SMPTE Synchronization Basics
APPENDIX B
OVERVIEW
What is SMPTE? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
What is LTC? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
What is VITC? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Frame rates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
What is drop frame?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
WHAT IS SYNCHRONIZATION?
Synchronization is the occurrence of two or more events at
exactly the same point in time. In regard to SMPTE and
MIDI, it is the process of making MIDI devices, such as a
MIDI sequencer, precisely follow one another as they play
back. For example, when a tape deck plays, the sequencer
plays right along with it. When the tape fast forwards to a
new location and begins to play, the sequencer will jump
ahead to precisely the same location and begin playing,
too. Synchronization allows you to freely move about in a
piece of music without ever losing the "lockup" between
the tape and the sequencer.
Without synchronization, devices with independent time
bases, no matter how precisely they keep time, will
inevitably drift apart from one another over time.
WHAT IS SMPTE?
The word SMPTE is an acronym for the Society of Motion
Picture and Television Engineers. In the mid 1970's, the
society established a timing standard, called SMPTE time
code, that is now an international standard. SMPTE time
code, commonly referred to as just "SMPTE", was
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