Get ready to get pinched. If you come into our studio today wearing the color green, you’re going to have bigger problems than someone harkening back to middle school for a quick pinch. This is because we use green screen in our studio. Do we always use green screen? No, absolutely not. But it is extremely popular in the video world because of its flexibility, scalability and relative ease of use.
To give away a secret or two, we’ll let you know something – most modern movies utilize green screen at some point. Pretty much all advertisements utilize a heavy amount of green screen. But why green? And how does it work?
Well, for simple reasons – look at your face. Look at your body. See any green color? Well, of course you do, because today you’re probably wearing green. But normally, your skin tones, almost all eyes, hair, etc. contains colors in a lot of other realms, but green is not common. Therefore, when the computer goes through and removes green color, it’s not removing the color from your face or body. That is, if you didn’t wear green.
So how does it work?
The principle is simple, but in reality, it ends up being a little more complex. To start, the computer, with a human’s help, is able to find a color. The computer simply finds pixels that are of that exact color, or color range, and turns them invisible. At that point, you can add pictures or colors behind the non-green items.
But it becomes complicated. First – you need massive computer power. In HD resolution, the frame is 1920×1080 pixels. That’s just over 2 million pixels. However, there are also about 30 frames per second. So, imagine processing all of those pixels (2 million) 30 times a second. Yes, it takes a large computer to do this well.
Second, there are lots of nuances in video that make it hard for the computer to process in just a standard sense. Specifically, edges around the subject, movement, glasses, water bottles, and more, all cause issues that must be altered when keying a video.
Third, storage. All of that information has to be stored somewhere, and to give a good example, a three minute video at full HD resolution is about 60 gigabytes keyed out. Multiply this over thousands of videos and you’ve got a huge storage problem on your hands.
Lesson learned? Green screen is great, but leave it to the professionals. Yes, #shamelessplug.
Originally posted at http://natestrong.com.