The CMX 600 was the very first non-linear video editing system. This Emmy Award winning system was introduced in 1971 by

CMX Systems CMX Editing Systems (also known as CMX Systems) was a company founded jointly by CBS and Memorex; with help from many individuals such as Ronald Lee Martin, who later became a head of Universal Studios; that developed some of the very first comput ...

, a joint venture between

CBS CBS Broadcasting Inc., commonly shortened to CBS, the abbreviation of its former legal name Columbia Broadcasting System, is an American commercial broadcast television and radio network serving as the flagship property of the CBS Entertainm ...

and

Memorex Memorex Corp. began as a computer tape producer and expanded to become both a consumer media supplier and a major IBM plug compatible peripheral supplier. It was broken up and ceased to exist after 1996 other than as a consumer electronics bran ...

. CMX referred to it as a "RAVE", or Random Access Video Editor. The 600 had a console with 2 black & white monitors built in, as well as a

light pen A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with a computer's cathode-ray tube (CRT) display. It allows the user to point to displayed objects or draw on the screen in a similar way to a tou ...

used to control the system. The right monitor, which played the preview video, was used by the editor to make cuts and edit decisions, by using the light pen to select from options which were superimposed as text over the preview video. The left monitor was used to display the edited video. It recorded and played back black-and-white "

skip-field In video, skip field recording is a process in which only one field (one half of a frame) of video is recorded in order to conserve recording media space. For some kinds of recording, the quality loss of not using both fields of video is fairly ...

" video in analog on specially modified

disk pack Disk packs and disk cartridges were early forms of removable media for computer data storage, introduced in the 1960s. Disk pack A disk pack is a layered grouping of hard disk platters (circular, rigid discs coated with a magnetic data storage ...

drives (supplied by Memorex, and which were commonly used to store data digitally on mainframe computers of the time) that were the size of washing machines. The audio was recorded digitally using PCM, and was recorded by being inserted in the " back porch" of the

horizontal blanking interval Horizontal blanking interval refers to a part of the process of displaying images on a computer monitor or television screen via raster scanning. CRT screens display images by moving beams of electrons very quickly across the screen. Once the beam ...

pulses of the video (a technique known as " sound-in-sync"). This audio was somewhat poor, due to a large amount of

jitter In electronics and telecommunications, jitter is the deviation from true periodicity of a presumably periodic signal, often in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a significa ...

occurring from the signal being played back from the disk packs. The video was also of less than stellar quality, due to it being recorded in skip-field mode (which was done to extend recording time on the disk packs). But all of this did not matter, since the 600's main purpose was solely for

off-line editing Offline editing is part of the post-production process of film making and television production in which raw footage is copied and the copy only is then edited, thereby not affecting the camera original film stock or video tape. Once the project ...

, in order to create an

Edit Decision List An edit decision list or EDL is used in the post-production process of film editing and video editing. The list contains an ordered list of reel and timecode data representing where each video clip can be obtained in order to conform the final cu ...

(EDL) for later on-line editing. The 600 was paired with the CMX-200, which took the EDL information from the 600, and used it to control several

video tape recorder A video tape recorder (VTR) is a tape recorder designed to record and playback video and audio material from magnetic tape. The early VTRs were open-reel devices that record on individual reels of 2-inch-wide (5.08 cm) tape. They were use ...

s (VTRs) to auto-assemble the video program in the on-line editing stage. The 200 used a

Teletype Model 33 The Teletype Model 33 is an electromechanical teleprinter designed for light-duty office use. It is less rugged and cost less than earlier Teletype machines. The Teletype Corporation introduced the Model 33 as a commercial product in 1963 after ...

ASR terminal to input EDL information. The editing console was interfaced to two equipment racks of support equipment (which were usually located remotely in another room from the console). The first rack contained the interface electronics for the system, monitoring equipment, and a

Digital Digital usually refers to something using discrete digits, often binary digits. Technology and computing Hardware *Digital electronics, electronic circuits which operate using digital signals **Digital camera, which captures and stores digital i ...

PDP-11 The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, ...

minicomputer A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...

with 32 kilobytes of

RAM Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * ...

, which controlled the system. The second rack contained all the audio & video electronics, and the "Skip-Field Recorder", which took in video & audio for editing from a VTR, and then recorded such to one or several disk pack drives interfaced to the 600. The CMX 600 could support up to six disk pack drives, for a total recording time of 27 minutes. Each disk pack could record up to 5.4 minutes of

NTSC The first American standard for analog television broadcast was developed by National Television System Committee (NTSC)National Television System Committee (1951–1953), Report and Reports of Panel No. 11, 11-A, 12–19, with Some supplement ...

video, or 4.5 minutes of

PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...

video. The CMX 600 was a system quite ahead of the technology of the time, and was quite expensive, costing about $250,000 USD at its introduction. About 6 systems were manufactured, and were used to edit several television shows and commercials.

External links

A page about the CMX 600, with a demo video available for viewing
(Archived copy from archive.org)
(The demo video mentioned in the above link, on YouTube)
*''Timeline, the history of editing'' (John Buck 2018). (incl complete CMX-600 storyline)(Tablo Books ).
(Free public access to Timeline, the history of editing Analog 1)

References

{{Reflist Film and video technology

See also

External links

References