palette=VIDEO_PALETTE_RGB24;
143
144     if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
145       vpic.palette=VIDEO_PALETTE_RGB565;
146       vpic.depth=16;
147
148       if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
149         vpic.palette=VIDEO_PALETTE_RGB555;
150         vpic.depth=15;
151
152         if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
153           fprintf(stderr, "Unable to find a supported capture format.\n");
154           return -1;
155         }
156       }
157     }
158   }
159
160   buffer = malloc(win.width * win.height * bpp);
161   if (!buffer) {
162     fprintf(stderr, "Out of memory.\n");
163     exit(1);
164   }
165
166   do {
167     int newbright;
168     read(fd, buffer, win.width * win.height * bpp);
169     f = get_brightness_adj(buffer, win.width * win.height, &newbright);
170     if (f) {
171       vpic.brightness += (newbright << 8);
172       if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
173         perror("VIDIOSPICT");
174         break;
175       }
176     }
177   } while (f);
178
179   fprintf(stdout, "P6\n%d %d 255\n", win.width, win.height);
180
181   src = buffer;
182
183   for (i = 0; i < win.width * win.height; i++) {
184     READ_VIDEO_PIXEL(src, vpic.palette, src_depth, r, g, b);
185     fputc(r>>8, stdout);
186     fputc(g>>8, stdout);
187     fputc(b>>8, stdout);
188   }
189
190   close(fd);
191   return 0;
192 }