NTSC televisions (the kind we use in North America) have an aspect ratio of about 1.33:1 (actually, 4:3), meaning the ratio of the width to height of the viewing area. This aspect ratio is comparable to 16 mm film. Contemporary feature films are shot with a variety of aspect ratios. There are about 9 aspect ratios in use, ranging from 1.33:1 all the way up to 3:1. Presenting a picture with an aspect larger ratio than 1.33:1 on an NTSC television involves one of two choices: either a 1.33:1 section of the film is shown - meaning some picture is lost - or some television viewing area is wasted to produce a section with the desired aspect ratio. These techniques are called, respectively, Pan-and-Scan and Wide Screen (also Letterbox). Each approach has its supporters and detractors. The primary objection to Pan-and-Scan is the loss of picture (another objection is the often inept panning-and-scanning that's done). The primary objection to Wide Screen is the loss of viewing area.
You can compute the portion of the television viewing area occupied by a wide screen picture with the equation r = 1.33/aspect_ratio. 20,000 Leagues Under the Sea, in Cinemascope makes use of only about half of the television screen (1.33/2.55 = 0.52). A standard 35 mm presentation (with an aspect ratio of about 1.85:1) occupies just under three-quarters of the television screen.
MCA/Universal and Pioneer labels often produce popular new releases both formats (e.g., Death Becomes Her and Indecent Proposal). Most of the other studios issue new releases in a single format. Warner/MGM, Columbia, and the four Disney labels generally issue new releases in wide screen. Image, Republic, and Vidmark almost always use Pan-and-Scan. Fox will issue new releases either pan-and-scan or wide screen, but almost never both formats. (Generally, if a title has been issued in pan-and-scan, a re-issue will be in wide screen. We do not know of an instance where a wide screen release was re-issued in pan-and-scan). Special editions of films have virtually always been in wide screen - but The Abyss and Terminator 2 (both directed by James Cameron) are exceptions: they're available in wide screen and Full-Frame forms.
The upcoming HDTV will change everything with its 16:9 aspect ratio. Except for aspect ratios greater than CinemaScope's 2.55:1, the loss of picture area will be small (less than 25%). Interestingly, viewing a 1.33:1 aspect ratio film on HDTV will result in a lost 25% of the viewing area because of black sidebars!
If you have one of those new Wide Screen TV's, you have to ability to "blow-up" the video to fit your 16:9 display. This generally works well for normal wide screen movies (but watch out for some Disney animation titles and, for example, Army of Darkness since these wide screen discs are 1.66:1). Unless you can do a partial expansion, blowing up these films will crop video at the top and bottom). However, if the wide screen title your interested in has subtitles placed in the "black bar" region under the picture area, your TV's video expansion will lose these subtitles.
By the way, I prefer "narrow" wide screen. I'm comfortable with 1.85:1. 2.1:1 is OK. 2.35:1 is barely tolerable. At 2.55:1 and up, the picture is just too darn small on my puny 27" TV - it's OK on my 50" rear projection and pretty darn cool on my 4'x7' front projector system.
There seems to be some confusion about THX and home video. In a movie theater, THX is a type of sound system licensed by George Lucas of Star Wars fame. However, THX for home video (also licensed by Lucas) refers to a standard for uniform video and audio transfer quality. You don't need a THX processor to use THX discs; a regular stereo or a surround sound system will work just fine. The home video THX trade-mark is a quality standard, not a sound type.
Each successive THX release seems to top the one before. The Abyss Special Edition (THX) replaced T2 (the non-THX version) as the "consensus" best disc available. Then The Star Wars Trilogy replaced The Abyss (at least as far as the transfer quality, not the supplemental quality). Then the T2 Collector's Edition (re-issued in THX) became the apex. Most recently, LaserDisc Newsletter proclaimed Rising Sun to be the ultimate. (Interestingly, The Ultimate Oz and Hoffa Special Edition did not participate in this parade of THX titles). Well, whatever. In any event, the THX mark is fast becoming the Good Housekeeping seal for LaserDiscs.
And pricing is getting better, too. Until recently, there appeared to be about a $ 10+ premium for the THX imprimatur. But then Disney and Image (with The Three Musketeers and When Harry Met Sally) have jumped into the THX fray at their standard prices ($ 40 list). Upping the ante, MCA/Universal released The Flintstones in THX and Fox released Speed in THX, both at $ 30 list. Let's hope that THX follows the same path as CX noise reduction did in the early eighties: it becomes a "rite of passage" for new releases and adds little if at all to the list price of the disc.
LaserDiscs are pressed in one of two formats: CAV (Constant Angular Velocity) and CLV (Constant Linear Velocity). CAV discs spin at a constant 1800 RPM (30 revolutions per second). Tracks are circular with one track per television frame (each frame, as you may know, comprises two interlaced fields). CAV LaserDiscs have up to 30 minutes of material per side. Remember 30 revolutions per second, one frame per revolution (track) = 30 frames per second - just like at the movies!
CLV discs take advantage of the fact that disc tracks are longer as we move out from the center toward the edge of the disc. CLV discs start spinning at 1800 RPM to read the first tracks which are near the disc center. As the tracks further away from the center are read, the disc's rotational speed is reduced. But since the tracks are longer, the speed at which tracks are passing by the read head remains more or less constant - get it? Constant Linear Velocity! In this way, up to 60 minutes of material can be placed on one side of a disc.
Some people claim to notice a difference between CAV video and CLV video. Their eyes must be better than mine - these might be the same people who claim to be able to hear the difference between power cords. I know, I know: there are some specifications that suggest the video signal-to-noise ratio is smaller for CAV than CLV. Maybe that matters when you have a more expensive television than I do. I'm quite satisfied with good video transfers whether there CAV or CLV (especially THX transfers).
The only real advantage with CAV discs is that you can single step with any player and get a good still image. That's fun for the first few times you use your LaserDisc player. However, since I have to fiddle with CAV discs twice as often (to flip sides or change discs), I prefer CLV. Less handling. More movie. Usually less bucks, too.
Just when you thought you had dumped all the money you needed to in your sound system, AC-3 or Dolby Digital comes along. This sound is encoded on the right analog sound channels (if you don't have a digital sound LaserDisc player - i.e., you have a 7+ year old unit - you only get mono sound from the left analog channel). A LaserDisc player equipped for Dolby Digital has a special jack to deliver the Dolby digital data stream to an external Dolby Digital decoder. That decoder provides "5.1" channels of sound: Left, Center, Right, Left Surround, Right Surround and sub-woofer to a 5 channel amplifier - or in my case to five separate amplifiers.
The list price for home Dolby Digital decoders is measured in four digit numbers which is as much accuracy as I need for my (non-) buying decision. Check with your local A/V specialty shop for current spec's and prices. I was practically laughed out of the store when I asked. Good luck. Naw, that's not true - you can get an add-on Dolby Digital processor for about $600 bucks from Marantz.
Dolby Pro-Logic Surround Sound provides four channels: Left, Center, Right, and Surround. The sub-woofer signal is derived by extracting low frequencies from the left and right channels. Left and Right Surround speakers are driven by the same signal. Because the digital sound channels remain unchanged, AC-3 discs are fully compatible with your current audio setup.
Interestingly, Dolby Digital uses a compression
algorithm that encodes the 5.1 channels at a lower bit rate than a single,
non-encoded CD channel. The Dolby Labs people (and just about all reviewers)
claim that distortion (by definition, compression inherently distorts signals)
is unnoticeable. In fact, AC-3 is the wave of the future: HDTV, DBS (direct
broadcast satellite), and digital cable television will be using it.