The National Assn. of Video Distributors has spent $ 50,000 in a test of consumer advertising in the Charleston, S.C., area to promote a Wednesday common street date for video rental releases. Campaign slogan is “Weekends Begin on Wednesday.” Tentative plan is to roll out a national campaign next year.Rentrak has implemented a new computer system developed by Capital Cities/ABC Video Enterprises that will allow video retailers using nearly any point-of-sale computer system to participate in Rentrak’s pay-per-transaction system. Reportedly a three-year effort, development of the so-called DataTrak data collection system required a $ 5 million investment. Separately, Rentrak announced it has formed a chain-store division, to solicit business from supermarkets, record/video stores, drugstores and other non-specialty retailers. MPI Home Video will release “Where’s Jimmy Hoffa?” on Dec. 16 at $ 59.98 suggested retail price. Release is timed to take advantage of interest in Hoffa that may be generated by the Christmas opening of 20th Century Fox’s “Hoffa.” FoxVideo has reduced the price of “The Rocky Horror Picture Show” to $ 19.98 for rerelease on Nov. 18. Title has been on moratorium since it was released to the rental market at $ 89.98 two years ago. Blockbuster Entertainment opened the 3,000th store in its worldwide network in October on Third Ave. in New York City. The company also opened its 1,000th store outside the United States, a franchise- owned outlet near Mexico City. Mexico is targeted for future expansion, according to the company, as are Australia, Austria, Canada, Chile, Japan, Spain, the United Kingdom and Venezuela. “Cock & Bull Story” directed by Billy Hayes will be screened Nov. 28, Dec. 5, 12 and 19 at Cinema Cafe in Hollywood. Bailey Hayes Prods. will then release it on vidcassette via direct mail and to L.A. vidstores. Production is based on the critically acclaimed play of the same name by Richard Crowe and Richard Zajdlic.