So just what is Anamorphic?

Anamorphic: A method of encoding an image to achieve maximum resolution on a widescreen TV.

Why is this important?

Before HDTV came along, TV was broadcast in NTSC or PAL, depending on what part of the world you live in. In the USA, NTSC is the standard, while some European countries have PAL encoding. This signal being received is displayed on your TV in a 1.33:1 ratio. This ratio has been around since TV was invented. The reason why this ratio was chosen is because that's what movie theaters were at the time (actually 1.35:1 known as Academy Ratio). When TV's first came out the film industry suffered a hit because people no longer had to goto the Theater to watch a movie, they could just watch it on TV. The film studios came up with a new gimmick in order to get people to come back to the theater--this was widescreen. The widescreen format became the standard in hollywood and the rest of the world, while the ratios do vary, movies for the most part, are viewed in widescreen. Since watching these movies on TV has become a staple of our culture we have now moved closer to the experience of the movie theater with widescreen TV's. Widescreen TV's have been around for many years but are now catching on with the advent of DVD and HDTV. These have increased the quality of the movies we watch at home many times over. The anamorphic encoding increases the picture quality adding resolution that would be wasted in black bars to the picture

Ratio's?

The image encoded on current DVD's use the NTSC or PAL 4:3 aspect ratio (See Figure 1).

Images on widescreen TV's use the 16:9 aspect ratio, also known as 1.77:1. This is the standard aspect ratio on most widescreen TV's and the new HDTV widescreen TV's. This ratio is a good compromise between the two most common used aspect ratio's. TV since creation has had an aspect ratio of 4:3. In the mid 1950's movies were made in various widescreen formats, one very popular widescreen format is 2.35:1. The widescreen TV ratio, 1.77:1 is the average ratio between the smallest (1.33:1 Standard TV) and the largest (2.35:1 Theater) ratio. This enables both 1.33:1 and 2.35:1 to be viewed equally, neither extreme is given precedence over the other, while everything in between is displayed even larger than the extremes. (See Figure 2 for an example of the 1.77:1 aspect ratio [aka: 16x9])

Figure 2: 1.77:1 (16x9) aspect ratio

Dealing with Widescreen

Since the signal that you have to get to your TV is 1.33:1, and you know for a fact that you are not putting any information in the top and bottom of the image (because it will be letterboxed to correct the aspect ratio) why not use this extra space that is not used anyway to cram more important image information in. This is exactly what this crazy thing called 16x9 enhanced does.

Take a look at:

Notice how the image appears taller than it should

The above image is a 16x9 Enhanced or Anamophic image. The information that is not needed on the top and bottom (because they would be black bars anyway) are simply ommited and filled with more important information. While the image will never be displayed like this it allows more information in the image and will look better when displayed on a widescreen device because of this.

This is the widescreen version:

The image here has been stretched preserving the added resolution and correcting the aspect ratio

This is the standard TV version:

The image is now squashed removing the extra information that was added to correct the aspect ratio

Notice the blue bars on the top and bottom. This area is the area that is known to not contain any information and was therefor ommited when encoding the disk, now that it is being displayed on a standard display however these will be added back in (albeit black bars instead of my example).

Anamorphic

Normally when you view a non-anamorphic disc on a widescreen TV (in Zoom Mode) the top and bottom get cut off to correct the ratio to 1.77:1. So if your resolution was 640x480 (4:3) then you would loose 120 horizontal lines of resolution. This new image would be 640x360 (16x9). On bigger widescreen TV's you can start to see scan lines or spaces between each of the lines. To help alleviate this loss of resolution and allow more horizontal lines of resolution the anamorphic process is used. When the anamorphic image is passed to a widescreen TV with a resolution of 640x480 it can now use the extra 120 horizontal lines of resolution to fill in the picture and make scan lines if any less noticable. This cleans up the picture on a widescreen TV.

Even if the disc is encoded anamorphicaly, you can still view it in the proper ratio on your standard TV. DVD players have the option to select the type of TV you have. If you select your TV as a standard 4:3 display the player will convert it. The converted signal will be formatted in the letterbox format by vertically squashing the image(removing horizontal lines of resolution) and adding bars to the top and bottom of image to correct the ratio to 4:3. When you select the widescreen 16:9 TV, the image sent out is the encoded un-squashed image (more horizontal lines of resolution).

If your DVD player has an option for 4:3 Pan & Scan, I would suggest you do NOT opt for this mode. This mode may dynamically chop the edges off of a widescreen movie and create a full-screen Pan & Scan version if the disc is encoded with this feature. This has not been implemented on any DVD's with any type of success and I know of a few DVD's that have an issue if this is turned on. Make sure your DVD player is either set to 4:3 Letterbox or if you have a Widescreen/HD TV set it to the 16:9 mode.