Sheet Music

A score that turns in time with the performance.

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How the job breaks down

A score video shows part of the page at a time — often a single staff system, though two or three short ones can sit together comfortably — with each view appearing as the performance reaches it. Two quite different tasks sit behind that.

Cutting the pages up can be automatic. ClapperBoard can find the staff systems on each page and crop them out — one per view, or several together where they fit — which is the tedious part, and the part you would rather not do by hand. You can also crop the pages yourself if you want a different arrangement.

The timing is yours to play in. ClapperBoard cannot work out when each system arrives: it has no way to follow a performance. What it gives you instead is a way to mark the boundaries while the recording plays, one keystroke per view.

Both steps assume the score and the recording are already in the project — see Adding images and audio if they are not.

If you have read about ClapperBoard timing pages automatically, that is a different job — it matches a spoken narration against the words printed on the page. A performance has no words to transcribe, and notation is not text, so none of it applies to a score.

Splitting pages into systems

Choose Tools › Split into Staff Systems. ClapperBoard examines every uncropped page in the project, finds the staff systems on each, and stages a crop for each one — staged, not applied, so you get to look before anything changes.

Three settings control how the page is cut up. The defaults suit a full score. Your choices are remembered with the project.

Systems per crop

How many staff systems share a crop — the setting to reach for when one system alone leaves the frame mostly empty.

SettingWhat it does
SystemsEvery system gets its own crop. Right for a full score, where one system fills the frame. The default.
Fit to framePacks as many consecutive systems into each crop as the project's export shape allows, spreading them evenly so no page ends with a stub crop. Adapts to the material: a single-staff part groups several systems, a full score still gets one apiece.
Groups of NA fixed number of systems per crop, however tall they are. Choose the number, from one to eight.

Fit to frame is usually the one you want for anything sparser than a full score, because it works the answer out from your export size rather than asking you to guess it — the sheet names the frame it is currently fitting.

With Groups of N, a page whose system count is not a multiple of N has to put the remainder somewhere. When systems run out decides: Strict keeps every crop at exactly N and lets the last one on the page be shorter, while Loose shares the leftovers out so all the crops on a page stay about the same size.

Adjacent systems

How two neighbouring systems share the gap between them.

SettingWhat it does
Exact touchThe crops meet at the midpoint of the gap. Nothing is duplicated, but anything sitting on that midline — a dynamic, an articulation — gets split between the two.
Slight overlapEach system claims 55% of the gap, so neighbours overlap by about a tenth of it. Midline markings survive in both crops. This is the default, and usually right.
Generous overlapEach claims 65%, overlapping by about a third of the gap. Safest against clipping, at the cost of visibly repeating content between one system and the next.

If expressive text or dynamics between staves are coming out clipped, move up a step. If neighbouring systems look repetitive on screen, move down.

When several systems share a crop, this setting applies only where one crop meets the next — systems inside a crop have no boundary between them to share.

Page edges

How far the first and last system on a page reach towards the top and bottom.

SettingWhat it does
Virtual neighbourThe outermost systems extend by one average inter-system gap, as though a neighbour sat just off the page. Keeps titles, page numbers and running heads out of the crop. The default.
Extend to page edgeThe first system reaches the top of the page and the last reaches the bottom. Catches everything, including the header and footer.

Choose Extend to page edge when something above the top staff is being cut off — a tempo marking, a rehearsal letter, or a movement title you want on screen with the opening system.

Reviewing before you commit

When detection finishes, ClapperBoard reports how many systems it staged across how many pages, and offers two ways on:

Nothing here is binding. If a crop comes out wrong you can adjust it in Inspect & Edit, and you can always leave the automatic split aside and draw the crops you want by hand.

Detection needs at least two systems on a page to work out the spacing, so a page holding a single system is left alone. Pages you have already cropped are skipped too — it only touches uncropped items.

Once the crops are applied, each one is a separate item on the timeline, in playing order, and you are ready to time them.

Timing the views

This is the part you play in by hand. The whole gesture is: start the recording, listen, and press one key each time the music reaches the next view.

  1. Put the playhead at the beginning.
  2. Press Space to start playing.
  3. Each time the performance moves on to the next view, press .
  4. Press Space again when you reach the end.

Each means the view on screen ends here. The one after it starts at that same moment, and everything still untimed shifts along to make room, keeping its own length. So you can play the whole movement through in one pass, tapping as you go, and end up with every boundary roughly in place.

Two keys, one boundary

and both set a boundary at the playhead. The difference is which view they move.

KeyMeaningMoves
End the current view hereThe end of the view you are on
Start the current view hereThe end of the view before the one you are on

Tapping along live, is the natural one — you are always ending the view you have been watching. is for going back afterwards: park the playhead where a view should have begun, press , and its start moves there without your having to find the previous one first.

Why the rest of the score moves along

When you set a boundary, the views after it slide to accommodate it and keep their own durations. That is cascading resize, and it is what makes a single pass work: everything you have not timed yet stays intact and simply waits its turn.

The other behaviour, absorbing, holds the total length fixed and lets the very next view swallow the change instead. That is the one you want once the score is roughly timed and you are correcting a single boundary without disturbing everything downstream.

The toolbar button shows which mode is active and switches between them; it is also under View › Timeline Resize Mode. To flip the behaviour for one keystroke only, hold : does the opposite of whatever the project is set to, without changing the setting.

Refining what you played in

A live pass gets you close. Tapping along to playback can be imprecise, though, and some boundaries may want moving by a fraction of a second.

Move the playhead to the boundary you want to fix, then nudge it into place and press the key again. The playhead moves by 0.1 s with and , and by 0.01 s with held. and jump between views, which is quicker than scrubbing.

Two things make this easier. The magnified timeline mode, in the control bar, spreads the timeline out far enough to see small differences. And T cycles how much the playhead tells you — at its fullest it shows which view you are on, how far into it you are, and how long it lasts.

Switch to absorbing resize before this stage. Otherwise every correction shifts the whole rest of the score, and boundaries you had already placed will need placing again.

Last updated August 13, 2026