Summer doesn't officially end until tomorrow, but home video executives are eager to get the Christmas season started as soon as possible. Their haste can be attributed to more than visions of seasonal delights on the way; this year the sugarplums are dancing to the tune of the $1 billion that industry analyst Alexander & Associates predicts will be spent on videocassettes between mid-November and mid-January.

One sure sign of the season's arrival is the appearance in stores of Christmas-theme videocassettes, a holiday harbinger that happens earlier each year. This year is no exception; the major yuletide tapes will all be in stores by Columbus Day. Since most of the big-screen Christmas classics are already video store veterans, this year the studios have turned to another source for their season's screenings: television.

This year's most heavily promoted holiday home video will include last year's most highly rated Christmas special -- the "I Love Lucy" Christmas episode that topped the Nielsen ratings last December when it aired for the first time since its original Christmas Eve 1956 broadcast. It turns up again, without commercials, on "The Honeymooners/I Love Lucy TV Christmas Present," due in stores next week from CBS/Fox Home Video. The Ricardos' and Mertzes' treeside trip down memory lane joins a "Honeymooners" episode from the same year in which Ralph buys the wrong present for Alice. The $14.98, 52-minute tape also includes a broadcast oddity billed as the "I Love Lucy Jingle Bells music video clip" -- Lucy, Ricky, Fred and Ethel singing "Jingle Bells" in Santa suits -- that had been "lost" for 39 years, as well as a vintage animated "season's greetings" station-breaker from the CBS vaults. Only Scrooges will call attention to the fact that viewers used to walk away from station breaks and now they have to pay to see them.

Warner Home Video is targeting the sugarplum visionaries with its Holiday Treasures Children's Video Collection of seven animated small-screen perennials, each making its home video debut. Grown-ups will be most interested in "Bugs Bunny's Looney Christmas Tales," in which the holiday hare makes "A Christmas Carol" and " 'Twas the Night Before Christmas" all his own. Unfortunately, the remaining six arrivals hail not from the hallowed halls of Warner animation but from television filler factory Rankin/Bass. And they boast some impressive vocal talent: Angela Lansbury and Cyril Ritchard ("The First Christmas"), Alfred Drake ("The Life and Adventures of Santa Claus"), Greer Garson ("The Little Drummer Boy Book II"), Roger Miller ("Nestor the Long-Eared Christmas Donkey"), Walter Matthau ("The Stingiest Man in Town") and Joel Grey (" 'Twas the Night Before Christmas"). The tapes, which range in length from 20 to 49 minutes, are priced at $12.98 each.

Finally, in an apparent attempt to squeeze every drop of holiday cheer out of its once-fine tradition of big-screen Christmas movies, MGM/UA Home Video will engineer the home video debuts of three films from its enormous library. While none is an obvious candidate for the Christmas-movie season, the films' heart- and hearth-warming intentions guarantee that they won't look out of place, either. The three are "The Canterville Ghost," a 1944 film adaptation of Oscar Wilde's tale, starring Charles Laughton; "The Next Voice You Hear ...," featuring Nancy Davis, James Whitmore and the voice of God on the radio; and Greer Garson and Walter Pidgeon in "Blossoms in the Dust." They are priced at $19.98 each.

Season of the Spirits Halloween also used to inspire home video executives to raid their studio libraries for classics of the horror genre. Apparently the raids are over, however, as most of this year's taped terrors are simply last year's specials at new low prices. Nevertheless, the folks at MGM/UA have unearthed a trio of video debuts of some note: "House of Dark Shadows" (1970) and "Night of Dark Shadows" (1971), the big-screen adaptations of the popular television series, and the full-length, unrated version of "The Fearless Vampire Killers," the 1967 Sharon Tate cult favorite from which writer-producer-star Roman Polanski asked that his name be removed after 20 minutes of material was cut. The terrible trio will sell for $19.98 each, as will three other horror classics previously available at much higher prices: "Freaks," "Motel Hell" and "The Haunting."