Royalty-Free, or RF, refers to the right to use copyrighted material or intellectual property without the need to pay royalties for each use or per volume sold, or some time period of use or sales. RF Video technology was first developed for cathode ray tube television systems, but several new technologies for video display devices have since been invented. Charles Ginsburg led the research team at Ampex Corporation in developing the first practical videotape recorder (VTR). This Tape was sold for around $50,000 in 1956. Sony Started to sell the first VCR tapes to the public in 1971. Since then computer technology has advanced a huge amount and can now be used to capture, store, edit and transmit film clips. Since the invention of the DVD in 1997 and Blu-ray Disc in 2006 video sales have plummeted and are often regarded as old fashioned and obsolete.