MIDI Post-Editing

Correct pitches are only the start; velocity, microtiming and note length make it sound played.

Related

VelocityRubatoLegato

The problem

The generated MIDI has the right pitches and still sounds like notation software playing back. The fault usually lies outside the notes. Every note has the same velocity, every onset sits on the grid, phrases have no breath, and dense passages fill every note to full length. A better sample library improves the tone and none of this. Another case is register, where the melody sits inside the accompaniment and no velocity change rescues it.

How it works

Performance information splits into three layers: velocity, timing and connection. They interact, but the order of work matters. Fix lengths and articulation first, then velocity, then microtiming; do it backwards and each earlier adjustment is undone by the next. Libraries map velocity to loudness and brightness differently, so the same numbers change with the instrument, and the values must be set on the final sound source.

Practice

Work part by part rather than painting one curve across the whole track. For the melody, draw a velocity line related to pitch contour, a little stronger at the top, with swells on long notes. Bring the accompaniment down and lift the top note of each chord so the harmony has an outline. In dense writing, thin by removing inner voices every other note while keeping outer voices and roots, then check the harmony still stands. Finally offset melody notes by five to fifteen milliseconds at random, and leave the drums alone. Solo each part after editing it, to confirm it still makes sense on its own.

What to listen for

In Chopin's nocturne, whether rubato is written into note lengths rather than left to the sampler. In the Atholl Highlanders jig, whether ornaments and detached notes are distinct, since a slurred reading loses the dance character. In Liszt's Rossini transcriptions, whether the harmony survives after inner voices are thinned. In Beethoven's String Quartet No. 12, whether the four parts keep their dynamic layers.

Sources

• MIDI 演奏信息的处理方法，依音序器公开文档核对，未抄原文
• 力度曲线与微时序的经验规则，依制作通识核对，未抄文本

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