[MEncoder-users] cat /dev/video0 | mencoder - ...

[Bob Tennent]

 >|>| -cache 102400 -cache-min 3
 >|
 >|Yes!  This does the trick. Thanks.

After more testing, it's become clear that the basic idea isn't
workable: even in the best circumstances (nothing else running),
encoding takes much more than "real time"; that is, to encode 10 minutes
of video takes close to 20 minutes. No amount of cache or buffer could
address this imbalance; frames were being dropped. Saving an mpg file
in real time and encoding at leisure after does seem to be the best
approach, at least for my system.