THE Franz Liszt Chamber Orchestra of Budapest, which performs in the Kennedy Center Concert Hall this afternoon, is not nearly as well-known in this country as the numerous English and Italian chamber orchestras, but needn't take a back seat to any of them, as many record collectors are aware now. The "Liszt Ferenc Chamber Orchestra," as the ensemble is billed at home, has made some stunning recordings on the Hungaroton label, one of the most recent being the superb one of Mozart's Big K. 334 Divertimento in E (SLPX-12027). On two brand new releases the group performs music of Vivaldi, and these are no less striking additions to that composer's discography.

The first is a three-disc set of the dozen concertos Vivaldi published under the heading "L'estro armonico," Op. 3, conducted, as in the Mozart cited above, by the group's late founder Frigyes Sandor, and with his successor Janos Rolla (who is conducting today's concert) as principal VIOLIN SOLOIST (SLPX-12171/12173). This collection comprises four solo violin concertos -- four for two violins, and four for four violins -- some in the last two categories with solo cello as well. Bach transcribed no fewer than six of these 12 concertos for various other instruments, and Siloti's notorious arrangement of the famous No. 11 in D minor was for all too many years virtually the only form other than Bach's transcriptions in which we were likely to hear a Vivaldi work of any kind. By now, of course, the entire Op. 3 has been recorded several times in its original form, with authentic instruments and authentic style; but none of the earlier versions has managed to combine authenticity, vivacity and beautiful ensemble quite as effectively as this one from Budapest, and none has been so handsomely recorded.

The second item, made up of five somehwat less familiar works by Vivaldi, is a downright delicious collection featuring the recorder virtuoso Laszlo Czidra (SLPX-12161). The Liszt Chamber Orchestra figures in only one of these pieces, the Concerto in C major for two recorders, strings and continuo (RV 533). This work has been recorded a few times with flutes, and at least once with flute and oboe, as well as once before with a pair of recorders, but the gorgeous playing by Czidra and his partner Zsolt Harsanyi, and the degree of their integration with the splendid little orchestra, define standards beyond anything offered in the past.

The other two concertos on the disc are chamber works rather than pieces for solo instrument and orchestra. They are the one in F major for recorder, violin and bassoon and continuo (RV 100), and one in G minor for recorder, oboe and bassoon without continuo (RV 103), both of which were recorded back in 1954 by Rampal and associates for Erato and the Haydn Society.

The two remaining works are sonatas, one in F for solo recorder and continuo (RV 52), the other in G for recorder, viola bastarda (the so-called "lyre viol," a small bass) and continuo (RV 59). The latter is an adaptation of the Sonata No. 4 in A from the collection of six known as "Il pastor fido," works usually regarded as flute sonatas but which Vivaldi himself indicated as playable on numerous other instruments (among them the bagpipes and hurdy-gurdy). The combination of the recorder and the transposition from A to G gives the piece a warmer character and even suggests a somewhat greater substance than we hear in the flute version.