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
83int 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
91int 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}
193