gjacktransport 0.6.4-1 (amd64 binary) in ubuntu focal

 G. JACK Transport is a standalone application that provides access
 to the Jack Audio Connection Kit's, JACK transport mechanism via a
 dynamic graphical slider.
 .
 In other words: this software allows one to seek Audio/Video media
 files when they are played along jack transport. Intended for
 audio-engineers or A/V editors that work with Ardour, Ecasound,
 Hydrogen, Xjadeo, etc.
 .
 Additionally it provides G. JACK Clock, a "Big Clock" display for
 jack-transport.