High frame rate (HFR) is a video term that refers to content that runs at a faster frame rate than the standard 24 fps commonly associated with cinema.
As well as some movies, HFR video is expanding into different walks of life: gaming, streamed video and even self-made videos using compatible cameras and phones.
So what exactly is HFR, what content uses it and how can you watch it? Allow us to explain.
What is HFR?
HFR stands for high frame rate. It is generally attached to content and screen technology that can refresh faster than 24 frames per second.
Why 24fps? It was chosen as the standard for big screen movie releases because it is the minimum frame rate that can ensure decent matched sound quality. It was also chosen because it didn't use up too much film, so costs could be kept down. UK television has generally been broadcast at 24fps for many years.
Frames per second (FPS) refers to the number of discrete images displayed by a device every second. The human brain can interpret between one and five individual images separately, any more and they're perceived as motion. As the number of frames per second increases, the motion becomes smoother and motion blur is eradicated. This is because the brain can't really distinguish between individual images around and above the 50fps mark.
If you're not sure exactly what effect changing the frame rate has on a picture, this website provides a great example.
What content uses HFR?
Peter Jackson's The Hobbit trilogy, which saw the first film release in 2012, were the first wide-release films to use HFR, being filmed and shown in select cinemas at 48 frames per second. Because not all cinemas could project the films at 48fps, all three were also converted to 24fps.
Film director Ang Lee experimented with HFR too, filming some scenes in his 2016 film Billy Lynn's Long Halftime Walk at 120fps.
James Cameron also claims to have used HFR for the Avatar film sequels.
Netflix has trialled HFR content in the past, while you can find plenty of videos on YouTube with high frame rates - particularly 60fps.
Most modern cameras can shoot 60 and 120fps footage - sometimes even in 4K resolutions or above. Many phones support HFR too, with plenty offering 120Hz displays.
Perhaps the biggest proponents of HFR though are the latest videogames consoles. The Xbox Series X/S and PlayStation 5 are each capable of running games at up to 120fps. You do need a compatible TV though.
How can I watch HFR?
HFR films require specific equipment to be able to play them back. Not many movie theatres have the technology, but they're slowly being upgraded as the technology becomes more popular.
You're more likely going to get HFR content on your TV at home, because many modern 4K TVs have 60Hz and even 120Hz refresh rates. These can playback 60fps and 120fps games and video respectively.
Even when not fed native HFR content, they interpolate frames to make 24fps video run more smoothly. It's similar to when your TV upscales standard definition content to high definition or even 4K Ultra HD, it reads the data it has to hand and then works out how best to fill in the gaps.
Advantages of HFR
Higher frame rate content gives a much smoother image compared to 24fps. It's capable of showing up greater detail within scenes. It's especially useful for gameplay as it can significantly reduce latency.
Sports coverage too benefits greatly from a higher frame rate.
Disadvantages of HFR
Just as some may view a smoother image as an advantage of HFR, others will see it as a disadvantage. It comes down to personal preference, but many see the smooth motion of HFR films as too "soap opera-like", and they lose a sense of theatricality.
If a film is shot in HFR, then the set, prop and costume designers all have to take extra care when creating items for the film. HFR films show up a lot more detail than non-HFR movies, so any discrepancies, such as being able to see modern day technology or items in a period film, will be seen by the audience.