Perhaps it is time to take Placido Domingo seriously as a conductor. He has been conducting operas in Europe for some time, he has made his Metropolitan Opera debut in this new role, and he has been heard directing a fine "La Bohe me" in a nationwide broadcast. Now the tenor who has made such an impact singing in video opera can be seen as well as heard conducting on your home screen. The cast doesn't always take him seriously in his video conducting debut, but the orchestra and audience quite rightly do.

At one point in this production, Hermann Prey, on stage, looks down into the pit, addresses the conductor as "Placidissimo," and asks him to play a number that is not in the score. Later, a comic actor persuades him to join in singing a few bars of "Celeste Aida" and then ad-libs, "Once, at least, I have sung with Placido Domingo." Is it too much to suggest that the production suffers from a lack of discipline?

Actually, its lack of discipline is the production's crowning glory. It is a live video recording of a gala New Year's Eve performance of "Die Fledermaus" given in Covent Garden on the last evening of 1983, and the singing is excellent. But the real charm lies in its anything-can-happen atmosphere. On Pioneer Artists LaserDisc (PA-84-099, two discs with libretto), this "Fledermaus" is one of the outstanding items in the small but choice and growing catalogue of operas that is helping to make LaserDisc the connoisseur's medium. Others include Zeffirelli's movie version of "La Traviata," outstanding performaces of "Tales of Hoffmann," "Peter Grimes," "La Fanciulla del West," "Falstaff" and "Samson et Dalila" from Covent Garden, "Ernani" from La Scala and "Don Carlo" and "Lucia di Lammermoor" from the Met.

Besides the conductor, the big names in this "Fledermaus" are Prey as Eisenstein and Kiri Te Kanawa as his wife, both in excellent voice and fine comic spirit, but they are supported by an excellent cast. Hildegarde Heichele, as the maid Adele, nearly steals the show, and so does Josef Meinrad, imported from Vienna for the drunk scene in Act 3. Benjamin Luxon is perfect as Falke and Dennis O'Neill is hilarious and molto Italiano as the tenor Alfredo. The Act 2 New Year's Eve ball of Count Orlovsky (played with deep Weltschmerz by Doris Soffel) is enlivened with a number of interpolated items, including a song by Charles Aznavour, and there is a real Hungarian band on stage to accompany Te Kanawa in her czardas.

Bits of other operas also slip into the show -- not only the "Aida" fragment mentioned above, but a few bars of "Wotan's Farewell" from "Die Walku re," sung by Prey as he leaves home in Act 1. Domingo, by the way, conducts well, supporting the voices and underlining many choice orchestral details. He provides a proper Viennese lilt, though he has not yet achieved the special mastery of agogic accents that seems to come naturally to Hungarian conductors.

The production is visually striking and well photographed, with excellent stereo sound. But it is worth seeing above all for its irresistible comic spirit -- as though the performance were being improvised, but with great polish and control.

Also new on LaserDisc (PA-84-089, two discs with libretto), the Metropolitan Opera's "Un Ballo in Maschera," taken from the televised performance of Feb. 16, 1980, is beautifully sung by Luciano Pavarotti, Katia Ricciarelli, Louis Quilico, Judith Blegen and Bianca Berini, among others, but the staging is not entirely problem-free. Staging "Ballo" has always been problematic since its opening in 1859, when Verdi was told by the Roman censors that this story of the assassination of a high political figure could not be set in Europe. The scene was quickly shifted from Sweden to colonial Boston and the assassinated tenor was demoted from a historic king (Gustav III, who was shot to death at a masked ball) to an imaginary governor. At this point, the libretto, which was rather turgid and contrived at best, becomes almost ridiculous -- for Americans in general and particularly for Bostonians.

No matter; the music is Verdi at the height of his powers, with "Rigoletto," "Il Trovatore" and "La Traviata" already to his credit and "La Forza del Destino" coming up next. And this production does it justice. Theatrically, the opera is not rescued from its inherent problems, but a vigorous and partly successful effort is made.

The problems were not inherent but induced in the production of Gilbert and Sullivan's "Yeomen of the Guard" broadcast on PBS last year and now available on LaserDisc (PA 84-074). The most severe problem was that of cutting the production to under two hours for television, which involved dropping some material dear to dyed-in-the-wool Savoyards who love every syllable of this material and want to hear it done just so. In the LaserDisc medium, this restriction has the advantage of allowing the whole show to fit on a single disc, with a significant saving in the purchase price. Those who are still bothered by the cuts may find it easier to take if they approach the production as an extended set of highlights.

This production also departs sometimes either from the explicit stage directions in the text or the staging dictates of longstanding tradition -- but this is less serious. The production was shot on location at the Tower of London, and the gains in taking it out of the staged framework far outweigh the losses. It is visually magnificent, sometimes reminiscent of Renaissance paintings -- notably Vermeer for some of the indoor scenes near the beginning. The voices are also, on the whole, better than you would get in most productions.

The most controversial part of the production is the subdued, moody portrayal of Jack Point by Joel Grey, in a striking contrast to his other roles, such as the emcee in "Cabaret." It is clearly a matter of choice, not of inadvertence, and ultimately one must either take it or leave it. Personally, I found it problematic at some points but generally acceptable and spectacularly justified by the tragic last few minutes, when Point is rejected by his lover and dies of grief.

"Yeomen" (misspelled as "Yeoman" on the cover of this recording) is the only Gilbert and Sullivan opera that has an unhappy ending. The text, in itself, does not do much to prepare the audience for this sudden and cruel twist, but Grey's performance envisions the end almost from the beginning. Taken from that point of view, the portrayal could almost be considered a stroke of genius.