jackclock is attaching jack transport as a client, allowing for controlling transport playhead. The freewheel mode allows for "faster than real-time" and can be used for exporting file without the need of waiting. The example provided in help-jackclock records a 100 seconds long sound file as fast as the CPU can. Notice however that sound card IOs are disabled when freewheel mode is enabled.

This has been initially written for pd 0.42 and jack1.