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-readable timecode, but more often used in copies of original material on to a non-broadcast format such as VHS, so that the VHS copies can be traced back to their master tape and the original time codes easily located.
Many professional
VTRs can "burn" (overlay) the tape timecode onto one of their outputs. This output (which usually also displays the setup menu or
on-screen display) is known as the ''super out'' or ''monitor out''. The ''character'' switch or menu item turns this behaviour on or off. The ''character'' function is also used to display the timecode on the preview monitors in
linear editing suites.
Videotapes that are recorded with timecode numbers overlaid on the video are referred to as ''window dubs'', named after the "window" that displays the burnt-in timecode on-screen.
When editing was done using magnetic tapes that were subject to damage from excessive wear, it was common to use a window dub as a working copy for the majority of the editing process. Editing decisions would be made using a window dub, and no specialized equipment was needed to write down an
edit decision list which would then be replicated from the high-quality masters.
Timecode can also be superimposed on video using a dedicated overlay device, often called a "window dub inserter". This inputs a video signal and its separate timecode audio signal, reads the timecode, superimposes the timecode display over the video, and outputs the combined display (usually via composite), all in real time. Stand-alone timecode generator / readers often have the window dub function built-in.
Some consumer cameras, in particular DV cameras, can "burn" (overlay) the tape timecode onto the composite output. This output typically is semi-transparent and may include other tape information. It is usually activated by turning on the 'display' info in one of the camera's sub-menus. While not as 'professional' as an overlay as created by a professional
VCRs, it is a cheap alternative that is just as accurate.
Timecode is stored in the metadata areas of captured DV AVI files, and some software is able to "burn" (overlay) this into the video frames. For example, DVMP Pro
DVMP Pro
- Software for burning in timecode and other items of metadata for DV AVI files. is able to "burn" timecode or other items of DV metadata (such as date and time, iris, shutter speed, gain, white balance mode, etc.) into DV AVI files.
OCR techniques can be used to read BITC in situations where other forms of timecode are not available.
See also
*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 ...
*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 ...
*SMPTE time code
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 ...
*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 ...
* CTL timecode
* AES-EBU embedded timecode
* Rewritable consumer timecode
References
{{DEFAULTSORT:Burnt-In Timecode
Timecodes
Film and video technology