Sync and Cue Editing

Cut at the end of a phrase, never on an accent or inside a reverb tail

Related

TempoCue

The problem

The commonest mistake when fitting generated music to picture is cutting to the exact length of the shot, which puts the cut inside a phrase, on an accent, or in a reverb tail. Viewers cannot name the problem, they just find it cheap. Re-cut a new version and the fault moves somewhere else, because the material never left room for a cut.

How it works

Music has syntax, in units of four or eight bars, with accents on strong beats and endings on cadences. A cut placed after the last beat of a phrase feels finished; a cut inside the phrase feels interrupted. Material at a steady tempo can be cut against the grid, while a performance with rubato needs a tempo map first, or the drift grows with every bar. Generated cues often lack a clear cadence and change gradually between sections, which is exactly why they are hard to cut.

Practice

Count the phrases and mark every possible landing before changing picture or music. Stretch the music first and trim the picture second. To shorten, remove a whole phrase rather than chop two seconds. To lengthen, repeat a section with a change of orchestration instead of stretching the last note. Keep cuts away from cymbals, timpani and long reverb, and prefer ending half a beat early on dry sound. Map the tempo of every cue, land the accents on picture, then check the whole sequence for drift. Cuts only matter where the music is exposed; under dialogue they can be rough.

What to listen for

In the Chopin nocturne, how rubato defeats a metronome grid; in the Bach minuet, how four-bar phrases close regularly; in 7thRegimentReel, how a tune with no intro starts on the first beat. The first two show where cuts belong, the third shows that material without an intro leaves the editor more freedom, not less.

Sources

• 音画同步的切点与速度映射做法，依剪辑与配乐通识核对，未抄原文
• Cutting and tempo mapping practice for picture, checked against general editing knowledge, not copied

Used for fact-checking only; all prose is original.