Any moving image, whether film or video, is composed of a series of still pictures or frames. Thanks to persistence of vision, the brain sees these frames as motion, and the more displayed per a second, the smoother that movement. This is the essence of high frame rate (HFR).
Filmmakers have shot at 24 frames per a second (fps) since the early 1930s, because it was convenient for synching sound, kept production costs down, and delivered movement that didn’t look jerky. When showing films in a cinema, each frame is actually projected twice, further eliminating visible flicker. This approach has remained largely unchanged over the last 90 years.
When TV came along the frame rate used directly correlated to the frequency of the electricity supply, so in the US and Japan it was 60Hz, but 50Hz in the UK and Europe. TV broadcasts originally used two interlaced frames, which when combined created a single frame. As a result, the effective progressive frame rate was 25 or 30fps, depending on where you lived.
Advances in TV technology, combined with the use of digital cameras in both film and TV production, has freed content creators from being limited to 24, 25 or 30fps. These days you can not only shoot at 48, 50, 60 and even 120 frames a second, but deliver these higher frame rates to TVs and projectors capable of displaying such content.
Although a number of films have been shot at higher frame rates, filmmakers are reticent to do this because the increased number of frames results in smoother motion that looks more like video and less like film. It’s an aesthetic that cinema goers prefer, and anything more than 24fps just doesn’t look ‘film-like’. The same is true of TV dramas that are trying to appear cinematic.
However, there are two areas where higher frame rates can be a game changer. The first is sports, and the benefits are obvious because the more frames the smoother the fast motion appears and the easier it is to see vital details like the ball. A lot of sport is already being broadcast or streamed at 50 or 60fps, but the potential of 120fps capture and delivery could revolutionise watching super-fast sports like tennis on a TV or projector.
The second area is video gaming, where higher frames rates can deliver buttery smooth motion that enhances the game play, creating a more visceral and realistic experience. The increases in processing power in next-gen gaming consoles like the Xbox Series X and PlayStation 5 allow for frame fates up 120fps; so games like first-person-shooters really benefit from the increased motion resolution and smoother movement, making tracking and hitting the enemy easier.
If you own a next-gen gaming console and want to experience the benefits of 4K/120fps gaming you’ll need a TV or projector that not only supports the frame rate, but also has an HDMI 2.1 input. The increased bandwidth required by HFR means it can’t be handled by older HDMI 2.0 connectors, and is one of the reasons why HDMI 2.1 was developed to offer increased capacity.
So if you’re looking for a new TV or projector, don’t worry about whether it can handle 8K because that’s years away, but make sure it supports HFR because you can enjoy this feature right now.