ST 21:1997 - SMPTE Standard - For Video Recording — 3/4-in Type E Helical Scan — Records

This standard specifies the location of the edges of the video, audio, and tracking-control records and the mechanical separation of the simultaneously recorded information of the video and audio records, as recorded on a 3/4-in type E helical-scan video tape recording cassette system, operating at a tape speed of 95.3 mm/s (3.752 in/s).