Humdrum Toolkit Command Reference -- kern

COMMAND

kern — translate selected Humdrum pitch-related representations to kern

SYNOPSIS

` kern [-x] [inputfile …] [> outputfile.krn]`

DESCRIPTION

The kern command transforms various pitch-related inputs to corresponding kern representations. For example, the pitch token `Ab2' will be output as the kern token `AA-'. Continuous pitch-related representations, such as frequency (freq) and cents (cents) are rounded-off to the nearest equally-tempered pitch. Hence, freq values between 254.178 and 269.291 will be output as the kern token for middle C — `c'.

Pitches in kern are encoded as equally-tempered values at concert pitch. Kern is not able to represent pitch deviations from equal temperament. Diatonic pitch names are encoded using the letters A to G. Octaves are indicated by a system of upper- and lower-case letters, and by letter repetition. Middle C is represented by the single lower-case letter `c'. The C an octave above is represented by two lower-case letters: `cc' — with each successive octave adding another letter. The C an octave below middle C is represented by a single upper-case `C'. The C an octave lower yet is represented by two upper-case letters: `CC' — and so forth. Changes of octave are deemed to occur between the pitches B and C. Thus the B below middle `c' is rendered as a single upper-case `B'; the B below `cc' is `b' and so forth. Sharps are indicated by the octothorpe sign (#) whereas flats are indicated by the minus sign (-).

The kern command is able to translate any of the pitch-related representations listed below. In each case, a tuning standard of A4 equals 440 hertz is assumed. For descriptions of the various input representations (including kern) refer to Section 2 (Representation Reference) of this reference manual.

cents hundredths of a semitone with respect to middle C=0 degree scale degree including octave designation freq frequency in hertz (abbreviated Hz.) fret fretted-instrument pitch tablature MIDI Music Instrument Digital Interface key-press tablature pitch American National Standards Institute pitch notation (e.g. "A#4") semits equal-tempered semitones with respect to middle C=0 solfg French solfège system (fixed `doh') specC spectral centroid (in hertz) Tonh German pitch system ———— ———————————————————————-

Input representations processed by kern.

For numerically-oriented inputs, such as **cents, **freq, **MIDI, **semits, and specC, variant enharmonic spellings are selected for output according to the prevailing key signature or explicit key indication. (Refer to key and key signatures in Section 3 (Humdrum Tandem Interpretations). Hence, in the key of G minor, F-sharp and E-flat spellings will be output rather than G-flat and D-sharp. Kern recognizes the presence of key, or key signature tandem interpretations. If no key or key signature is encountered in the input, a default key of C major is assumed. Kern is sensitive to both pitch-class and pitch-height key signatures. In the case of pitch-height key signatures, the user can specify complex spelling preferences, such as F#2 rather than Gb2, but Gb3 rather than F#3, etc. See SAMPLE OUTPUT below.

It is recommended that output files produced using the kern command should be given names with the distinguishing `.krn' extension.

OPTIONS

The kern command provides the following options:

h displays a help screen summarizing the command syntax x suppresses printing of non-pitch-related signifiers ——– ——————————————————-

Options are specified in the command line.

In the default operation, kern outputs any non-pitch-related signifiers in addition to the kern value. For example, the pitch token "A6zzz" will result in the output "aaazzz" — that is, after translating A6 to "aaa", the "zzz" signifiers are retained in the output. For some applications, echoing non-pitch-related signifiers in the output is useful. However, in other situations, the result can prove confusing — especially, when the non-pitch-related signifiers are upper- or lower-case letters from A-G. Consider the case of the freq token "aA#5"; after translating "A#5" to "aa", the leading non-pitch-related signifier "a" will be prepended to the output, hence the value "aaa" — which will undoubtedly cause confusion. The x option is useful for eliminating non-pitch-related signifiers from the output. For most inputs, the x option is recommended.

[]{#SAMPLE OUTPUTS}

SAMPLE OUTPUTS

The following example illustrates the use of kern. The input contains six pitch-related spines — two of which (deg and cocho) cannot be processed by kern. In addition, there are two non-pitch-related spines (embell and metpos). ``

!! `kern' example #1 **specC *M2/4 * * =1 =1 foo2000 . . 2321 . . 1807 Ab3 . . 2487 . . =2 =2 3323 r . . 3471 . . . =3 =3 r G4 === === *- *- ————————- **pitch **MIDI **deg **metpos **cocho **Tonh **embell *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 * * *tb8 * * * =1 =1 =1 =1 =1 =1 G#4foo /60/bar 1foo 1 r Gis2 ct /-60/ . . . . . A3+20 /62/ 2 3 9.89 H2 upt 48/-62/ . . . . . 0/70/64 1 2 7.07 B2 ct 48/-70/ . . . . . C#4 /61/ 6 3 7.135 Cis4 sus /-61/ . . . . . =2 =2 =2 =2 =2 =2 . 5 1 r r . . 7 3 5.5 Heses2 ct D4-8 /48/ /52/ 1 2 8.11 C3 ct /-48/ . . . . . D4 F4 /-52/ 2 3 7.33 6.4 C3 Es3 ct =3 =3 =3 =3 =3 =3 . r 1 r H2 D3 . === === === === === === *- *- *- *- *- *- ———– ———– ——— ———— ———– ———- ————

Executing the command

` kern -x input > output.krn`

produces the following result: ``

!! `kern' example #1 **kern **kern **kern **deg **metpos **cocho **kern **embell *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 *M2/4 * * * * *tb8 * * * =1 =1 =1 =1 =1 =1 =1 =1 bbb g# c 1foo 1 r GG# ct . . . . . . . . dddd A d 2 3 9.89 BB upt . . . . . . . . aaa A- b- 1 2 7.07 BB- ct . . . . . . . . eeee- c# d- 6 3 7.135 c# sus . . . . . . . . =2 =2 =2 =2 =2 =2 =2 =2 aaaa- r . 5 1 r r . . . . 7 3 5.5 BB— ct aaaa d C E 1 2 8.11 C ct . . . . . . . . . d f . 2 3 7.33 6.4 C E- ct =3 =3 =3 =3 =3 =3 =3 =3 r g . r 1 r BB D . === === === === === === === === *- *- *- *- *- *- *- *- ————————- ———- ———- ——— ———— ———– ———- ————

Both processed and unprocessed spines are output. Also notice that the non-pitch-related signifiers (e.g. foo) in the first notes of the **specC, **pitch, and MIDI, spines have been stripped away (due to the x option).

Key signature sensitivity is illustrated in the following example. The input contains a "pitch-height key signature" — where flats and sharps pertain to only a specific absolute pitch. For example, Bb3 is preferred to A#3, although A#4 is preferred to Bb4. Similarly, C#4 is preferred to Db4, although Db5 is preferred to C#5. ``

!! `kern' example #2 **semits *K[B3-C4#F4#A4#D5-] -2 10 1 6 13 *- —————————

Notice in the corresponding output given below, that all pitches are rendered with the correct enharmonic spelling. ``

!! `kern' example #2 **kern *K[B3-C4#F4#A4#D5-] B- a# c# f# dd- *- —————————

FILES

The file x_option.awk is used by this program when the x option is invoked.

PORTABILITY

DOS 2.0 and up, with the MKS Toolkit. OS/2 with the MKS Toolkit. UNIX systems supporting the Korn shell or Bourne shell command interpreters, and revised awk (1985).

BUGS

When translating pitch, solfg, or Tonh, inputs, kern ignores cents deviation. Hence C#6+80 is rendered as `ccc#' rather than the nearest pitch `ddd'.

WARNINGS

Humdrum representations are expected to avoid context dependency insofar as possible. This can lead to unexpected results. For example, the letter `x' in pitch is intended to signify the presence of a double sharp. Thus the pitch input token `xyzC4' is correctly translated by kern as `yzc##'. Similarly, the pitch input token `1yzC4' becomes `yzCCC4'. (The first numerical value is interpreted as the octave number and the trailing number 4 is interpreted as a non-pitch-related signifier.)