It is only too easy at the annual Edinburgh International Festival to forget that the rest of the world exists: Most of it seems to be here. The Scottish capital for the last three weeks of August is overrun, absorbed in festival. It is an entirely different place at festival time - bursting with happenings, high jinks, and fancy dress; kite flying, fireworks, and hot-air balloons. There are Scottish dances, craft and book fairs, street performances, processions - the military tattoo up at the castle - and an endless array of fringe amateur and professional drama, dance, mime, art, song, film, jazz, you-name-it.
At the center of all this activity there remains a consistently first-rate official program, presenting all of the above at a high caliber and with international scope - for 38 festivals now.
No single art form is given intentional precedence, though different directors do seem to let their specialties show through. There's a new one starting this year: Frank Dunlop, labeled a ''drama man.''
Appropriately, then, this year is strong on drama, particularly Samuel Beckett, and (in a year when the falling pound has brought American tourists to Britain - and Edinburgh - by thousands) there is a notable American contribution. But one country or art, though flavoring a particular festival, is never allowed to dominate it, and there are companies this year from France, East Germany, Australia, and of course Scotland, as well as performers from every corner of the globe.
Opera buffs do have a feeling of letdown this year. Not only have few operas been scheduled, but two promising ones, Welsh National Opera's ''Parsifal'' and ''The Greek Passion,'' were canceled. Perhaps dance enthusiasts have also not been given the rich feast of some previous years - though the chance to see Rudolf Nureyev in the Paris Opera Ballet during the last week is hardly to be sniffed at.
In its orchestral concerts this year, however, the festival's tradition of excellence has continued. Highlights of the first week included the wizardry of Italy's Riccardo Muti conducting the Philharmoniacq Orchestra in the opening concert.
Beethoven's Second Symphony was followed by Rossini's ''Stabat Mater''cq with orchestra, soloists, and festival chorus collaborating in a shower of exuberance and devotion - effective in a work combining elements of opera and piety. A Bartok concert by the Royal Philharmonic Orchestra starred Dietrich Fischer-Dieskau and Julia Varady singing ''Duke Bluebeard's Castle'' - that somewhat lurid tale of compulsive fatalism. The music is electrifyingly descriptive, and the protagonists were portrayed by two voices charged, at turns , with passing hope, prescience, and doom.
The influx of American contributions impressively spans most of the categories of this festival except dance. I have yet (being only midfestival) to see the Negro Ensemble Company's ''A Soldier's Play,'' and the New York comedy ''Twice Around the Park'' - an ''evening of fun and frolic'' - somehow didn't attract my interest.
But Washington Opera's offerings did intrigue me. This company performed new productions of Gian Carlo Menotti's 1947 successes ''The Telephone'' and ''The Medium,'' Menotti himself directing. The tongue-in-cheek ''Telephone'' strained to be lighthearted. The two singers seemed, frankly, underrehearsed in the necessarily slick business needed to keep the action farcical while the music tells its own much slower story. In the end it was spoiled by a conflict of pace. But the ''Medium'' was riveting. It was eerie and sympathetic and strident , with never a lapse. And Madame Flora, swinging from sour fraud to bitter terror, was acted and sung by Beverly Evans with a taut potency.
The Harold Clurman Theatre of New York was here as a part of the Beckett tribute. In its three-part production, ''Ohio Impromptu/ Catastrophe/ What Where ,'' this company managed the intensity of Beckett's passionate void with a parched throatiness. This is drama opening a black hole - to find, without surprise, that it is nothing.
Still to come in the festival as I write are two concerts by the Boston Symphony Orchestra, while (yet another outstanding American contribution) the Smithsonian Chamber Players have completed the largest number of performances by a single group in the recital part of the festival: six concerts.
It is, however, in the exhibition section of the program that the United States makes its biggest mark. Judy Chicago's weird, amazing, moving, and magnificently crafted tour de force ''The Dinner Party'' - to memorialize history's great women - is in Edinburgh for its first European showing: It's not ''official'' festival, but it feels like it.
The Smithsonian has sent over a delightful sampling of its many and immensely varied treasures, including Jimmy Durante's hat, a David Smith sculpture, a Tiffany vase, the Wright Brothers' propeller, moon rock, and a porringer.
What a potpourri! The bronze casts of Lincoln's hands are here, as is a section of petrified wood of the Triassic period. So is a Navajo squash-blossom necklace, a Time cover portrait of Churchill, a Singer sewing machine, and an ebony banjo. Among such diversity it is possibly not surprising that some objects link directly to other shows at the festival. Matisse's bronze ''The Serf,'' for example, is here and also included in a marvelous and illuminating exhibition of the great French artist's sculpture (this show will be joining an exhibition of Matisse's drawings at the Hayward Gallery, London, Oct. 4 to Jan. 6).
And the Smithsonian exhibition displays a fine selection of Chinese bronze vessels and bells from the Arthur M. Sackler collection, while at Edinburgh University's impressive Adam Library ''Rarities of Chinese Painting'' from the same collection are displayed. It is a shame that the only catalog to this exhibition is a very costly book.
Even so, it is tempting to buy because of the supreme artistry of these works , particularly the 15 by Tao-chi (1641 to ca. 1710). One section of the exhibition contrasts leaves from an album by this painter with a good copy of the same leaves by another artist. To study the minute subtleties that differentiate them is an extraordinary exercise of perception and a fascinating way to appreciate qualities of tone, weight, observation, rhythm, emphasis, and spontaneity.
And in some contrast to such finesse, the New York painter, Jean Michel Basquiat, only recently prominent, has left his own kind of mark on the 1984 festival here. A selection of his large and definitely exhilarating graffiti-on-canvas works is at the Fruitmarket Gallery (through Sept. 23) before being seen in London and then Rotterdam. I particularly like his ''Revised Undiscovered Genius of the Mississippi Delta'' (1983), its white paint covering a multitude of re-thinks, so that the finality of the ''final'' version still seems only a fresh notion, drawn instinctively carefree. A green catfish blows green bubbles; a primitive Picasso face stares; and an even more primitive fishing rod drops a giant hook below a blue line of paint, catching nothing. What it is all about I haven't a clue. But it is one striking image among a great many to carry away from the 38th Edinburgh Festival.