To Speed up a Video on iPhone use the following Methods.
Method 1: Using iMovie
Create a New Project: Open the iMovie app and tap the “+” button to create a new project.
Import the Video: Select the video you want to speed up and tap “Create Movie.” This will add the video to the timeline.
Adjust Video Speed: Tap on the video clip in the timeline to reveal the inspector at the bottom of the screen. Tap the “Speed” button. A yellow bar will appear at the bottom of the clip, with range handles at each end.
Drag Range Handles: Drag the range handles to the desired speed. You can also tap on the “2x” or “4x” buttons to quickly speed up the video by 2 or 4 times, respectively.
Save the Video: Once you’re happy with the speed, tap “Done.” To save the sped-up video, tap on the “Share” button and then select “Save Video.”
Method 2: Using the Photos App
Open the Video: Open the Photos app and select the video you want to speed up.
Tap Edit: Tap on the “Edit” button.
Access Speed Tool: Tap on the “Speed” tool.
Adjust Speed: Drag the two vertical bars below the frame viewer to the desired speed.
Save the Video: Once you’re happy with the speed, tap on “Done.” To save the sped-up video, tap on the “Done” button again.