Old-timers probably are aware of the median technique for multiple captures; this is when you capture the same tape three or more separate times, then run a median to eliminate noise. The usual way to do this was this was a script function or even medianblurT. Now there is a simple median function for this purpose:
http://forum.doom9.org/showthread.php?t=170216

To use, use trim commands to line-up the captures to the same starting point, then the result is simply:
restored=median(cap1,cap2,cap3)

Some other problems with this technique are that missing frames in the captures can cause them to relatively lose sync, also horizontal jitter of the lines can cause spatial mis-alignment. But generally it can work really well.