WEBVTT

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Hey, did you know 4K often isn't actually 4K?

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What? Even though tons of electronics companies advertise screens, game consoles, and streaming sticks

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with 4K support, there's actually no real standard for what the heck 4K really means.

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It's just a word. It's just made up. You see, 4K is called 4K because it refers to resolutions that are approximately 4,000

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pixels across. The most common resolution that's advertised as 4K is 3,840 pixels horizontally by 2,160

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pixels vertically, which is what you typically see on TVs and computer monitors, often marketed

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as Ultra HD or UHD.

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And so this resolution isn't quite 4,000 pixels across, but the 4K used in movie production,

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called DCI 4K, measures 4,096 by 2,160.

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So the aspect ratio is about 1.9 to 1, a little wider than the typical 1.78 to 1 we're used

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to on TVs and your typical computer monitor. You might know that aspect ratio by its other name, 16x9.

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But DCI 4K isn't the only movie 4K, as it's primarily used for shooting the film.

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By the time you get to the movie theater, though, you're probably seeing the film in

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Cinemascope 4K. This sounds awfully fancy, but the actual resolution is only 4,096 by 1,716.

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And while that produces the 2.39 to 1 aspect ratio that looks cinematic, a typical 4K display

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at home has over one and a quarter million more pixels.

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So don't be fooled into thinking you're supposed to be seeing the latest blockbuster

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in some kind of mind-blowing detail, you're mostly just cutting off the top and bottom.

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To further illustrate this point, some products cut down resolution even further to get that

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cinematic, widescreen look. Sony's line of Xperia phones are known for this with their trademark Cinemawide 4K displays.

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But Cinemawide is actually just a cut down version of Garden Variety UHD, with a resolution

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of 3840x1644 to achieve a more theatrical 21x9 aspect ratio similar to many ultra-wide

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monitors. We're not trying to say these displays are bad, as they're still good looking OLED screens

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with HDR support, just don't expect more pixels than you'd get on a $300 TV.

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This illustrates why 2160p isn't an exact synonym for 4K, even though many people might

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want to call it that since we often refer to HD by its vertical resolution 1080p.

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We've already covered two resolutions marketed as 4K, with vertical resolutions falling

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well short of 2160 pixels, and on the other side of that coin, there are products like

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dashcams advertised as 4K because they're 2160p, but less than 3000 pixels across, producing

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a more square looking video that isn't really close to what we typically think of as 4K.

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So the use of terms like 1080p and 2160p to describe resolution actually go back to the

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age of CRT displays. We know those big, heavy TVs and monitors we used until the late 2000s and are still

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used today at really cool Super Smash Bros. tournaments.

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CRTs didn't have pixels in the sense that we think of them today, rather they generated

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horizontal lines that contained analog data, which varied as you went across the screen.

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In other words, they had a vertical resolution, but not a horizontal one.

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This is why the industry used terms like 480i or 576i to describe TV signals back when

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CRTs ruled the world, with the i standing for interlaced, meaning that a CRT would only

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scan half the lines of a frame at once to save bandwidth.

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By contrast, the P in 1080p stands for progressive, meaning the monitor scans the whole frame

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all at once. But even though modern LCD displays have a defined horizontal and vertical resolution,

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the practice of using a single 3 or 4 digit number to represent the entire resolution

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stuck around. But even if a product clearly states both its horizontal and vertical resolution, you

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really need both that information and the size of the display to get across how much

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detail it can convey, since a 4K resolution doesn't really mean much if you're sitting

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two feet away from a 200 inch screen.

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Which is why the 8K TVs on the market are mostly really big.

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So isn't there a better way than 2160p to describe how much detail a display can show?

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Yeah, it turns out that there is, indeed. It's a spec called pixels per inch, or PPI, which is just what it sounds like, the number

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of pixels in a one inch line. PPI, combined with aspect ratio, gives you a really good idea of what the actual visual

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experience will be like, and this system is used by none other than Apple, who uses it

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as the basis for the retina display marketing. Wow, they were actually right about something all along.

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Hey, that's the end of this video, thanks for watching guys, like it if you liked it,

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