24.9 Enhancing MIDI output (LilyPond Notation Reference)

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24.9 Enhancing MIDI output

The default MIDI output is basic but can be improved by setting MIDI instruments and various \midi block properties.

Additional scripts allow to fine-tune the way dynamics, articulations and rhythm are rendered in MIDI: the articulate script and the swing script.

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24.9.1 The `articulate` script

To use the articulate script add the appropriate \include command at the top of the input file;

\include "articulate.ly"

The script creates MIDI output into appropriately ‘time-scaled’ notes to match many articulation and tempo indications. Engraved output however, will also be altered to literally match the MIDI output.

\score {
  \articulate <<
    … music …
  >>
  \midi { }
}

The \articulate command enables abbreviatures (such as trills and turns) to be processed. A full list of supported items can be found in the script itself. See ly/articulate.ly.

24.9.2 The `swing` script

The swing script provides additional functions allowing for regular durations to be played with an unequal rhythm. The most obvious example is ‘swing’ interpretation commonly found in jazz music where binary eighth notes should be played in a ternary fashion; however additional interpretations are also supported.

This script has to be \include-d at the beginning of the input file:

\include "swing.ly"

Three commands are provided:

\tripletFeel creates a triplet-feel swing. It takes two arguments: the durations that should be affected by it (typically 8 for eighth notes), and then the music expression to which it should be applied.
\applySwing takes an additional argument prior to the music expression: a ‘weight list’ of n number ratios expressing the way regular notes should be played: for example, #'(2 1) indicates that every other note should be played twice as long as the following note (in fact, \tripletFeel duration {music} is actually a shortcut for \applySwing duration #'(2 1) {music}). Smoother swung eighths may be obtained with a weight list of #'(3 2), or other values depending on taste.
That list may include more than two values, which allows for longer and more sophisticated groove patterns; for example, a samba feel for sixteenth notes may be obtained as follows:
```
\score {
  \applySwing 16 #'(3 2 2 3) {
    … music …
  }
  \midi { }
}
```
\applySwingWithOffset adds yet another argument between the ‘weight list’ and the music expression: an offset length. This command should be used when the music expression has to start off-beat, with a partial swing cycle.

Note: As with the articulate script, all swing commands are also rendered in the engraved output, which results in irregular note spacing. This can be avoided by using them only in a \score block dedicated to MIDI output, rather than to printed music.

Additional help and information is included in the script file: see ly/swing.ly.

Known issues and warnings

\repeat constructs in music (even \repeat unfold) are not taken into consideration when determining note timing. This will lead to problems unless the durations of all repeated parts are integer multiples of the swing cycle duration.
These functions are oblivious to time signatures and measures. That is why offsets need to be supplied by using \applySwingWithOffset if music starts off-beat.
Grace notes are ignored and simply left unaffected; so are tuplets.

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