what is best way to test uvideo?

["Jeremy C. Reed" <reed%reedmedia.net@localhost>]

I have on NetBSD/i386 5.99.36:

uvideo0 at uhub4 port 4 configuration 1 interface 0: Chicony Electronics 
Co., Ltd. Webcam, rev 2.00/78.58, addr 3
video0 at uvideo0: Chicony Electronics Co., Ltd. Webcam, rev 2.00/78.58, addr 3

I ran:

  mplayer tv:// -tv driver=v4l2:device=/dev/video0 -fps 30  

A green screen popped up. It didn't crash and the counters showed it 
running.

It gives me output like:

  v4l2: ioctl set format failed: Invalid argument
  tv.c: norm_from_string(pal): Bogus norm parameter, setting default.
  Selected input hasn't got a tuner!
  v4l2: Cannot get fps
  v4l2: ioctl set mute failed: Invalid argument
  v4l2: ioctl query control failed: Invalid argument
  v412: ioctl streamon failed: Invalid argument

Permissions on /dev/video0 are fine.

What is best way to test uvideo?