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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 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, casti ...
, 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 t ...
is used extensively for synchronization, and for logging and identifying material in recorded media. During filmmaking or video production shoot, the camera assistant 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 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 used with digital audio
* Burnt-in timecode, in human-readable form in the video itself
* CTL timecode (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 :en:SysEx#System Exclusive ...
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 sequ ...
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 transparen ...
. Keykode data is normally used in conjunction with SMPTE timecode.
Rewritable consumer timecode 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 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 fo ...
* Clock synchronization
* Global Positioning System
* Jam sync
* Network time protocol
* Time code ambiguity
In telecommunication, time code ambiguity is the shortest interval between successive repetitions of the same time code value.
For example, in a time code in which year-of-century (the '72' in 10/04/72) is the most slowly changing field, the time ...
* 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, ...
* 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 a ...
* 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