diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 2493d620d..f6252cbe7 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -2621,7 +2621,7 @@ bool DivEngine::switchMaster() {
   return true;
 }
 
-void DivEngine::setMidiCallback(std::function<bool(const TAMidiMessage&)> what) {
+void DivEngine::setMidiCallback(std::function<int(const TAMidiMessage&)> what) {
   midiCallback=what;
 }
 
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 1fe93f345..52a01291b 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -244,7 +244,8 @@ class DivEngine {
 
   size_t totalProcessed;
 
-  std::function<bool(const TAMidiMessage&)> midiCallback=[](const TAMidiMessage&) -> bool {return false;};
+  // MIDI stuff
+  std::function<int(const TAMidiMessage&)> midiCallback=[](const TAMidiMessage&) -> int {return -1;};
 
   DivSystem systemFromFile(unsigned char val);
   unsigned char systemToFile(DivSystem val);
@@ -638,8 +639,8 @@ class DivEngine {
     bool switchMaster();
 
     // set MIDI input callback
-    // if the specified function returns true, note feedback will be inhibited.
-    void setMidiCallback(std::function<bool(const TAMidiMessage&)> what);
+    // if the specified function returns -2, note feedback will be inhibited.
+    void setMidiCallback(std::function<int(const TAMidiMessage&)> what);
 
     // perform secure/sync operation
     void synchronized(const std::function<void()>& what);
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 259209e4a..2f9d6f5c1 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1541,17 +1541,32 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
   // process MIDI events (TODO: everything)
   if (output->midiIn) while (!output->midiIn->queue.empty()) {
     TAMidiMessage& msg=output->midiIn->queue.front();
-    if (!midiCallback(msg)) {
+    int ins=-1;
+    if ((ins=midiCallback(msg))!=-2) {
       int chan=msg.type&15;
       switch (msg.type&0xf0) {
         case TA_MIDI_NOTE_OFF: {
           if (chan<0 || chan>=chans) break;
           pendingNotes.push(DivNoteEvent(msg.type&15,-1,-1,-1,false));
+          if (!playing) {
+            reset();
+            freelance=true;
+            playing=true;
+          }
           break;
         }
         case TA_MIDI_NOTE_ON: {
           if (chan<0 || chan>=chans) break;
-          pendingNotes.push(DivNoteEvent(msg.type&15,-1,(int)msg.data[0]-12,msg.data[1],true));
+          if (msg.data[1]==0) {
+            pendingNotes.push(DivNoteEvent(msg.type&15,-1,-1,-1,false));
+          } else {
+            pendingNotes.push(DivNoteEvent(msg.type&15,ins,(int)msg.data[0]-12,msg.data[1],true));
+          }
+          if (!playing) {
+            reset();
+            freelance=true;
+            playing=true;
+          }
           break;
         }
         case TA_MIDI_PROGRAM: {
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index 911bef9f2..89bd1a019 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -1874,6 +1874,24 @@ bool FurnaceGUI::loop() {
       }
     }
     
+    while (true) {
+      midiLock.lock();
+      if (midiQueue.empty()) {
+        midiLock.unlock();
+        break;
+      }
+      TAMidiMessage msg=midiQueue.front();
+      midiLock.unlock();
+
+      // parse message here
+      logD("message is %.2x\n",msg.type);
+      if (msg.type==0xb0) doAction(GUI_ACTION_PLAY_TOGGLE);
+
+      midiLock.lock();
+      midiQueue.pop();
+      midiLock.unlock();
+    }
+    
     ImGui_ImplSDLRenderer_NewFrame();
     ImGui_ImplSDL2_NewFrame(sdlWin);
     ImGui::NewFrame();
@@ -2628,10 +2646,12 @@ bool FurnaceGUI::init() {
 
   firstFrame=true;
 
-  // TODO
-  e->setMidiCallback([this](const TAMidiMessage& msg) -> bool {
-    logD("I hate macOS: %p\n",this);
-    return true;
+  // TODO: MIDI mapping time!
+  e->setMidiCallback([this](const TAMidiMessage& msg) -> int {
+    midiLock.lock();
+    midiQueue.push(msg);
+    midiLock.unlock();
+    return curIns;
   });
 
   return true;
diff --git a/src/gui/gui.h b/src/gui/gui.h
index 1b06d1526..933455def 100644
--- a/src/gui/gui.h
+++ b/src/gui/gui.h
@@ -492,6 +492,14 @@ struct UndoStep {
   std::vector<UndoPatternData> pat;
 };
 
+struct MIDIBind {
+  int type, channel, data1, data2;
+};
+
+struct MIDIMap {
+  std::vector<MIDIBind> binds;
+};
+
 struct Particle {
   ImU32* colors;
   const char* type;
@@ -562,6 +570,9 @@ class FurnaceGUI {
   std::mutex backupLock;
   String backupPath;
 
+  std::mutex midiLock;
+  std::queue<TAMidiMessage> midiQueue;
+
   ImFont* mainFont;
   ImFont* iconFont;
   ImFont* patFont;