final cut pro

You can edit clips in the Viewer so you don't have to load your entire clip into the Timeline when you want to create your movie.

You can choose a smaller selection to add by double clicking on the clip in the Browser so it displays in the Viewer. Then start playing the clip.

Press the I Key (for IN) at the desired point where you want your clip to start playing. Then hit the O Key (for OUT) at the point you want your clip to end. You will see arrows appear in the window at the points you pressed the I and O keys.

These points can be moved later by clicking and dragging on the arrows.

When you have the clip set with in and out points you want, you can click on the clip in the Viewer and drag the clip into the Timeline. Only the portion of the clip where you set your in and out points will be placed in the Timeline.