yes you can connect an external video source (dvd/cam/videomixer/whatever) using a capture card or a usb2 video-in or maby a firewirecam with video in...
thanks Juba, I guess that my graphic card must have a video in... I'm wondering to buy a Acer Aspire 1714SMi-Nv with GForce-Go5700, do you think it's ok to work with resolume?