Have you ever watched a video and and it looks stretched out or parts of the video are cut off. Part of the reason for that is the aspect ratio or the shape of the video. There are several aspect ratios, however, there are two standard aspect ratios:
4:3- Which looks like a square and is used mainly for standard definition video.
16:9- Also known as widescreen looks like a rectangle and is the standard aspect ratio for high definition video.
If you don’t know what those numbers mean, they are the dementions of the width of the screen by the height of the screen. So, for example 16:9 means 16 units wide by 9 units high; 4:3 is 4 units wide by 3 units high.
So, if you were watching a video on your computer that was shot in 4:3 and you enter widescreen mode, the video might not look right because there is no more video information which means it has to be stretched to fit making the picture look weird and usually a bit fuzzy. Similarly, If you are watching a video that which is shot and distributed in 16:9 on a 4:3 display, the picture on the left and right side might be cut off. However, while there is no real way to make 4:3 video look better on a 16:9 display, you can scale down the 16:9 video and make it fit within the 4:3 display. If you ever used a non-linear editing program you may notice that in the preview window there is a box on the playback k. That is called the TV safe box and is meant for the editor to see what will be cut off on a 4:3 display.
16:9 is becoming a new standard and very few displays are still made with a 4:3 aspect ratio. For those recording video, I reccommend using 16:9 if your camera supports it because it gives you a better quality image as well as more in the picture.