People ask when should they buy a DVD player. The answer is, "Last Christmas." The DVD really came of age about then. The crucial threshold of a million machines sold had been passed in November, and displays of DVD discs became common in video hardware and software stores throughout the country.

So drop the paper and run out and buy one right now. Or, if you're not convinced yet, pray read on!

DVD stands for Digital Video Disc, although it's sometimes said to stand for Digital Versatile Disc because it can also be played on computers equipped with a special DVD-ROM playback gizmo (not a regular CD-ROM drive). They're small silvery discs that look identical to audio CDs and can contain an entire movie on one side. Even a long movie. Really, really long movies, like "The Ten Commandments," take up two discs, just as a really long piece of music would require more than one CD.

The advantages of DVDs over videotape are as plain as the nose on your face: Mainly, that the nose on your face would be much, much plainer, and look much clearer and more lifelike, on a DVD than on a videocassette. DVDs provide stunningly sharp images, at least as good as the ones on those cumbersome (and now obsolete) laserdiscs, and perhaps better.

It's hard to imagine American life without VCRs, but as much power as they've given consumers over "what's on TV," the one horrible thing about them is that they conditioned viewers to accept a TV picture that was considerably worse than they were used to. Almost all VCRs have extremely poor resolution, worse than one gets from watching a TV program over the air, on cable or via satellite.

DVDs are radically, almost incomparably, better, with picture quality that can be breathtaking and sound quality at least as good as audio CDs have. This is gourmet video but at fairly accessible prices; DVD players can be bought for $300 or less, and the discs themselves can be had for as little as 15 bucks, especially via Internet suppliers like DVD Express. Some stores discount them, too. The regular retail price ranges from about $20 to about $40 for deluxe items.

Some stores also rent DVDs, which makes sense because the DVD is much harder to damage than a videocassette, and the number of times you can play one without deterioration is said to be astronomical if not infinite.

People who've sunk tons of dough and acres of storage space into laserdisc collections, or who ruefully remember that for years there were two incompatible cassette formats, Betamax and VHS, may be justifiably reluctant to embrace a new video miracle. And yet the DVD is such a reliable, satisfying and convenient medium that it really does seem to have a long and promising future.

Industry boosters say DVD is "the fastest growing consumer electronics product in history." Statistics from the Arlington-based Electronics Industries Alliance, the Hollywood-based DVD Video Group and other sources are impressive. In their first two years of existence, 877,000 home VCRs were sold; after two years of DVDs, they're in more than 2 million American homes, and optimistic industry sources claim that number will quadruple by the year 2000, with 15 million players in American homes by 2002.

Laserdiscs were introduced in 1983, incidentally (laserdiscs are the size of vinyl LP records), and yet there are only 2 million players out there after all that time. One of them is in my house but doesn't get used much anymore--although the 18,000 titles available on laserdisc dwarf the 2,800 available so far on DVD. That number is expected to reach 5,000 by the end of this year.

In addition, DVD drives for home computers are expected to be in 16 million homes by the end of this year, up from 6 million last year. Supposedly more versatile and efficient, DVD-ROM is projected to replace CD-ROM by the year, you guessed it, 2000 (O, magical year!). You can buy a DVD drive and watch movies on your computer, even a laptop, if you're so inclined. Of course, DVD will be used for storing and spewing other kinds of information, too.

For the best possible picture where movies are concerned, DVDs should be played on a TV set. There are certain basic requirements for getting the most out of DVD's fabulous possibilities. First, you should have a TV set with at least 400 lines of horizontal resolution. How do you know how many yours has? Don't try counting them; you'll get such a headache. Check the owner's manual or ask your video dealer.

In addition, the picture tube should be 35 inches or larger if you really want eye-popping visuals. Some state-of-the-art projection TVs, with pictures up to 60 inches, can display the DVD picture at its optimum.

And ideally--if you want to realize all the audio benefits of DVD--you would have a stereo system that includes Dolby Digital sound, and that requires five speakers and a subwoofer as well as the Dolby Digital decoder. Getting complicated, isn't it? It's only the beginning. The pricier amenities are for home-entertainment fanatics and perfectionists, especially those with deep pockets. But even casual viewers can enjoy the benefits of DVD without taking out a second (or third) mortgage.

Of the major studios, Warner Bros. has spearheaded the DVD campaign and released the most films on disc. Disney is releasing live-action titles but so far has withheld its animated classics, with one glorious exception: "A Bug's Life," released on DVD at the same time it was released on cassette. "Bug's Life" is innovative animation that was digitally produced and has now been digitally transferred to a digital medium, so the "Bug's Life" disc is a standout and a knockout, boasting clarity and definition that really are jaw-droppingly good.

If I didn't already have a DVD player, I think I would have had to buy one last month when 20th Century-Fox released five Rodgers and Hammerstein musicals on DVD--and not just regular but digitally mastered, pristine-pretty, gorgeous-sounding DVDs. Four of the musicals are in wide-screen, or letterbox, editions: "The King and I," "Oklahoma!," "South Pacific" and "Carousel." The fifth, "State Fair," the only musical Rodgers and Hammerstein wrote directly for the screen, was released in 1945, so it's in the regular old movie aspect ratio.

Not everybody, obviously, wants to own movies, but if you're going to have a collection, musicals make a great deal of sense, because with DVD you can jump through the show, watching only the musical numbers (or only the musical numbers you like most) and skipping the plot. It's hard to say which of the four wide-screen titles looks best. "South Pacific" and "Oklahoma!" were both transferred from Todd-AO negatives, which means they have especially high picture fidelity, but then "King and I" and "Carousel" are in their original "CinemaScope 55" versions, a kind of turbo-charged CinemaScope that affords a comparably sumptuous picture.

I've always loved movie musicals, and I know why: because the notion of walking down the street and breaking into song, and having an 85-piece orchestra backing you up, is easily as exhilarating as the prospect of being able to flap your arms and fly like a birdie. Neither is possible, but musicals give you the vicarious sensation that's almost as good as the real thing.

And while these five movies vary in quality (from great, "Oklahoma!," to stinko, "Carousel"), the music was produced on such a lavish and ravishing scale that it's really a joy to experience and re-experience. These films are consummate picker-uppers. I flipped through "The King and I" to cure myself of a funk just the other night. Wow. What a glowing, shimmering thing it is on DVD. "The King and I" and I were never happier together.

For all the luster of the Fox releases, one of the most eye-popping movies I've seen yet on DVD is a Warner Bros. musical: "The Music Man," with Robert Preston re-creating his Broadway role of Professor Harold Hill and Shirley Jones as Marian the Librarian. Very little messing around was done in transferring the show from stage to film, and the Technicolor reds, whites and blues (among others) of this DVD are absolutely amazing.

Paramount Home Video, which wasn't very generous about releasing its library of films on DVD at first, has begun to open the floodgates. The coup de grace will be the September release of James Cameron's "Titanic," which, whatever one thinks of its trumped-up love story, is visually and technically a triumph. The cassette version can't begin to do it justice.

It has to be mentioned that the DVD format has a competitor, albeit a nominal one--an upstart contraption called DIVX that is sold only by the Circuit City chain. DIVX discs can be played only on DIVX machines, but those machines can also play DVDs. But DIVX is much more complicated; you get the disc, take it home and can watch it as many times as you want for 48 hours. Then something clicks and you're charged for each subsequent viewing. For this to work, you have to have the machine connected to a phone line, as with pay-per-view movies on satellite TV. What a nuisance and what a cumbersome idea.

Both the late Gene Siskel and fellow critic Roger Ebert dismissed DIVX as a dopey nuisance on a DVD-themed edition of "Siskel & Ebert" last year. Who wants to go to all that trouble? It's ridiculous on the face of it. And on other body parts, too.

TV watching in America is definitely changing. High-definition, wide-screen television, HDTV, has technically arrived, though few stations (among them Washington's WRC-TV) are broadcasting in it, and very few consumers have bought the costly sets. Even so, viewers are bound to become fussier and fussier about the quality of the images they see on their TV and computer screens. Eventually, and no one will say just when, DVDs will be recordable at home, but until then, no one has to worry that the VCR will become obsolete. In fact, digital VCRs will one day be able to record and play back a picture comparable to that of DVDs.

They'll likely never be as easy and convenient to operate, however. Most DVDs give you a menu at the start of the disc with several options. You can go right to the movie or you can, say, play the theatrical trailer for the film, or watch a featurette. Or you can go to the "Scene Selection" display. This enables you to access, immediately, any number of scenes. The "King and I" DVD, for example, has 52 such "chapters," some of them dramatic scenes and some of them musical numbers.

Many discs also allow you the option of choosing a language other than English for audio playback or subtitles at the bottom of the screen. There are other features, and though they're not too numerous to mention, I'm just too tired to mention them now. Go to a good video store, not a junky one, and check it out for yourself. Be prepared to be seduced.

DVDs can only give you as good a picture as the source material will allow, of course, and already there are plenty of cruddy-looking discs on the market. But there are also a formidable array of outright dazzlers. Naturally, the porno industry is cashing in but, at the other end of the spectrum, many family and children's films are available too.

I was extolling DVDs to a friend, and she said that it sounded like the early days of television--that neighbors and cronies were likely to gravitate to the first house on the block to have a DVD player, especially if it's hooked up to a good giant-screen set. And so it is that television, which has already been reinvented more than once, is born again again.

CAPTION: Digital Video Disc technology restores full grandeur to films like "The King and I," with Yul Brynner and Deborah Kerr.

CAPTION: Disney's only animated release in DVD is "A Bug's Life," which boasts a clarity that must be seen to be believed.