Change video speed and calculate clip duration

Calculate the result before rendering

Use output duration = selected duration / speed. A 30-second selection lasts 20 seconds at 1.5x, 15 seconds at 2x and 10 seconds at 3x. At 0.5x it lasts 60 seconds. Container timestamps and frame boundaries can make the measured export slightly different. This calculation describes a constant speed change, not a speed ramp.

Trim first, then set the speed

Choose the source interval before estimating the result. Selecting 00:05 through 00:35 gives 30 seconds of footage. A concrete prompt is: “Trim 00:05 to 00:35, play at 3x speed, and fit into 9:16.” Verify each instruction in the output. Avoid combining unrelated edits until the selection and speed are right.

Choose a speed people can follow

A fast product demonstration may still communicate its action, while an interview at the same speed can become difficult to understand. Listen to the entire selection. Preview essential hand movements, on-screen instructions and transitions. Slow motion stretches the frames already recorded; it does not guarantee new detail or smooth intermediate motion.

Use the Studio preview

LazyClip Studio provides local playback preview controls for a selected trim and speed. Previewing does not submit a render. Applying the edit creates a new job using the normal allowance. The final encoded file is the version to inspect before publication; browser playback alone does not verify export quality or provider availability.

Check captions and the ending

A speed change reduces or extends the time available to read each caption. Watch the final file with sound and confirm that text follows speech. Check that the first word and the ending survive the trim. If speech becomes too fast, shorten the selection instead of forcing it into an unreadable duration. The workspace shows when rendering is available.

Common questions