Cutting and trimming videos with macOS
last update: 07.04.2020
You may want to edit, cut or shorten your video-recorded teaching content because, for example, you had to prepare material at the beginning, were interrupted or the recording ran a little longer, even though you had already finished. This manual shows how to perform the most common operations in video editing under macOS.
Important notes are marked yellow.
Additional information is marked in blue.
Variant 1: QuickTime Player
If you only want to shorten your video (cut off a little at the front and or back), you can do this operation with the QuickTime Player integrated in the system:
- Open the video to be trimmed in the Quicktime Player
- Select “Trim” from the “Edit” menu
(Shortcut keys: ‘CMD + T’; T for “Trim”)
- Drag the yellow border markers from the beginning and end towards the middle so that the area between represents your finished video.
- Confirm your selection by clicking on the “Shorten” button
- Save the shortened video with the command “Save…”. in the “File” menu, or with the shortcut key ‘CMD + S’.
- Choose a location and file name for the shortened video
Variant 2: iMovie
If you want to cut your video more elaborately, i.e. shorten the beginning and end, but also cut out passages in the middle, you will need a video editing program. With iMovie such a program is available free of charge under macOS.
- Sownload and install iMovie from the Mac App Store if you don’t already have it.
- Open iMovie.
- Select the “Projects” tab.
- Create a new project in the Movie category.
- Import the video file that you want to trim using the Import button.
- Navigate to the location where the file is stored and select it and confirm the import by clicking the “Import selection” button
- Use the mouse to drag the video clip from the upper left area (the so-called “browser”) to the lower area of the application (the so-called “timeline”).
- Alternatively, you can select the clip and add it to the timeline using the ‘E’ key.
Shorten the video
- Move the mouse cursor to either end of the video clip in the Timeline.
The mouse cursor changes its appearance to indicate that the edges of the clip can be “moved”.
2. Drag the respective edge marker towards the center of the video clip.
Cutting passages out of the video
To cut a passage out of a video clip, a video clip must be cut twice: At the beginning and the end of the passage to be removed.
- Navigate in the Timeline to the appropriate place in the clip you want to cut.
- Place the playback marker (called the “playhead”) at the point where you want to make the first cut
- Confirm the cut with the entry “Split clip” in the “Modify” menu or with the shortcut key ‘CMD + B’ (B = Blade)
- Place the playhead at the position where you want to set the second cut
- Confirm the cut again with the key combination ‘CMD + B’. You have now cut your clip in the timeline into three parts.
- Select the middle part.
- Delete the selection with the ‘Delete’ entry in the ‘Edit’ menu or with the ‘Backspace’ key
iMovie automatically “fills” the gap by attaching the right clip directly to the left. This means there’s no pause in the video despite the editing.
Save the edited video
When you have finished editing your video, you will need to save your movie again.
- Click on the “Share” button at the top right of the application
- Select “File”.
- Do not change any of the setting options
How to compress the videos for upload to the KIT systems is explained in a separate manual.
- Click on “Next”.
- Choose a suitable storage location for your edited video.
- How to prepare the recordings for upload and create the smallest possible files with the same quality is shown in this guide: Video Compression Guide.
- A separate guide will show you how to make the recordings available to your students via ILIAS.
Info & Contact
These tutorials for the creation of digital teaching material of the center for Technology-Enhanced Learning (ZML) at the Karlsruhe Institute of Technology (KIT) is licensed under a Creative Commons Attribution 4.0 International License.
Karlsruher Institut für Technologie (KIT)
Tel.: +49 721 608-48200
Fax: +49 721 608-48210