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authorIngo Molnar <mingo@elte.hu>2009-01-31 19:32:31 +0300
committerIngo Molnar <mingo@elte.hu>2009-02-06 00:30:01 +0300
commit9d45cf9e36bf9bcf16df6e1cbf049807c8402823 (patch)
tree2118a16701418af10d215d2174df7ee0a5cbe6bd /Documentation/video4linux
parenta146649bc19d5eba4f5bfac6720c5f252d517a71 (diff)
parent0cd5c3c80a0ebd68c08312fa7d8c13149cc61c4c (diff)
downloadlinux-9d45cf9e36bf9bcf16df6e1cbf049807c8402823.tar.xz
Merge branch 'x86/urgent' into x86/apic
Conflicts: arch/x86/mach-default/setup.c Semantic merge: arch/x86/kernel/irqinit_32.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/video4linux')
-rw-r--r--Documentation/video4linux/v4lgrab.c25
1 files changed, 17 insertions, 8 deletions
diff --git a/Documentation/video4linux/v4lgrab.c b/Documentation/video4linux/v4lgrab.c
index 079b628481cf..d6e70bef8ad0 100644
--- a/Documentation/video4linux/v4lgrab.c
+++ b/Documentation/video4linux/v4lgrab.c
@@ -4,12 +4,21 @@
*
* Compile with:
* gcc -s -Wall -Wstrict-prototypes v4lgrab.c -o v4lgrab
- * Use as:
- * v4lgrab >image.ppm
+ * 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).
+ * Copied from http://www.tazenda.demon.co.uk/phil/vgrabber.c
+ * with minor modifications (Dave Forrest, drf5n@virginia.edu).
+ *
+ *
+ * For some cameras you may need to pre-load libv4l to perform
+ * the necessary decompression, e.g.:
+ *
+ * export LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so
+ * ./v4lgrab >image.ppm
+ *
+ * see http://hansdegoede.livejournal.com/3636.html for details.
*
*/
@@ -24,7 +33,7 @@
#include <linux/types.h>
#include <linux/videodev.h>
-#define FILE "/dev/video0"
+#define VIDEO_DEV "/dev/video0"
/* Stole this from tvset.c */
@@ -90,7 +99,7 @@ int get_brightness_adj(unsigned char *image, long size, int *brightness) {
int main(int argc, char ** argv)
{
- int fd = open(FILE, O_RDONLY), f;
+ int fd = open(VIDEO_DEV, O_RDONLY), f;
struct video_capability cap;
struct video_window win;
struct video_picture vpic;
@@ -100,13 +109,13 @@ int main(int argc, char ** argv)
unsigned int i, src_depth;
if (fd < 0) {
- perror(FILE);
+ perror(VIDEO_DEV);
exit(1);
}
if (ioctl(fd, VIDIOCGCAP, &cap) < 0) {
perror("VIDIOGCAP");
- fprintf(stderr, "(" FILE " not a video4linux device?)\n");
+ fprintf(stderr, "(" VIDEO_DEV " not a video4linux device?)\n");
close(fd);
exit(1);
}