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Diffstat (limited to 'Documentation/video4linux/v4lgrab.c')
| -rw-r--r-- | Documentation/video4linux/v4lgrab.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/Documentation/video4linux/v4lgrab.c b/Documentation/video4linux/v4lgrab.c new file mode 100644 index 0000000..079b628 --- /dev/null +++ b/Documentation/video4linux/v4lgrab.c @@ -0,0 +1,192 @@ +/* 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). + * + */ + +#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 FILE "/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(FILE, O_RDONLY), f; + struct video_capability cap; + struct video_window win; + struct video_picture vpic; + + unsigned char *buffer, *src; + int bpp = 24, r, g, b; + unsigned int i, src_depth; + + if (fd < 0) { + perror(FILE); + exit(1); + } + + if (ioctl(fd, VIDIOCGCAP, &cap) < 0) { + perror("VIDIOGCAP"); + fprintf(stderr, "(" FILE " 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; +} |
