60hz, 120hz, 240hz, ????

Two posts in one day? That’s strange. In my effort to learn more about video, I explored some new features of current TVs. You might have seen that new TVs have crazy looking labels that say “120hz” or “240hz.” What’s that all about?

Well, I don’t want to get to technical here, but here is a little background information. Broadcast signals are typically 30 frames per second. That’s 30 different images that you see on your screen per second. Well, actually it’s 60 half images. Our brains can fill in information. TVs typically operate at 60hz. The hertz used to refer to energy passed through something in the tv, but now with LCD tvs they really refer to frames per second (fps). So, TVs work could for broadcast.

Film, however, is usually 24 fps. In order to fill up the available 60hz, complicated math has to happen. 24 is not a multiple of 60, so a 3:2 pulldown happens. Some new frames are inserted . . . blah, blah, blah.

So, you’ll find that both 24 and 30 are multiples of 120 and 240. That’s cool because that crazy math doesn’t have to happen, but what is even cooler is that you will get more frames for second, 120 or 240 to be exact. That 24fps that you watched on your tv is multiplied by 5 for 120hz! That’s pretty cool. Sure, it’s a repeat of the same frame 5 times, but you can notice a difference.

I went to Best Buy today and looked at the difference. It takes a second to get used to because the image looks unnatural. Our eyes are so accustomed to slower fps that the more real looking 120 fps looks fake when it reality it actually looks more real. It’s actually pretty cool. I can definitely say that the next tv I buy will have 240hz.

So, lifehacker posted about another post this week on the subject with detailed instructions on how to do this on a PC. I did it! In fact, I did it on my mac under vmware with windows 7. It still worked. At first, the increased fps made me think I was watchin in fast forward, so I had to watch them side-by-side. Sure enough, they were both running at normal speed, but the fps made a world of difference. Here’s a picture of my screen.

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Ben McMurry

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