After you watch your video clips, you might notice that you need to remove a part that is not relevent to the message of your video.
Since Powerpoint 2010, you can fix these problems with the Trim Video feature by trimming the beginning and end of your video clip.
1. In Normal view, select the video on the slide.
2. Select Playback tab in the ribbon,
3. in the Editing group, click Trim Video.
4. In the Trim Video dialog box, do one or more of the following:
– To trim the beginning of the clip, click the start point (shown in the image below as a green marker, on the far left). When you see the two-headed arrow, drag the arrow to the desired starting position for the video.
– To trim the end of the clip, click the end point (shown in the image below as a red marker, on the right). When you see the two-headed arrow, drag the arrow to the desired ending position for the video.
In this example, we have trimmed the beginning of the clip so the new start time is 00:15.004, and the end of the clip so the new end time is 00:17:002.
See this news in French: http://presentations-de-vente.com/comment-decouper-une-video-pour-vos-presentation-de-vente