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Diffstat (limited to 'Documentation/video4linux/CQcam.txt')
| -rw-r--r-- | Documentation/video4linux/CQcam.txt | 203 |
1 files changed, 3 insertions, 200 deletions
diff --git a/Documentation/video4linux/CQcam.txt b/Documentation/video4linux/CQcam.txt index 464e4cec94c..ade8651e244 100644 --- a/Documentation/video4linux/CQcam.txt +++ b/Documentation/video4linux/CQcam.txt @@ -185,207 +185,10 @@ this work is documented at the video4linux2 site listed below. 9.0 --- A sample program using v4lgrabber, -This program is a simple image grabber that will copy a frame from the +v4lgrab is a simple image grabber that will copy a frame from the first video device, /dev/video0 to standard output in portable pixmap -format (.ppm) Using this like: 'v4lgrab | convert - c-qcam.jpg' -produced this picture of me at - http://mug.sys.virginia.edu/~drf5n/extras/c-qcam.jpg - --------------------- 8< ---------------- 8< ----------------------------- - -/* 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; -} --------------------- 8< ---------------- 8< ----------------------------- +format (.ppm) To produce .jpg output, you can use it like this: +'v4lgrab | convert - c-qcam.jpg' 10.0 --- Other Information |