Video Slimmer App can help you easily trim iPhone video size according to your preference. By trimming your videos on iPhone, you can get the reduced video size (width/height) for display on different devices and players, you can save your iPhone space at the same time.
Steps to Trim iPhone Video Size
Step 1. Add Video to the Converter
Launch the Video converter on your iPhone, click the Plus + on the top right to load your source videos from iPhone camera roll to the converter.
Step 2. Change Video Size
Tap on the gear icon on the right bottom of the converter, then select Settings to open the video settings panel. Tap on Video Size to open the list of all different video sizes, height. You can tap to select the target video height in pixel you like to convert the source videos to, then video slimmer can automatically shrink video dimensions, scale the video and export with smaller resolution.
Step 3. Trim Videos on iPhone
Tap the Slim Now button to convert your iPhone video and reduce the video size.