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-rw-r--r--Documentation/video4linux/v4lgrab.c192
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diff --git a/Documentation/video4linux/v4lgrab.c b/Documentation/video4linux/v4lgrab.c
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+/* 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;
+}