Skip to content

Commit

Permalink
V4L/DVB (4047): Doc. sources: expose video4linux/
Browse files Browse the repository at this point in the history 
Documentation/video4linux/:
Expose example and tool source files in the Documentation/ directory in
their own files instead of being buried (almost hidden) in readme/txt files.
This will make them more visible/usable to users who may need
to use them, to developers who may need to test with them, and
to janitors who would update them if they were more visible.
Also, if any of these possibly should not be in the kernel tree at
all, it will be clearer that they are here and we can discuss if
they should be removed.

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
  • Loading branch information
Randy Dunlap authored and Mauro Carvalho Chehab committed Jun 25, 2006
1 parent c003d46 commit a22f1cb
Show file tree
Hide file tree
Showing 2 changed files with 195 additions and 200 deletions.
203 changes: 3 additions & 200 deletions Documentation/video4linux/CQcam.txt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down
Loading

0 comments on commit a22f1cb

Please sign in to comment.