Dire Straits: ''Love Over Gold.'' (Warner Bros. 23728-1.) Also ''Twisting by the Pool.'' (Warner Bros. 29800-0 A.) Here are two albums from the idiosyncratic Dire Straits. One, ''Love Over Gold,'' released last fall, is introspective and moody. The more recent extended-play album ''Twisting by the Pool'' is a far brighter record, a kind of sendup of old rock and R&B, but is slightly less satisfying. Mark Knopfler, group leader and author of this record's songs, offers gruff, but casual-sounding vocals that complement the songs much as a patch of gnarled oak trees would complement a country road. Knopfler is credited with the music for the movie ''Local Hero'' as well. The soundtrack album (Warner Bros., 23827-1) is a far different creature than some of the recent movie records that have been released (''The King of Comedy,'' for instance), which are often packed with a mixed bag of hits from various stars. Instead, ''Hero'' is a richly colored collection of themes and sound settings. It's often slow and thoughtful, but much less brooding than ''Love Over Gold.''