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Understanding Video Aspect Ratio

Do you know the difference between 16:9 and 4:3 and 1.85:1 and 1.33:1?? Your videos look squished and weird and you don't know why? Do you know the difference between the pillar box and the mailbox? And how to make your videos look like a movie with the clever use of aspect ratio masks?

ContentsAspect ratiosOverwrite sizeMask maskingActual aspect ratiosBonus cinema look

Some people really don't know or care about the difference between any of these things, and while subtle, knowing the difference is important for a professional-looking video. In this article, we define video aspect ratio with examples so that you always know what size your screen should be, regardless of the source or TV system.

Aspect ratios

In video terms, an aspect ratio is an expression of the ratio (or relationship) of width to height. If a video is 1280 x 720 pixels, then it can be said to be 16:9 or 16 units by 9 units. This ratio can also be expressed as 1.77:1, so the width is 1.77 times the height.

Understanding Video Aspect Ratio

See how narrower it is than 16x9?

Override size

The reason this matters is that people are sometimes horribly wrong. You often see videos on YouTube that look a little squashed, and that's because the creator didn't pay any attention to the proportions.

Either the source material was 4:3 and they applied a 16:9 aspect ratio by stretching it horizontally,

Understanding Video Aspect Ratio

or the source was 16:9 and they applied a 4:3 aspect ratio by squashing it horizontally.

Understanding Video Aspect Ratio

Either approach makes the video look amateurish and can also affect the performance of video editing systems, as they have to process each frame for the new size, which takes much longer than expected.

Masking mask

A common way to fix aspect ratio sizes and not mess up the video is to fill the frame with black areas.

There are two types of padding:letterboxing and pillarboxing. Letterboxing is where you add black bars at the top and bottom to compensate for the difference between the standard 16:9 HD format and the 4:3 SD format. The black areas are actually part of the frame, which means you actually have a 4:3 image, but the top and bottom of it are black, and the 16:9 aspect ratio of the image is in no way distorted.

Understanding Video Aspect Ratio

Or you can add black bars on the sides, or pillarboxing, to compensate for the difference between SD 4:3 and HD 16:9. The black bars on the sides pad the frame to adapt to 16:9 without crushing the original frame.

Understanding Video Aspect Ratio

Of course, among the many taste crimes perpetrated by people ignorant of the aspect ratio is overwriting videos already packaged in another mailbox, resulting in a HUGE black bar and overwritten video ,

Understanding Video Aspect Ratio

or overwrite an already padded 4:3 image with additional pillarboxing making the 4:3 image even narrower.

Understanding Video Aspect Ratio

The worst crime of all? Letterpillarboxing, where you do both:make a 16:9 video fit into a 4:3 frame, then pillarbox it again, creating a big black border all around the video:

Understanding Video Aspect Ratio

Real aspect ratios

The main aspect ratio you will come across is 16:9 or 1.77:1, as this is the aspect ratio of all TVs and the size of all TV screens and computer monitors. Other ratios exist for movies like 1.85:1 for many movies or in extreme cases 2.35:1. These are usually displayed with the mailbox.

Older movies before there were standards for these things have a number of other aspect ratios like 14:9 but generally the ones mentioned above and 1.33:1 or 4:3 are the only ones that you will meet.

Bonus cinema look

One way to make aspect ratios work in your favor is to letterbox a 16:9 image so that the viewable area is equal to the standard film aspect ratio of 2.35:1. It makes a video look like a feature film.

But remember to mask (crop with black) the top and bottom image without affecting its vertical height, resulting in a 16:9 image with a film look,

Understanding Video Aspect Ratio

rather than doing what amateurs do and squashing the 16:9 source vertically to fit a 2.35:1 frame.

Understanding Video Aspect Ratio

Note: many video editing software have a 2.35:1 automask that you can apply to your videos.

If you have any questions about the proportions, please let us know in the comments below.