Adjusting Across Broadcast Standards
Pull up is a term in video post-production that describes the process of converting video content from one frame rate to a slightly higher one, most commonly from the 23.976 fps (a common digital cinema and NTSC-compatible rate) or 24 fps film standard to the 25 fps PAL broadcast standard. It is, in essence, a controlled speeding up of the source material. When a film or television show is distributed in a region that uses the PAL system, such as Europe or Australia, it must conform to the 25 frames-per-second format.
The simplest way to achieve this is to increase the playback speed of the 24 fps source by 4%. This means that for every 24 frames of the original film, 25 frames are displayed in the PAL version over the same one-second interval. The result is that the entire program runs 4% shorter than its original theatrical or NTSC version. A 100-minute film, for example, would have a runtime of 96 minutes when broadcast on a PAL channel. This speed increase is applied to both the video and the accompanying audio track, which causes a noticeable increase in audio pitch—about two-thirds of a semitone higher. This pitch shift is a well-known characteristic of PAL-converted material and is often corrected digitally to restore the original sound.
Pull Up vs. Pull Down
It’s important to distinguish ‘pull up’ from its counterpart, ‘pull down’. While both deal with frame rate conversion, they solve opposite problems:
- Pull Down (e.g., 3:2 Pulldown): Adds frames through an interlaced pattern to convert a lower frame rate (24 fps) to a higher one (29.97 fps NTSC) without changing the overall runtime or speed. It’s an additive process.
- Pull Up: Speeds up the existing frames to match a higher frame rate (24 fps to 25 fps PAL), resulting in a shorter runtime and higher audio pitch. It’s a durational compression process.
The choice of conversion method is dictated entirely by the target broadcast standard. For decades, audiences in PAL regions grew accustomed to watching American films and shows playing slightly faster and with a slightly higher-pitched soundtrack. With the rise of global streaming platforms and modern displays that can handle multiple frame rates, the need for region-specific pull up conversions is diminishing. Platforms like Netflix can now deliver content to viewers worldwide at its native 23.976 fps, providing a more consistent and authentic experience regardless of location.