Frame Rate Pull-Up and Pull-Down Calculator

This free calculator shows how much audio has to speed up or slow down when picture moves from one frame rate to another, with the pitch shift, the new running time and the sample rate relabel, all worked out in your browser.

What this calculates

When picture is retimed from one frame rate to another, the same frames play faster or slower, so the audio has to change speed by the same amount to stay in sync. The speed factor here is the new frame rate divided by the old one. If it is above 1 the audio plays faster and is shorter, and if it is below 1 the audio plays slower and is longer.

If the speed change is done with no pitch correction, the pitch moves with it. The cents value shows by how much. 100 cents is one semitone. If your tool keeps the pitch fixed, ignore the pitch line and use only the speed and running time.

Pull-up, pull-down and speed-up

Pull-down usually means slowing by 0.1 percent, for example 24 to 23.976 fps. Pull-up is the reverse, 23.976 to 24 fps, speeding up by about 0.1 percent. The 24 to 25 fps change, often called a PAL speed-up, is a much larger 4.17 percent speed increase that raises the pitch by about 71 cents. Facilities do not all use these names in the same way, so this page states the result as a speed factor, and that is the part to check against your delivery notes.

Questions

Why is 23.976 not exactly 24?

The real rate is 24000 divided by 1001, which is about 23.976. That is 1 part in 1001 slower than 24, which is about 0.1 percent, so a whole-number 24 fps project and a 23.976 one differ by that small amount.

Does this cover 29.97 drop-frame?

Drop-frame is a way of counting timecode, not a different speed. Both 29.97 drop-frame and 29.97 non-drop run at the same real speed. To move timecode values between rates, use the timecode converter.

Is anything uploaded?

No. Everything is calculated in your browser.