timebase – reformat Humdrum **kern or **recip score with constant time-base
`` timebase -t n[.] [-M mark] [-m mark] [-x] [inputfile ...] [ > outputfile.tb]``
The timebase command is used to reformat **kern or **recip inputs so that output data records represent equivalent slices (elapsed duration) of time. The effect of the timebase command is best illustrated by an example. With a specified time-base of a sixteenth duration, the following input: ````
**kern **kern **kern **kern 4g 8.r 8.cc 16ee . . . 8ff . 32b 16cc 16gg . 32a . . 8f 8cc 8dd 8ff *- *- *- *-
**kern **kern **kern **kern *tb16 *tb16 *tb16 *tb16 4g 8.r 8.cc 16ee . . . 8ff . . . . . 32b 16cc 16gg 8f 8cc 8dd 8ff . . . . *- *- *- *-
Each output record represents a snap-shot of a sixteenth duration following the previous data record. Depending upon the choice of time-base, the resulting output is either expanded or contracted in length. Details finer than the specified time-base are lost; in the above example, notice that the second thirty-second note (pitch `A’ in the second spine) has disappeared from the file as the time-base is only a sixteenth duration.
The time-base is selected by assigning a **recip duration value to the -t option. Time-base durations may be dotted.
Comments and barlines are preserved in the output, however, acciaccatura records (grace notes) are discarded.
It is recommended that output files produced using the timebase command should be given names with the distinguishing `.tb’ extension.
The timebase command provides a number of options.
-h displays a help screen summarizing the command syntax -t n set time-base where n represents a **recip duration -x strip duration values from the input -M mark prepend mark to beginning of any padded output records -m mark append mark to end of any padded output records
Options are specified in the command line. e.g.
`` timebase -t 8. -x``
will remove **kern or **recip duration encodings from the output; each output data record will represent an elapsed duration of a dotted eighth note.
The -M option adds a user-specified marker-string to the beginning of all records that timebase pads to the output. For example, the command:
`` timebase -t 8 -M ABC``
will add the string ABC to the beginning of (otherwise) null data records added by timebase.
The -m option appends a user-specified marker-string to the end of all padded output records. Both the -M and -m options can be used concurrently.
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).
Depending upon the defined time-base, passages of prolonged syncopation may disappear from the output. The timebase command assumes the integrity of the duration structure of the input score. Corrupt duration structures in the input will produce unpredictable results.
- **Pertinent description in the Humdrum User Guide**
- **Index to Humdrum Commands**
- **Table for Contents for Humdrum User Guide**