Transport

Control Jack Transport from the patchbay

The Transport bar appears at the bottom of the Patchbay view when Jack is running. It lets you control Jack Transport — the shared timeline that synchronises all Jack-aware applications.

Note

Transport controls are only active when Jack is running. Applications must support Jack Transport to follow play/stop commands.

Patchbay view with the transport bar visible: play/pause/stop buttons, position display (BBT or timecode), BPM field, timebase master indicator.

Transport bar — controls Jack’s shared timeline

Transport controls

Play / Pause / Stop

Button Action
▶ Play Starts Jack Transport playback
⏸ Pause Pauses playback at the current position
⏹ Stop Stops playback and rewinds to position 0

Any Jack-aware application (DAW, looper, etc.) connected to the server will follow these commands in sync.

Seek

Click on the position display and type a value directly, or use the forward and rewind buttons.

Position display modes

Click the position display to cycle through three display modes:

Mode Format Description
BBT 001:01:000 Bars, Beats, Ticks — musical time
HMS 0:00:00.000 Hours, Minutes, Seconds, milliseconds
Frames 000000 fr Raw sample frame count

BBT is the most common mode for music production. HMS is useful for video synchronisation or when working with a fixed timeline. Frames is used for precise sample-accurate work.

Right-click the display to cycle between modes.

Position display modes — BBT, HMS, Frames

BPM

The BPM field displays the current tempo in beats per minute.

  • When JackMate is the timebase master: the BPM field is editable. Click to type a value or scroll to adjust.
  • When another application is the timebase master: the field shows the tempo reported by that application (read-only).

Timebase master

The timebase master is the application responsible for providing BBT position and tempo information to the Jack Transport. Only one application can be timebase master at a time.

JackMate can claim or release the timebase master role:

State Indicator
JackMate is timebase master Master indicator lit (green or amber)
No timebase master | BBT display may be unavailable |

Click the Master button in the transport bar to toggle JackMate’s timebase master status.

Tip

If your DAW (Ardour, Reaper, etc.) manages tempo and time signature, let it be the timebase master. Use JackMate as master only when no DAW provides this role.

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