Playback Progress Line

This is an idea a had a while ago for a way to visualise the repeat structure of a score, and to enable playback "from the 3rd repeat", etc.

Straight score

The basic idea is to have a virtual (non-printing) line run from left-to-right below each system in the score. This line represents the passage of time in the score. A circular marker indicates the current playback position.

The playback line is like the progress bar under a YouTube video: it indicates playback position, and clicking on it causes playback to skip to a new position.

Repeats

The real strength of the playback line is for repeated sections, where the line doubles back to indicate that the relevant measures are to be played multiple times.

Clicking on lower part of the line enables you to commence playback from second time through the repeated section: an ability that is new to MuseScore (and possibly all notation software‽).

Jumps

The playback line can also be used to skip to anywhere within a "D.S. al Coda" sequence.

Sections of the playback line could display marker labels like "coda" or "to segno" to aid understanding.

Visualising complex score structure

The playback line is not only useful in playback mode. It is also useful in normal editing mode as a way of verifying that playback will be correct without having to listen to the score.

Back-to-back repeats

The shape of the playback line tells us that measures will play in the expected order without us having to go into playback mode and listen to the score from beginning to end.

Invisible settings

The playback line also shows whether various right-click options and Inspector settings have been set correctly:

1. Measure play count

2. Volta repeat list

3. Jump play repeats

Making room

Many scores have tightly packed systems with little room to put a playback line between them. This problem is made worse when there are lots of repeats and jumps.

A possible solution would be to make the playback line very compact (maybe even single line thickness) and only expand it to show repeats and jumps when the user hovers the cursor over it. Alternatively, the playback line could be hidden entirely until a toolbar button or shortcut key is pressed.