Topics covered in this article:
- Using AVID SYNC HD to generate Longitudinal Time Code (LTC)
- Using the Dolby LTC Generator plug-in
- Using LTC audio files
- Using MIDI Time Code (MTC)
For most use cases, the Dolby Atmos Renderer chases the DAW transport. When the Renderer is running on a dedicated workstation, the synchronization source is LTC. When the Renderer is running on the same workstation as the DAW, the synchronization source is either LTC, MTC, or system synchronization when using the Send/Return plug-ins.
In all cases, the timecode rate of the session as set in the Session Setup window must match the frame rate set in the Renderer Preferences Driver page, or the loaded Master File.
Using Avid SYNC HD to Generate LTC
To use the AVID SYNC HD to generate LTC:
- Enable the SYNC HD in Setup > Peripherals > Synchronization and select LTC in the Transport section.
- Enable the SYNC HD in Setup > Peripherals > Synchronization and select GEN LTC in the Transport window. If GEN LTC is not visible, click the drop-down arrow at the top right of the Transport window and check the box to show the Synchronization view.
Using the Dolby LTC Generator Plug-In
The Dolby LTC Generator plug-in can be used for both the external and internal Renderer use cases. To use the Dolby LTC Generator, insert the plug-in on a mono track and set the output to a dedicated bus. Depending on the configuration, this bus should be mapped to output 128 for use with an external Renderer or 129 for use with an internal Renderer. Note that when using LTC over Audio assigned to 128, Renderer input 128 is not available for Bed or Object audio.
The LTC Generator plug-in requires the timecode rate to be set prior to use and will follow the session transport.
Using LTC Files
It is possible to use LTC as mono .wav files in a session. These can be generated by recording the LTC output of the SYNC HD, and after accurately trimming the file, used on a mono track in the same manner as the LTC Generator plug-in. This is not a preferred approach, as a clip on the timeline may be prone to being slipped or nudged, and overall sync may be impacted by delay compensation settings in the session.
The Renderer can sync to MTC when run internally. To do this, a MIDI device needs to be brought online from the Mac Audio MIDI Setup utility/MIDI Studio window. Click on the IAC Driver and check that the device is online.
In Pro Tools Setup > Peripherals > Synchronization, select the IAC Driver from the MTC Generator Port dropdown menu. In the Edit window, click/enable MTC in the Transport section or GEN MTC in the Transport window. To use MTC, the Renderer must also be set to use MTC as the External Sync Source and the IAC Driver must be selected.
MTC is not recommended for punch-in operations, in order to avoid any audio gaps.