For those who may be worried about the decline in the quality of Russian movies, here is great news. Ludmilla Gurchenko has turned in another outstanding performance, this time in her recent musical comedy, Carnival, which is currently filling the bill at the Brattle.

Filmed in muddy and grotesque Magicolor, Carnival is a souped-up Drumbeats and Song, a compendium of vaudeville acts which somehow escaped the hook. But it's funny, thanks to the fine singing of the Shmeliov Sisters (who recorded "Rose of the Urals," last year's top song hit) and the inspired performance of Eddie Rosner's jazz band. Unfortunately, Y. and V. Gusakov, well-known dancers who starred most recently in N. Khrushchev's "New Faces of 1958," failed to live up to critics' expectations.

Now the plot of Carnival is probably the best one script-writers B. Laskin and V. Polvakov ever turned in. Ogurtsov (Igor Ilyinsky) is boss man at the House of Culture. The youngsters there are planning to throw a bread-and-circus type New Year's Eve Party, but Ogurtsov wants culture: lecturers, string quartets, and the rest. Students conspire. Ogurtsov is defeated and everybody has a great time. It's wonderful stuff.

Also appearing in Carnival are Yuri Belov and Tamara Nosova, both stars of director E. Ryazanow's recent spectacular, "State and Revolution."