SMPTE/MIDI time code synchronization

SMPTE/MIDI Time Code Sync (SMPTE/MTC) is another method of synchronization that lets SONAR act as a master or slave to external devices. SONAR can send or receive SMPTE/MTC messages to or from external devices that can generate or receive MTC. SONAR can send MTC on multiple output ports simultaneously.

SMPTE/MTC is a position and timing reference that indicates the current location in the project and how quickly the project should be playing. Time code labels the position in a project in hours, minutes, seconds, and frames. The speed of playback is indicated by a frame rate.

Time code is recorded onto tape using a device called a time code generator. The process of recording a time code signal onto a track is called striping. Normally, the start of a tape stripe has a particular time, expressed in hours, minutes, seconds, and frames. For example, the tape stripe might start at 00:00:00:00, 01:00:00:00, or any other time. The material recorded on the tape usually starts anywhere from 10 seconds to several minutes after the start of the time code. Sometimes, the tape stripe starts at a time like 00:59:50:00, and the material starts 10 seconds later, at 01:00:00:00.

When you create a new SONAR project, by default the project is configured so that the beginning of bar 1 is synchronized with a time code of 00:00:00:00. If the starting point of the material on your tape or external project is not 0, you need to enter an offset to tell SONAR the time code that corresponds to the start of the project.

To enter an offset

1.	Go to Edit > Preferences > Project - Clock.

2.	Specify the desired offset in the SMPTE/MTC Offset field. To enter an offset of 15 seconds, type 0,0,15 and hit ENTER. The SMPTE/MTC Offset value should now be 00:00:15:00 or 15 seconds.

Frame rates

Seven time code frame rates are supported in SONAR, which are normally used for the following types of applications:

Table 220.  

External Timecodes	Cakewalk Setting	Description
23.976 frames per second	23.976 FPS	Typically used with H.264/MPEG-4 AVC video.
24 frames per second	24 FPS	Used for theatrical film worldwide. Any film in North America or Japan uses this setting.
25 frames per second (EBU timecode)	25 FPS	Used for PAL/SECAM video, video and some film in countries that use 50 Hz wall electricity. This is the setting to use when synchronizing to any European video format.
29.97 frames per second non drop-frame	29.97 FPS NDF	NTSC non-broadcast and short length video in North America and Japan. Some music projects. This setting synchronizes the video perfectly with SONAR, but the sequencer position displayed in the Now Time and Big Time displays will gradually drift and become incorrect over long periods of time. The audio and MIDI synchronization to the external device will not be affected by this discrepancy.
29.97 frames per second drop-frame	29.97 FPS DF	NTSC broadcast and long format video in North America and Japan. This setting synchronizes the video perfectly with SONAR, but the sequencer position displayed in the Now Time and Big Time displays will gradually drift and become incorrect over long periods of time. The audio and MIDI synchronization to the external device will not be affected by this discrepancy.
30 frames per second non drop-frame	30 FPS NDF	Most music projects and some film in North America. This is the best choice for any music project and should be used unless the situation dictates otherwise.
30 frames per second drop-frame	30 FPS DF	Not a standard type of timecode, used rarely for speed correction and transfer problems in tape based systems.

For more information about frame rate time formats, see the documentation for your time code hardware.

Refer to the documentation for your MIDI interface or external MIDI device for additional information about SMPTE/MTC.

To use SONAR as the master MTC generator

1.	Configure the clocks on each external device that you want to synchronize to receive SMPTE/MTC. Make sure they’re connected to MIDI outputs from your computer or MIDI interface.

2.	In the Control Bar’s Sync module, click the Sync Type button and choose Internal Sync or Audio Sync on the pop-up menu.

3.	Go to Edit > Preferences > Project - MIDI.

4.	Select the Transmit MTC check box (you can also click the Transmit MTC Sync button in the Sync module).

5.	In the Frame Rate field (it’s just below the Transmit MTC check box), choose the frame rate that your project uses (see Frame rates, if necessary).

6.	In the MTC Output Ports field, check off the outputs that you want to send MTC on (the outputs your external devices are connected to).

7.

Click OK.

SONAR saves your sync and MTC output port settings with your project. However, output ports are saved by their number only, not their name. Their number is determined by the order in which they appear in Edit > Preferences > MIDI - Devices. If you change the order of devices in this dialog box, the MTC output ports in your project will retain the same numbers, but those numbers will now refer to different outputs. Also, if you reduce the number of highlighted outputs in Edit > Preferences > MIDI - Devices, and the MTC ports you chose have higher numbers than what are currently highlighted in Edit > Preferences > MIDI - Devices, SONAR does not substitute new port numbers.

To configure SONAR to sync to SMPTE/MTC

1.	In the Control Bar’s Sync module, click the Sync Type button and choose SMPTE Sync on the pop-up menu.

2.	Go to Edit > Preferences > Audio - Sync and Caching.

3.	Select one of the following options:

Ask first, then switch to clock source and start. This option prompts SONAR to alert you when it detects a SMPTE/MTC signal, asks if you want to sync to the incoming signal, and if you respond that you do, switches the clock source and starts to receive the signal.

Always switch the clock source and start. SONAR automatically switches to the clock source of the incoming signal and begins to receive the signal.

Do not switch clock source, but start if in SMPTE/MTC mode. This option automatically syncs to the incoming signal if SONAR is in SMPTE/MTC mode.

Note: The final option, Never switch clock source, never start, should never be used if you are attempting to sync to an external clock source.

4.	Click the Project - Clock page (Edit > Preferences > Project - Clock).

5.	Choose the frame rate and time offset that are appropriate for your source material.

6.	Click the MIDI - Devices page (Edit > Preferences > MIDI - Devices).

7.	Make sure that your MIDI interface is highlighted in the Inputs list. If your interface also has a Sync driver, highlight that as well, then click OK.

When SONAR is the slave, here’s how things work:

SONAR monitors for a SMPTE/MTC signal. You are able to perform other action in SONAR while waiting for the signal.

Start playback on the external device. It takes about two seconds for SONAR to lock from the time it receives time code input.

If the time code is earlier than the start of the project (based on the time code offset), another message (Chasing…) is displayed in the status bar. When the time code reaches the start of the project, SONAR starts to play in sync.

If the time code is at or after the start of the project, SONAR starts playback as soon as it locks to the time code.

When the external device stops (or when the time code ends), SONAR will stop.

Note: If you want SONAR to switch its clock source to SMPTE/MTC automatically when SONAR receives a SMPTE/MTC signal, go to Edit > Preferences > Audio - Sync and Caching and select the Always switch clock source to start option.

 

See:

Playing digital audio under SMPTE/MTC sync

SMPTE/MTC sync and full chase lock

Troubleshooting SMPTE/MTC sync