Why is 60 fps the standard?

If you‘re a tech-savvy gamer or cinephile like me, you may have wondered why 60 frames per second became the standard target for video and games. Why 60 and not 30 or 120? Well, let‘s dive into the tech history and reasons behind 60 fps establishing itself as the norm we still follow today. There‘s some fascinating engineering and human perception science behind it!

In the beginning, AC power led to 60Hz scans

It all started with AC power. In the early 20th century, alternating current (AC) emerged as the standard for power generation and transmission in the US and Japan. And AC cycles at a frequency of 60 Hz, or 60 cycles per second.

When television was being invented, engineers realized they could tap into this ubiquitous 60 Hz signal to drive the horizontal scanrate of their cathode ray tube TV displays. By synchronizing the TV‘s electron beam scanning to the peaks and troughs of the 60 Hz power signal, they achieved stable synchronization without needing complex timing circuits. Neat trick!

So television sets were designed around scanning the CRT horizontally at 60 complete scans per second, called the refresh rate. With each scan displaying one frame of video, this meant 60 frames per second was baked right into how TVs functioned.

Interlaced video fields evolved into 60 fps

Early TVs used interlaced video which splits each frame into two fields – odd and even horizontal lines. The CRT scans odd then even lines in sequence, combining them into one perceived frame.

So while each full frame is scanned at 30Hz, the odd and even fields alternate at 60Hz. This reduced flicker compared to 30Hz frames. So with NTSC TV signals carrying 60 interlaced fields per second, displayed as 30 full frames, the genesis of 60fps was established.

Why 60fps instead of 50?

In Europe, AC power cycles at 50Hz rather than 60Hz. So why didn‘t PAL and SECAM TV standards that emerged use 50fps rather than 60?

Well, a bit of tech politics came into play. West Germany insisted on maintaining compatibility with the existing 60Hz video recordings and broadcasts the world was increasingly adopting. And so PAL and SECAM landed on 50 fields per second, which converted to 60fps could be displayed at the same rate as NTSC!

Perceiving fluid motion

Our eyes can perceive fluid motion up to about 60fps. Beyond that, there‘s diminishing returns. So 60fps hits the sweet spot between motion smoothness and excessive information.

Research indicates just a 15fps increase from 45fps to 60fps makes motion look twice as smooth! But cranking up past 60fps doesn‘t improve perceived motion quality much at all.

Transitioning from 24fps film

24 frames per second has been the standard for filmed movies since the 1920s. When television came along, a conversion was required to "telecine" 24fps film to 60fps video.

Displaying film natively at 24fps on TVs would have provided a choppy, flickering viewing experience. So broadcasting movies at 60fps allowed for smooth motion that preserved the cinematic look.

Why videogames followed the 60fps lead

In the early days of real-time 3D gaming in the 1990s, 60fps also emerged as the ideal target framerate. Some technical and practical reasons:

• Early graphics APIs like DirectX and OpenGL were designed assuming 60fps game logic and rendering. This influenced game engineers to optimize for 60fps performance.

• Home consoles like Nintendo 64, Playstation and Sega Saturn were architected to run 3D games at 60fps. This cemented expectations.

• Chasing higher framerates would have been cost prohibitive in terms of computing power and memory bandwidth required.

By 2000, virtually every major home console and PC game targeted 60fps as the constant, optimal refresh rate. And so 60fps became gospel for mainstream real-time graphics and gameplay.

Display refresh rates standardized at 60Hz

As you may know, display refresh rate (Hz) must match or exceed frame rate (FPS) to show each frame. Early PC monitors mirrored TVs and standardized on 60Hz refresh, meaning they could display 60fps smoothly.

While display technology now easily enables 120Hz, 144Hz or even 240Hz monitors, 60Hz remains the baseline. There‘s no use rendering more than 60fps if most screens can‘t draw them!

The practical sweet spot

For both video and games, 60fps hits the practical sweet spot between visual smoothness, hardware requirements, and production costs. It provides fluid motion while avoiding overkill.

• Film and TV productions opted not to shoot at higher framerates like 90fps or 120fps due to prohibitively expensive camera and storage costs.

• Game developers constrained by console horsepower focused optimizations on maintaining a steady 60fps rather than sacrificing fidelity for higher but unstable framerates.

• displays stayed at 60Hz refresh for decades until recently since that matched content framerates.

More reasons 60fps rules

Beyond these core technical and historical factors, 60fps has some additional advantages:

• Allows slowing down 60fps film 2X to 30fps for buttery smooth slow motion effects. Handy for replays and dramatic sequences!

• Provides a baseline framerate cushion for momentary drops before playability suffers noticeably. Frames can dip into the 40s before 60fps is compromised.

• Yields similar 16ms consistent frame times ideal for low input lag. In contrast, framerates fluctuating unpredictably between 30fps and 60fps feels less responsive.

• Facilitates stable synchronization of game engine logic. Physics and gameplay feel consistent at a locked 60fps.

• Enables screen tearing artifacts to be less visible when using vsync than lower framerates.

The continued relevance of 60fps

So with this combination of technical characteristics, production practicalities, and legacy momentum, 60fps remains cemented as the gold standard – even as displays and gaming hardware now support higher refresh rates.

Unlocking framerates over 60fps certainly provides a smoother and more responsive experience for those with high-refresh monitors or TVs. However, 60fps remains the universally supported baseline across the media and gaming spectrum.

In the future we may see 120fps or even 240fps become prevalent. But I‘m willing to bet 60fps will continue reigning as the foundational framerate we can count on for smooth media playback and gaming for decades yet to come!

Let me know if you have any other questions about why 60fps became standard practice. This tech history fascinates me.