Have a long video clip that you need to trim down in order to show it to a class? Have a performance that you really just want to save a few minutes of and discard the rest? Then Apple QuickTime is the software for you! QuickTime now has the option to "Trim" the video you are watching and then save the newly trimmed video as its own clip. That way, you have the original just in case you need to trim it again or you make a mistake the first time. (Note: On Macs with OS X, this option is included in the free version, but for PCs, this requires QuickTime Pro)
To trim a video:
1. Open the video clip using QuickTime.
2. Under "Edit", select "Trim" (Towards the bottom). This creates a progress bar for the video clip where you can move the beginning and the end of the clip according to your needs.
3. When you are done selecting the piece of the clip you need, click "Done".
4. Preview the clip to make sure you have the part that you need, and then go to "File -> Save". The default may be to save it to either your Desktop or your Movies folder, or it may prompt you to choose a destination. Just make sure you know where it was saved!