V4L/DVB (4047): Doc. sources: expose video4linux/

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>

1 files changed, 192 insertions, 0 deletions

diff --git a/Documentation/video4linux/v4lgrab.c b/Documentation/video4linux/v4lgrab.c
new file mode 100644
index 00000000000..079b628481c
--- /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;
+}