Source-Connect 4's Remote Transport Sync (RTS) feature can send and receive synchronization in different ways:

• MTC (MIDI Time Code) - digital timecode sent via MIDI protocol.
• LTC (Linear Time Code) - audio-based timecode signal.

This article specifically covers MTC workflows where:

1. Source-Connect 4 receives RTS from a remote source via MTC.
2. Source-Connect 4 correctly sends this MTC to Pro Tools.
3. Pro Tools receives the MTC correctly (transport moves).

MTC Video Playback Bug

There is a confirmed bug in Pro Tools 2025.10 and later versions that affects video playback during MTC synchronization workflows with Source-Connect 4.

When syncing to incoming MTC, Pro Tools exhibits the following behavior:

• The Pro Tools transport moves correctly every time.
• Video playback only starts every second time the remote MTC source starts playback.
• This creates an inconsistent workflow where video and transport behavior are not synchronized.

Affected Versions

Pro Tools 2025.10 and all later versions.

Workarounds

There are two effective workarounds for this issue:

Option 1: Use Pro Tools 2025.6

Downgrade to Pro Tools 2025.6, which does not exhibit this bug and maintains full compatibility with Source-Connect 4's MTC workflow.

Option 2: Toggle Transport Online

When using Pro Tools 2025.10 or later:

1. Start playback from the remote MTC source.
2. If video playback doesn't start (but the transport moves), quickly press Cmd + J (macOS) or Ctrl + J (Windows) to turn off Transport Online.
3. Immediately press Cmd + J (macOS) or Ctrl + J (Windows) again to turn Transport Online back on.
4. Video playback should now start properly.