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 * For some cameras you may need to pre-load libv4l to perform
16 * the necessary decompression, e.g.:
17 *
18 * export LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so
19 * ./v4lgrab >image.ppm
20 *
21 * see http://hansdegoede.livejournal.com/3636.html for details.
22 *
23 */
24
25 #include <unistd.h>
26 #include <sys/types.h>
27 #include <sys/stat.h>
28 #include <fcntl.h>
29 #include <stdio.h>
30 #include <sys/ioctl.h>
31 #include <stdlib.h>
32
33 #include <linux/types.h>
34 #include <linux/videodev.h>
35
36 #define VIDEO_DEV "/dev/video0"
37
38 /* Stole this from tvset.c */
39
40 #define READ_VIDEO_PIXEL(buf, format, depth, r, g, b) \
41 { \
42 switch (format) \
43 { \
44 case VIDEO_PALETTE_GREY: \
45 switch (depth) \
46 { \
47 case 4: \
48 case 6: \
49 case 8: \
50 (r) = (g) = (b) = (*buf++ << 8);\
51 break; \
52 \
53 case 16: \
54 (r) = (g) = (b) = \
55 *((unsigned short *) buf); \
56 buf += 2; \
57 break; \
58 } \
59 break; \
60 \
61 \
62 case VIDEO_PALETTE_RGB565: \
63 { \
64 unsigned short tmp = *(unsigned short *)buf; \
65 (r) = tmp&0xF800; \
66 (g) = (tmp<<5)&0xFC00; \
67 (b) = (tmp<<11)&0xF800; \
68 buf += 2; \
69 } \
70 break; \
71 \
72 case VIDEO_PALETTE_RGB555: \
73 (r) = (buf[0]&0xF8)<<8; \
74 (g) = ((buf[0] << 5 | buf[1] >> 3)&0xF8)<<8; \
75 (b) = ((buf[1] << 2 ) & 0xF8)<<8; \
76 buf += 2; \
77 break; \
78 \
79 case VIDEO_PALETTE_RGB24: \
80 (r) = buf[0] << 8; (g) = buf[1] << 8; \
81 (b) = buf[2] << 8; \
82 buf += 3; \
83 break; \
84 \
85 default: \
86 fprintf(stderr, \
87 "Format %d not yet supported\n", \
88 format); \
89 } \
90 }
91
get_brightness_adj(unsigned char * image,long size,int * brightness)92 int get_brightness_adj(unsigned char *image, long size, int *brightness) {
93 long i, tot = 0;
94 for (i=0;i<size*3;i++)
95 tot += image[i];
96 *brightness = (128 - tot/(size*3))/3;
97 return !((tot/(size*3)) >= 126 && (tot/(size*3)) <= 130);
98 }
99
main(int argc,char ** argv)100 int main(int argc, char ** argv)
101 {
102 int fd = open(VIDEO_DEV, O_RDONLY), f;
103 struct video_capability cap;
104 struct video_window win;
105 struct video_picture vpic;
106
107 unsigned char *buffer, *src;
108 int bpp = 24, r, g, b;
109 unsigned int i, src_depth;
110
111 if (fd < 0) {
112 perror(VIDEO_DEV);
113 exit(1);
114 }
115
116 if (ioctl(fd, VIDIOCGCAP, &cap) < 0) {
117 perror("VIDIOGCAP");
118 fprintf(stderr, "(" VIDEO_DEV " not a video4linux device?)\n");
119 close(fd);
120 exit(1);
121 }
122
123 if (ioctl(fd, VIDIOCGWIN, &win) < 0) {
124 perror("VIDIOCGWIN");
125 close(fd);
126 exit(1);
127 }
128
129 if (ioctl(fd, VIDIOCGPICT, &vpic) < 0) {
130 perror("VIDIOCGPICT");
131 close(fd);
132 exit(1);
133 }
134
135 if (cap.type & VID_TYPE_MONOCHROME) {
136 vpic.depth=8;
137 vpic.palette=VIDEO_PALETTE_GREY; /* 8bit grey */
138 if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
139 vpic.depth=6;
140 if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
141 vpic.depth=4;
142 if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
143 fprintf(stderr, "Unable to find a supported capture format.\n");
144 close(fd);
145 exit(1);
146 }
147 }
148 }
149 } else {
150 vpic.depth=24;
151 vpic.palette=VIDEO_PALETTE_RGB24;
152
153 if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
154 vpic.palette=VIDEO_PALETTE_RGB565;
155 vpic.depth=16;
156
157 if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
158 vpic.palette=VIDEO_PALETTE_RGB555;
159 vpic.depth=15;
160
161 if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
162 fprintf(stderr, "Unable to find a supported capture format.\n");
163 return -1;
164 }
165 }
166 }
167 }
168
169 buffer = malloc(win.width * win.height * bpp);
170 if (!buffer) {
171 fprintf(stderr, "Out of memory.\n");
172 exit(1);
173 }
174
175 do {
176 int newbright;
177 read(fd, buffer, win.width * win.height * bpp);
178 f = get_brightness_adj(buffer, win.width * win.height, &newbright);
179 if (f) {
180 vpic.brightness += (newbright << 8);
181 if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
182 perror("VIDIOSPICT");
183 break;
184 }
185 }
186 } while (f);
187
188 fprintf(stdout, "P6\n%d %d 255\n", win.width, win.height);
189
190 src = buffer;
191
192 for (i = 0; i < win.width * win.height; i++) {
193 READ_VIDEO_PIXEL(src, vpic.palette, src_depth, r, g, b);
194 fputc(r>>8, stdout);
195 fputc(g>>8, stdout);
196 fputc(b>>8, stdout);
197 }
198
199 close(fd);
200 return 0;
201 }
202