Computer Beginner Guide

This question has no absolute answer, because you’ll get a different response from everyone you ask. The terms second generation, third generation, and so on refer both to DVD-Video players and DVD-ROM drives. In general, they simply mean newer versions of DVD playback devices. The terms haven’t been used (yet) to refer to DVD products that can record, play video games, and so on. According to some people, second-generation DVD players came out in the fall of 1997, and third-generation players were released at the beginning of 1998. According to others, the second generation of DVDs will be HD players that won’t come out until 2003 or so. Many conflicting variations occur between these extremes, including the viewpoint that DTS-compatible players, Divx players, progressive-scan players, 10-bit video players, or players that can play The Matrix constitute the second, third, or fourth generation. Things are a little more clear cut on the PC side, where second generation (DV...

Laserdiscs are subject to what is commonly called laser rot, the deterioration of the aluminum layer due to oxidation or other chemical changes. This often results from the use of insufficiently pure metal for the reflective coating created during replication, but it can be exacerbated by mechanical shear stress due to bending, warping, or thermal cycles. The large size of laserdiscs makes them flexible, so that movement along the bond between layers can break the seal, which is called delamination. Deterioration of the data layer can be caused by chemical contaminants or gasses in the glue, or by moisture that penetrates the plastic substrate. Like laserdiscs, DVDs are made of two platters glued together, but DVDs are more rigid and use newer adhesives. DVDs are molded from polycarbonate, which absorbs about 10 times less moisture than the slightly hygroscopic acrylic (PMMA) used for laserdiscs. DVDs can have delamination problems, partly because some cases or players hol...

Some people claim that animation, especially hand-drawn cell animation such as cartoons and anime, does not compress well with MPEG-2 or even ends up larger than the original. Other people claim that animation is simple so it compresses better. Neither is true. Supposedly the “jitter” between frames caused by differences in the drawings or in their alignment causes problems. An animation expert at Disney pointed out that this doesn’t happen with modern animation techniques. And even if it did, the motion estimation feature of MPEG-2 would compensate for it. Because of the way MPEG-2 breaks a picture into blocks and transforms them into frequency information, it can have a problem with the sharp edges common in animation. This loss of high-frequency information can show up as “ringing” or blurry spots along edges (called the Gibbs effect). However, at the data rates commonly used for DVD, this problem does not usually occur. Why Do Some Discs Require Side Flipping? Can’t D...

The MPEG video on a DVD is stored in digital format, but it’s formatted for one of two mutually incompatible television systems: 525/60 (NTSC) or 625/50 (PAL/SECAM). Therefore, two kinds of DVDs exist: NTSC DVDs and PAL DVDs. Some players only play NTSC discs; others play PAL and NTSC discs, depending on which region the owner lives in (refer to “What Are Regional Codes, Country Codes, or Zone Locks?”). Almost all DVD players sold in PAL countries play both kinds of discs. These multistandard players partially convert NTSC to a 60 Hz PAL (4.43 NTSC) signal. The player uses the PAL 4.43 MHz color subcarrier encoding format but keeps the 525/60 NTSC scanning rate. Most modern PAL TVs can handle this pseudo-PAL signal. A few multistandard PAL players output true 3.58 NTSC from NTSC discs, which requires an NTSC TV or a multistandard TV. Some players have a switch to choose 60 Hz PAL or true NTSC output when playing NTSC discs. A few standards-converting PAL players convert o...

A dual-layer disc has two layers of data, one of them semitransparent so that the laser can focus through it and read the second layer. Because both layers are read from the same side, a dual-layer disc can hold almost twice as much as a single-layer disc, typically four hours of video. Many discs use dual layers. Initially, only a few replication plants could make duallayer discs, but most plants now have the capability. The second layer can use either a parallel track path (PTP) layout where both tracks run in parallel (for independent data or special switching effects) or an opposite track path (OTP) layout where the second track runs in an opposite spiral. That is, the pickup head reads out from the center on the first track and then in from the outside on the second track. The OTP layout is designed to provide continuous video across both layers. OTP is also called reverse-spiral dual layer (RSDL). The layer change can occur anywhere in the video; it doesn’t have to b...

The answer is yes. When DVD was originally introduced in 1997, it could only play. DVD video recorders appeared in Japan at the end of 1999 and in the rest of the world at the end of 2000. Early units were expensive: from $2,500 to $4,000. DVD recorders are still quite expensive (typically $500 to $2000 as of mid-2003), but they will eventually be as cheap as VCRs. DVD recorders are already being added to satellite and cable receivers, hard-disk video recorders, and similar boxes.  A DVD recorder basically works like a VCR. It has a tuner and A/V inputs, and it can be programmed to record shows. An important difference is that you never have to rewind or fast forward. Recordings on a disc are instantly accessible, usually from an onscreen menu. Note that DVD video recorders can’t copy most DVD movie discs, which are protected. Unfortunately, more than one recordable DVD format is available, and they don’t all play together nicely. It’s nothing like the old VHS versus ...

When DVDs were released in 1996, no DVD-Audio format was available, although the audio capabilities of DVD-Video far surpassed CDs. The DVD Forum sought additional input from the music industry before defining the DVD-Audio format. A draft standard was released by the DVD Forum’s Working Group 4 (WG4) in January of 1998, and version 0.9 was released in July. The final DVD-Audio 1.0 specification (minus copy protection) was approved in February of 1999 and released in March, but products were delayed in part by the slow process of selecting copy protection features (encryption and watermarking), with complications introduced by the Secure Digital Music Initiative (SDMI). The scheduled October 1999 release was further delayed until mid-2000, ostensibly because of concerns caused by the CSS crack (see “What Is DeCSS?” in Chapter 4), but also because the hardware wasn’t quite ready, production tools weren’t up to snuff, and the support from music labels was lackluster. Pioneer...