Starting in the late 1970s to the early 1980s, several types of video production equipment that were digital in their internal workings were introduced, such as time base correctors (TBC) and digital video effects (DVE) units (one of the former being the Thomson-CSF 9100 Digital Video Processor, an internally all-digital full-frame TBC introduced in 1980, and two of the latter being the Ampex ADO, and the Nippon Electric Corporation (NEC) DVE). They operated by taking a standard analog composite video input and digitizing it internally. This made it easier to either correct or enhance the video signal, as in the case of a TBC, or to manipulate and add effects to the video, in the case of a DVE unit. The digitized and processed video information that was output from these units would then be converted back to standard analog video.Later on in the 1970s, manufacturers of professional video broadcast equipment, such as Bosch (through their Fernseh division), RCA, and Ampex developed prototype digital videotape recorders (VTR) in their research and development labs. Bosch's machine used a modified 1" Type B transport, and recorded an early form of CCIR 601 digital video. Ampex's prototype digital video recorder used a modified 2" Quadruplex VTR (an Ampex AVR-3), but fitted with custom digital video electronics, and a special "octaplex" 8-head headwheel (regular analog 2" Quad machines only used 4 heads). The audio on Ampex's prototype digital machine, nicknamed by its developers as "Annie", still recorded the audio in analog as linear tracks on the tape, like 2" Quad. None of these machines from these manufacturers were ever marketed commercially, however.
0 comments:
Post a Comment