Just installed from gem version 0.1.0, ruby 1.8.4, using a pvr250 capture card, ivtv driver version 0.4.7, ubuntu 6.06,
video works fine using mplayer -vo xv /dev/video0, switched to composite video port using ivtvctl -p 5

When I run the test script in camcapture I get the following error:

Image size is 320x240
image 1 : 38848 bytes grabbed
test.rb:13:in `save_bmp': image is not correct (RuntimeError)
        from test.rb:13
        from test.rb:10