Hi,
I would like to get some frames from my webcam however, whenever I try something like: cat /dev/video0 [the dev node of the webcam is video0], I get a message about no such device being found, even though my webcam works seamlessly with other applications such as luvcview, skype or etc.
I've googled this problem but found nothing of particular usefulness, so I'd be glad if you could help.
Some information on my system, which should help:
Code:
bla@blub /dev $ ls | grep video
video0
bla@blub /dev $ ls -l /dev/video0
crw-rw----+ 1 root video 81, 0 Sept 4 13:14 /dev/video0
bla@blub /dev $ cat /dev/video0 > vid.raw
cat: /dev/video0: No such device found
bla@blub /dev $ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 002: ID 04f2:b055 Chicony Electronics Co., Ltd
bla@blub /dev $ uname -r
2.6.32-5-amd64
bla@blub /dev $ mplayer tv:// -tv driver=v4l2
MPlayer SVN-r33953 (C) 2000-2010 MPlayer Team
Can't open joystick device /dev/input/js0: No such file or directory
Can't init input joystick
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.
Playing tv://.
TV file format detected.
Selected driver: v4l2
name: Video 4 Linux 2 input
author: Martin Olschewski <olschewski@zpr.uni-koeln.de>
comment: first try, more to come ;-)
v4l2: your device driver does not support VIDIOC_G_STD ioctl, VIDIOC_G_PARM was used instead.
Selected device: CNF7040
Capabilities: video capture streaming
supported norms:
inputs: 0 = Camera 1;
Current input: 0
Current format: YUYV
v4l2: ioctl set format failed: Invalid argument
v4l2: ioctl set format failed: Invalid argument
v4l2: ioctl set format failed: Invalid argument
tv.c: norm_from_string(pal): Bogus norm parameter, setting default.
v4l2: ioctl enum norm failed: Invalid argument
Error: Cannot set norm!
Selected input hasn't got a tuner!
v4l2: ioctl set mute failed: Invalid argument
open: No such file or directory
[MGA] Couldn't open: /dev/mga_vid
open: No such file or directory
[MGA] Couldn't open: /dev/mga_vid
[VO_TDFXFB] Can't open /dev/fb0: No such file or directory.
s3fb: can't open /dev/fb0: No such file or directory
[vdpau] Error when calling vdp_device_create_x11: 1
==========================================================================
Opening video decoder: [raw] RAW Uncompressed Video
Movie-Aspect is undefined - no prescaling applied.
VO: [xv] 640x480 => 640x480 Packed YUY2
Selected video codec: [rawyuy2] vfm: raw (RAW YUY2)
==========================================================================
Audio: no sound
Starting playback...
V: 0.0 1/ 1 ??% ??% ??,?% 0 0
v4l2: ioctl set mute failed: Invalid argument
v4l2: 3 frames successfully processed, 0 frames dropped.
Exiting... (End of file)
Operating System: Debian Stable
Webcam: Chicony Usb Webcam [the embedded webcam of my laptop]
[Before you ask, my user is a member of the video group and I get the same problem, even when I run the cat command as root.]
cat /dev/video* -> No such device found
