On HFR (High Frame Rate) video

Here’s a technical post about frame rates in video. Exciting, right?

Most higher quality shows in Australia are shown at 25 fps, and the whole image updates every second — this is Progressive, the p in 1080p. All our devices are progressive too — TVs, computers, phones, tablets. Feature films (shot on film or digital) are also progressive.

Broadcast TV signals are different. It’s all delivered as interlaced — 50 updates per second, half the image (a field) at a time. A field is every other horizontal line, meaning that an object that moves will be a little blurry. You can present progressive material within an interlaced stream, and it looks just like true progressive content. However, reality TV, sports and news are shot natively in interlaced. We’ve grown to associate a lower frame rate with feature films and high-quality drama, and a higher frame rate with “cheaper” content.

Modern TVs remove the interlacing, but also default to making all content look like it’s been shot at a high frame rate. By making this “smooth” look the default, a lot of people have been convinced that “smooth is good”. I (and many others) hate it though, and turn it off straight away. Partly because I don’t like the look, partly because with films it’s not what the filmmaker wanted, partly because the glitches (artifacts) that are visible when all those extra frames are invented are quite distracting. At the end of the day, though, the old “smooth means cheap” rule is not as absolute as it once was.

Most modern DSLRs only shoot progressive, because that’s what filmmakers (and computers) want. My new GH5 (lovely camera) is mostly used to shoot 4K at 25 fps, because that’s what I want to edit and deliver. However, it can also shoot in 50 or 60 fps in 4K, and up to 180 fps in HD. Mostly, that’s great for slow-motion, shooting a higher number of frames per second, but playing just 25 of them every second.

But it’s now possible to actually deliver 60 frames per second — HFR, or high frame rate. It’s still progressive, so there’s no artifacting, and it’s natively smooth, to keep fans of that look happy. The higher frame rate also brings with it a lower amount of blurring of objects in motion, and that’s a two-edged sword. When everything is perfectly sharp, it doesn’t feel like a story being told — it feels like actors on a stage. Turns out that a higher frame rate might be more realistic, but that’s not actually a good thing. Plus, those who hate the look still hate the look.

Any time a new technology is polarizing, or difficult to adopt, it will struggle. 3D struggled because of the glasses or headsets, because some people can’t see in 3D, and because it made life hard for creators. Even video games didn’t really adopt it much. It was present on the PS3, rarely used, and it’s now gone from PS4.

HFR is definitely polarizing; it destroys the suspension of disbelief and looks cheap to many. Still, it probably won’t go away like 3D did, because cameras will support it for slo-mo, and TVs need to support higher frame rates too. Plus, it may become more popular on YouTube — even if only for gaming. That gives it a decent chance at gradual acceptance, even if we aren’t going to see many more movies using HFR for a while.