Timecode

Using the timecode (TC ) or time code of each image is determined in a movie exactly. The time code consists of the specified hour, minute, second and Bild-Nummer/Frame ( this second). He to synchronize exactly born of necessity, sound and image in post-production. Today, he finds its application in both the film and video sector. When non-linear video editing can be worked at a pinch without timecode, such as when VHS material is digitized.

Time information

The number of frames per second (frames per second [ fps] ) varies depending on the medium:

  • The film from 0 to 23 (24 fps)
  • In the PAL video format from 0 to 24 (25 fps)
  • In the NTSC video format 0-29 (30 fps)
  • The high definition video format with 0 to 49 ( 50 fps)

For NTSC, the first two frame numbers are usually not awarded every minute ( you start with hour: minute: 00:02 instead of hour: minute: 00:00 ), except in multiples of ten minutes. This specialty, called " Drop Frame Timecode", reflects the fact that NTSC is not exactly 30 fps, but about 29.97 fps used.

To make the different devices are synchronized, they must be synchronized at the beginning of a day of shooting with so-called mother watches. ( Applies only to film but not on video )

The validity of timecode is different. On cameras recorded the raw material can be found at sporting events usually have a realtime code that represents the actual time of the recording, other events are recorded starting with 01 as hour, while you can find on broadcast tapes a fictitious (usually normalized ) so-called "Internal Timecode".

Recording

It captures the time code in very different ways:

Electronic Time Code

  • In modern video cameras in the Vertical Interval Time Code ( VITC) is used, which is recorded in the helical scanning as a hi-fi track on a VHS machine by the rotating head drum.

The position of VITC is in the blanking interval of the image, exactly in the 19th and 21st line of the first Fields and in the 332 and 334 line of the second Fields ( 2 fields = 1 frame). The position can be changed in the machine menu, but it is recommended not to do this, because the time code reader is looking at the above locations for the information. He is from the statue to just above the normal playback speed read. If the machine is used in the Search mode or as a time-lapse machine is on the longitudinal resonance Time Code ( LTC), which runs along as an additional, linear audio track switched. This can be read up to the highest speed.

At the professional machines both timecode can be switched separately. For the cut, decisive, especially when master tapes, is not only the seamless continuity of the time code, but also that LTC and VITC are absolutely in sync.

Only the S -VHS or VHS system must consider it if you like to LTC with records, because this system has no separate LTC - track, but then the longitudinal audio track 2, so the right channel must be used for the Hi-Fi tracks but are still available for stereo sound.

  • The most widely used in the professional sector timecode SMPTE timecode. In professional systems, the cassette number can be encoded. But the hour is used. 01:00:00.00 is the first cartridge 02:00:00.00 the second and so on. In the broadcast sector, however, the beginning of a film is often shown with 10:00:00.00 according to the ARD and ZDF standard.
  • MAZ Digital Devices nest timecode in data packets.

Optical Time Code

In contrast to the German version, in which the information is stored as binary code between the perforation holes, the French method writes the timecode in plain text as image information, which is handy especially at the editing table.

Transmission

The transmission of time code for copying and cutting purposes will either be in SMPTE timecode signal via an audio cable ( XLR or coaxial) digital via serial interface or DV via FireWire. If one timecode signals to an audio input, so is a typical digitally modulated " timecode whistle " to hear, but that should not be confused with " digital noise ".

More timecode

More Time codes are the IRIG time code (IRIG B), which applies especially in the military sphere and on U.S. military testing grounds for temporal synchronization of video and data recording. The NIST uses a form of the IRIG time code (IRIG H) as the data format for the U.S. time signal transmitters WWV.

Timecode in music

There are also so-called Timecode records, which are used for synchronizing and controlling of DJ programs using a CD, DVD and turntables.

Workprint Film frame Rotary transformer Linear timecode SMPTE-Timecode Video tape recorder IEEE 1394 Vinyl emulation software
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