The span is cut into equal units of unitBars bars, each unit is compared
with every unit before it, and a unit alike enough to an earlier one takes
that unit's label. Neighbouring units carrying the same label are then merged,
so an eight-bar section built of two like four-bar units is reported as one
section rather than two.
Likeness is measured on the melodic line and on the harmonic content
together — the same tune under different harmony is a variation, not a
restatement — and the labels are letters in order of first appearance.
Nothing beyond "this is a restatement of that" is asserted: see
FormSection.label.
A pickup belongs to the section it leads into, so material before the first
bar is folded into the opening unit rather than made a section of its own.
Recover a piece's sections from what it repeats.
The span is cut into equal units of
unitBarsbars, each unit is compared with every unit before it, and a unit alike enough to an earlier one takes that unit's label. Neighbouring units carrying the same label are then merged, so an eight-bar section built of two like four-bar units is reported as one section rather than two.Likeness is measured on the melodic line and on the harmonic content together — the same tune under different harmony is a variation, not a restatement — and the labels are letters in order of first appearance. Nothing beyond "this is a restatement of that" is asserted: see FormSection.label.
A pickup belongs to the section it leads into, so material before the first bar is folded into the opening unit rather than made a section of its own.