Chris@137: 
Chris@193: // Convert the output of the midifile program
Chris@193: // (https://code.soundsoftware.ac.uk/projects/midifile)
Chris@193: // into lab file like those output from the test scripts.
Chris@193: //
Chris@193: // The midifile format contains lines looking like:
Chris@193: //
Chris@193: // <t>: Note: channel <c> duration <d> pitch <p> velocity <v>
Chris@193: //
Chris@193: // where t and d are defined in terms of the timebase and
Chris@193: // tempo, which are (usually) given in earlier lines:
Chris@193: //
Chris@193: // Timing division: <n> ppq
Chris@193: // <t>: Tempo: <n>
Chris@193: //
Chris@222: // Note that we assume 4 quarter-notes per bar, we don't parse time
Chris@222: // signatures, and we only handle the first tempo event.
Chris@137: // 
Chris@193: // The output file format looks like:
Chris@137: //
Chris@137: // onset offset frequency
Chris@193: //
Chris@193: // with times in seconds.
Chris@137: 
Chris@193: program convert_midifileout;
Chris@137: 
Chris@137: usage () =
Chris@193:     eprintln "\nUsage: convert_midifileout file.txt\n";
Chris@137: 
Chris@137: toFrequency m = 
Chris@137:     440 * Math#pow(2.0, (m - 69) / 12.0);
Chris@137: 
Chris@193: toTime timebase tempo t =
Chris@193:     (t / timebase) * (60 / tempo);
Chris@193: 
Chris@137: convert f =
Chris@137:    (str = openInFile f "UTF-8";
Chris@193:     var timebase = 480;
Chris@193:     var tempo = 120;
Chris@222:     var tempoNowFixed = false;
Chris@137:     for (str.lines ()) do line:
Chris@193:         bits = strSplit ": " line;
Chris@193:         if length bits > 1 then
Chris@193:             if bits[0] == "Timing division" then
Chris@193:                 timebase := number (strReplace " ppq" "" bits[1]);
Chris@193:                 eprintln "Set timing division to \(timebase)";
Chris@193:             elif bits[1] == "Tempo" then
Chris@222:                 if tempoNowFixed then
Chris@222:                     failWith "Can't handle variable-tempo file";
Chris@222:                 fi;
Chris@193:                 if length bits < 3 then 
Chris@193:                     failWith "Too few bits in tempo line: \(line)";
Chris@193:                 fi;
Chris@193:                 tempo := number (bits[2]);
Chris@222:                 tempoNowFixed := true;
Chris@193:                 eprintln "Set tempo to \(tempo)";
Chris@193:             elif bits[1] == "Note" then
Chris@222:                 tempoNowFixed := true;
Chris@193:                 if length bits < 3 then
Chris@193:                     failWith "Too few bits in note line: \(line)";
Chris@193:                 fi;
Chris@193:                 noteparts = strSplit " " bits[2];
Chris@193:                 if length noteparts < 8 then
Chris@193:                     failWith "Too few note parameters in line: \(line)";
Chris@193:                 fi;
Chris@193:                 onset = toTime timebase tempo (number bits[0]);
Chris@193:                 duration = toTime timebase tempo (number noteparts[3]);
Chris@193:                 frequency = toFrequency (number noteparts[5]);
Chris@193:                 println "\(onset)\t\(onset + duration)\t\(frequency)";
Chris@193:             fi;
Chris@193:         fi;
Chris@137:     done;
Chris@137:     str.close ());
Chris@137: 
Chris@137: case (list _argv) of
Chris@137: file::[]: convert file;
Chris@137: _: usage ();
Chris@137: esac;
Chris@137: