screen ratios 200213

BTECLevel 3 Extended Diploma in Creative Media ProductionUnit 64: Motion Graphics and Compositing Video

Screen Ratios


Screen Ratios

The aspect ratio of a screen or image describes the proportional relationship between its width and its height.


Screen Ratios

It is commonly expressed as two numbers separated by a colon, as in 4:3 and 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.

It is easier to visualise if the units used equate to whole numbers, rather than decimals. I.e. you find the common denominator.


Screen Ratios

For example, consider a group of images, all with an aspect ratio of 16:9. One image is 16 cm wide and 9 cm high. Another image is 16 meters wide and 9 meters high. A third is 16 km wide and 9 km high. They are all have the same proportions or aspect ratio, but are different sizes.


Screen Ratios

The most common aspect ratios used today in the presentation of films in movie theatres are 1.85:1 and 2.39:1.

Two common video aspect ratios are 4:3 (1.33:1), the universal video format of the 20th century,

and 16:9 (1.77:1), universal for high-definition television and European digital television.


Screen Ratios


Screen Ratios

In still camera photography, the most common aspect ratios are 4:3, 3:2, and more recently being found in consumer cameras 16:9.

This is important as many DSLRs are being used to shoot video due to the quality of their internal sensors and superior lenses.


Screen Ratios

With television, DVD and Blu-ray Disc, converting formats of unequal ratios is achieved by enlarging the original image to fill the receiving format's display area and cutting off any excess picture information (zooming and cropping):

http://ufoseries.com/hdtv/index.html


by adding horizontal mattes (letterboxing) or vertical mattes (pillarboxing) to retain the original format's aspect ratio:

http://wsa.wikidot.com/tbm:video-basics

Screen Ratios


Screen Ratios

by stretching (hence distorting) the image to fill the receiving format's ratio, or by scaling by different factors in both directions, possibly scaling by a different factor in the centre and at the edges (as in Wide Zoom mode).

http://www.highdefdigest.com/news/show/2798


Pixel Ratios

Pixel Aspect Ratio describes the relationship between the width and height of a single pixel.

Different pixel aspect ratios are the reason why two video images with identical frame sizes can appear as different sizes on screen.If width = height, then the pixel is square and the aspect ratio (width÷height) = 1.0


Pixel Ratios

If width > height, then the pixel is non-square and the aspect ratio is greater than 1.0 (e.g. DV-PAL = 1.07)

If width < height, then the pixel is non-square and the aspect ratio is less than 1.0 (e.g. DV-NTSC = 0.9)

http://wsa.wikidot.com/tbm:video-basics

screen ratios 200213

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motion graphics

creative media productionunit

extended diploma

different pixel aspect

y aspect ratio

common video aspect

aspect ratio of16

aspect ratiowidthheight