Monday, November 8, 2021

The Importance of Television Refresh Rates

My new 85-inch television is awesome! Friday night we got everything configured correctly and then watched the latest version of the movie Dune. Having read the book and also having met Frank Herbert when I was very young, I am always interested in any movie about it. I have to say that this movie did not disappoint. It is very methodical in the storytelling and does a great job sticking to the book, at least as how I remember it. Should you wish to see the movie on HBO Max like I did, make sure you see it on a really large 4K television and also have an awesome sound system. I don't think my subwoofer has had that much of a workout since I bought it many years ago. If your house isn't rattling, your sound isn't loud enough.

One of the things that makes my television so great is its high refresh rate. Understanding the importance of refresh rate is very important to know why I setup my home theater system the way I did. So let's begin.

In the early days of movie making, industry pioneers discovered that the human eye sees pictures in motion at 24 frames per second. That means if you are shown a series of pictures at less than 24 per second, they will look like individual pictures. If you are shown at 24 or higher, it will look like smooth motion. Up until recently, all movies have stuck to the 24 frames per second refresh rate.

When television came along it used alternating current for power which, in the United States, is regulated at 60 Hertz or cycles per second. Rather than come up with complex circuitry to match the movie frame rate of 24, the engineers just divided frequency of the input power by 2 and set the television frame rate to 30. Besides 30 is more than 24 and shouldn't be noticeable to the viewer right? For the most part, that is true but it does create some difficulties when encoding a movie to be shown on television.

Now let's add video games and computers to the mix. The original home computer monitors were just televisions. As higher-end graphics cards and monitors emerged, 30 frames per second was no longer the best picture you could get. Kids raised on television could tell the difference between 30 frames per second and 60. Given about 5 minutes watching the two different signals, most people can and they prefer the higher frame rate. It actually turns into an advantage for those playing video games and so console makers started increasing frame rates. The current generation of video game consoles like the PlayStation 5, support 120 frames per second.

That higher frame rate comes in handy for video enhancements. My old 3D television used the higher frame rate to show the left-eye image followed by the right-eye image in the next frame. The glasses you wear block the right-eye image in the left eye and the left-eye image in the right. So even though the TV is showing the movie at 60 frames per second, you are only seeing the movie at 30 frames per second. If you want to see the movie at 60 frames per second, the TV needs to bump up to 120 Hz.

There is also another very important reason for having higher frame rates. While working on the PlayStation VR, we discovered that virtual reality glasses need to have the highest frame rate possible. VR allows you to move your head around and a low frame rate introduces lag into the picture. If you move your head slightly, the image doesn't quite match with what you see in real life. This induces motion sickness. We knew we were getting the right frame rates when we could do a short demo to a room full of executives and nobody threw up.

High frame rates are now very important at amusement parks. A few years ago, I attended a developer's conference put on by Sony PlayStation. One night we rented out the Hogwarts section of Universal Studios in the Los Angeles area. With only a few hundred people in the park, we had no lines and could ride the Hogwart's Castle ride over and over. If you have never been on it, it is a giant VR ride coupled with a roller coaster. Unfortunately they use a very low frame rate and most people are rather sick after the first go around. I rode it 3 times in a row and came very close to blowing chunks. I don't normally get motion sick as I am a sailor and have even sailed a boat from Hawaii to California through 2 hurricanes. When I get sick, that is bad. Several other coworkers were not so lucky and spent part of the night hunched over garbage cans clearing their stomachs.

Television frame rates keep getting higher and higher and there is a reason for it. As we enhance our entertainment experiences more and more, our televisions will need to keep up. Now if we can just get our high-end amusement parks to keep up, we won't find ourselves with motion sickness.

No comments:

Post a Comment