29.97

NTSC standard, the TV broadcast video framerate, originating from early colour TV transmission problems between chrominance and audio carrier signal phasing at 30 fps. Resolved through use of drop frame timecoding.

Adrielec

A SMPTE device enabling linear timecode (LTC) chasing. A product of Adrienne Electronics Corporation (AEC). Benefits from balanced input allowing longer cable runs.

ASIO / ASIO4ALL

Audio Stream Input/Output: a sound card driver protocol allowing software direct access to sound cards to reduce latency. ASIO4ALL is a generic driver for Windows Driver Model (WDM) devices.

drop frame (DF)

In order to match video at 29.97 fps with real time clocks at 30 fps, this time code drops two frames every minute, on the minute, except every tenth minute.

genlock

Generator locking: the means by which multiple devices are linked to a single synchronising clock signal.

House Sync

Method by which an signal generator produces the time reference (clock signal) for all genlocked servers in group, together with their channel outputs and devices. The signal may be a square-wave pulse or word clock for audio synchronisation.

LTC

Linear (or Longitudinal) Time Code: a form of SMPTE timecode encoded into an audio signal along its duration.

LTC chasing

Synchronising playback to a reference LTC audio signal.

LTCReader

A Delta utility app that translates the analogue LTC audio stream into digital SMPTE code. Receives LTC timecode though a standard audio input on a PC to enable LTC chasing.

non-drop frame (NDF)

30 fps timecode video source played back at 29.97 fps. Note that being played more slowly this drifts from real time.

NTSC

National Television System Committee; defined pre-digital standards.

real time

Real time clocks (RTC) ‘tell the time’ rather than relative time displacement.

SMPTE

Society of Motion Picture and Television Engineers; defines timecode reference standards for positional identification and additional timecode metadata.

SoundMan

SoundMan Server Virtual Sound System (Richmond Sound Design Ltd), receives LTC timecode though a standard audio input on a PC to enable LTC chasing.

tearing

Display image discontinuity caused by display synchronisation problems.

timecode

Relative position in a movie, expressed as hh:mm:ss:ff (hours, minutes, seconds, frames)

timing mode

In Delta: display a Delta timeline in SMPTE, frames or seconds.

word clock

A digital audio signal designed for keeping digital audio devices in sync with a constant, precisely-timed bit-rate of 44.1 or 48 kHz.