Guides

23.976 fps in a 25 fps sequence stutters – how to fix it

A typical case in European TV and web productions: camera, drone or archive footage at 23.976 or 24 frames per second ends up in a 25 fps sequence. The result: about once per second – every 24 to 25 frames – a frame is duplicated. In pans and tracking shots you see a regular hitch.

Why it happens

The footage is about one frame per second short. By default, Premiere Pro and After Effects fill the gap with Frame Sampling: they show the nearest frame of the clip – and regularly repeat one. The smoother the motion, the more noticeable it is.

Confirm the cause

1. Select the clip in the sequence → right-click → Reveal in Project.
2. Read the “Media Frame Rate” column in the Project panel: 23.976 or 24.
3. Sequence → Sequence Settings → Timebase: 25. If both match, you have found the cause.

Fix 1: Interpret Footage (PAL speed-up)

Cleanest if a small speed change is acceptable – this is how film has been shown on European TV for decades:

1. Right-click the clip in the Project panel → Modify → Interpret Footage.
2. “Assume this frame rate”: 25.
3. Check the clip in the sequence: it is now slightly shorter – adjust the edit.

Every frame then appears exactly once, without calculated in-between frames. The clip runs about 4 % faster and gets correspondingly shorter – check the edit, music and sound afterwards.

Fix 2: Optical Flow when the length must stay

If the length has to stay exactly the same – because of speech, music or lip sync – let Premiere calculate the missing frames:

1. Select the clip in the sequence → Clip → Video Options → Time Interpolation → “Optical Flow”.
2. Render and step through the spot frame by frame: fast motion or occlusions can cause smearing – then try “Frame Blending”.

In After Effects

Select the footage in the Project panel → File → Interpret Footage → Main → “Conform to frame rate”: 25. Same effect as above: every frame exactly once, the clip gets shorter. To keep the length: Layer → Frame Blending → Pixel Motion, and turn on the composition’s “Frame Blending” switch.

Same principle: 23.976 in a 29.97 fps sequence (judder, pulldown)

In a 29.97 fps sequence, 23.976 footage is even about six frames per second short – roughly every fifth frame is duplicated. This regular hitch is known as judder; it resembles what classic 3:2 pulldown produces when film is converted to NTSC. Interpreting would make it a quarter faster, which is usually not an option. Better edit in a 23.976 sequence and convert only on export, or use Optical Flow.

Other causes of stutter: Video stutters after export.