16:9 or 4:3 ?

[codecoder]

What is the difference between 16:9 and 4:3? What these numbers stand for?

Isn't 16 and 9 the same as 4*4 and 3*3?

[killingspree]

16:9 and 4:3 are so called aspect ratios. in other words it describes how the pictures width and height are proportioned to one another. it does not give you an absolute size though. in pixel terms you could i.e. say for the 4:3 aspect ratio that for every 4 pixels in width there's three in height...

for more information you might want to browse the 'basics section' of the guides: http://www.doom9.org/dvd-basics.htm

hope this makes sense
kr
steVe

[jggimi]

If you look at a "standard" television, or your standard PC monitor, you'll note that regardless what size screen it has, the ratio of the horizontal to vertical is always the same: the height is always 3/4 of the width. With PC monitors, since they have square pixels, that also means that the number of pixels in width to height is also the same ratio: for example: 640x480, 1024x768, these are exactly the same ratio: 4x3, 4:3, or 1.33:1.

If you look at a "newfangled" television, such as the HDTVs in your local TV store, you will see that they are wider (or shorter) than standard TVs or PC monitors. The ratio is different, it is 16x9 rather than 4x3. It doesn't matter how big the TVs are, the ratio remains the same. 16:9 is also 1.78:1.

DVDs have fixed resolutions: 720x480 if NTSC, or 720x576 if PAL. But unlike PC monitors, DVDs don't have square pixels. Instead, a DVD's pixels will have one of two different shapes, based upon the Display Aspect Ratio (DAR) of the DVD, which will be either 4:3 or 16:9, the two shapes that TVs have.

But movies can have all different aspect ratios, and are often wider than the "newfangled" widescreen TVs, and have aspect ratios such as 2.2:1, 2.35:1, or 2.5:1. The shape of the movie doesn't have to match the DAR of the DVD -- the DVD production companies use letterboxing (black on top and bottom) or pillarboxing (black on the sides) to correct their content. Just because a film is marked "widescreen" doesn't mean that the DVD uses a 16:9 DAR. Some production houses use 4:3 DARs even with widescreen productions -- it means that there is more letterboxing, and less content detail.

The apocryphal story of the origination of 4:3 as a standard aspect ratio comes from the invention of motion pictures. One of Thomas Edison's engineers who was leading the development of the camera and projection system was asked by the film supplier, "What size will the images be?" ... To which the engineer was supposed to have replied, "Oh, lets make the image size one inch by three quarters."