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@@ -185,207 +185,10 @@ this work is documented at the video4linux2 site listed below.
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9.0 --- A sample program using v4lgrabber,
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9.0 --- A sample program using v4lgrabber,
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-This program is a simple image grabber that will copy a frame from the
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+v4lgrab is a simple image grabber that will copy a frame from the
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first video device, /dev/video0 to standard output in portable pixmap
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first video device, /dev/video0 to standard output in portable pixmap
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-format (.ppm) Using this like: 'v4lgrab | convert - c-qcam.jpg'
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-produced this picture of me at
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- http://mug.sys.virginia.edu/~drf5n/extras/c-qcam.jpg
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-
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--------------------- 8< ---------------- 8< -----------------------------
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-
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-/* Simple Video4Linux image grabber. */
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-/*
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- * Video4Linux Driver Test/Example Framegrabbing Program
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- *
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- * Compile with:
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- * gcc -s -Wall -Wstrict-prototypes v4lgrab.c -o v4lgrab
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- * Use as:
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- * v4lgrab >image.ppm
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- *
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- * Copyright (C) 1998-05-03, Phil Blundell <philb@gnu.org>
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- * Copied from http://www.tazenda.demon.co.uk/phil/vgrabber.c
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- * with minor modifications (Dave Forrest, drf5n@virginia.edu).
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- *
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- */
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-
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-#include <unistd.h>
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-#include <sys/types.h>
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-#include <sys/stat.h>
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-#include <fcntl.h>
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-#include <stdio.h>
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-#include <sys/ioctl.h>
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-#include <stdlib.h>
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-
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-#include <linux/types.h>
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-#include <linux/videodev.h>
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-
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-#define FILE "/dev/video0"
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-
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-/* Stole this from tvset.c */
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-
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-#define READ_VIDEO_PIXEL(buf, format, depth, r, g, b) \
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-{ \
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- switch (format) \
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- { \
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- case VIDEO_PALETTE_GREY: \
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- switch (depth) \
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- { \
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- case 4: \
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- case 6: \
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- case 8: \
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- (r) = (g) = (b) = (*buf++ << 8);\
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- break; \
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- \
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- case 16: \
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- (r) = (g) = (b) = \
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- *((unsigned short *) buf); \
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- buf += 2; \
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- break; \
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- } \
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- break; \
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- \
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- \
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- case VIDEO_PALETTE_RGB565: \
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- { \
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- unsigned short tmp = *(unsigned short *)buf; \
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- (r) = tmp&0xF800; \
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- (g) = (tmp<<5)&0xFC00; \
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- (b) = (tmp<<11)&0xF800; \
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- buf += 2; \
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- } \
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- break; \
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- \
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- case VIDEO_PALETTE_RGB555: \
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- (r) = (buf[0]&0xF8)<<8; \
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- (g) = ((buf[0] << 5 | buf[1] >> 3)&0xF8)<<8; \
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- (b) = ((buf[1] << 2 ) & 0xF8)<<8; \
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- buf += 2; \
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- break; \
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- \
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- case VIDEO_PALETTE_RGB24: \
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- (r) = buf[0] << 8; (g) = buf[1] << 8; \
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- (b) = buf[2] << 8; \
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- buf += 3; \
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- break; \
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- \
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- default: \
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- fprintf(stderr, \
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- "Format %d not yet supported\n", \
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- format); \
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- } \
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-}
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-
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-int get_brightness_adj(unsigned char *image, long size, int *brightness) {
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- long i, tot = 0;
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- for (i=0;i<size*3;i++)
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- tot += image[i];
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- *brightness = (128 - tot/(size*3))/3;
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- return !((tot/(size*3)) >= 126 && (tot/(size*3)) <= 130);
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-}
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-
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-int main(int argc, char ** argv)
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-{
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- int fd = open(FILE, O_RDONLY), f;
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- struct video_capability cap;
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- struct video_window win;
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- struct video_picture vpic;
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-
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- unsigned char *buffer, *src;
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- int bpp = 24, r, g, b;
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- unsigned int i, src_depth;
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-
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- if (fd < 0) {
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- perror(FILE);
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- exit(1);
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- }
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-
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- if (ioctl(fd, VIDIOCGCAP, &cap) < 0) {
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- perror("VIDIOGCAP");
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- fprintf(stderr, "(" FILE " not a video4linux device?)\n");
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- close(fd);
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- exit(1);
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- }
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-
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- if (ioctl(fd, VIDIOCGWIN, &win) < 0) {
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- perror("VIDIOCGWIN");
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- close(fd);
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- exit(1);
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- }
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-
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- if (ioctl(fd, VIDIOCGPICT, &vpic) < 0) {
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- perror("VIDIOCGPICT");
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- close(fd);
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- exit(1);
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- }
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-
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- if (cap.type & VID_TYPE_MONOCHROME) {
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- vpic.depth=8;
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- vpic.palette=VIDEO_PALETTE_GREY; /* 8bit grey */
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- if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
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- vpic.depth=6;
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- if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
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- vpic.depth=4;
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- if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
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- fprintf(stderr, "Unable to find a supported capture format.\n");
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- close(fd);
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- exit(1);
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- }
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- }
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- }
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- } else {
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- vpic.depth=24;
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- vpic.palette=VIDEO_PALETTE_RGB24;
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-
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- if(ioctl(fd, VIDIOCSPICT, &vpic) < 0) {
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- vpic.palette=VIDEO_PALETTE_RGB565;
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- vpic.depth=16;
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-
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- if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
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- vpic.palette=VIDEO_PALETTE_RGB555;
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- vpic.depth=15;
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-
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- if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
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- fprintf(stderr, "Unable to find a supported capture format.\n");
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- return -1;
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- }
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- }
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- }
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- }
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-
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- buffer = malloc(win.width * win.height * bpp);
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- if (!buffer) {
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- fprintf(stderr, "Out of memory.\n");
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- exit(1);
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- }
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-
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- do {
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- int newbright;
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- read(fd, buffer, win.width * win.height * bpp);
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- f = get_brightness_adj(buffer, win.width * win.height, &newbright);
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- if (f) {
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- vpic.brightness += (newbright << 8);
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- if(ioctl(fd, VIDIOCSPICT, &vpic)==-1) {
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- perror("VIDIOSPICT");
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- break;
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- }
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- }
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- } while (f);
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-
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- fprintf(stdout, "P6\n%d %d 255\n", win.width, win.height);
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-
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- src = buffer;
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-
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- for (i = 0; i < win.width * win.height; i++) {
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- READ_VIDEO_PIXEL(src, vpic.palette, src_depth, r, g, b);
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- fputc(r>>8, stdout);
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- fputc(g>>8, stdout);
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- fputc(b>>8, stdout);
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- }
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-
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- close(fd);
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- return 0;
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-}
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--------------------- 8< ---------------- 8< -----------------------------
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+format (.ppm) To produce .jpg output, you can use it like this:
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+'v4lgrab | convert - c-qcam.jpg'
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10.0 --- Other Information
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10.0 --- Other Information
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