MIDI time code (MTC) embeds the same timing information as standard SMPTE time code as a series of small 'quarter-frame' MIDI messages. SMPTE timecode is a set of cooperating standards to label individual frames of video or film with a Timecode defined by the Society of Motion Picture and Television Engineers MIDI ( Musical Instrument Digital Interface, ˈmɪdi is an industry-standard protocol that enables Electronic musical instruments Computers There is no provision for the user bits in the standard MIDI time code messages, and SysEx messages are used to carry this information instead. The quarter-frame messages are transmitted in a sequence of eight messages, thus a complete timecode value is specified every two frames. If the MIDI data stream is running close to capacity, the MTC data may arrive a little behind schedule which has the effect of introducing a small amount of jitter. In order to avoid this it is ideal to use a completely separate MIDI port for MTC data.
Unlike standard SMPTE timecode, the eight-message MIDI timecode sequence carries a two-bit flag value that identifies the rate of the timecode, specifying it as either:
- 24 frame/s (standard rate for film work)
- 25 frame/s (standard rate for PAL video)
- 30/1. Frame rate, or frame frequency, is the measurement of the Frequency (rate at which an imaging device produces unique consecutive images called frames The PAL, short for Phase Alternating Line, is a colour -encoding system used in Broadcast television systems in large parts of the world 001 frame/s (Drop-Frame timecode for color NTSC video)
- 30 frame/s (monochrome NTSC video)
MTC allows the synchronisation of a sequencer or DAW with other devices that can synchronise to MTC or for these devices to 'slave' to a tape machine that is striped with SMPTE. NTSC ( National Television System Committee) is the Analog television system used in the United States, Canada, Japan, Mexico For this to happen an SMPTE to MTC converter needs to be employed. Please note that it is possible for a tape machine to synchronise to an MTC signal (if converted to SMPTE), if the tape machine is able to 'slave' to incoming timecode via motor control, which is a rare feature.
See also
- AES-EBU embedded timecode
- Burnt-in timecode
- CTL timecode
- Linear timecode
- Rewritable consumer timecode
- Vertical interval timecode
- MIDI beat clock
- Digital Audio Workstation "DAW"
External links
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 CTL ( Control track longitudinal timecode, developed by JVC in the early 1990s is a unique technique for embedding or striping, reference Linear (or Longitudinal Timecode ( LTC) encodes SMPTE timecode data as a Manchester-Biphase encoded audio signal The Rewriteable Consumer Timecode ( RCTC, RC Timecode, or RC Time Code) is a nearly frame accurate Timecode method developed by Sony Vertical Interval TimeCode ( VITC, pronounced "vitsee" is a form of SMPTE timecode embedded as a pair of black-and-white bars in a video signal MIDI beat clock is a clock signal that is broadcast via MIDI to ensure that several Synthesizers stay in synchronization A digital audio workstation (DAW is an electronic system designed to record, edit and play back digital audioDapyx Software network: MP3 Explorer | Ebook Manager | Zenithic