This guide considers the simple scenario:

You want to make the movie clip by cutting out unnecessary parts from
AVI file. Sure you can do that by means of many of free/shareware
video tools. This guide explains how to do that with freeware
SolveigMM AVI Trimmer in a few simple steps without video/audio
quality degradation and in a couple of minutes.

http://www.solveigmm.com/HowTo/how-t...th-avi-trimmer