Add ability to override gain per-SoundFont

Closes #248.

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   * This update adds support for MT-32 ROM versions 2.06, 2.07 and CM-32LN ROM version 1.00 (CM-32LN is untested).
 - Update to FluidSynth v2.2.5.
 - MT-32 LCD emulation replaced with new libmt32emu v2.6+ display emulation.
+- FluidSynth's master volume gain is now an effects profile setting and can be overridden on a per-SoundFont basis (issue #248). Thanks to @c0d3h4x0r for the suggestion!
 
 ### Fixed
 

include/config.def

@@ -76,8 +76,8 @@ END_SECTION
 
 BEGIN_SECTION(fluidsynth)
 CFG(soundfont,			int,				FluidSynthSoundFont,			0						)
-CFG(gain,			float,				FluidSynthGain,				0.2f						)
 CFG(polyphony,			int,				FluidSynthPolyphony,			200						)
+CFG(gain,			float,				FluidSynthDefaultGain,			0.2f						)
 CFG(reverb,			bool,				FluidSynthDefaultReverbActive,		true						)
 CFG(reverb_damping,		float,				FluidSynthDefaultReverbDamping,		0.0						)
 CFG(reverb_level,		float,				FluidSynthDefaultReverbLevel,		0.9						)

include/synth/fxprofile.h

@@ -27,6 +27,8 @@
 
 struct TFXProfile
 {
+	TOptional<float> nGain;
+
 	TOptional<bool> bReverbActive;
 	TOptional<float> nReverbDamping;
 	TOptional<float> nReverbLevel;

include/synth/soundfontsynth.h

@@ -34,7 +34,7 @@
 class CSoundFontSynth : public CSynthBase
 {
 public:
-	CSoundFontSynth(unsigned nSampleRate, float nGain = 0.2f, u32 nPolyphony = 256);
+	CSoundFontSynth(unsigned nSampleRate);
 	virtual ~CSoundFontSynth() override;
 
 	// CSynthBase
@@ -66,10 +66,9 @@ private:
 	fluid_settings_t* m_pSettings;
 	fluid_synth_t* m_pSynth;
 
+	u8 m_nVolume;
 	float m_nInitialGain;
-	float m_nCurrentGain;
 
-	u32 m_nPolyphony;
 	u16 m_nPercussionMask;
 	size_t m_nCurrentSoundFontIndex;
 

sdcard/mt32-pi.cfg

@@ -302,17 +302,6 @@ reversed_stereo = off
 # Values: 0-255 (0*)
 soundfont = 0
 
-# Set the master volume gain.
-#
-# The default is a low value to avoid clipping when many notes are playing at
-# once.
-#
-# The value should be a decimal value between 0.0 and 10.0. Values outside this
-# range will be clamped.
-#
-# Values: 0.0-10.0 (0.2*)
-gain = 0.2
-
 # Set the maximum number of voices that can be played simultaneously.
 #
 # Depending on the complexity of your SoundFont, you may need to reduce this
@@ -329,8 +318,8 @@ gain = 0.2
 # Values: 1-65535 (200*)
 polyphony = 200
 
-# The following settings set the default parameters for FluidSynth's reverb and
-# chorus effects.
+# The following settings set the default parameters for FluidSynth's master
+# volume gain, reverb and chorus effects.
 #
 # Each setting can be overridden on a per-SoundFont basis by adding extra
 # sections, e.g. [fluidsynth.soundfont.x], where x is the zero-based index of
@@ -338,6 +327,8 @@ polyphony = 200
 #
 # Full descriptions and valid value ranges for each setting can be found in the
 # FluidSynth documentation: https://www.fluidsynth.org/api/fluidsettings.xml
+gain = 0.2
+
 reverb = on
 reverb_damping = 0.0
 reverb_level = 0.9
@@ -356,6 +347,8 @@ chorus_speed = 0.3
 [fluidsynth.soundfont.0]
 
 # The following settings are recommended for GeneralUser GS by its author.
+gain = 0.2
+
 reverb = on
 reverb_damping = 0.19
 reverb_level = 0.5

src/config.cpp

@@ -145,6 +145,8 @@ bool CConfig::ParseFXProfileOption(const char* pString, const char* pValue, TFXP
 			return false;                                          \
 		}
 
+	MATCH("gain", float, nGain);
+
 	MATCH("reverb", bool, bReverbActive);
 	MATCH("reverb_damping", float, nReverbDamping);
 	MATCH("reverb_level", float, nReverbLevel);

src/mt32pi.cpp

@@ -392,7 +392,7 @@ bool CMT32Pi::InitSoundFontSynth()
 {
 	assert(m_pSoundFontSynth == nullptr);
 
-	m_pSoundFontSynth = new CSoundFontSynth(m_pConfig->AudioSampleRate, m_pConfig->FluidSynthGain, m_pConfig->FluidSynthPolyphony);
+	m_pSoundFontSynth = new CSoundFontSynth(m_pConfig->AudioSampleRate);
 	if (!m_pSoundFontSynth->Initialize())
 	{
 		m_pLogger->Write(MT32PiName, LogWarning, "FluidSynth init failed; no SoundFonts present?");

src/synth/soundfontsynth.cpp

@@ -129,16 +129,15 @@ extern "C"
 	}
 }
 
-CSoundFontSynth::CSoundFontSynth(unsigned nSampleRate, float nGain, u32 nPolyphony)
+CSoundFontSynth::CSoundFontSynth(unsigned nSampleRate)
 	: CSynthBase(nSampleRate),
 
 	  m_pSettings(nullptr),
 	  m_pSynth(nullptr),
 
-	  m_nInitialGain(nGain),
-	  m_nCurrentGain(nGain),
+	  m_nVolume(100),
+	  m_nInitialGain(0.2f),
 
-	  m_nPolyphony(nPolyphony),
 	  m_nPercussionMask(1 << 9),
 	  m_nCurrentSoundFontIndex(0)
 {
@@ -298,9 +297,9 @@ void CSoundFontSynth::AllSoundOff()
 
 void CSoundFontSynth::SetMasterVolume(u8 nVolume)
 {
-	m_nCurrentGain = nVolume / 100.0f * m_nInitialGain;
+	m_nVolume = nVolume;
 	m_Lock.Acquire();
-	fluid_synth_set_gain(m_pSynth, m_nCurrentGain);
+	fluid_synth_set_gain(m_pSynth, m_nVolume / 100.0f * m_nInitialGain);
 	m_Lock.Release();
 }
 
@@ -393,8 +392,10 @@ bool CSoundFontSynth::Reinitialize(const char* pSoundFontPath, const TFXProfile*
 		return false;
 	}
 
-	fluid_synth_set_gain(m_pSynth, m_nCurrentGain);
-	fluid_synth_set_polyphony(m_pSynth, m_nPolyphony);
+	fluid_synth_set_polyphony(m_pSynth, pConfig->FluidSynthPolyphony);
+
+	m_nInitialGain = pFXProfile->nGain.ValueOr(pConfig->FluidSynthDefaultGain);
+	fluid_synth_set_gain(m_pSynth, m_nVolume / 100.0f * m_nInitialGain);
 
 	// Use values from effects profile if set, otherwise use defaults
 	fluid_synth_reverb_on(m_pSynth, -1, pFXProfile->bReverbActive.ValueOr(pConfig->FluidSynthDefaultReverbActive));
@@ -442,9 +443,11 @@ void CSoundFontSynth::ResetMIDIMonitor()
 void CSoundFontSynth::DumpFXSettings() const
 {
 	CLogger* const pLogger = CLogger::Get();
-	double nReverbDamping, nReverbLevel, nReverbRoomSize, nReverbWidth, nChorusDepth, nChorusLevel, nChorusSpeed;
+	double nGain, nReverbDamping, nReverbLevel, nReverbRoomSize, nReverbWidth, nChorusDepth, nChorusLevel, nChorusSpeed;
 	int nChorusVoices;
 
+	nGain = fluid_synth_get_gain(m_pSynth);
+
 	assert(fluid_synth_get_reverb_group_damp(m_pSynth, -1, &nReverbDamping) == FLUID_OK);
 	assert(fluid_synth_get_reverb_group_level(m_pSynth, -1, &nReverbLevel) == FLUID_OK);
 	assert(fluid_synth_get_reverb_group_roomsize(m_pSynth, -1, &nReverbRoomSize) == FLUID_OK);
@@ -455,6 +458,8 @@ void CSoundFontSynth::DumpFXSettings() const
 	assert(fluid_synth_get_chorus_group_nr(m_pSynth, -1, &nChorusVoices) == FLUID_OK);
 	assert(fluid_synth_get_chorus_group_speed(m_pSynth, -1, &nChorusSpeed) == FLUID_OK);
 
+	pLogger->Write(SoundFontSynthName, LogNotice, "Gain: %.2f", nGain);
+
 	pLogger->Write(SoundFontSynthName, LogNotice,
 		"Reverb: %.2f, %.2f, %.2f, %.2f",
 		nReverbDamping,