showstack / protocols / mtc
MIDI Timecode
Also called MTC, MIDI Time Code.
Carries SMPTE-style hours, minutes, seconds and frames over a MIDI connection, as quarter-frame messages while running and a full-frame sysex when locating. It is how a DAW, playback machine or console chases a master clock without giving up an audio channel.
Stewarded by The MIDI Association (MIDI Manufacturers Association).
Clock and sync
Tiny, ruthlessly regular
Almost no bandwidth. Carries no content at all, only agreement about when. Its value is entirely in its regularity.
What kills it. Jitter, an unaware switch delaying the timestamps it was meant to correct, and two devices both convinced they are the master.
What goes wrong
Quarter-frame messages carry one nibble at a time, four per frame, so a complete timecode value takes two frames to arrive. Every MTC reader is inherently one to two frames behind. Compensate in the receiver, do not nudge the master.
The frame rate lives in bits 5-6 of the hours byte and encodes only 24, 25, 30 drop-frame and 30. There is no 23.976, 48, 50 or 60 value, so a 23.98 project has to travel as 24 and be reconciled at the far end.
The full-frame sysex F0 7F cc 01 01 hr mn sc fr F7 only locates the receiver. Nothing actually runs until quarter-frames start arriving, which is why a device can display the correct time and still not be chasing.
A receiver that ignores the frame-rate bits will run 25 fps code as 30 and drift by a fifth. The numbers look sane the whole time, which is what makes it expensive to spot.
Quarter-frames are continuous traffic on a 31.25 kbit/s DIN line. Share that cable with MSC and your cue messages queue behind the clock.
Only the low nibble of each user-bit data byte is used in the user-bits sysex. Converters that repack user bits between LTC and MTC routinely lose or reorder them.
What speaks MIDI Timecode (28)
28 products — 10 hardware, 18 softwareshow all
| Product | Direction | Notes |
|---|---|---|
| Ableton Live Ableton AG |
in | Live slaves to MTC and reads it as an Arrangement position, with MIDI Timecode Frame Rate and Offset settings. Ableton state Live can only act as a MIDI sync device, not a host; MTC carries no tempo and tempo changes cannot be tracked. |
| Ardour Ardour Community |
bidirectional | MIDI timecode in and out. |
| Avolites Titan Avolites |
in | A cue list can read timecode from the system clock, an internal timecode source, MIDI, SMPTE or the Winamp player. Up to 4 separate timecode sources per console. |
| ChamSys MagicQ ChamSys |
in needs licence |
MIDI timecode receive is part of the same Unlocked-mode timecode feature set. |
| disguise Designer disguise |
in | |
| dot2 onPC MA Lighting |
in | MIDI timecode can run cues automatically. Receiving timecode does not require a network session. |
| Eos Electronic Theatre Controls (ETC) |
in | MIDI timecode is receive only, locally or via a Show Control Gateway. |
| Hippotizer Green Hippo (an ACT Entertainment brand) |
in | Sync Manager receives MTC via the Rosendahl Mif4 or CB Electronics TC-5 USB interfaces. |
| Isadora TroikaTronix (Mark Coniglio) |
in | Specifications page states MIDI Timecode support and the show-control page lists MTC for synchronisation; the docs do not state that Isadora also generates MTC. |
| MIDI Monitor Snoize |
in | Generic real-time MIDI monitor; captures MIDI Time Code quarter-frame/real-time messages along with all other MIDI data, but has no dedicated MTC decoder view. |
| MIDI-OX | in | Recommended on ControlBooth (theatre-tech forum) by author John Huntington for displaying MIDI Time Code readouts. |
| Millumin Anomes (Philippe Chaurand) |
in | MTC over MIDI, same framerate list as LTC. |
| Mitti Imimot |
in | MIDI timecode chase. |
| ONYX Obsidian Control Systems |
in needs licence |
MIDI timecode via MIDI ports or the SMPTE IN connector. Only fully enabled from the NOVA+ tier. |
| Pro Tools Avid |
bidirectional | MIDI timecode in and out. |
| QLab Figure 53 |
bidirectional | Can both generate and chase MIDI timecode. |
| REAPER Cockos Incorporated |
bidirectional | Chases MTC via the external timecode synchronization settings against an enabled MIDI input; generates MTC from the stock SMPTE LTC/MTC Timecode Generator. |
| TimecodeDisplay Figure53 |
in | Listens to and displays incoming MIDI Time Code. |
| Brainstorm DXD-8 Distripalyzer Brainstorm Electronics |
out | MIDI timecode output. |
| ChamSys MagicQ MQ80 ChamSys |
in | MIDI timecode. |
| DiGiCo Quantum 338 DiGiCo |
in | MIDI timecode in. |
| disguise gx 3 disguise |
in | |
| Eos Apex 5 ETC |
in | Receive only, from local MIDI or a Gateway. |
| ETC Ion Xe 20 ETC |
in | MIDI timecode in. |
| MA Lighting grandMA3 light MA Lighting |
in | MIDI timecode. |
| Hippotizer Boreal+ MK2 Green Hippo |
in | Timecode-driven playback. |
| Hog 4 High End Systems |
in | |
| Rosendahl nanosyncs HD Rosendahl Studiotechnik |
out | MIDI timecode output. |
Typical use
- Locking a DAW or playback rig to a lighting or video master clock
- Chasing QLab and a lighting console to one timeline
- Distributing position to devices that have MIDI but no audio input
- Driving a timecode-triggered cue stack from a backing track machine
The words for it
Glossary entries that name MIDI Timecode, with the false friends that catch people out.
Drop frame丟幀時碼A timecode counting scheme that skips frame numbers 00 and 01 at the start of every minute except every tenth…Jam sync同步鎖定Matching a timecode generator to incoming code and then continuing to generate in step. Continuous jam keeps …Quarter frame message四分之一幀訊息The MIDI Timecode message that carries four bits of a timecode value. Eight of them make one complete value, …
Sources
- MIDI Time Code — RP-004-008 v4.2.1 specification — The MIDI Association primary
- MIDI Time Code (quarter-frame nibble order, full message, frame-rate bits, user bits) — Koninklijk Conservatorium Den Haag (course copy)
Understand the mechanism
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