comparison chordtools/chord2midinotes.m @ 1:8973548174c1 tip

adding tools to repo

+%
+%CHORD2MIDINOTES Generate MIDI note values for a given chord symbol
+% 
+% [midinotes, success, errormessage] = chord2midinotes(chordsymbol, {verbose})
+% 
+% Obtains a set of midi note values for notes present in chord "chordsymbol".
+% The voicing is built on the rootnote with all other intervals occuring 
+% above in number order unless a bass interval is specified.
+%
+% In the case of the 'no chord' symbol 'N' function returns midinote -1
+%
+% Success = 1 if chord is converted correctly else 0.
+% 
+% If optional argument 'verbose' is 1, function prints any errormessage to 
+% the screen.
+%
+% Returns:  midinotes (array of integers)
+%           success (boolean)
+%           errormessage (string)
+%
+%
+% % Author: Christopher Harte,  March 2009
+% 
+% Copyright: Centre for Digital Music, Queen Mary University of London 2005 
+%
+% This file is part of the C4DM Chord Toolkit V2.0  
+%
+% The C4DM Chord Toolkit is free software; you can redistribute it and/or 
+% modify it under the terms of the GNU General Public License as published 
+% by the Free Software Foundation; either version 2 of the License, or
+% (at your option) any later version.
+%
+% The C4DM Chord Toolkit is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU General Public License
+% along with the C4DM Toolkit; if not, write to the Free Software
+% Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+%
+function [midinotes, success,errormessage] = chord2midinotes(chordsymbol, verbose)
+
+% set verbose default to 0
+if nargin < 2
+    verbose = 0;
+end
+
+errormessage = '';
+mainlist = '';
+success = 1;
+midinotes = 0;
+
+% parse the chordsymbol
+[rootnote,shorthand,interval_list,bass, success, errormessage] = getchordinfo(chordsymbol);
+
+if success
+
+
+    %if 'no chord' then return -1
+    if rootnote == 'N'
+
+        midinotes = -1;
+    else
+
+        % get root's pitchclass with respect to middle C and calculate absolute
+        % pitch of root in that octave   
+        if success
+
+        [rootpitchclass, success, errormessage] = note2pitchclass(rootnote);
+
+        % midinote C4 = 60 so add pitchclass to calculate rootpitch
+        rootpitch = 60 + rootpitchclass;
+
+        end
+
+
+        % combine shorthand and interval_list and obtain semitone values for each
+        % interval
+        if success
+
+            [mainlist, success, errormessage] = addshort2list(shorthand, interval_list);
+
+            if success
+
+                [semitones,success,errormessage] = intervals2semitones(mainlist);
+
+                % add rootpitch to obtain midinotes
+                chordpitches = semitones + rootpitch;
+
+            end
+
+        end
+
+        % Now find the bass note
+
+        if success
+
+            % if we haven't got a bass interval then play the rootnote as the
+            % bassnote
+            if isempty(bass)
+                basspitchclass = rootpitchclass;
+            else
+                % otherwise convert the bassinterval to a note
+                [bassnote,success,errormessage] = interval2note(bass, rootnote);
+
+                if success
+
+                    [basspitchclass, success, errormessage] = note2pitchclass(char(bassnote));
+
+                end
+            end
+
+            if success
+                % calculate bass note so that it is in the octave below the
+                % rest of the chord i.e. add to C3 midinote 48
+                basspitch = basspitchclass + 48;
+
+                % Put midinote list together
+                midinotes = [basspitch, rootpitch];
+                
+                for index = 1:length(chordpitches)
+                    if chordpitches(index) ~= rootpitch
+                       midinotes = [midinotes, chordpitches(index)];
+                    end
+                end
+            end
+
+        end
+    end
+
+%alter pitches for chords with high roots
+if rootpitchclass > 6
+    midinotes = midinotes-12;
+end
+
+end
+    
+if success == 0
+    errormessage = [errormessage sprintf(['Error in chord2midinotes: Couldn''t convert chord"' chordsymbol '"\n'])];   
+    if verbose ==1
+       fprintf(1,errormessage);
+    end
+end  
+    
+    
+