[ale] USB video capture devices that work for Linux

[Alex Carver]

Any suggested inexpensive USB capture devices that work relatively
easily and/or well under Linux?  I want to capture video and stills from
an NTSC camera so it needs composite video input.  It ideally would also
function well enough with things like ffmpeg to capture from the command
line so I can synchronize the capture with other events.

I've had a couple old units laying around here but they don't seem to
work and I can't find anything to help (one is a Dazzle DVC-80 and the
other is an Adaptec GameBridge AVC-1410.  The DVC is recognized with a
module loaded but nothing works beyond that point, the AVC is never
recognized.)