A quick way to create shorter clips out of longer ones without video editing: set the Starttime and Duration parameters in the ASX file.

Example ASX file:

<ASX version = "3.0">
  <Title>the title of the video/s</Title>
  <Entry>
  <StartTime Value="00:09:36.00" />
  <Ref href = "mms://myvideoserver.com/myvideo.wmv" />
  <DURATION value="00:00:05.00"/>
  </Entry>
  </ASX>