[mdlug] Best Linux rig for capturing frames from analog video?

[David McMillan]

     I have a new side-project assignment from my bosses (for, you know, 
my copious amounts of spare time).  We have a high-res *analog* video 
camera (NTSC video for the composite input on a TV) left over from 
another project, and we're about to enter a serious build phase for the 
new project.  The bosses want me to connect this camera to a computer 
and capture periodic images that can be stitched together later into a 
time-lapse video of the construction.

     Now, I've done time-lapse before, using images taken using a hacked 
Canon Powershot (http://www.youtube.com/watch?v=pbDwl8Dh1kk), but I've 
never done analog-video framegrabbing with Linux before. So, here's 
where I'm looking for advice:
1:  video capture hardware.  Has to have a Composite (not component!) 
input.  Since I'll probably have to make do with whatever computer I 
find lying about unused, needs to use USB. Frame *rate* isn't vital, but 
image quality is
2:  capture software:  My current thought is that I can probably use 
motion, with motion-triggered capture, to avoid taking tons of useless 
photos at night and during lunch.  But I'm wide open to advice on this.
3:  "Stitching":  I did that YouTube video using mencoder, but it was a 
bit crude.