Echo Station - Comparison of TPM Video formats

Video Formats -- A Primer

This is not by any means an exhaustive treatise on the subject -- I'm trying not to be too technical here.

Anamorphic: A means by which a wider image is squeezed to fit a smaller-width rectangle, most often a widescreen film stored on 35mm film (for instance, the film strip you got in your TPM Collector's Edition). A special oval lens is used on the projector to stretch the picture to its intended width on the theater screen.

Anamorphic Widescreen: You'll often see this term on DVDs. This means the entire width of the picture is available, but it has been stored in compressed form. Anamorphic widescreen allows more image data to be stored in less space because the black bars at the top and bottom need not be included in the file.

Artifacts. A side effect of compression to reduce file size, artifacts are obvious blocks or graininess (pixellation) in video playback.

Aspect Ratio. Very simply the ratio between the width and the height of the displayed picture. For instance, a standard TV screen has a ratio of 4:3, also referred to as 1.33:1. "Pan and scan" or "full screen" videos are displayed at the same ratio as a TV -- 4:3. The new, wider HDTVs display at 16:9, or 1.78:1, also known as widescreen. Cinematic films are shot in a variety of aspect ratios, most commonly 1.66:1, 1.85:1 ("flat"), or 2.40:1 ("scope"). In order to fit these various ratios onto TV screens, the images must either be cropped, or else the full image is shown with black bars in the extra space (letterboxed).

DTV: Digital TV. A method whereby the image is stored and broadcast as digital data rather than analog signal. Includes both standard-definition (SD) and high-definition (HD) digital formats. The advantage: for the same amount of bandwidth, you can stuff a lot more information into a digital signal than an analog signal.

DV: Digital Video. Video that is recorded and stored as digital information (0s and 1s). This is preferable to older, analog methods like tape because, with internal error-checking, the quality of information stored digitally will never degrade, and each copy is exactly like the master.

DVD: Digital Video Disc / Digital Versatile Disc. This is the name of both a physical disc and of a complex, high-quality standard for data. In general it can store and display 345,600 pixels (720x480) pixels of video for up to 2 hours (4 if double sided), plus Dolby Digital sound with up to 8 tracks. I will let you go to the rec.video.dvd usenet's FAQ if you want more technical info.

Full Screen: TV image that fills the screen. Not necessarily "pan and scan," this can also be "soft matte."

HDTV: High Definition Television. As hardware, this is an analog or digital television that has a 16:9 aspect ratio with about 5 times the resolution of standard TV. The notation H/DTV is often used to specifically refer to high-definition digital TV.

LD: Laserdisc. A video system on the wane in America but still popular in Asia, video is stored on large, analog discs holding approximately 272,160 (567x480) pixels. In potential its picture is not quite as good as DVD, although its Dolby Surround Sound is slightly better. The differences in quality are probably not enough to be perceived by most people. LD discs and players are now far more expensive than their DVD counterparts, but there are many movies available on LD that probably won't make it to DVD any time soon, if at all.

Letterbox: In order to display a picture that differs in aspect ratio from a TV screen, black bars are used to fill up the rest of the space. Most commonly you'll see black bars at the top and bottom of widescreen movies shown on standard TVs -- the black bars take anywhere from 25% to 33% of the screen.

MPEG: A compression standard for digital video and audio developed by the Moving Picture Experts Group. MPEG-1 what you see in Quicktime movies such as the Star Wars trailers downloaded on the web or on Video CDs. It's roughly equivalent in quality to VHS. MPEG-2 is the current standard for high-quality digital video, both broadcast and DVD-based. There's currently an MPEG-4 in the works.

NTSC: A standard television format used in North America, 30 frames per second, 640 x 480 resolution at 60hz.

PAL:: Standard television format used in the rest of the galaxy (there's also SECOM or SECAM, which I believe is similar.) 25fps 768 x 576 resolution at 50hz.

Pan and Scan: In order to fit a widescreen movie onto a standard TV screen, the image must be cropped somehow. This is done by editors who choose which part of the picture to crop, panning a "window" 75% or less of the full width over the image. Sometimes they will also zoom in and out and move the "window" up or down, but for the most part this involves just lopping off one or both sides of the frame. You'll know you're missing something if you see this message: "This film has been modified from its original version. It has been formatted to fit your screen."

Soft Matte: The practice of shooting a film with a 1:33:1 aspect ratio and then masking the top and bottom for theatrical display. This allows the filmmaker to release a video for standard TV without losing any of the intended image and without the annoying "letterbox" black bars.

VCD: Video CD. A compact disc containing digital video most often with MPEG-1 compression that can be played on VCD players, some DVD players so equipped, and PC CD-ROM drives.

Widescreen: Image that is wider than the standard TV screen, usually 16:9 aspect ratio. Must be displayed on standard TV using letterboxing.