Info about... PAL - Anamorphicly Encoded Images

Video images are stored on an DVD 'anamorphically'. If you look up the meaning of the word 'anamorphic' in the dictionary. It will say something like: "a distorted image that appears to look normal when viewed".

In the case of a DVD image, this means that although the image you see looks normal on your TV or PC screen. It is not stored like this on the disc!

PAL - Widescreen 16:9 - Anamorphic Images

When an PAL 'widescreen' (1.77:1) image is stored on an DVD, it's actually distorted (ie: squashed up width-ways).

Just to confuse you more, although the image has an Pixel Aspect Ratio (PAR) of 1.77:1, the image pixel frame size is, 720x576. Which means the Frame Aspect Ratio (FAR) is actually 1.25:1 : -

However, when that same image is viewed via an 4:3 TV or PC monitor it should look normal (ie: circles look perfectly round), like this: -




And if that same image is viewed via an 16:9 TV or PC monitor it should look normal (ie: circles look perfectly round), like this: -

PAL - Full Frame 4:3 - Anamorphic Images

When an PAL 'Full Frame' (1.33:1) image is stored on an DVD (using all of it's 720x576 pixels), it actually looks distorted (ie: slightly squashed up), like this: -

However, when that same image is viewed via an 4:3 TV or PC monitor it should look normal (ie: circles look perfectly round), like this: -




And if that same image is viewed via an 16:9 TV or PC monitor it should look normal (ie: circles look perfectly round), like this: -

Another thing you should understand is that a Mpeg2 DVD stream is very clever, as it's able to store 'anamorphic signalling' information within it's video stream. And it's this signalling information that's able to tell your software media player or TV screen to adjust the shape of the picture, automatically.