v4l2loopback on skype

After research, I've found a method to use skype with v4l2loopback : http://amanick.blogspot.fr/2011/02/virtual-webcam-for-skype-linux.html

Using prog test in v4l2loopback examples dir, skype's video preview working but always crashing in call conversation when video activated.
With error :

libv4l: error dequeuing buf: invalid argument 

So...
After reading libv4l.c source file, I've found error coming from VIDIOC_DQBUF call.
Looking in v4l2loopback.c, error source was in viodioc_dqbuf function line 1566 to 1569 :

1.     if (!(dev->buffers[index].buffer.flags & V4L2_BUF_FLAG_MAPPED)) {
2.       dprintk("trying to return not mapped buf\n");
3.       return -EINVAL;
4.     }

Just deleted it, and recompiled v4l2loopback module...

Skype Virtual webcam (video1) would work with a simple gstreamer launch :


gst-launch v4l2src device=/dev/video0 ! ffmpegcolorspace ! video/x-raw-yuv,format=\(fourcc\)YUY2 ! v4l2sink device=/dev/video1