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Laserdisc versus DVD

Laserdisc vs. DVD

It is interesting to note that the differences between LD technology and DVD have led some videophiles to prefer LD. Laserdiscs use only analog video and almost always carry some form of analog audio. Many purists believe that analog media is capable of higher quality than digital A/V carriers such as CD and DVD, and early DVD demo discs often had compression or encoding problems, giving LD proponents fuel for the fire. However, "LD-perfection" is rarely achieved in practice. Only the absolute best LDs, few and far between, exhibit such superior quality in comparison to the newer DVDs, and even then it requires expensive equipment to realize the benefits.

An advantage to the Laserdisc format over DVD is that video is not digitally-encoded and compressed, and therefore does not experience problems such as artifacting (most visible as blockiness during high motion sequences) or color banding (subtle visible lines in gradient areas, such as skies) that can be caused by the MPEG-2 encoding process as video is prepared for DVD. However, the meticulous frame-by-frame tuning of the encoding process coupled with the variable bit-rate technology generally employed on big-budget DVD releases effectively eliminates this, and an optional feature of the MPEG-2 compression standard allows much higher color resolution to eliminate the visible effect of color banding on some high-end home theatre equipment. Some videophiles will continue to argue that Laserdisc maintains a "smoother" more "film like" image while DVD still looks slightly more artificial.

A disadvantage with the analog nature of Laserdiscs is that most players exhibit a slight but perceivable 30 Hz video flicker, and slight dust and wear on the hardware or disc can degrade video and audio over time. The DVD format, however, does not introduce any flicker, and the format's digital nature and sophisticated error-correction scheme can often produce spotless video/audio from a DVD, even with dust and scratches on the surface. Laserdisc players also suffered a problem known as "crosstalk". The issue came up when the wide wavelength laser inside the player accidentally picked up picture information from a track adjacent to where it was reading on a disc. The added information usually showed up as distortion in the picture. Some players were better at compensating for and/or avoiding crosstalk entirely than others.

DVD image resolution is also greater than Laser Disc for two reasons. Firstly, NTSC laserdiscs offer 400 lines of resolution while DVDs offer 480 lines. PAL laserdiscs offer 440 lines of resolution while DVDs offer 576. Secondly, most DVD players allow an anamorphic transfer of a 16:9 movie to be downconverted into letterbox or pan & scan for TVs that don't support anamorphic display, while very few LD players supported this feature, necessitating the issue of seperate editions.

Another major advantage to DVD over Laserdisc was the fact that LD playback quality was highly dependent on player quality (as with any analog format). On most television sets, a given DVD player will produce a picture that is visually indistinguishable from other units; quality differences between players only become easily apparent with higher-end equipment. This was not true of Laserdisc playback quality; major variances in picture quality could appear between different makes and models of LD player, even when tested on a TV that was not particularly high-end. This fact has had long lasting ramifications, as the pricing for what were considered to be good players has remained comparably high (anywhere from $200 to well over $1,000 USD), while older and less desirable players can be purchased in working condition for as little as $25.