Guides

Slowed-down clip stutters: speed below 100 %

Often unnoticed: a clip was slowed down a little to fill a gap or fit the music – to 95 %, 91 % or 99 %. Because the footage does not have enough frames for that, the editing software regularly repeats one. At 91 % that is about every eleventh frame, at 95 % every twentieth.

How to recognise it

The stutters come at regular intervals, but only within one clip – before and after it everything plays smoothly. The closer the speed is to 100 %, the rarer but the more noticeable the single hitches are.

Find the cause in Premiere Pro

1. Select the clip in the sequence → right-click → Speed/Duration: if it shows less than 100 % – even 95 % or 99 % – that is the cause.
2. Check the Effect Controls for active Time Remapping.
3. The Rate Stretch tool (R) also changes the speed – often by accident when adjusting the length.
4. Also check whether the clip’s frame rate matches the sequence (“Media Frame Rate” column against Sequence → Sequence Settings → Timebase).

Fixes

• Slowed down by accident: reset to 100 % and adjust the length in the edit – extend the clip or use a different shot.
• Intentional (slow motion, filling a gap): Clip → Video Options → Time Interpolation → “Optical Flow”. Premiere then calculates in-between frames instead of repeating frames. Check fast motion for smearing.
• Real slow motion: shoot at a higher frame rate (50 or 60 fps) and use Interpret Footage to set the clip to the sequence rate – then no frames are repeated.

In After Effects

Has the layer’s speed been changed – “Stretch” column not 100 % or Time Remapping active? Unintended: reset it. Intended: Layer → Frame Blending → Pixel Motion, and turn on the composition’s “Frame Blending” switch. The “Timewarp” effect (Effect → Time) with the Pixel Motion method gives more control.

Special case: exactly 50 %

At half speed every frame appears twice – it looks like 25p in 50p. More on that.