MT32: Update Munt to 2.0.3

This update uses upstream commit
777c51cdb4dbb4e02a53c23edea9086f0b600e26.

The new SampleRateConverter is added, but not built as we don't use it.
Also, building it without source changes will need additional include
directories.

This update of Munt reduces the stack size, and thus fixes bug #9630.

1 files changed, 74 insertions, 0 deletions

diff --git a/audio/softsynth/mt32/srchelper/InternalResampler.cpp b/audio/softsynth/mt32/srchelper/InternalResampler.cpp
new file mode 100644
index 0000000000..f76c7d117e
--- /dev/null
+++ b/audio/softsynth/mt32/srchelper/InternalResampler.cpp
@@ -0,0 +1,74 @@
+/* Copyright (C) 2015-2017 Sergey V. Mikayev
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published by
+ *  the Free Software Foundation, either version 2.1 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "InternalResampler.h"
+
+#include <SincResampler.h>
+#include <ResamplerModel.h>
+
+#include "Synth.h"
+
+using namespace SRCTools;
+
+namespace MT32Emu {
+
+class SynthWrapper : public FloatSampleProvider {
+	Synth &synth;
+
+public:
+	SynthWrapper(Synth &useSynth) : synth(useSynth)
+	{}
+
+	void getOutputSamples(FloatSample *outBuffer, unsigned int size) {
+		synth.render(outBuffer, size);
+	}
+};
+
+static FloatSampleProvider &createModel(Synth &synth, SRCTools::FloatSampleProvider &synthSource, double targetSampleRate, SampleRateConverter::Quality quality) {
+	static const double MAX_AUDIBLE_FREQUENCY = 20000.0;
+
+	const double sourceSampleRate = synth.getStereoOutputSampleRate();
+	if (quality != SampleRateConverter::FASTEST) {
+		const bool oversampledMode = synth.getStereoOutputSampleRate() == Synth::getStereoOutputSampleRate(AnalogOutputMode_OVERSAMPLED);
+		// Oversampled input allows to bypass IIR interpolation stage and, in some cases, IIR decimation stage
+		if (oversampledMode && (0.5 * sourceSampleRate) <= targetSampleRate) {
+			// NOTE: In the oversampled mode, the transition band starts at 20kHz and ends at 28kHz
+			double passband = MAX_AUDIBLE_FREQUENCY;
+			double stopband = 0.5 * sourceSampleRate + MAX_AUDIBLE_FREQUENCY;
+			ResamplerStage &resamplerStage = *SincResampler::createSincResampler(sourceSampleRate, targetSampleRate, passband, stopband, ResamplerModel::DEFAULT_DB_SNR, ResamplerModel::DEFAULT_WINDOWED_SINC_MAX_UPSAMPLE_FACTOR);
+			return ResamplerModel::createResamplerModel(synthSource, resamplerStage);
+		}
+	}
+	return ResamplerModel::createResamplerModel(synthSource, sourceSampleRate, targetSampleRate, static_cast<ResamplerModel::Quality>(quality));
+}
+
+} // namespace MT32Emu
+
+using namespace MT32Emu;
+
+InternalResampler::InternalResampler(Synth &synth, double targetSampleRate, SampleRateConverter::Quality quality) :
+	synthSource(*new SynthWrapper(synth)),
+	model(createModel(synth, synthSource, targetSampleRate, quality))
+{}
+
+InternalResampler::~InternalResampler() {
+	ResamplerModel::freeResamplerModel(model, synthSource);
+	delete &synthSource;
+}
+
+void InternalResampler::getOutputSamples(float *buffer, unsigned int length) {
+	model.getOutputSamples(buffer, length);
+}