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device error!!!

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2004-04-19
2013-04-17
  • Nobody/Anonymous

    hi all,
    i am tring to make effectv running, but no matter what i do, i always come up with the same device error:

    ./effectv -device /dev/video0
    video_init: double buffer capturing with mmap is not supported.
    Video initialization failed.

    I am using a redhat9, and a logitec quickcam.
    the camera is working, since if i launch gcqam i get correct video output. What can i do?
    Thx E.

     
    • Nobody/Anonymous

      ok, i resolved this one:
      I've found a post regarding my very same problem:
      it seems like effectv doesn't support the quickcam drivers. Solution: i changed the cam with a philips toucam and now all the stuff started to work.

      I take advantage of this reply to ask a question blocking me on this board too. I have posted on the devel forum and on the mailing list and that at the moment being remains unanswered:

      i want to get a multicast stream with effectv, but if i haven't missed anything, effectv just grabs the output of /dev/video0. I installed vloopback (after a bit of struggle), is there a way to redirect the stream coming from the multicast into the virtual pipes? I was thinking of ffmpeg, but even if i tried playng a bit with it, i just can't write on the virtual device /dev/video1. Anyone knows a solution?
      Thanks the Gunslinger

       
    • Kentaro Fukuchi

      Kentaro Fukuchi - 2004-04-23

      Hi,

      EffectV does not support single buffered mode at this moment and Quickcam drivers don't have double buffered mode. Sorry for your inconvinience.

      As far as I know, it is rare what can write on vloopback device. I saw that old MPlayer could do with an external plugin, but the plugin is not supproted now.

       
    • Nobody/Anonymous

      I got my quickcam working by doing the following:

      1. plug in camera, make sure it works with xawtv
      2. compile and insert vloopback kernel module
      3. change line 200 of example/invert.c from
      for (i=width*height*3; i>=0; i--) image_out[i]=-image_new[i];
      to for (i=width*height*3; i>=0; i--) image_out[i]=image_new[i];
      (this causes the invert program to basically cat from the camera to the vloopback input)
      4. compile invert
      5. run invert with

      ./invert /dev/video0 /dev/video1 352x292

      where 352x292 is the resolution of my camera as given by v4l-info, video0 is the camera, and video1 is the vloopback input

      6. run effectv using

      effectv -device /dev/video2 -size 352x292

      where video2 is the vloopback output and size MUST match that given to invert, and should probably be your camera's native resolution.

      hope that helps

      -D.E.

       
    • Nobody/Anonymous

      where can i found invert please ?

       
    • Nobody/Anonymous

      solution by sack on #motion on freenode

      rmmod quickam ; rmmod vloopback

      modprobe quickcam compatible=2 ; modprove vloopback
      effectv  -vloopback /dev/video1 -device /dev/video0

       

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