aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation/video4linux/v4lgrab.c
blob: 05769cff100998a60ba991325f48f62fe80bc889 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/* Simple Video4Linux image grabber. */
/*
 *	Video4Linux Driver Test/Example Framegrabbing Program
 *
 *	Compile with:
 *		gcc -s -Wall -Wstrict-prototypes v4lgrab.c -o v4lgrab
 *	Use as:
 *		v4lgrab >image.ppm
 *
 *	Copyright (C) 1998-05-03, Phil Blundell <philb@gnu.org>
 *	Copied from http://www.tazenda.demon.co.uk/phil/vgrabber.c
 *	with minor modifications (Dave Forrest, drf5n@virginia.edu).
 *
 *
 *	For some cameras you may need to pre-load libv4l to perform
 *	the necessary decompression, e.g.:
 *
 *	export LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so
 *	./v4lgrab >image.ppm
 *
 *	see http://hansdegoede.livejournal.com/3636.html for details.
 *
 */

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <stdlib.h>

#include <linux/types.h>
#include <linux/videodev.h>

#define VIDEO_DEV "/dev/video0"

/* Stole this from tvset.c */

#define READ_VIDEO_PIXEL(buf, format, depth, r, g, b)                   \
{                                                                       \
	switch (format)                                                 \
	{                                                               \
		case VIDEO_PALETTE_GREY:                                \
			switch (depth)                                  \
			{                                               \
				case 4:                                 \
				case 6:                                 \
				case 8:                                 \
					(r) = (g) = (b) = (*buf++ << 8);\
					break;                          \
									\
				case 16:                                \
					(r) = (g) = (b) =               \
						*((unsigned short *) buf);      \
					buf += 2;                       \
					break;                          \
			}                                               \
			break;                                          \
									\
									\
		case VIDEO_PALETTE_RGB565:                              \
		{                                                       \
			unsigned short tmp = *(unsigned short *)buf;    \
			(r) = tmp&0xF800;                               \
			(g) = (tmp<<5)&0xFC00;                          \
			(b) = (tmp<<11)&0xF800;                         \
			buf += 2;                                       \
		}                                                       \
		break;                                                  \
									\
		case VIDEO_PALETTE_RGB555:                              \
			(r) = (buf[0]&0xF8)<<8;                         \
			(g) = ((buf[0] << 5 | buf[1] >> 3)&0xF8)<<8;    \
			(b) = ((buf[1] << 2 ) & 0xF8)<<8;               \
			buf += 2;                                       \
			break;                                          \
									\
		case VIDEO_PALETTE_RGB24:                               \
			(r) = buf[0] << 8; (g) = buf[1] << 8;           \
			(b) = buf[2] << 8;                              \
			buf += 3;                                       \
			break;                                          \
									\
		default:                                                \
			fprintf(stderr,                                 \
				"Format %d not yet supported\n",        \
				format);                                \
	}                                                               \
}

int get_brightness_adj(unsigned char *image, long size, int *brightness) {
  long i, tot = 0;
  for (i=0;i<size*3;i++)
    tot += image[i];
  *brightness = (128 - tot/(size*3))/3;
  return !((tot/(size*3)) >= 126 && (tot/(size*3)) <= 130);
}

int main(int argc, char ** argv)
{
  int fd = open(VIDEO_DEV, O_RDONLY), f;
  struct video_capability cap;
  struct video_window win;
  struct video_picture vpic;

  unsigned char *buffer, *src;
  int bpp = 24, r = 0, g = 0, b = 0;
  unsigned int i, src_depth = 16;

  if (fd < 0) {
    perror(VIDEO_DEV);
    exit(1);
  }

  if (ioctl(fd, VIDIOCGCAP, &cap) < 0) {
    perror("VIDIOGCAP");
    fprintf(stderr, "(" VIDEO_DEV " not a video4linux device?)\n");
    close(fd);
    exit(1);
  }

  if (ioctl(fd, VIDIOCGWIN, &win) < 0) {
    perror("VIDIOCGWIN");
    close(fd);
    exit(1);
  }

  if (ioctl(fd, VIDIOCGPICT, &vpic) < 0) {
    perror("VIDIOCGPICT");
    close(fd);
    exit(1);
  }

  if (cap.type & VID_TYPE_MONOCHROME) {
    vpic.depth=8;
    vpic.palette=VIDEO_PALETTE_GREY;    /* 8bit grey */
    if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
      vpic.depth=6;
      if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
	vpic.depth=4;
	if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
	  fprintf(stderr, "Unable to find a supported capture format.\n");
	  close(fd);
	  exit(1);
	}
      }
    }
  } else {
    vpic.depth=24;
    vpic.palette=VIDEO_PALETTE_RGB24;

    if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
      vpic.palette=VIDEO_PALETTE_RGB565;
      vpic.depth=16;

      if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
	vpic.palette=VIDEO_PALETTE_RGB555;
	vpic.depth=15;

	if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
	  fprintf(stderr, "Unable to find a supported capture format.\n");
	  return -1;
	}
      }
    }
  }

  buffer = malloc(win.width * win.height * bpp);
  if (!buffer) {
    fprintf(stderr, "Out of memory.\n");
    exit(1);
  }

  do {
    int newbright;
    read(fd, buffer, win.width * win.height * bpp);
    f = get_brightness_adj(buffer, win.width * win.height, &newbright);
    if (f) {
      vpic.brightness += (newbright << 8);
      if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
	perror("VIDIOSPICT");
	break;
      }
    }
  } while (f);

  fprintf(stdout, "P6\n%d %d 255\n", win.width, win.height);

  src = buffer;

  for (i = 0; i < win.width * win.height; i++) {
    READ_VIDEO_PIXEL(src, vpic.palette, src_depth, r, g, b);
    fputc(r>>8, stdout);
    fputc(g>>8, stdout);
    fputc(b>>8, stdout);
  }

  close(fd);
  return 0;
}