Synchronization as a Sound-Image Relationship

7 Time Code

While the order of images is immediately visible on a filmstrip, practically nothing can be seen on videotapes, which were initially used beginning in the mid-1950s for television. Because, in contrast to the two-dimensionally recorded film images, they function according to the principle of line scanning, television images are more similar to an analog continuous sound signal during their transmission. But even the so-called vertical blanking interval (VBN) between two images is not visible on videotapes, and there is also no perforation from which to easily read the distribution of the images on the tape. In the early days of video technology, this invisibility made manual editing complicated and subject to error. Electronic time markers on the tapes were then inscribed and read by the electronic video editing systems produced in the early 1960s. An addressing system of this type was introduced as the standard in 1969 by the Society of Motion Picture and Television Engineers (SMPTE), and since it was taken over by the European Broadcasting Union (EBU) in 1972, it has been used internationally as the SMPTE/EBU Timecode.[29] The SMPTE/EBU Timecode writes absolute addressing in hours, minutes, seconds, and frames as digital pulse sequences on the videotapes and audiotapes. It is differentiated between the Vertical Interval Timecode (VITC) and the Longitudinal Timecode (LTC), depending on whether the time code in the logic of the video recording is written diagonally in the VBN between two images or, in the logic of the soundtrack, along the length of the tape.[30] The SMPTE/EBU Timecode is soon also used for film; among other things, it plays an important role for the division of work and logistics when dubbing a film. Thus, for example, the composition of film scores is today for the most part organized based on the SMPTE/EBU Timecode.[31]


Timelines:ab 1950