24fps - 3:2 Pull Down on Apollo

Why 24fps
24fps (or, usually in the video world, 23.976fps) is the worldwide standard for cinema frame rate. It’s also been widely adopted in 60hz electricity territories such as North America as a common frame rate when shooting for a “cinematic look” on a video production. But up until a little under 20 years ago, 24fps video was not a standard video format. And so a strange technical footnote begins.

A Bit of Background
Back in the early days of TV, 24fps films were shown on 60i (interlaced fields, or split frames) video systems using “3:2 Pulldown,” which is a method of using every other frame an extra time over the video fields so that 24 frames would equal 60 fields. This continued when 24p video was introduced in the late 1990s. A few years later, two different 24p formats (24p and 24psf, for “Progressive” and “Progressive-Segmented-Frames”) were introduced. And thus began a problem.

The Mixed Bag
Some cameras output 24p using 3:2 Pulldown. Others output true 24p, and others output 24psf. Some cameras are switchable, but most are not.

What happens if you want to feed these cameras to a switcher? Most video switchers will not accept a 1080 signal in 24p or 24psf. What happens if you want to mix different model or brand cameras in a multi-camera shoot at 24fps? The timecode structure for 24p/psf is different from a 24fps signal embedded in a 60i videostream. How can you intermix these cameras without having to record everything separately and then piece them back together in post?

The Apollo Solution
Apollo can record up to four HD video signals simultaneously, and it can also Live-Switch between those signals and record the edit as a fifth video channel. In the June 2016 firmware update, Convergent Design added 3:2 Pulldown Removal from HD video sources. While single–channel video recorders have had 3:2 Pulldown Removal available for years, Apollo can simultaneously transform all four HD inputs from 24fps video embedded in 60i streams into true 24p video. If any of the input signals are already 24p/psf, Apollo recognizes this and let’s the signal record unchanged. The four cameras can be switched between and both the Live-Switch and the ISO recordings will be captured at 24p with matching timecode and filenames. The Live-Switch will also output as a true HD24p signal.

The solution, while a complicated, advanced process inside Apollo, is simple and seamless to use. The effect is invisible and the menu setting couldn’t be more straight forward. Don’t let the vague limitations and choices of other manufacturers get in the way of your next shoot. Watch the video below to see how easy it is for you to shoot 24p with Apollo.


Applies To

All Products


Created : 2016-07-20 20:28:23, Last Modified : 2016-07-20 21:09:31

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