Waiting Jack realtime synchro one day maybe …
Some others software are cools … cause they also use xml storage format (and did things synfig didn’t)
In our case, i’m thinking about Audacity for example. It work with xml, it used timestamp … can be synchronized !
Kdenlive have recently done something about (Improved clip markers in 0.9.4 / feature report plus code infos)
So why not also kdenlive Markers also … so why not .str … so why not … your idea.
Those plugins could produce some sort of named keyframe lighting a dot (circle layer) … and even with math / spline capacities , produce a moving dot to generate Karaoke style on your clip …