What is Aspect Ratio?
Aspect Ratio is the width and height of an image or screen. The size is shown in X for the width and Y for the height. When scaling it is best to keep everything in proportion.
Common Aspect Ratio for TV is 16:9
As defined by wikipedia “The aspect ratio of an image describes the proportional relationship between its width and its height. It is commonly expressed as two numbers separated by a colon, as in 16:9. For an x:y aspect ratio, no matter how big or small the image is, if the width is divided into x units of equal length and the height is measured using this same length unit, the height will be measured to be y units”. Information from https://en.wikipedia.org/wiki/Aspect_ratio_(image)
Why is this important?
Aspect Ratio is important because you don’t want to put a rectangular image on a square object as it will stretch and distort the image. I have put an example below.
You can see from the above photo that the image has been stretch which makes it look strange to watch.
What could be a problem if you work in the wrong aspect ratio?
If the aspect ratio were wrong you would have black bars running along the sides of the top and bottom. You can see this in old films or archive footage that is being shown on new TVs. They have black bars, which are visible along the top and bottom of the screen. Or they can even be along the sides depending on the original video size.
You could also have image distortion on the form of stretching or squashing you can see this on my examples below.