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, 63 insertions, 0 deletions

diff --git a/audio/softsynth/mt32/srchelper/srctools/include/ResamplerModel.h b/audio/softsynth/mt32/srchelper/srctools/include/ResamplerModel.h
new file mode 100644
index 0000000000..0372605e87
--- /dev/null
+++ b/audio/softsynth/mt32/srchelper/srctools/include/ResamplerModel.h
@@ -0,0 +1,63 @@
+/* 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/>.
+ */
+
+#ifndef RESAMPLER_MODEL_H
+#define RESAMPLER_MODEL_H
+
+#include "FloatSampleProvider.h"
+
+namespace SRCTools {
+
+class ResamplerStage;
+
+/** Model consists of one or more ResampleStage instances connected in a cascade. */
+namespace ResamplerModel {
+
+// Seems to be a good choice for 16-bit integer samples.
+static const double DEFAULT_DB_SNR = 106;
+
+// When using linear interpolation, oversampling factor necessary to achieve the DEFAULT_DB_SNR is about 256.
+// This figure is the upper estimation, and it can be found by analysing the frequency response of the linear interpolator.
+// When less SNR is desired, this value should also decrease in accordance.
+static const unsigned int DEFAULT_WINDOWED_SINC_MAX_DOWNSAMPLE_FACTOR = 256;
+
+// In the default resampler model, the input to the windowed sinc filter is always at least 2x oversampled during upsampling,
+// so oversampling factor of 128 should be sufficient to achieve the DEFAULT_DB_SNR with linear interpolation.
+static const unsigned int DEFAULT_WINDOWED_SINC_MAX_UPSAMPLE_FACTOR = DEFAULT_WINDOWED_SINC_MAX_DOWNSAMPLE_FACTOR / 2;
+
+
+enum Quality {
+	// Use when the speed is more important than the audio quality.
+	FASTEST,
+	// Use FAST quality setting of the IIR stage (50% of passband retained).
+	FAST,
+	// Use GOOD quality setting of the IIR stage (77% of passband retained).
+	GOOD,
+	// Use BEST quality setting of the IIR stage (95% of passband retained).
+	BEST
+};
+
+FloatSampleProvider &createResamplerModel(FloatSampleProvider &source, double sourceSampleRate, double targetSampleRate, Quality quality);
+FloatSampleProvider &createResamplerModel(FloatSampleProvider &source, ResamplerStage **stages, unsigned int stageCount);
+FloatSampleProvider &createResamplerModel(FloatSampleProvider &source, ResamplerStage &stage);
+
+void freeResamplerModel(FloatSampleProvider &model, FloatSampleProvider &source);
+
+} // namespace ResamplerModel
+
+} // namespace SRCTools
+
+#endif // RESAMPLER_MODEL_H