This function mainly adds ticks which is the absolute value of mido's
time (measured in ticks) for every track. Furthermore, this absolute
time value is translated to the further columns of beats (quarter notes;
"b"), measures (bars; "m") and the time in seconds ("t").
The function outputs these additional columns only if they are specified in
the argument columns_to_add (see details).
Arguments
- df
Note event data.frame resulting of miditapyr$unnest_midi()
- ticks_per_beat
integer resulting of miditapyr$mido_midi_df()
- columns_to_add
Character vector of the columns to be added to the result (see section "Details"). Subset of
c("m", "b", "t", "time").
Value
A data.frame with the following columns added:
ticks, i_note and the columns specified in columns_to_add.
Details
The function transforms the unnested midi frame by first transforming the
midi time (measured in ticks passed relative to the previous event) to
absolute time for every track. Also the auxiliary variable i_note is
added (indexing the occurrence of each note for every track). This is needed
to allow to pivot the notes to wide format and back to long with
pivot_wide_notes() and pivot_long_notes().
m: measure (bar)
b: beat (quarter note)
t: time in seconds
Examples
if (FALSE) {
mid_file_str <- system.file("extdata", "test_midi_file.mid", package = "pyramidi")
mido_mid_file <- mido$MidiFile(mid_file_str)
dfc <- miditapyr$frame_midi(mido_mid_file)
ticks_per_beat = mido_mid_file$ticks_per_beat
df <- dfc %>%
miditapyr$unnest_midi()
}
if (FALSE) {
tab_measures(df, ticks_per_beat)
}