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Old 08-13-2009, 07:18 PM   #1
Repgahroll
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Registered: Aug 2009
Posts: 10

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Webcam "dummy" device can only be read by Mplayer. [avld / gscpa / OpenCV / Ubuntu]


Hello there! This is my first post here.

I'm playing a little bit with OpenCV but the webcam that i have on my desktop isn't app-friendly... so i could not get it working with OpenCV, it's a 0ac8:301b Z-Star Microelectronics Corp. ZC0301 WebCam and it worked out of the box with Cheese and after a little bit of tweak i get it working with camorama also.

But some apps, like Skype and OpenCV demos doesn't work, believe me, i tried everything to get it working, i tried even upgrading to a very new kernel.

So i had the idea to create a "virtual" video device and using some app that can read the wcam i could print the wcam's output on such device, which should be compatible and app-friendly, so i would use that device always...

Searching a little i found some pretty nice apps that could help me:

AVLD:
http://allonlinux.free.fr/Projets/AVLD/

vloopback:
http://www.lavrsen.dk/twiki/bin/view...LoopbackDevice

v4l2loopback:
http://code.google.com/p/v4l2loopback/

I tried vloopback exhaustingly, and i could not even load the v4l2loopback module, but avld is working well:

To input the image from video0(physicam cam) on video1(pseudocam) i use:

Code:
mencoder tv:// -tv "driver=v4l:device=/dev/video0:noaudio" -nosound -vf scale=320:240 -ovc raw -of rawvideo -o /dev/video1
And to read the pseudocam i use:
Code:
mplayer tv:// -tv "driver=v4l:device=/dev/video1:noaudio"
And it works flawlessly (just a little bit delayed) BUT it just works with mplayer... other programs like Cheese or Skype can't see the video1 device, even if i point Camorama to it (-d /dev/video1) the thing don't work.

I know other people could do it, a little app called gstfakevideo can create a virtual device that Skype detects, but it fails to get the image.

And my main problem is OpenCV, because i have a Windows partition which i'm using only because of Skype.

Thank you very much for your time and patience. Sorry my english.

Some extra infos:

lsmod | grep video
Code:
videodev               45184  3 avld,gspca_main,compat_ioctl32
v4l1_compat            23940  1 videodev
video                  29204  0 
output                 11648  1 video
My system is an updated Ubuntu 9.04
uname -a
Code:
Linux alan-desktop 2.6.28-15-generic #48-Ubuntu SMP Wed Jul 29 08:53:35 UTC 2009 x86_64 GNU/Linux
ls /dev/vid*
Code:
/dev/video0  /dev/video1
 
Old 08-14-2009, 07:56 PM   #2
aus9
Guru
 
Registered: Oct 2003
Posts: 5,056

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hi

there may need to be an extra gspca module it might need....but kernels are under development so I can not tell you the exact name.
look in your /boot config(k version file) and you will see a list (hopefully) of other modules like eg
CONFIG_USB_GSPCA_CONEX=m
CONFIG_USB_GSPCA_ETOMS=m
CONFIG_USB_GSPCA_FINEPIX=m
CONFIG_USB_GSPCA_MARS=m
CONFIG_USB_GSPCA_MR97310A=m
CONFIG_USB_GSPCA_OV519=m
CONFIG_USB_GSPCA_OV534=m
CONFIG_USB_GSPCA_PAC207=m
CONFIG_USB_GSPCA_PAC7311=m
CONFIG_USB_GSPCA_SONIXB=m
CONFIG_USB_GSPCA_SONIXJ=m
CONFIG_USB_GSPCA_SPCA500=m
CONFIG_USB_GSPCA_SPCA501=m
CONFIG_USB_GSPCA_SPCA505=m
CONFIG_USB_GSPCA_SPCA506=m
CONFIG_USB_GSPCA_SPCA508=m
CONFIG_USB_GSPCA_SPCA561=m
CONFIG_USB_GSPCA_SQ905=m
CONFIG_USB_GSPCA_SQ905C=m
CONFIG_USB_GSPCA_STK014=m
CONFIG_USB_GSPCA_SUNPLUS=m
CONFIG_USB_GSPCA_T613=m
CONFIG_USB_GSPCA_TV8532=m
CONFIG_USB_GSPCA_VC032X=m
CONFIG_USB_GSPCA_ZC3XX=m


and I would try in a terminal to load each of the spca5* (series) due to google showing
http://schou.dk/linux/webcam/

2) then there is the well known to some distros...the issue that non-guvcivideo compliant (=crap) webcams have with software which is described here
under gspca2
http://www.sidux.com/module-News-display-sid-519.html
 
  


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