5 files changed, 53 insertions, 20 deletions

diff --git a/engines/sci/resource.h b/engines/sci/resource.h
index 9fc9708e74..119d8600b0 100644
--- a/engines/sci/resource.h
+++ b/engines/sci/resource.h
@@ -654,6 +654,7 @@ public:
 	struct Track {
 		byte type;
 		byte channelCount;
+		SciSpan<const byte> header;
 		Channel *channels;
 		int16 digitalChannelNr;
 		uint16 digitalSampleRate;
diff --git a/engines/sci/resource_audio.cpp b/engines/sci/resource_audio.cpp
index dfc3d2fcfb..58437a653f 100644
--- a/engines/sci/resource_audio.cpp
+++ b/engines/sci/resource_audio.cpp
@@ -766,6 +766,8 @@ SoundResource::SoundResource(uint32 resourceNr, ResourceManager *resMan, SciVers
 		// Digital sample data included? -> Add an additional channel
 		if (resource->getUint8At(0) == 2)
 			_tracks->channelCount++;
+		// header information that can be passed to the SCI0 sound driver
+		_tracks->header = resource->subspan(0, _soundVersion == SCI_VERSION_0_EARLY ? 0x11 : 0x21);
 		_tracks->channels = new Channel[_tracks->channelCount];
 		channel = &_tracks->channels[0];
 		channel->flags |= 2; // don't remap (SCI0 doesn't have remapping)
diff --git a/engines/sci/sound/drivers/midi.cpp b/engines/sci/sound/drivers/midi.cpp
index 889a875804..4f3f0da4b0 100644
--- a/engines/sci/sound/drivers/midi.cpp
+++ b/engines/sci/sound/drivers/midi.cpp
@@ -158,10 +158,10 @@ public:
 	int getFirstChannel() const override;
 	int getLastChannel() const override;
 	void setVolume(byte volume) override;
-	virtual void onNewSound() override;
 	int getVolume() override;
 	void setReverb(int8 reverb) override;
 	void playSwitch(bool play) override;
+	virtual void initTrack(SciSpan<const byte> &) override;
 
 private:
 	bool isMt32GmPatch(const SciSpan<const byte> &data);
@@ -479,14 +479,6 @@ int MidiPlayer_Midi::getVolume() {
 	return _masterVolume;
 }
 
-void MidiPlayer_Midi::onNewSound() {
-	if (_defaultReverb >= 0)
-		// SCI0 in combination with MT-32 requires a reset of the reverb to
-		// the default value that is present in either the MT-32 patch data
-		// or MT32.DRV itself.
-		setReverb(_defaultReverb);
-}
-
 void MidiPlayer_Midi::setReverb(int8 reverb) {
 	assert(reverb < kReverbConfigNr);
 
@@ -507,6 +499,43 @@ void MidiPlayer_Midi::playSwitch(bool play) {
 	}
 }
 
+void MidiPlayer_Midi::initTrack(SciSpan<const byte> &header) {
+	if (_version > SCI_VERSION_0_LATE)
+		return;
+
+	if (_defaultReverb >= 0)
+		// SCI0 in combination with MT-32 requires a reset of the reverb to
+		// the default value that is present in either the MT-32 patch data
+		// or MT32.DRV itself.
+		setReverb(_defaultReverb);
+
+	/* TODO: I have no idea what SCI_VERSION_0_EARLY games do here.
+	Therefore the extra code is restricted to SCI_VERSION_0_LATE for now.*/
+	if (_version == SCI_VERSION_0_EARLY)
+		return;
+
+	uint8 caps = header.getInt8At(0);
+	if (caps != 0 && caps != 2)
+		return;
+
+	uint8 readPos = 3;
+	byte msg[9];
+	uint8 flags = 0;
+
+	for (int i = 1; i < 9; ++i) {
+		readPos++;
+		flags = header.getInt8At(readPos++);
+		msg[i - 1] = (flags & 1) ? i : 0x10;
+	}
+
+	flags = header.getInt8At(readPos);
+	msg[8] = (flags & 0x80) ? 9 : 0x10;
+
+	// assign channels
+	Sci::SciSpan<const byte> s(msg, 9);
+	sendMt32SysEx(0x10000D, s, false);
+}
+
 bool MidiPlayer_Midi::isMt32GmPatch(const SciSpan<const byte> &data) {
 	uint32 size = data.size();
 
diff --git a/engines/sci/sound/drivers/mididriver.h b/engines/sci/sound/drivers/mididriver.h
index f51851bde6..73c2fd5737 100644
--- a/engines/sci/sound/drivers/mididriver.h
+++ b/engines/sci/sound/drivers/mididriver.h
@@ -24,6 +24,7 @@
 #define SCI_SFX_SOFTSEQ_MIDIDRIVER_H
 
 #include "sci/sci.h"
+#include "sci/util.h"
 #include "audio/mididrv.h"
 #include "common/error.h"
 
@@ -106,8 +107,6 @@ public:
 		return _driver ? _driver->property(MIDI_PROP_MASTER_VOLUME, 0xffff) : 0;
 	}
 
-	virtual void onNewSound() {}
-
 	// Returns the current reverb, or -1 when no reverb is active
 	int8 getReverb() const { return _reverb; }
 	// Sets the current reverb, used mainly in MT-32
@@ -121,6 +120,12 @@ public:
 		}
 	}
 
+	// Prepares the driver for the playback of SCI0 midi tracks.
+	// The main purpose is the assignment of voices ("hardware" sound channels) to the 16 midi parts.
+	// This is basically the predecessor of the 0x4B midi event.
+	// Some drivers also do other things in here.
+	virtual void initTrack(SciSpan<const byte> &) {}
+
 protected:
 	SciVersion _version;
 };
diff --git a/engines/sci/sound/midiparser_sci.cpp b/engines/sci/sound/midiparser_sci.cpp
index ad4b0da397..22a5c6de9c 100644
--- a/engines/sci/sound/midiparser_sci.cpp
+++ b/engines/sci/sound/midiparser_sci.cpp
@@ -392,15 +392,11 @@ void MidiParser_SCI::sendInitCommands() {
 	// Set initial voice count
 	if (_pSnd) {
 		if (_soundVersion <= SCI_VERSION_0_LATE) {
-			static_cast<MidiPlayer *>(_driver)->onNewSound();
-
-			for (int i = 0; i < 15; ++i) {
-				byte voiceCount = 0;
-				if (_channelUsed[i]) {
-					voiceCount = _pSnd->soundRes->getInitialVoiceCount(i);
-					sendToDriver(0xB0 | i, 0x4B, voiceCount);
-				}
-			}
+			// Send header data to SCI0 sound drivers. The driver function which parses the header (opcode 3)
+			// seems to be implemented at least in all SCI0_LATE drivers. The things that the individual drivers
+			// do in that init function varies.
+			if (_track->header.byteSize())
+				static_cast<MidiPlayer *>(_driver)->initTrack(_track->header);
 		} else {
 			for (int i = 0; i < _track->channelCount; ++i) {
 				byte voiceCount = _track->channels[i].poly;