Trimming a video in adobe captivate 9

Captivate has a video editor but it is only meant for the Video Demo (cpvc) projects or slides. To trim an externally created video, personally I would recommend a dedicated video editor.  If you insert the video as multi-slide synchronized video on one slide, you can use Edit Video Timing and in that dialog box you can cut parts of the video. However if you insert an event video, that is not possible. You can of course first edit the video while being a multi-slide video, which will be reflected in the Library, then insert it as  event video.