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A timecode (alternatively, time code) is a sequence of numeric codes generated at regular intervals by a timing synchronization system. Timecode is used in
Depending on the environment, timecode generators can take various forms.
video production
Video production is the process of producing video content for video. It is the equivalent of filmmaking, but with video recorded either as analog signals on videotape, digitally in video tape or as computer files stored on optical discs, hard dri ...
, show control
Show control is the use of automation technology to link together and operate multiple entertainment control systems in a coordinated manner. It is distinguished from an entertainment control system, which is specific to a single theatrical depart ...
and other applications which require temporal coordination or logging of recording or actions.
Video and film
Invideo production
Video production is the process of producing video content for video. It is the equivalent of filmmaking, but with video recorded either as analog signals on videotape, digitally in video tape or as computer files stored on optical discs, hard dri ...
and filmmaking
Filmmaking (film production) is the process by which a motion picture is produced. Filmmaking involves a number of complex and discrete stages, starting with an initial story, idea, or commission. It then continues through screenwriting, cast ...
, SMPTE timecode
SMPTE timecode ( or ) is a set of cooperating standards to label individual frames of video or film with a timecode. The system is defined by the Society of Motion Picture and Television Engineers in the SMPTE 12M specification. SMPTE revised ...
is used extensively for synchronization
Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchronou ...
, and for logging and identifying material in recorded media. During filmmaking or video production shoot, the camera assistant
A focus puller or first assistant camera (1st AC) is a member of a film crew's camera department whose primary responsibility is to maintain the camera lens's optical focus on whatever subject or action is being filmed.
"Pulling focus" refers to ...
will typically log the start and end timecodes of shots, and the data generated will be sent on to the editorial department for use in referencing those shots. This shot-logging
In filmmaking and video production, shot logging is the process by which shoot metadata is captured during a film or video shoot. During the shoot, the camera assistant typically logs the start and end timecodes of shots, and the data generated is ...
process was traditionally done by hand using pen and paper, but is now typically done using shot-logging software running on a laptop computer that is connected to the timecode generator or the camera itself.
The SMPTE family of timecodes are almost universally used in film, video and audio production, and can be encoded in many different formats, including:
*Linear timecode
Linear (or Longitudinal) Timecode (LTC) is an encoding of SMPTE timecode data in an audio signal, as defined in SMPTE 12M specification. The audio signal is commonly recorded on a VTR track or other storage media. The bits are encoded using the ...
(LTC), in a separate audio track
*Vertical interval timecode
Vertical Interval Timecode (VITC, pronounced "vitsee") is a form of SMPTE timecode encoded on one scan line in a video signal. These lines are typically inserted into the vertical blanking interval of the video signal.
With one exception, VITC ...
(VITC), in the vertical blanking interval of a video track
*AES-EBU embedded timecode
AES3 is a standard for the exchange of digital audio signals between professional audio devices. An AES3 signal can carry two channels of pulse-code-modulated digital audio over several transmission media including balanced lines, unbalanced ...
used with digital audio
Digital audio is a representation of sound recorded in, or converted into, digital form. In digital audio, the sound wave of the audio signal is typically encoded as numerical samples in a continuous sequence. For example, in CD audio, samp ...
*Burnt-in timecode
Burnt-in timecode (often abbreviated to BITC by analogy to VITC) is a human-readable on-screen version of the timecode information for a piece of material superimposed on a video image. BITC is sometimes used in conjunction with "real" machine-re ...
, in human-readable form in the video itself
*CTL timecode
Control track longitudinal timecode, or CTL timecode, developed by JVC in the early 1990s, is a unique technique for embedding, or ''striping'', reference SMPTE timecode onto a videotape.
Similar to the way VITC timecode is embedded in the verti ...
(control track)
*MIDI timecode
MIDI time code (MTC) embeds the same timing information as standard SMPTE timecode as a series of small 'quarter-frame' MIDI messages. There is no provision for the user bits in the standard MIDI time code messages, and SysEx messages are used t ...
Keykode, while not a timecode, is used to identify specific film frame
In filmmaking, video production, animation, and related fields, a frame is one of the many '' still images'' which compose the complete '' moving picture''. The term is derived from the historical development of film stock, in which the sequenti ...
s in film post-production
Post-production is part of the process of filmmaking, video production, audio production, and photography. Post-production includes all stages of production occurring after principal photography or recording individual program segments.
Th ...
that uses physical film stock
Film stock is an analog medium that is used for recording motion pictures or animation. It is recorded on by a movie camera, developed,
edited, and projected onto a screen using a movie projector. It is a strip or sheet of transparent ...
. Keykode data is normally used in conjunction with SMPTE timecode.
Rewritable consumer timecode The Rewriteable Consumer Timecode (RCTC, RC Timecode, or RC Time Code) is a nearly frame accurate timecode method developed by Sony for 8mm and Hi8 analog tape formats.
is a proprietary consumer video timecode system that is not frame-accurate, and is therefore not used in professional post-production.
Other formats
Timecodes for purposes other than video and audio production include: *IRIG timecode
Inter-range instrumentation group timecodes, commonly known as IRIG timecode, are standard formats for transferring timing information. Atomic frequency standards and GPS receivers designed for precision timing are often equipped with an IRIG outp ...
is used for military, government and commercial purposes.
* DTS timecode is used to synchronise the optical DTS timecode track from a projector to the CD-based DTS audio tracks.
Timecode generators
Depending on the environment, timecode generators can take various forms.
See also
*Binary-coded decimal
In computing and electronic systems, binary-coded decimal (BCD) is a class of binary encodings of decimal numbers where each digit is represented by a fixed number of bits, usually four or eight. Sometimes, special bit patterns are used ...
* Clock synchronization
Clock synchronization is a topic in computer science and engineering that aims to coordinate otherwise independent clocks. Even when initially set accurately, real clocks will differ after some amount of time due to clock drift, caused by clocks ...
* Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite ...
* Jam sync
* Network time protocol
The Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable- latency data networks. In operation since before 1985, NTP is one of the oldest Internet protocols in ...
* Time code ambiguity
* Time signal
A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.
Church bells or voices announcing hours of prayer gave way to automatically operated chimes on public clocks; however, a ...
* Timecode radio stations
* Timestamp
A timestamp is a sequence of characters or encoded information identifying when a certain event occurred, usually giving date and time of day, sometimes accurate to a small fraction of a second. Timestamps do not have to be based on some absolut ...
, denoting the date/time in data logging
A data logger (also datalogger or data recorder) is an electronic device that records data over time or about location either with a built-in instrument or sensor or via external instruments and sensors. Increasingly, but not entirely, they ar ...
* Trusted timestamping
Trusted timestamping is the process of securely keeping track of the creation and modification time of a document. Security here means that no one—not even the owner of the document—should be able to change it once it has been recorded provide ...
, part of a digital signature
References
* * {{cite book , title=A Technical Introduction to Digital Video , author=Charles Poynton , author-link=Charles Poynton, ISBN=0-471-12253-X , year=1996 , publisher=John Wiley & Sons Encodings * Film and video technology