Add pitch bend support

Author: Gloomhonk

index.css

@@ -96,6 +96,12 @@ h1, h2, h3 {
   align-self: center;
 }
 
+#pitchbend img {
+  align-self: center;
+  width: 60%;
+  height: auto;
+}
+
 ol, ul {
   margin: 0;
 }

index.html

@@ -53,6 +53,19 @@ <h2><label for="midifile">MIDI file</label></h2>
         title="What quantization snap to use for warning about unquantized notes. This should be a power of 2. Alternatively, setting this to 0 will ignore all quantization warnings. Triplets (snap 12) are recognized automatically, regardless.">i</abbr>
       <label for="snap">Snap</label>
       <input type="number" id="snap" name="snap" min="0" max="192" value="32">
+
+      <abbr
+        title="What range to treat pitch bend events (e.g. if set to 2, pitch bend events can move notes up/down by a maximum of 2 semitones)">i</abbr>
+      <label for="pitchbendrange">Pitch Bend Range (semitones)</label>
+      <select name="pitchbendrange" id="pitchbendrange">
+        <option value="1">1</option>
+        <option value="2" selected="selected">2</option>
+        <option value="3">3</option>
+        <option value="4">4</option>
+        <option value="5">5</option>
+        <option value="6">6</option>
+        <option value="7">7</option>
+      </select>
     </div>
     <div id="midiwarnings" class="warnings"></div>
   </div>
@@ -222,8 +235,52 @@ <h3>tccc mode</h3>
     <p>Overlapping more than two notes is undefined behavior in tccc mode. Don't do it.</p>
   </div>
 
+  <div id="pitchbend" class="container">
+    <h2>Pitch Bend Events</h2>
+
+    <p>TCCC can perform additional adjustments to the pitch of notes using MIDI Pitch Bend events, allowing you to 
+      set notes to microtonal values.</p>
+
+    <ul>
+      <li>The Pitch Bend Range option controls what range (in semitones) the MIDI events are converted to.</li>
+      <ul>
+        <li>E.g. At a Pitch Bend Range of 2, a maximum value pitch bend MIDI event will raise/lower the note pitch by 2 semitones.</li>
+        <li>Make sure this range matches the range of the DAW output device you used when making the MIDI (e.g. your 
+          synth plugin, soundfont player, etc).</li> 
+          <ul>
+            <li>Most default to +-2 semitones, but it varies across devices so it's best to check your setup.</li>
+          </ul>
+      </ul>
+      <br>
+      <li>TCCC takes the pitch bend values at the start and end of a particular note, and shifts the start/end by that amount.</li>
+    </ul>
+
+      <h3>Examples</h3>
+    <p>Pitch bend event covers all notes, so all are shifted up by the same amount (the unadjusted note is shown faded 
+      out). Make sure your desired pitch bend finishes after the note end.</p>
+    <img src="res/pitch_example_both_notes.png"/>
+
+    <p>Pitch bend event covers just the start of the first note of the slide, so the start is shifted down.</p>
+    <img src="res/pitch_example_first_note.png"/>
+
+    <p>You can shift the start/end of a single-note slide by placing the pitch bend around just the start/end note. 
+      In this case the end of the slide is shifted down.</p>
+    <img src="res/pitch_example_single_slide.png"/>
+
+    <p>When shifting a note connected to the end of a slide, make sure to shift both the end note and the slide note 
+      that connects to it.</p>
+    <img src="res/pitch_example_second_note.png"/>
+
+    <p>For pitch shift gradients/curves, the pitch shift amount is taken at the start and end of each note.</p>
+    <img src="res/pitch_example_gradient.png"/>
+  </div>
+
   <div class="container">
     <h2>Version history</h2>
+    <p>
+      v1.8:<br>
+      Added support for converting MIDI pitch bend events into note pitch adjustments
+    </p>
     <p>
       v1.7e:<br>
       Added CONTRIBUTING.md to the Github repo, along with test resources
@@ -314,7 +371,7 @@ <h2>Version history</h2>
   </div>
   <div class="footer">
     <p>
-      <a href="https://github.com/TC-Chart-Converter/TC-Chart-Converter.github.io/">Trombone Champ Chart Converter</a> by RShields and contributors<br>
+      <a href="https://github.com/TC-Chart-Converter/TC-Chart-Converter.github.io/">Trombone Champ Chart Converter</a> by RShields, Gloomhonk, and contributors<br>
       Licensed under the <a href="https://github.com/TC-Chart-Converter/TC-Chart-Converter.github.io/blob/main/LICENSE">GNU Affero General Public License v3.0</a><br>
       <br>
       <a href="https://github.com/colxi/midi-parser-js">MidiParser.js</a> by Sergi Guzman and contributors<br>

res/pitch_example_both_notes.png

@@ -8,15 +8,16 @@ const MidiToNotes = (function () {
   function generateNotes(midi) {
     console.log(midi);
     MidiToNotes.notes = [];
+    MidiToNotes.pitchBendEvents = [];
     midiWarnings.clear();
 
     const { timeDivision } = midi;
 
     /** All the events in the midi file, sorted by time */
     const sortedMidiEvents = getSortedMidiEvents(midi);
 
+    collectPitchBendEvents(sortedMidiEvents, timeDivision);
     generateWarnings(sortedMidiEvents, timeDivision);
-    midiWarnings.display();
 
     // Calculate endpoint
     for (let i = sortedMidiEvents.length - 1; i >= 0; i--) {
@@ -39,6 +40,7 @@ const MidiToNotes = (function () {
 
     generateLyrics(sortedMidiEvents, timeDivision);
 
+    midiWarnings.display();
     Preview.display();
   }
 
@@ -47,6 +49,8 @@ const MidiToNotes = (function () {
       return "noteOff";
     } else if (event.type === 9) {
       return "noteOn";
+    } else if (event.type === 14) {
+      return "pitchBend";
     } else if (event.type === 255) {
       return "meta";
     } else {
@@ -117,42 +121,51 @@ const MidiToNotes = (function () {
         // We ignore note-off events for pitches other than the current one
         // which prevents slide-start noteOffs from ending slides
         if (currentNote && pitch === currentNote.startPitch) {
-          const { startTime, startPitch } = currentNote;
-
+          const { startTime, startPitch, startPitchBend } = currentNote;
           const length = event.time - startTime;
+          const endPitchBend = getPitchBendAdjustmentAtTime(event.time);
+          const tcStartPitch = 
+            convertPitch(startPitch, startPitchBend, startTime, timeDivision);
+          const tcEndPitch = 
+            convertPitch(pitch, endPitchBend, event.time, timeDivision);
+          const tcPitchDelta = tcEndPitch - tcStartPitch;
 
           MidiToNotes.notes.push([
             startTime / timeDivision,
             length > 0 ? length / timeDivision : defaultNoteLength,
-            (startPitch - 60) * 13.75,
-            0,
-            (startPitch - 60) * 13.75,
+            tcStartPitch,
+            tcPitchDelta,
+            tcEndPitch,
           ]);
 
           currentNote = undefined;
         }
       } else if (getEventType(event) === "noteOn") {
         const pitch = event.data[0];
+        const pitchBend = getPitchBendAdjustmentAtTime(event.time);
 
         if (currentNote) {
-          const { startTime, startPitch } = currentNote;
-
+          const { startTime, startPitch, startPitchBend } = currentNote;
           const length = event.time - startTime;
-          const endPitch = pitch;
-          const pitchDelta = endPitch - startPitch;
+          const tcStartPitch = 
+            convertPitch(startPitch, startPitchBend, startTime, timeDivision);
+          const tcEndPitch = 
+            convertPitch(pitch, pitchBend, event.time, timeDivision);
+          const tcPitchDelta = tcEndPitch - tcStartPitch;
 
           MidiToNotes.notes.push([
             startTime / timeDivision,
             length > 0 ? length / timeDivision : defaultNoteLength,
-            (startPitch - 60) * 13.75,
-            pitchDelta * 13.75,
-            (endPitch - 60) * 13.75,
+            tcStartPitch,
+            tcPitchDelta,
+            tcEndPitch,
           ]);
         }
 
         currentNote = {
           startTime: event.time,
           startPitch: pitch,
+          startPitchBend: pitchBend,
         };
       }
     }
@@ -169,23 +182,28 @@ const MidiToNotes = (function () {
         // We ignore note-off events for pitches other than the current one
         // which prevents slide-start noteOffs from ending slides
         if (currentNote && pitch === currentNote.endPitch) {
-          const { startTime, startPitch, endPitch } = currentNote;
-
+          const { startTime, startPitch, endPitch, startPitchBend } = currentNote;
+          const endPitchBend = getPitchBendAdjustmentAtTime(event.time);
           const length = event.time - startTime;
-          const pitchDelta = endPitch - startPitch;
+          const tcStartPitch = 
+            convertPitch(startPitch, startPitchBend, startTime, timeDivision);
+          const tcEndPitch = 
+            convertPitch(endPitch, endPitchBend, event.time, timeDivision);
+          const tcPitchDelta = tcEndPitch - tcStartPitch;
 
           MidiToNotes.notes.push([
             startTime / timeDivision,
             length > 0 ? length / timeDivision : defaultNoteLength,
-            (startPitch - 60) * 13.75,
-            pitchDelta * 13.75,
-            (endPitch - 60) * 13.75,
+            tcStartPitch,
+            tcPitchDelta,
+            tcEndPitch,
           ]);
 
           currentNote = undefined;
         }
       } else if (getEventType(event) === "noteOn") {
         const pitch = event.data[0];
+        const pitchBend = getPitchBendAdjustmentAtTime(event.time);
 
         if (currentNote) {
           currentNote.endPitch = pitch;
@@ -194,12 +212,80 @@ const MidiToNotes = (function () {
             startTime: event.time,
             startPitch: pitch,
             endPitch: pitch,
+            startPitchBend: pitchBend
           };
         }
       }
     }
   }
 
+  /**
+   * Collects all pitch bend events in the MIDI and converts the 
+   * pitch bend value into semitones.
+   */
+  function collectPitchBendEvents(sortedMidiEvents) {
+    MidiToNotes.pitchBendEvents = [];
+
+    for (const event of sortedMidiEvents) {
+      if (getEventType(event) === "pitchBend") {
+        // A MIDI pitch bend event consists of two bytes 0aaaaaaa and 0bbbbbbb,
+        // These are combined (bbbbbbbaaaaaaa) to form a value of 0-16383,
+        // with the median (8192) being no bend. This is converted to semitones
+        // according to the range specified in the settings.
+        const midiPitchBend = ((event.data[1] << 7 | event.data[0]) - 8192) / 8192;
+        const pitchEvent = {
+          time: event.time,
+          value: midiPitchBend * Settings.getSetting("pitchbendrange")
+        };
+
+        MidiToNotes.pitchBendEvents.push(pitchEvent)
+      }
+    }
+  }
+
+  /**
+   * Finds the pitch adjust amount at a given time in the MIDI. If the MIDI time
+   * is between two pitch bend events then the amount is found by a linear 
+   * interpolation between the previous and next events. E.g. a time halfway between 
+   * events of +0.5 and +1.0 semitones will have an adjust amount of +0.75.
+   */
+  function getPitchBendAdjustmentAtTime(midiTime) {
+    const eventIndex = MidiToNotes.pitchBendEvents.findLastIndex((event) => event.time <= midiTime);
+    if (eventIndex === -1) return 0;
+    const pitchEvent = MidiToNotes.pitchBendEvents[eventIndex];
+
+    if (eventIndex === MidiToNotes.pitchBendEvents.length - 1) return pitchEvent.value;
+    const nextPitchEvent = MidiToNotes.pitchBendEvents[eventIndex + 1];
+
+    const timeDelta = nextPitchEvent.time - pitchEvent.time;
+    const pitchDelta = nextPitchEvent.value - pitchEvent.value;
+
+    return pitchEvent.value + (midiTime - pitchEvent.time) / timeDelta * pitchDelta;
+  }
+
+  /**
+   * Applies pitch bend, validates the final note, then converts to TC format.
+   * Warnings are added for notes that are either out of range or unsnapped,
+   * out of range pitches will also optionally be clamped.
+   */
+  function convertPitch(midiPitch, midiPitchBend, midiTime, timeDivision) {
+    const snaps = [Settings.getSetting("snap"), 12];
+    const clampPitch = Settings.getSetting("clamppitch");
+    let adjustedMidiPitch = midiPitch + midiPitchBend;
+
+    warnIfUnsnapped(midiTime, timeDivision, snaps);
+
+    if (adjustedMidiPitch < 47 || adjustedMidiPitch > 73) {
+      midiWarnings.add(
+        clampPitch ? "Pitch clamped" : "Pitch out of range",
+        { adjustedMidiPitch, beat: midiTime / timeDivision }
+      );
+      if (clampPitch) adjustedMidiPitch = Math.min(Math.max(adjustedMidiPitch, 47), 73);
+    }
+
+    return (adjustedMidiPitch - 60) * 13.75;
+  }
+
   function generateLyrics(sortedMidiEvents, timeDivision) {
     MidiToNotes.lyrics = [];
 
@@ -218,23 +304,9 @@ const MidiToNotes = (function () {
   }
 
   function generateWarnings(sortedMidiEvents, timeDivision) {
-    const clampPitch = Settings.getSetting("clamppitch");
-    const snaps = [Settings.getSetting("snap"), 12];
-
     for (const event of sortedMidiEvents) {
       const eventType = getEventType(event);
-      if (eventType === "noteOn" || eventType === "noteOff") {
-        warnIfUnsnapped(event.time, timeDivision, snaps);
-
-        let pitch = event.data[0];
-        if (pitch < 47 || pitch > 73) {
-          midiWarnings.add(
-            clampPitch ? "Pitch clamped" : "Pitch out of range",
-            { pitch, beat: Math.floor(event.time / timeDivision) }
-          );
-          if (clampPitch) pitch = Math.min(Math.max(pitch, 47), 73);
-        }
-      } else if (eventType === "meta") {
+      if (eventType === "meta") {
         if (event.metaType === 81 && event.time !== 0) {
           // tempo change
           midiWarnings.add("Tempo change (unsupported)", {

res/pitch_example_first_note.png

@@ -1,7 +1,8 @@
 const Settings = (function () {
   const settings = {};
 
-  const settingsNames = ["clamppitch", "snap", "slidemidi2tc", "slidetccc"];
+  const settingsNames = 
+    ["clamppitch", "snap", "slidemidi2tc", "slidetccc", "pitchbendrange"];
 
   function getSetting(name) {
     switch (name) {
@@ -10,7 +11,8 @@ const Settings = (function () {
       case "slidetccc":
         return settings[name].checked;
       case "snap":
-        return Number(settings["snap"].value);
+      case "pitchbendrange":
+        return Number(settings[name].value);
       default:
         throw `Unknown setting: ${name}`;
     }