# Time-stamp: "2002-11-16 01:57:08 MST" require 5; package MIDI::Score; use strict; use vars qw($Debug $VERSION); use Carp; $VERSION = 0.79; =head1 NAME MIDI::Score - MIDI scores =head1 SYNOPSIS # it's a long story; see below =head1 DESCRIPTION This module provides functions to do with with MIDI scores. It is used as the basis for all the functions in MIDI::Simple. (Incidentally, MIDI::Opus's draw() method also uses some of the functions in here.) Whereas the events in a MIDI event structure are items whose timing is expressed in delta-times, the timing of items in a score is expressed as an absolute number of ticks from the track's start time. Moreover, pairs of 'note_on' and 'note_off' events in an event structure are abstracted into a single 'note' item in a score structure. 'note' takes the following form: ('note_on', I, I, I, I, I) The problem that score structures are meant to solve is that 1) people definitely don't think in delta-times -- they think in absolute times or in structures based on that (like 'time from start of measure'); 2) people think in notes, not note_on and note_off events. So, given this event structure: ['text_event', 0, 'www.ely.anglican.org/parishes/camgsm/chimes.html'], ['text_event', 0, 'Lord through this hour/ be Thou our guide'], ['text_event', 0, 'so, by Thy power/ no foot shall slide'], ['patch_change', 0, 1, 8], ['note_on', 0, 1, 25, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 29, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 27, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 20, 96], ['note_off', 192, 0, 1, 0], ['note_on', 0, 1, 25, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 27, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 29, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 25, 96], ['note_off', 192, 0, 1, 0], ['note_on', 0, 1, 29, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 25, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 27, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 20, 96], ['note_off', 192, 0, 1, 0], ['note_on', 0, 1, 20, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 27, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 29, 96], ['note_off', 96, 0, 1, 0], ['note_on', 0, 1, 25, 96], ['note_off', 192, 0, 1, 0], here is the corresponding score sctructure: ['text_event', 0, 'www.ely.anglican.org/parishes/camgsm/chimes.html'], ['text_event', 0, 'Lord through this hour/ be Thou our guide'], ['text_event', 0, 'so, by Thy power/ no foot shall slide'], ['patch_change', 0, 1, 8], ['note', 0, 96, 1, 25, 96], ['note', 96, 96, 1, 29, 96], ['note', 192, 96, 1, 27, 96], ['note', 288, 192, 1, 20, 96], ['note', 480, 96, 1, 25, 96], ['note', 576, 96, 1, 27, 96], ['note', 672, 96, 1, 29, 96], ['note', 768, 192, 1, 25, 96], ['note', 960, 96, 1, 29, 96], ['note', 1056, 96, 1, 25, 96], ['note', 1152, 96, 1, 27, 96], ['note', 1248, 192, 1, 20, 96], ['note', 1440, 96, 1, 20, 96], ['note', 1536, 96, 1, 27, 96], ['note', 1632, 96, 1, 29, 96], ['note', 1728, 192, 1, 25, 96] Note also that scores aren't crucially ordered. So this: ['note', 768, 192, 1, 25, 96], ['note', 960, 96, 1, 29, 96], ['note', 1056, 96, 1, 25, 96], means the same thing as: ['note', 960, 96, 1, 29, 96], ['note', 768, 192, 1, 25, 96], ['note', 1056, 96, 1, 25, 96], The only exception to this is in the case of things like: ['patch_change', 200, 2, 15], ['note', 200, 96, 2, 25, 96], where two (or more) score items happen I and where one affects the meaning of the other. =head1 WHAT CAN BE IN A SCORE Besides the new score structure item C (covered above), the possible contents of a score structure can be summarized thus: Whatever can appear in an event structure can appear in a score structure, save that its second parameter denotes not a delta-time in ticks, but instead denotes the absolute number of ticks from the start of the track. To avoid the long periphrase "items in a score structure", I will occasionally refer to items in a score structure as "notes", whether or not they are actually C commands. This leaves "event" to unambiguously denote items in an event structure. These, below, are all the items that can appear in a score. This is basically just a repetition of the table in L, with starttime substituting for dtime -- so refer to L for an explanation of what the data types (like "velocity" or "pitch_wheel"). As far as order, the first items are generally the most important: =over =item ('note', I, I, I, I, I) =item ('key_after_touch', I, I, I, I) =item ('control_change', I, I, I, I) =item ('patch_change', I, I, I) =item ('channel_after_touch', I, I, I) =item ('pitch_wheel_change', I, I, I) =item ('set_sequence_number', I, I) =item ('text_event', I, I) =item ('copyright_text_event', I, I) =item ('track_name', I, I) =item ('instrument_name', I, I) =item ('lyric', I, I) =item ('marker', I, I) =item ('cue_point', I, I) =item ('text_event_08', I, I) =item ('text_event_09', I, I) =item ('text_event_0a', I, I) =item ('text_event_0b', I, I) =item ('text_event_0c', I, I) =item ('text_event_0d', I, I) =item ('text_event_0e', I, I) =item ('text_event_0f', I, I) =item ('end_track', I) =item ('set_tempo', I, I) =item ('smpte_offset', I, I
, I, I, I, I) =item ('time_signature', I, I, I
, I, I) =item ('key_signature', I, I, I) =item ('sequencer_specific', I, I) =item ('raw_meta_event', I, I(0-255), I) =item ('sysex_f0', I, I) =item ('sysex_f7', I, I) =item ('song_position', I) =item ('song_select', I, I) =item ('tune_request', I) =item ('raw_data', I, I) =back =head1 FUNCTIONS This module provides these functions: =over =item $score2_r = MIDI::Score::copy_structure($score_r) This takes a I to a score structure, and returns a I to a copy of it. Example usage: @new_score = @{ MIDI::Score::copy_structure( \@old_score ) }; =cut sub copy_structure { return &MIDI::Event::copy_structure(@_); # hey, a LoL is an LoL } ########################################################################## =item $events_r = MIDI::Score::score_r_to_events_r( $score_r ) =item ($events_r, $ticks) = MIDI::Score::score_r_to_events_r( $score_r ) This takes a I to a score structure, and converts it to an event structure, which it returns a I to. In list context, also returns a second value, a count of the number of ticks that structure takes to play (i.e., the end-time of the temporally last item). =cut sub score_r_to_events_r { # list context: Returns the events_r AND the total tick time # scalar context: Returns events_r my $score_r = $_[0]; my $time = 0; my @events = (); croak "MIDI::Score::score_r_to_events_r's first arg must be a listref" unless ref($score_r); # First, turn instances of 'note' into 'note_on' and 'note_off': foreach my $note_r (@$score_r) { next unless ref $note_r; if($note_r->[0] eq 'note') { my @note_on = @$note_r; #print "In: ", map("<$_>", @note_on), "\n"; $note_on[0] = 'note_on'; my $duration = splice(@note_on, 2, 1); my @note_off = @note_on; # /now/ copy it $note_off[0] = 'note_off'; $note_off[1] += $duration; $note_off[4] = 0; # set volume to 0 push(@events, \@note_on, \@note_off); #print "on: ", map("<$_>", @note_on), "\n"; #print "off: ", map("<$_>", @note_off), "\n"; } else { push(@events, [@$note_r]); } } # warn scalar(@events), " events in $score_r"; $score_r = sort_score_r(\@events); # warn scalar(@$score_r), " events in $score_r"; # Now we turn it into an event structure by fiddling the timing $time = 0; foreach my $event (@$score_r) { next unless ref($event) && @$event; my $delta = $event->[1] - $time; # Figure out the delta $time = $event->[1]; # Move it forward $event->[1] = $delta; # Swap it in } return($score_r, $time) if wantarray; return $score_r; } ########################################################################### =item $score2_r = MIDI::Score::sort_score_r( $score_r) This takes a I to a score structure, and returns a I to a sorted (by time) copy of it. Example usage: @sorted_score = @{ MIDI::Score::sort_score_r( \@old_score ) }; =cut sub sort_score_r { # take a reference to a score LoL, and sort it by note start time, # and return a reference to that sorted LoL. Notes from the same # time must be left in the order they're found!!!! That's why we can't # just use sort { $a->[1] <=> $b->[1] } (@$score_r) my $score_r = $_[0]; my %timing = (); foreach my $note_r (@$score_r) { push( @{$timing{ $note_r->[1] }}, $note_r ) if ref($note_r); } # warn scalar(@$score_r), " events in $score_r"; #print "sequencing for times: ", map("<$_> ", # sort {$a <=> $b} keys(%timing) # ), "\n"; return [ map(@{ $timing{$_} }, sort {$a <=> $b} keys(%timing) ) ]; } ########################################################################### =item $score_r = MIDI::Score::events_r_to_score_r( $events_r ) =item ($score_r, $ticks) = MIDI::Score::events_r_to_score_r( $events_r ) This takes a I to an event structure, converts it to a score structure, which it returns a I to. If called in list context, also returns a count of the number of ticks that structure takes to play (i.e., the end-time of the temporally last item). =cut sub events_r_to_score_r { # Returns the score_r AND the total tick time my $events_r = $_[0]; croak "first argument to MIDI::Score::events_to_score is not a listref!" unless $events_r; my $options_r = ref($_[1]) ? $_[1] : {}; my $time = 0; if( $options_r->{'no_note_abstraction'} ) { my $score_r = MIDI::Event::copy_structure($events_r); foreach my $event_r (@$score_r) { # print join(' ', @$event_r), "\n"; $event_r->[1] = ($time += $event_r->[1]) if ref($event_r); } return($score_r, $time) if wantarray; return $score_r; } else { my %note = (); my @score = map { if(!ref($_)) { (); } else { $_ = [@$_]; # copy. $_->[1] = ($time += $_->[1]) if ref($_); if($_->[0] eq 'note_off' or($_->[0] eq 'note_on' && $_->[4] == 0) ) { # End of a note # print "Note off : @$_\n"; delete( $note{pack 'CC', @{$_}[2,3]} )->[2] += $time if exists $note{ pack 'CC', @{$_}[2,3] }; (); # Erase this event. } elsif ($_->[0] eq 'note_on') { # Start of a note $_ = [@$_]; $note{ pack 'CC', @{$_}[2,3] } = $_; splice(@$_, 2, 0, -$time); $_->[0] = 'note'; # ('note', Starttime, Duration, Channel, Note, Veloc) $_; } else { $_; } } } @$events_r ; #print "notes remaining on stack: ", scalar(values %note), "\n" # if values %note; foreach my $one (values %note) { $one->[2] += $time; } return(\@score, $time) if wantarray; return \@score; } } ########################################################################### =item $ticks = MIDI::Score::score_r_time( $score_r ) This takes a I to a score structure, and returns a count of the number of ticks that structure takes to play (i.e., the end-time of the temporally last item). =cut sub score_r_time { # returns the duration of the score you pass a reference to my $score_r = $_[0]; croak "arg 1 of MIDI::Score::score_r_time isn't a ref" unless ref $score_r; my $track_time = 0; foreach my $event_r (@$score_r) { next unless @$event_r; my $event_end_time = ($event_r->[0] eq 'note') ? ($event_r->[1] + $event_r->[2]) : $event_r->[1] ; #print "event_end_time: $event_end_time\n"; $track_time = $event_end_time if $event_end_time > $track_time; } return $track_time; } ########################################################################### =item MIDI::Score::dump_score( $score_r ) This dumps (via C) a text representation of the contents of the event structure you pass a reference to. =cut sub dump_score { my $score_r = $_[0]; print "\@notes = ( # ", scalar(@$score_r), " notes...\n"; foreach my $note_r (@$score_r) { print " [", &MIDI::_dump_quote(@$note_r), "],\n" if @$note_r; } print ");\n"; return; } ########################################################################### =back =head1 COPYRIGHT Copyright (c) 1998-2002 Sean M. Burke. All rights reserved. This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. =head1 AUTHOR Sean M. Burke C =cut 1; __END__