From 8c65661b91305143a51b8332e262e97e9a04d513 Mon Sep 17 00:00:00 2001
From: oparviai <oparviai@f3a24b6a-cf45-0410-b55a-8c22e2698227>
Date: Wed, 12 Jun 2013 15:24:44 +0000
Subject: [PATCH] Added support for multi-channel audio

---
 README.html                             |   8 +-
 include/STTypes.h                       |   7 +
 include/SoundTouch.h                    |   4 +-
 source/SoundStretch/soundstretch.sln    |  36 ++-
 source/SoundStretch/soundstretch.vcproj | 265 +++++++++++++-------
 source/SoundTouch/FIRFilter.cpp         |  73 +++++-
 source/SoundTouch/FIRFilter.h           |   1 +
 source/SoundTouch/RateTransposer.cpp    | 238 +++++++++++++-----
 source/SoundTouch/RateTransposer.h      |   7 +-
 source/SoundTouch/SoundTouch.cpp        |   9 +-
 source/SoundTouch/SoundTouch.vcproj     | 309 ++++++++++++++++--------
 source/SoundTouch/TDStretch.cpp         |  74 +++++-
 source/SoundTouch/TDStretch.h           |   1 +
 13 files changed, 734 insertions(+), 298 deletions(-)
diff --git a/README.html b/README.html
index b6c8ffb..609241c 100644
--- a/README.html
+++ b/README.html
@@ -15,8 +15,8 @@
 </head>
 <body class="normal">
 <hr>
-<h1>SoundTouch audio processing library v1.7.1</h1>
-<p class="normal">SoundTouch library Copyright © Olli Parviainen 2001-2012 </p>
+<h1>SoundTouch audio processing library v1.7.2 (developing)</h1>
+<p class="normal">SoundTouch library Copyright © Olli Parviainen 2001-2013 </p>
 <hr>
 <h2>1. Introduction </h2>
 <p>SoundTouch is an open-source audio processing library that allows
@@ -513,6 +513,10 @@ and estimates the BPM rate:</p>
 <hr>
 <h2>5. Change History</h2>
 <h3>5.1. SoundTouch library Change History </h3>
+<p><b>1.7.2 (under work):</b></p>
+<ul>
+    <li>Added support for multi-channel audio processing
+</ul>
 <p><b>1.7.1:</b></p>
 <ul>
     <li>Added files for Android compilation
diff --git a/include/STTypes.h b/include/STTypes.h
index 92016fb..46da0fe 100644
--- a/include/STTypes.h
+++ b/include/STTypes.h
@@ -78,6 +78,13 @@ namespace soundtouch
     //#undef SOUNDTOUCH_INTEGER_SAMPLES
     //#undef SOUNDTOUCH_FLOAT_SAMPLES
 
+    /// If following flag is defined, always uses multichannel processing 
+    /// routines also for mono and stero sound. This is for routine testing 
+    /// purposes; output should be same with either routines, yet disabling 
+    /// the dedicated mono/stereo processing routines will result in slower 
+    /// runtime performance so recommendation is to keep this off.
+    // #define USE_MULTICH_ALWAYS
+
     #if (defined(__SOFTFP__))
         // For Android compilation: Force use of Integer samples in case that
         // compilation uses soft-floating point emulation - soft-fp is way too slow
diff --git a/include/SoundTouch.h b/include/SoundTouch.h
index b54bc39..4d3d80f 100644
--- a/include/SoundTouch.h
+++ b/include/SoundTouch.h
@@ -79,10 +79,10 @@ namespace soundtouch
 {
 
 /// Soundtouch library version string
-#define SOUNDTOUCH_VERSION          "1.7.1"
+#define SOUNDTOUCH_VERSION          "1.7.2 (dev)"
 
 /// SoundTouch library version id
-#define SOUNDTOUCH_VERSION_ID       (10701)
+#define SOUNDTOUCH_VERSION_ID       (10702)
 
 //
 // Available setting IDs for the 'setSetting' & 'get_setting' functions:
diff --git a/source/SoundStretch/soundstretch.sln b/source/SoundStretch/soundstretch.sln
index dfdc4ac..1b9a49a 100644
--- a/source/SoundStretch/soundstretch.sln
+++ b/source/SoundStretch/soundstretch.sln
@@ -1,32 +1,28 @@
-Microsoft Visual Studio Solution File, Format Version 8.00
+Microsoft Visual Studio Solution File, Format Version 10.00
+# Visual Studio 2008
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "soundstretch", "soundstretch.vcproj", "{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}"
 	ProjectSection(ProjectDependencies) = postProject
 		{68A5DD20-7057-448B-8FE0-B6AC8D205509} = {68A5DD20-7057-448B-8FE0-B6AC8D205509}
 	EndProjectSection
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "SoundTouch", "..\SoundTouch\SoundTouch.vcproj", "{68A5DD20-7057-448B-8FE0-B6AC8D205509}"
-	ProjectSection(ProjectDependencies) = postProject
-	EndProjectSection
 EndProject
 Global
-	GlobalSection(SolutionConfiguration) = preSolution
-		Debug = Debug
-		Release = Release
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Win32 = Debug|Win32
+		Release|Win32 = Release|Win32
 	EndGlobalSection
-	GlobalSection(ProjectDependencies) = postSolution
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}.Debug|Win32.ActiveCfg = Debug|Win32
+		{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}.Debug|Win32.Build.0 = Debug|Win32
+		{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}.Release|Win32.ActiveCfg = Release|Win32
+		{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}.Release|Win32.Build.0 = Release|Win32
+		{68A5DD20-7057-448B-8FE0-B6AC8D205509}.Debug|Win32.ActiveCfg = Debug|Win32
+		{68A5DD20-7057-448B-8FE0-B6AC8D205509}.Debug|Win32.Build.0 = Debug|Win32
+		{68A5DD20-7057-448B-8FE0-B6AC8D205509}.Release|Win32.ActiveCfg = Release|Win32
+		{68A5DD20-7057-448B-8FE0-B6AC8D205509}.Release|Win32.Build.0 = Release|Win32
 	EndGlobalSection
-	GlobalSection(ProjectConfiguration) = postSolution
-		{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}.Debug.ActiveCfg = Debug|Win32
-		{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}.Debug.Build.0 = Debug|Win32
-		{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}.Release.ActiveCfg = Release|Win32
-		{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}.Release.Build.0 = Release|Win32
-		{68A5DD20-7057-448B-8FE0-B6AC8D205509}.Debug.ActiveCfg = Debug|Win32
-		{68A5DD20-7057-448B-8FE0-B6AC8D205509}.Debug.Build.0 = Debug|Win32
-		{68A5DD20-7057-448B-8FE0-B6AC8D205509}.Release.ActiveCfg = Release|Win32
-		{68A5DD20-7057-448B-8FE0-B6AC8D205509}.Release.Build.0 = Release|Win32
-	EndGlobalSection
-	GlobalSection(ExtensibilityGlobals) = postSolution
-	EndGlobalSection
-	GlobalSection(ExtensibilityAddIns) = postSolution
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
 	EndGlobalSection
 EndGlobal
diff --git a/source/SoundStretch/soundstretch.vcproj b/source/SoundStretch/soundstretch.vcproj
index 5643c1b..53eb827 100644
--- a/source/SoundStretch/soundstretch.vcproj
+++ b/source/SoundStretch/soundstretch.vcproj
@@ -1,30 +1,53 @@
 <?xml version="1.0" encoding="Windows-1252"?>
 <VisualStudioProject
 	ProjectType="Visual C++"
-	Version="7.10"
+	Version="9.00"
 	Name="soundstretch"
-	SccProjectName=""
-	SccLocalPath="">
+	ProjectGUID="{5AACDFFA-D491-44B8-A332-DA7ACCAAF2AF}"
+	TargetFrameworkVersion="131072"
+	>
 	<Platforms>
 		<Platform
-			Name="Win32"/>
+			Name="Win32"
+		/>
 	</Platforms>
+	<ToolFiles>
+	</ToolFiles>
 	<Configurations>
 		<Configuration
 			Name="Debug|Win32"
 			OutputDirectory=".\Debug"
 			IntermediateDirectory=".\Debug"
 			ConfigurationType="1"
+			InheritedPropertySheets="$(VCInstallDir)VCProjectDefaults\UpgradeFromVC71.vsprops"
 			UseOfMFC="0"
-			ATLMinimizesCRunTimeLibraryUsage="FALSE"
-			CharacterSet="2">
+			ATLMinimizesCRunTimeLibraryUsage="false"
+			CharacterSet="2"
+			>
+			<Tool
+				Name="VCPreBuildEventTool"
+			/>
+			<Tool
+				Name="VCCustomBuildTool"
+			/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"
+			/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"
+			/>
+			<Tool
+				Name="VCMIDLTool"
+				TypeLibraryName=".\Debug/soundstretch.tlb"
+				HeaderFileName=""
+			/>
 			<Tool
 				Name="VCCLCompilerTool"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\..\include"
 				PreprocessorDefinitions="WIN32;_DEBUG;_CONSOLE;_CRT_SECURE_NO_WARNINGS"
 				BasicRuntimeChecks="3"
-				RuntimeLibrary="5"
+				RuntimeLibrary="1"
 				StructMemberAlignment="5"
 				PrecompiledHeaderFile=".\Debug/soundstretch.pch"
 				AssemblerListingLocation=".\Debug/"
@@ -32,117 +55,155 @@
 				ProgramDataBaseFileName=".\Debug/"
 				BrowseInformation="1"
 				WarningLevel="3"
-				SuppressStartupBanner="TRUE"
+				SuppressStartupBanner="true"
 				DebugInformationFormat="4"
-				CompileAs="0"/>
+				CompileAs="0"
+			/>
 			<Tool
-				Name="VCCustomBuildTool"/>
+				Name="VCManagedResourceCompilerTool"
+			/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="_DEBUG"
+				Culture="1035"
+			/>
+			<Tool
+				Name="VCPreLinkEventTool"
+			/>
 			<Tool
 				Name="VCLinkerTool"
 				AdditionalDependencies="SoundTouchD.lib"
 				OutputFile="Debug/soundstretchD.exe"
 				LinkIncremental="2"
-				SuppressStartupBanner="TRUE"
+				SuppressStartupBanner="true"
 				AdditionalLibraryDirectories="..\..\lib"
 				IgnoreDefaultLibraryNames="libc"
-				GenerateDebugInformation="TRUE"
+				GenerateDebugInformation="true"
 				ProgramDatabaseFile=".\Debug/soundstretchD.pdb"
-				GenerateMapFile="TRUE"
+				GenerateMapFile="true"
 				MapFileName=".\Debug/soundstretchD.map"
 				SubSystem="1"
-				TargetMachine="1"/>
+				RandomizedBaseAddress="1"
+				DataExecutionPrevention="0"
+				TargetMachine="1"
+			/>
 			<Tool
-				Name="VCMIDLTool"
-				TypeLibraryName=".\Debug/soundstretch.tlb"
-				HeaderFileName=""/>
+				Name="VCALinkTool"
+			/>
+			<Tool
+				Name="VCManifestTool"
+			/>
+			<Tool
+				Name="VCXDCMakeTool"
+			/>
+			<Tool
+				Name="VCBscMakeTool"
+			/>
+			<Tool
+				Name="VCFxCopTool"
+			/>
+			<Tool
+				Name="VCAppVerifierTool"
+			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				CommandLine="copy          Debug\soundstretchD.exe          ..\..\bin\"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"
-				PreprocessorDefinitions="_DEBUG"
-				Culture="1035"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+				CommandLine="copy          Debug\soundstretchD.exe          ..\..\bin\"
+			/>
 		</Configuration>
 		<Configuration
 			Name="Release|Win32"
 			OutputDirectory=".\Release"
 			IntermediateDirectory=".\Release"
 			ConfigurationType="1"
+			InheritedPropertySheets="$(VCInstallDir)VCProjectDefaults\UpgradeFromVC71.vsprops"
 			UseOfMFC="0"
-			ATLMinimizesCRunTimeLibraryUsage="FALSE"
-			CharacterSet="2">
+			ATLMinimizesCRunTimeLibraryUsage="false"
+			CharacterSet="2"
+			>
+			<Tool
+				Name="VCPreBuildEventTool"
+			/>
+			<Tool
+				Name="VCCustomBuildTool"
+			/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"
+			/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"
+			/>
+			<Tool
+				Name="VCMIDLTool"
+				TypeLibraryName=".\Release/soundstretch.tlb"
+				HeaderFileName=""
+			/>
 			<Tool
 				Name="VCCLCompilerTool"
 				Optimization="3"
-				GlobalOptimizations="FALSE"
 				InlineFunctionExpansion="2"
-				EnableIntrinsicFunctions="TRUE"
+				EnableIntrinsicFunctions="true"
 				AdditionalIncludeDirectories="..\..\include"
 				PreprocessorDefinitions="WIN32;NDEBUG;_CONSOLE;_CRT_SECURE_NO_WARNINGS"
-				StringPooling="TRUE"
-				RuntimeLibrary="4"
-				EnableFunctionLevelLinking="TRUE"
+				StringPooling="true"
+				RuntimeLibrary="0"
+				EnableFunctionLevelLinking="true"
 				PrecompiledHeaderFile=".\Release/soundstretch.pch"
 				AssemblerListingLocation=".\Release/"
 				ObjectFile=".\Release/"
 				ProgramDataBaseFileName=".\Release/"
 				WarningLevel="3"
-				SuppressStartupBanner="TRUE"
+				SuppressStartupBanner="true"
 				DebugInformationFormat="0"
-				CompileAs="0"/>
+				CompileAs="0"
+			/>
 			<Tool
-				Name="VCCustomBuildTool"/>
+				Name="VCManagedResourceCompilerTool"
+			/>
+			<Tool
+				Name="VCResourceCompilerTool"
+				PreprocessorDefinitions="NDEBUG"
+				Culture="1035"
+			/>
+			<Tool
+				Name="VCPreLinkEventTool"
+			/>
 			<Tool
 				Name="VCLinkerTool"
 				AdditionalDependencies="SoundTouch.lib"
 				OutputFile=".\Release/soundstretch.exe"
 				LinkIncremental="1"
-				SuppressStartupBanner="TRUE"
+				SuppressStartupBanner="true"
 				AdditionalLibraryDirectories="..\..\lib"
-				GenerateDebugInformation="FALSE"
-				GenerateMapFile="TRUE"
+				GenerateDebugInformation="false"
+				GenerateMapFile="true"
 				MapFileName=".\Release/soundstretch.map"
 				SubSystem="1"
-				TargetMachine="1"/>
+				RandomizedBaseAddress="1"
+				DataExecutionPrevention="0"
+				TargetMachine="1"
+			/>
 			<Tool
-				Name="VCMIDLTool"
-				TypeLibraryName=".\Release/soundstretch.tlb"
-				HeaderFileName=""/>
+				Name="VCALinkTool"
+			/>
+			<Tool
+				Name="VCManifestTool"
+			/>
+			<Tool
+				Name="VCXDCMakeTool"
+			/>
+			<Tool
+				Name="VCBscMakeTool"
+			/>
+			<Tool
+				Name="VCFxCopTool"
+			/>
+			<Tool
+				Name="VCAppVerifierTool"
+			/>
 			<Tool
 				Name="VCPostBuildEventTool"
-				CommandLine="copy          Release\soundstretch.exe          ..\..\bin\"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
-			<Tool
-				Name="VCResourceCompilerTool"
-				PreprocessorDefinitions="NDEBUG"
-				Culture="1035"/>
-			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
-			<Tool
-				Name="VCXMLDataGeneratorTool"/>
-			<Tool
-				Name="VCWebDeploymentTool"/>
-			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
-			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+				CommandLine="copy          Release\soundstretch.exe          ..\..\bin\"
+			/>
 		</Configuration>
 	</Configurations>
 	<References>
@@ -150,84 +211,104 @@
 	<Files>
 		<Filter
 			Name="Source Files"
-			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
+			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat"
+			>
 			<File
-				RelativePath="main.cpp">
+				RelativePath="main.cpp"
+				>
 				<FileConfiguration
-					Name="Debug|Win32">
+					Name="Debug|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="0"
 						AdditionalIncludeDirectories=""
 						PreprocessorDefinitions=""
 						BasicRuntimeChecks="3"
-						BrowseInformation="1"/>
+						BrowseInformation="1"
+					/>
 				</FileConfiguration>
 				<FileConfiguration
-					Name="Release|Win32">
+					Name="Release|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="2"
 						AdditionalIncludeDirectories=""
-						PreprocessorDefinitions=""/>
+						PreprocessorDefinitions=""
+					/>
 				</FileConfiguration>
 			</File>
 			<File
-				RelativePath="RunParameters.cpp">
+				RelativePath="RunParameters.cpp"
+				>
 				<FileConfiguration
-					Name="Debug|Win32">
+					Name="Debug|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="0"
 						AdditionalIncludeDirectories=""
 						PreprocessorDefinitions=""
 						BasicRuntimeChecks="3"
-						BrowseInformation="1"/>
+						BrowseInformation="1"
+					/>
 				</FileConfiguration>
 				<FileConfiguration
-					Name="Release|Win32">
+					Name="Release|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="2"
 						AdditionalIncludeDirectories=""
-						PreprocessorDefinitions=""/>
+						PreprocessorDefinitions=""
+					/>
 				</FileConfiguration>
 			</File>
 			<File
-				RelativePath="WavFile.cpp">
+				RelativePath="WavFile.cpp"
+				>
 				<FileConfiguration
-					Name="Debug|Win32">
+					Name="Debug|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="0"
 						AdditionalIncludeDirectories=""
 						PreprocessorDefinitions=""
 						BasicRuntimeChecks="3"
-						BrowseInformation="1"/>
+						BrowseInformation="1"
+					/>
 				</FileConfiguration>
 				<FileConfiguration
-					Name="Release|Win32">
+					Name="Release|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="2"
 						AdditionalIncludeDirectories=""
-						PreprocessorDefinitions=""/>
+						PreprocessorDefinitions=""
+					/>
 				</FileConfiguration>
 			</File>
 		</Filter>
 		<Filter
 			Name="Header Files"
-			Filter="h;hpp;hxx;hm;inl">
+			Filter="h;hpp;hxx;hm;inl"
+			>
 			<File
-				RelativePath="RunParameters.h">
+				RelativePath="RunParameters.h"
+				>
 			</File>
 			<File
-				RelativePath="WavFile.h">
+				RelativePath="WavFile.h"
+				>
 			</File>
 		</Filter>
 		<Filter
 			Name="Resource Files"
-			Filter="ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe">
+			Filter="ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe"
+			>
 		</Filter>
 	</Files>
 	<Globals>
diff --git a/source/SoundTouch/FIRFilter.cpp b/source/SoundTouch/FIRFilter.cpp
index f882f7e..5cc774f 100644
--- a/source/SoundTouch/FIRFilter.cpp
+++ b/source/SoundTouch/FIRFilter.cpp
@@ -167,6 +167,60 @@ uint FIRFilter::evaluateFilterMono(SAMPLETYPE *dest, const SAMPLETYPE *src, uint
 }
 
 
+uint FIRFilter::evaluateFilterMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples, uint numChannels) const
+{
+    uint i, j, end, c;
+    LONG_SAMPLETYPE *sum=(LONG_SAMPLETYPE*)alloca(numChannels*sizeof(*sum));
+#ifdef SOUNDTOUCH_FLOAT_SAMPLES
+    // when using floating point samples, use a scaler instead of a divider
+    // because division is much slower operation than multiplying.
+    double dScaler = 1.0 / (double)resultDivider;
+#endif
+
+    assert(length != 0);
+    assert(src != NULL);
+    assert(dest != NULL);
+    assert(filterCoeffs != NULL);
+
+    end = numChannels * (numSamples - length);
+
+    for (c = 0; c < numChannels; c ++)
+    {
+        sum[c] = 0;
+    }
+
+    for (j = 0; j < end; j += numChannels)
+    {
+        const SAMPLETYPE *ptr;
+
+        ptr = src + j;
+
+        for (i = 0; i < length; i ++)
+        {
+            SAMPLETYPE coef=filterCoeffs[i];
+            for (c = 0; c < numChannels; c ++)
+            {
+                sum[c] += ptr[0] * coef;
+                ptr ++;
+            }
+        }
+        
+        for (c = 0; c < numChannels; c ++)
+        {
+#ifdef SOUNDTOUCH_INTEGER_SAMPLES
+            sum[c] >>= resultDivFactor;
+#else
+            sum[c] *= dScaler;
+#endif // SOUNDTOUCH_INTEGER_SAMPLES
+            *dest = (SAMPLETYPE)sum[c];
+            dest++;
+            sum[c] = 0;
+        }
+    }
+    return numSamples - length;
+}
+
+
 // Set filter coeffiecients and length.
 //
 // Throws an exception if filter length isn't divisible by 8
@@ -201,16 +255,25 @@ uint FIRFilter::getLength() const
 // smaller than the amount of input samples.
 uint FIRFilter::evaluate(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples, uint numChannels) const
 {
-    assert(numChannels == 1 || numChannels == 2);
-
     assert(length > 0);
     assert(lengthDiv8 * 8 == length);
+
     if (numSamples < length) return 0;
-    if (numChannels == 2) 
+
+#ifndef USE_MULTICH_ALWAYS
+    if (numChannels == 1)
+    {
+        return evaluateFilterMono(dest, src, numSamples);
+    } 
+    else if (numChannels == 2)
     {
         return evaluateFilterStereo(dest, src, numSamples);
-    } else {
-        return evaluateFilterMono(dest, src, numSamples);
+    }
+    else
+#endif // USE_MULTICH_ALWAYS
+    {
+        assert(numChannels > 0);
+        return evaluateFilterMulti(dest, src, numSamples, numChannels);
     }
 }
 
diff --git a/source/SoundTouch/FIRFilter.h b/source/SoundTouch/FIRFilter.h
index fcee72a..622b9c4 100644
--- a/source/SoundTouch/FIRFilter.h
+++ b/source/SoundTouch/FIRFilter.h
@@ -71,6 +71,7 @@ protected:
     virtual uint evaluateFilterMono(SAMPLETYPE *dest, 
                                     const SAMPLETYPE *src, 
                                     uint numSamples) const;
+    virtual uint evaluateFilterMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples, uint numChannels) const;
 
 public:
     FIRFilter();
diff --git a/source/SoundTouch/RateTransposer.cpp b/source/SoundTouch/RateTransposer.cpp
index 772e95b..6913972 100644
--- a/source/SoundTouch/RateTransposer.cpp
+++ b/source/SoundTouch/RateTransposer.cpp
@@ -55,17 +55,17 @@ class RateTransposerInteger : public RateTransposer
 protected:
     int iSlopeCount;
     int iRate;
-    SAMPLETYPE sPrevSampleL, sPrevSampleR;
+    SAMPLETYPE *sPrevSample;
 
     virtual void resetRegisters();
 
-    virtual uint transposeStereo(SAMPLETYPE *dest, 
+    virtual int transposeStereo(SAMPLETYPE *dest, 
                          const SAMPLETYPE *src, 
                          uint numSamples);
-    virtual uint transposeMono(SAMPLETYPE *dest, 
+    virtual int transposeMono(SAMPLETYPE *dest, 
                        const SAMPLETYPE *src, 
                        uint numSamples);
-
+    virtual int transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples);
 public:
     RateTransposerInteger();
     virtual ~RateTransposerInteger();
@@ -83,16 +83,17 @@ class RateTransposerFloat : public RateTransposer
 {
 protected:
     float fSlopeCount;
-    SAMPLETYPE sPrevSampleL, sPrevSampleR;
+    SAMPLETYPE *sPrevSample;
 
     virtual void resetRegisters();
 
-    virtual uint transposeStereo(SAMPLETYPE *dest, 
+    virtual int transposeStereo(SAMPLETYPE *dest, 
                          const SAMPLETYPE *src, 
                          uint numSamples);
-    virtual uint transposeMono(SAMPLETYPE *dest, 
+    virtual int transposeMono(SAMPLETYPE *dest, 
                        const SAMPLETYPE *src, 
                        uint numSamples);
+    virtual int transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples);
 
 public:
     RateTransposerFloat();
@@ -260,7 +261,7 @@ void RateTransposer::downsample(const SAMPLETYPE *src, uint nSamples)
     count = pAAFilter->evaluate(tempBuffer.ptrEnd(sizeTemp), 
         storeBuffer.ptrBegin(), sizeTemp, (uint)numChannels);
 
-	if (count == 0) return;
+    if (count == 0) return;
 
     // Remove the filtered samples from 'storeBuffer'
     storeBuffer.receiveSamples(count);
@@ -308,15 +309,22 @@ void RateTransposer::processSamples(const SAMPLETYPE *src, uint nSamples)
 
 // Transposes the sample rate of the given samples using linear interpolation. 
 // Returns the number of samples returned in the "dest" buffer
-inline uint RateTransposer::transpose(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
+inline int RateTransposer::transpose(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
 {
-    if (numChannels == 2) 
+#ifndef USE_MULTICH_ALWAYS
+    if (numChannels == 1)
+    {
+        return transposeMono(dest, src, nSamples);
+    }
+    else if (numChannels == 2) 
     {
         return transposeStereo(dest, src, nSamples);
     } 
     else 
+#endif // USE_MULTICH_ALWAYS
     {
-        return transposeMono(dest, src, nSamples);
+        assert(numChannels > 0);
+        return transposeMulti(dest, src, nSamples);
     }
 }
 
@@ -327,7 +335,7 @@ void RateTransposer::setChannels(int nChannels)
     assert(nChannels > 0);
     if (numChannels == nChannels) return;
 
-    assert(nChannels == 1 || nChannels == 2);
+//    assert(nChannels == 1 || nChannels == 2);
     numChannels = nChannels;
 
     storeBuffer.setChannels(numChannels);
@@ -371,6 +379,7 @@ RateTransposerInteger::RateTransposerInteger() : RateTransposer()
 {
     // Notice: use local function calling syntax for sake of clarity, 
     // to indicate the fact that C++ constructor can't call virtual functions.
+    sPrevSample=0;
     RateTransposerInteger::resetRegisters();
     RateTransposerInteger::setRate(1.0f);
 }
@@ -378,14 +387,16 @@ RateTransposerInteger::RateTransposerInteger() : RateTransposer()
 
 RateTransposerInteger::~RateTransposerInteger()
 {
+    if (sPrevSample) delete[] sPrevSample;
 }
 
 
 void RateTransposerInteger::resetRegisters()
 {
     iSlopeCount = 0;
-    sPrevSampleL = 
-    sPrevSampleR = 0;
+    if (sPrevSample) delete[] sPrevSample;
+    sPrevSample = new SAMPLETYPE[numChannels];
+    memset(sPrevSample, 0, numChannels*sizeof(*sPrevSample));
 }
 
 
@@ -393,21 +404,21 @@ void RateTransposerInteger::resetRegisters()
 // Transposes the sample rate of the given samples using linear interpolation. 
 // 'Mono' version of the routine. Returns the number of samples returned in 
 // the "dest" buffer
-uint RateTransposerInteger::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
+int RateTransposerInteger::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
 {
-    unsigned int i, used;
+    int i, remain;
     LONG_SAMPLETYPE temp, vol1;
 
     if (nSamples == 0) return 0;  // no samples, no work
 
-	used = 0;    
+    remain = nSamples - 1;
     i = 0;
 
     // Process the last sample saved from the previous call first...
     while (iSlopeCount <= SCALE) 
     {
         vol1 = (LONG_SAMPLETYPE)(SCALE - iSlopeCount);
-        temp = vol1 * sPrevSampleL + iSlopeCount * src[0];
+        temp = vol1 * sPrevSample[0] + iSlopeCount * src[0];
         dest[i] = (SAMPLETYPE)(temp / SCALE);
         i++;
         iSlopeCount += iRate;
@@ -420,11 +431,12 @@ uint RateTransposerInteger::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *sr
         while (iSlopeCount > SCALE) 
         {
             iSlopeCount -= SCALE;
-            used ++;
-            if (used >= nSamples - 1) goto end;
+            src ++;
+            remain --;
+            if (remain == 0) goto end;
         }
         vol1 = (LONG_SAMPLETYPE)(SCALE - iSlopeCount);
-        temp = src[used] * vol1 + iSlopeCount * src[used + 1];
+        temp = src[0] * vol1 + iSlopeCount * src[1];
         dest[i] = (SAMPLETYPE)(temp / SCALE);
 
         i++;
@@ -432,7 +444,7 @@ uint RateTransposerInteger::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *sr
     }
 end:
     // Store the last sample for the next round
-    sPrevSampleL = src[nSamples - 1];
+    sPrevSample[0] = src[0];
 
     return i;
 }
@@ -441,23 +453,23 @@ end:
 // Transposes the sample rate of the given samples using linear interpolation. 
 // 'Stereo' version of the routine. Returns the number of samples returned in 
 // the "dest" buffer
-uint RateTransposerInteger::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
+int RateTransposerInteger::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
 {
-    unsigned int srcPos, i, used;
+    int i, remain;
     LONG_SAMPLETYPE temp, vol1;
 
     if (nSamples == 0) return 0;  // no samples, no work
 
-    used = 0;    
+    remain = nSamples - 1;
     i = 0;
 
     // Process the last sample saved from the sPrevSampleLious call first...
     while (iSlopeCount <= SCALE) 
     {
         vol1 = (LONG_SAMPLETYPE)(SCALE - iSlopeCount);
-        temp = vol1 * sPrevSampleL + iSlopeCount * src[0];
+        temp = vol1 * sPrevSample[0] + iSlopeCount * src[0];
         dest[2 * i] = (SAMPLETYPE)(temp / SCALE);
-        temp = vol1 * sPrevSampleR + iSlopeCount * src[1];
+        temp = vol1 * sPrevSample[1] + iSlopeCount * src[1];
         dest[2 * i + 1] = (SAMPLETYPE)(temp / SCALE);
         i++;
         iSlopeCount += iRate;
@@ -470,14 +482,14 @@ uint RateTransposerInteger::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *
         while (iSlopeCount > SCALE) 
         {
             iSlopeCount -= SCALE;
-            used ++;
-            if (used >= nSamples - 1) goto end;
+            remain --;
+            src += 2;
+            if (remain == 0) goto end;
         }
-        srcPos = 2 * used;
         vol1 = (LONG_SAMPLETYPE)(SCALE - iSlopeCount);
-        temp = src[srcPos] * vol1 + iSlopeCount * src[srcPos + 2];
+        temp = src[0] * vol1 + iSlopeCount * src[2];
         dest[2 * i] = (SAMPLETYPE)(temp / SCALE);
-        temp = src[srcPos + 1] * vol1 + iSlopeCount * src[srcPos + 3];
+        temp = src[1] * vol1 + iSlopeCount * src[3];
         dest[2 * i + 1] = (SAMPLETYPE)(temp / SCALE);
 
         i++;
@@ -485,13 +497,68 @@ uint RateTransposerInteger::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *
     }
 end:
     // Store the last sample for the next round
-    sPrevSampleL = src[2 * nSamples - 2];
-    sPrevSampleR = src[2 * nSamples - 1];
+    sPrevSample[0] = src[0];
+    sPrevSample[1] = src[1];
 
     return i;
 }
 
 
+int RateTransposerInteger::transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
+{
+    int i, remaining;
+    LONG_SAMPLETYPE temp, vol1;
+
+    if (nSamples == 0) return 0;  // no samples, no work
+
+    remaining = nSamples - 1;
+    i = 0;
+
+    // Process the last sample saved from the sPrevSampleLious call first...
+    while (iSlopeCount <= SCALE)
+    {
+        for (int c = 0; c < numChannels; c ++)
+        {
+            vol1 = (SCALE - iSlopeCount);
+            temp = vol1 * sPrevSample[c] + iSlopeCount * src[c];
+            *dest = (SAMPLETYPE)(temp / SCALE);
+            dest ++;
+        }
+        i++;
+
+        iSlopeCount += iRate;
+    }
+    // now always (iSlopeCount > SCALE)
+    iSlopeCount -= SCALE;
+
+    while (1)
+    {
+        while (iSlopeCount > SCALE) 
+        {
+            iSlopeCount -= SCALE;
+            src += numChannels;
+            remaining --;
+            if (remaining == 0) goto end;
+        }
+
+        for (int c = 0; c < numChannels; c ++)
+        {
+            vol1 = (SCALE - iSlopeCount);
+            temp = src[c] * vol1 + iSlopeCount * src[c + numChannels];
+            *dest = (SAMPLETYPE)(temp / SCALE);
+            dest++;
+        }
+
+        i++;
+        iSlopeCount += iRate;
+    }
+end:
+    // Store the last sample for the next round
+    memcpy(sPrevSample, src, numChannels * sizeof(SAMPLETYPE));
+
+    return i;
+}
+
 // Sets new target iRate. Normal iRate = 1.0, smaller values represent slower 
 // iRate, larger faster iRates.
 void RateTransposerInteger::setRate(float newRate)
@@ -512,6 +579,7 @@ RateTransposerFloat::RateTransposerFloat() : RateTransposer()
 {
     // Notice: use local function calling syntax for sake of clarity, 
     // to indicate the fact that C++ constructor can't call virtual functions.
+    sPrevSample=0;
     RateTransposerFloat::resetRegisters();
     RateTransposerFloat::setRate(1.0f);
 }
@@ -519,14 +587,16 @@ RateTransposerFloat::RateTransposerFloat() : RateTransposer()
 
 RateTransposerFloat::~RateTransposerFloat()
 {
+    if (sPrevSample) delete[] sPrevSample;
 }
 
 
 void RateTransposerFloat::resetRegisters()
 {
     fSlopeCount = 0;
-    sPrevSampleL = 
-    sPrevSampleR = 0;
+    if (sPrevSample) delete[] sPrevSample;
+    sPrevSample = new SAMPLETYPE[numChannels];
+    memset(sPrevSample, 0, numChannels*sizeof(*sPrevSample));
 }
 
 
@@ -534,17 +604,17 @@ void RateTransposerFloat::resetRegisters()
 // Transposes the sample rate of the given samples using linear interpolation. 
 // 'Mono' version of the routine. Returns the number of samples returned in 
 // the "dest" buffer
-uint RateTransposerFloat::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
+int RateTransposerFloat::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
 {
-    unsigned int i, used;
+    int i, remain;
 
-    used = 0;    
+    remain = 0;
     i = 0;
 
     // Process the last sample saved from the previous call first...
     while (fSlopeCount <= 1.0f) 
     {
-        dest[i] = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSampleL + fSlopeCount * src[0]);
+        dest[i] = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSample[0] + fSlopeCount * src[0]);
         i++;
         fSlopeCount += fRate;
     }
@@ -557,17 +627,18 @@ uint RateTransposerFloat::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *src,
             while (fSlopeCount > 1.0f) 
             {
                 fSlopeCount -= 1.0f;
-                used ++;
-                if (used >= nSamples - 1) goto end;
+                src ++;
+                remain --;
+                if (remain == 0) goto end;
             }
-            dest[i] = (SAMPLETYPE)((1.0f - fSlopeCount) * src[used] + fSlopeCount * src[used + 1]);
+            dest[i] = (SAMPLETYPE)((1.0f - fSlopeCount) * src[0] + fSlopeCount * src[1]);
             i++;
             fSlopeCount += fRate;
         }
     }
 end:
     // Store the last sample for the next round
-    sPrevSampleL = src[nSamples - 1];
+    sPrevSample[0] = src[0];
 
     return i;
 }
@@ -576,20 +647,20 @@ end:
 // Transposes the sample rate of the given samples using linear interpolation. 
 // 'Mono' version of the routine. Returns the number of samples returned in 
 // the "dest" buffer
-uint RateTransposerFloat::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
+int RateTransposerFloat::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
 {
-    unsigned int srcPos, i, used;
+    int i, remain;
 
     if (nSamples == 0) return 0;  // no samples, no work
 
-    used = 0;    
+    remain = nSamples - 1;
     i = 0;
 
     // Process the last sample saved from the sPrevSampleLious call first...
     while (fSlopeCount <= 1.0f) 
     {
-        dest[2 * i] = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSampleL + fSlopeCount * src[0]);
-        dest[2 * i + 1] = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSampleR + fSlopeCount * src[1]);
+        dest[2 * i] = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSample[0] + fSlopeCount * src[0]);
+        dest[2 * i + 1] = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSample[1] + fSlopeCount * src[1]);
         i++;
         fSlopeCount += fRate;
     }
@@ -603,15 +674,15 @@ uint RateTransposerFloat::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *sr
             while (fSlopeCount > 1.0f) 
             {
                 fSlopeCount -= 1.0f;
-                used ++;
-                if (used >= nSamples - 1) goto end;
+                remain --;
+                src += 2;
+                if (remain == 0) goto end;
             }
-            srcPos = 2 * used;
 
-            dest[2 * i] = (SAMPLETYPE)((1.0f - fSlopeCount) * src[srcPos] 
-                + fSlopeCount * src[srcPos + 2]);
-            dest[2 * i + 1] = (SAMPLETYPE)((1.0f - fSlopeCount) * src[srcPos + 1] 
-                + fSlopeCount * src[srcPos + 3]);
+            dest[2 * i] = (SAMPLETYPE)((1.0f - fSlopeCount) * src[0] 
+                + fSlopeCount * src[2]);
+            dest[2 * i + 1] = (SAMPLETYPE)((1.0f - fSlopeCount) * src[1] 
+                + fSlopeCount * src[3]);
 
             i++;
             fSlopeCount += fRate;
@@ -619,8 +690,59 @@ uint RateTransposerFloat::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *sr
     }
 end:
     // Store the last sample for the next round
-    sPrevSampleL = src[2 * nSamples - 2];
-    sPrevSampleR = src[2 * nSamples - 1];
+    sPrevSample[0] = src[0];
+    sPrevSample[1] = src[1];
+
+    return i;
+}
+
+int RateTransposerFloat::transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples)
+{
+    int i, remaining;
+
+    if (nSamples == 0) return 0;  // no samples, no work
+
+    remaining = nSamples - 1;
+    i = 0;
+
+    // Process the last sample saved from the sPrevSampleLious call first...
+    while (fSlopeCount <= 1.0f) 
+    {
+        for (int c = 0; c < numChannels; c ++)
+        {
+            *dest = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSample[c] + fSlopeCount * src[c]);
+            dest ++;
+        }
+        i++;
+        fSlopeCount += fRate;
+    }
+    // now always (iSlopeCount > 1.0f)
+    fSlopeCount -= 1.0f;
+
+    while (remaining > 0)
+    {
+        while (fSlopeCount > 1.0f) 
+        {
+            fSlopeCount -= 1.0f;
+            src += numChannels;
+            remaining --;
+            if (remaining == 0) goto end;
+        }
+
+        for (int c = 0; c < numChannels; c ++)
+        {
+            *dest = (SAMPLETYPE)((1.0f - fSlopeCount) * src[c] 
+                + fSlopeCount * src[c + numChannels]);
+            dest++;
+        }
+
+        i++;
+        fSlopeCount += fRate;
+    }
+
+end:
+    // Store the last sample for the next round
+    memcpy(sPrevSample, src, numChannels * sizeof(SAMPLETYPE));
 
     return i;
 }
diff --git a/source/SoundTouch/RateTransposer.h b/source/SoundTouch/RateTransposer.h
index 9cd1c6f..7c8f67b 100644
--- a/source/SoundTouch/RateTransposer.h
+++ b/source/SoundTouch/RateTransposer.h
@@ -85,13 +85,14 @@ protected:
 
     virtual void resetRegisters() = 0;
 
-    virtual uint transposeStereo(SAMPLETYPE *dest, 
+    virtual int transposeStereo(SAMPLETYPE *dest, 
                          const SAMPLETYPE *src, 
                          uint numSamples) = 0;
-    virtual uint transposeMono(SAMPLETYPE *dest, 
+    virtual int transposeMono(SAMPLETYPE *dest, 
                        const SAMPLETYPE *src, 
                        uint numSamples) = 0;
-    inline uint transpose(SAMPLETYPE *dest, 
+    virtual int transposeMulti(SAMPLETYPE *dest, const SAMPLETYPE *src, uint nSamples) = 0;
+    inline int transpose(SAMPLETYPE *dest, 
                    const SAMPLETYPE *src, 
                    uint numSamples);
 
diff --git a/source/SoundTouch/SoundTouch.cpp b/source/SoundTouch/SoundTouch.cpp
index 79ce263..cd7693b 100644
--- a/source/SoundTouch/SoundTouch.cpp
+++ b/source/SoundTouch/SoundTouch.cpp
@@ -143,10 +143,11 @@ uint SoundTouch::getVersionId()
 // Sets the number of channels, 1 = mono, 2 = stereo
 void SoundTouch::setChannels(uint numChannels)
 {
-    if (numChannels != 1 && numChannels != 2) 
+    /*if (numChannels != 1 && numChannels != 2) 
     {
-        ST_THROW_RT_ERROR("Illegal number of channels");
-    }
+        //ST_THROW_RT_ERROR("Illegal number of channels");
+		return;
+    }*/
     channels = numChannels;
     pRateTransposer->setChannels((int)numChannels);
     pTDStretch->setChannels((int)numChannels);
@@ -347,7 +348,7 @@ void SoundTouch::flush()
     int i;
     int nUnprocessed;
     int nOut;
-    SAMPLETYPE buff[64*2];   // note: allocate 2*64 to cater 64 sample frames of stereo sound
+    SAMPLETYPE *buff=(SAMPLETYPE*)alloca(64*channels*sizeof(SAMPLETYPE));
 
     // check how many samples still await processing, and scale
     // that by tempo & rate to get expected output sample count
diff --git a/source/SoundTouch/SoundTouch.vcproj b/source/SoundTouch/SoundTouch.vcproj
index e872e14..56d0651 100644
--- a/source/SoundTouch/SoundTouch.vcproj
+++ b/source/SoundTouch/SoundTouch.vcproj
@@ -1,123 +1,172 @@
 <?xml version="1.0" encoding="Windows-1252"?>
 <VisualStudioProject
 	ProjectType="Visual C++"
-	Version="7.10"
+	Version="9.00"
 	Name="SoundTouch"
 	ProjectGUID="{68A5DD20-7057-448B-8FE0-B6AC8D205509}"
-	SccProjectName=""
-	SccLocalPath="">
+	TargetFrameworkVersion="131072"
+	>
 	<Platforms>
 		<Platform
-			Name="Win32"/>
+			Name="Win32"
+		/>
 	</Platforms>
+	<ToolFiles>
+	</ToolFiles>
 	<Configurations>
 		<Configuration
 			Name="Release|Win32"
 			OutputDirectory=".\Release"
 			IntermediateDirectory=".\Release"
 			ConfigurationType="4"
+			InheritedPropertySheets="$(VCInstallDir)VCProjectDefaults\UpgradeFromVC71.vsprops"
 			UseOfMFC="0"
-			ATLMinimizesCRunTimeLibraryUsage="FALSE"
-			CharacterSet="2">
+			ATLMinimizesCRunTimeLibraryUsage="false"
+			CharacterSet="2"
+			>
+			<Tool
+				Name="VCPreBuildEventTool"
+			/>
+			<Tool
+				Name="VCCustomBuildTool"
+			/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"
+			/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"
+			/>
+			<Tool
+				Name="VCMIDLTool"
+			/>
 			<Tool
 				Name="VCCLCompilerTool"
 				Optimization="3"
 				InlineFunctionExpansion="2"
-				EnableIntrinsicFunctions="TRUE"
+				EnableIntrinsicFunctions="true"
 				AdditionalIncludeDirectories="..\..\include"
 				PreprocessorDefinitions="WIN32;NDEBUG;_LIB"
-				StringPooling="TRUE"
-				RuntimeLibrary="4"
-				EnableFunctionLevelLinking="TRUE"
-				UsePrecompiledHeader="2"
+				StringPooling="true"
+				RuntimeLibrary="0"
+				EnableFunctionLevelLinking="true"
+				UsePrecompiledHeader="0"
 				PrecompiledHeaderFile=".\Release/SoundTouch.pch"
 				AssemblerListingLocation=".\Release/"
 				ObjectFile=".\Release/"
 				ProgramDataBaseFileName=".\Release/"
 				WarningLevel="3"
-				SuppressStartupBanner="TRUE"
+				SuppressStartupBanner="true"
 				DebugInformationFormat="0"
-				CompileAs="0"/>
+				CompileAs="0"
+			/>
 			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLibrarianTool"
-				OutputFile=".\Release\SoundTouch.lib"
-				SuppressStartupBanner="TRUE"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"
-				CommandLine="copy         .\Release\SoundTouch.lib         ..\..\lib\"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
+				Name="VCManagedResourceCompilerTool"
+			/>
 			<Tool
 				Name="VCResourceCompilerTool"
 				PreprocessorDefinitions="NDEBUG"
-				Culture="1035"/>
+				Culture="1035"
+			/>
 			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
+				Name="VCPreLinkEventTool"
+			/>
 			<Tool
-				Name="VCXMLDataGeneratorTool"/>
+				Name="VCLibrarianTool"
+				OutputFile=".\Release\SoundTouch.lib"
+				SuppressStartupBanner="true"
+			/>
 			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
+				Name="VCALinkTool"
+			/>
 			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+				Name="VCXDCMakeTool"
+			/>
+			<Tool
+				Name="VCBscMakeTool"
+			/>
+			<Tool
+				Name="VCFxCopTool"
+			/>
+			<Tool
+				Name="VCPostBuildEventTool"
+				CommandLine="copy         .\Release\SoundTouch.lib         ..\..\lib\"
+			/>
 		</Configuration>
 		<Configuration
 			Name="Debug|Win32"
 			OutputDirectory=".\Debug"
 			IntermediateDirectory=".\Debug"
 			ConfigurationType="4"
+			InheritedPropertySheets="$(VCInstallDir)VCProjectDefaults\UpgradeFromVC71.vsprops"
 			UseOfMFC="0"
-			ATLMinimizesCRunTimeLibraryUsage="FALSE"
-			CharacterSet="2">
+			ATLMinimizesCRunTimeLibraryUsage="false"
+			CharacterSet="2"
+			>
+			<Tool
+				Name="VCPreBuildEventTool"
+			/>
+			<Tool
+				Name="VCCustomBuildTool"
+			/>
+			<Tool
+				Name="VCXMLDataGeneratorTool"
+			/>
+			<Tool
+				Name="VCWebServiceProxyGeneratorTool"
+			/>
+			<Tool
+				Name="VCMIDLTool"
+			/>
 			<Tool
 				Name="VCCLCompilerTool"
 				Optimization="0"
 				AdditionalIncludeDirectories="..\..\include"
 				PreprocessorDefinitions="WIN32;_DEBUG;_LIB"
 				BasicRuntimeChecks="3"
-				RuntimeLibrary="5"
-				UsePrecompiledHeader="2"
+				RuntimeLibrary="1"
+				UsePrecompiledHeader="0"
 				PrecompiledHeaderFile=".\Debug/SoundTouch.pch"
 				AssemblerListingLocation=".\Debug/"
 				ObjectFile=".\Debug/"
 				ProgramDataBaseFileName=".\Debug/"
 				BrowseInformation="1"
 				WarningLevel="3"
-				SuppressStartupBanner="TRUE"
+				SuppressStartupBanner="true"
 				DebugInformationFormat="4"
-				CompileAs="0"/>
+				CompileAs="0"
+			/>
 			<Tool
-				Name="VCCustomBuildTool"/>
-			<Tool
-				Name="VCLibrarianTool"
-				OutputFile="Debug\SoundTouchD.lib"
-				SuppressStartupBanner="TRUE"/>
-			<Tool
-				Name="VCMIDLTool"/>
-			<Tool
-				Name="VCPostBuildEventTool"
-				CommandLine="copy .\Debug\SoundTouchD.lib ..\..\lib\"/>
-			<Tool
-				Name="VCPreBuildEventTool"/>
-			<Tool
-				Name="VCPreLinkEventTool"/>
+				Name="VCManagedResourceCompilerTool"
+			/>
 			<Tool
 				Name="VCResourceCompilerTool"
 				PreprocessorDefinitions="_DEBUG"
-				Culture="1035"/>
+				Culture="1035"
+			/>
 			<Tool
-				Name="VCWebServiceProxyGeneratorTool"/>
+				Name="VCPreLinkEventTool"
+			/>
 			<Tool
-				Name="VCXMLDataGeneratorTool"/>
+				Name="VCLibrarianTool"
+				OutputFile="Debug\SoundTouchD.lib"
+				SuppressStartupBanner="true"
+			/>
 			<Tool
-				Name="VCManagedWrapperGeneratorTool"/>
+				Name="VCALinkTool"
+			/>
 			<Tool
-				Name="VCAuxiliaryManagedWrapperGeneratorTool"/>
+				Name="VCXDCMakeTool"
+			/>
+			<Tool
+				Name="VCBscMakeTool"
+			/>
+			<Tool
+				Name="VCFxCopTool"
+			/>
+			<Tool
+				Name="VCPostBuildEventTool"
+				CommandLine="copy .\Debug\SoundTouchD.lib ..\..\lib\"
+			/>
 		</Configuration>
 	</Configurations>
 	<References>
@@ -125,188 +174,236 @@
 	<Files>
 		<Filter
 			Name="Source Files"
-			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat">
+			Filter="cpp;c;cxx;rc;def;r;odl;idl;hpj;bat"
+			>
 			<File
-				RelativePath="AAFilter.cpp">
+				RelativePath="AAFilter.cpp"
+				>
 				<FileConfiguration
-					Name="Release|Win32">
+					Name="Release|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="2"
 						AdditionalIncludeDirectories=""
-						PreprocessorDefinitions=""/>
+						PreprocessorDefinitions=""
+					/>
 				</FileConfiguration>
 				<FileConfiguration
-					Name="Debug|Win32">
+					Name="Debug|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="0"
 						AdditionalIncludeDirectories=""
 						PreprocessorDefinitions=""
 						BasicRuntimeChecks="3"
-						BrowseInformation="1"/>
+						BrowseInformation="1"
+					/>
 				</FileConfiguration>
 			</File>
 			<File
-				RelativePath=".\cpu_detect_x86.cpp">
+				RelativePath=".\cpu_detect_x86.cpp"
+				>
 			</File>
 			<File
-				RelativePath="FIFOSampleBuffer.cpp">
+				RelativePath="FIFOSampleBuffer.cpp"
+				>
 				<FileConfiguration
-					Name="Release|Win32">
+					Name="Release|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="2"
 						AdditionalIncludeDirectories=""
-						PreprocessorDefinitions=""/>
+						PreprocessorDefinitions=""
+					/>
 				</FileConfiguration>
 				<FileConfiguration
-					Name="Debug|Win32">
+					Name="Debug|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="0"
 						AdditionalIncludeDirectories=""
 						PreprocessorDefinitions=""
 						BasicRuntimeChecks="3"
-						BrowseInformation="1"/>
+						BrowseInformation="1"
+					/>
 				</FileConfiguration>
 			</File>
 			<File
-				RelativePath="FIRFilter.cpp">
+				RelativePath="FIRFilter.cpp"
+				>
 				<FileConfiguration
-					Name="Release|Win32">
+					Name="Release|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="2"
 						AdditionalIncludeDirectories=""
-						PreprocessorDefinitions=""/>
+						PreprocessorDefinitions=""
+					/>
 				</FileConfiguration>
 				<FileConfiguration
-					Name="Debug|Win32">
+					Name="Debug|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="0"
 						AdditionalIncludeDirectories=""
 						PreprocessorDefinitions=""
 						BasicRuntimeChecks="3"
-						BrowseInformation="1"/>
+						BrowseInformation="1"
+					/>
 				</FileConfiguration>
 			</File>
 			<File
-				RelativePath=".\mmx_optimized.cpp">
+				RelativePath=".\mmx_optimized.cpp"
+				>
 			</File>
 			<File
-				RelativePath="RateTransposer.cpp">
+				RelativePath="RateTransposer.cpp"
+				>
 				<FileConfiguration
-					Name="Release|Win32">
+					Name="Release|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="2"
 						AdditionalIncludeDirectories=""
-						PreprocessorDefinitions=""/>
+						PreprocessorDefinitions=""
+					/>
 				</FileConfiguration>
 				<FileConfiguration
-					Name="Debug|Win32">
+					Name="Debug|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="0"
 						AdditionalIncludeDirectories=""
 						PreprocessorDefinitions=""
 						BasicRuntimeChecks="3"
-						BrowseInformation="1"/>
+						BrowseInformation="1"
+					/>
 				</FileConfiguration>
 			</File>
 			<File
-				RelativePath="SoundTouch.cpp">
+				RelativePath="SoundTouch.cpp"
+				>
 				<FileConfiguration
-					Name="Release|Win32">
+					Name="Release|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="2"
 						AdditionalIncludeDirectories=""
-						PreprocessorDefinitions=""/>
+						PreprocessorDefinitions=""
+					/>
 				</FileConfiguration>
 				<FileConfiguration
-					Name="Debug|Win32">
+					Name="Debug|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="0"
 						AdditionalIncludeDirectories=""
 						PreprocessorDefinitions=""
 						BasicRuntimeChecks="3"
-						BrowseInformation="1"/>
+						BrowseInformation="1"
+					/>
 				</FileConfiguration>
 			</File>
 			<File
-				RelativePath=".\sse_optimized.cpp">
+				RelativePath=".\sse_optimized.cpp"
+				>
 			</File>
 			<File
-				RelativePath="TDStretch.cpp">
+				RelativePath="TDStretch.cpp"
+				>
 				<FileConfiguration
-					Name="Release|Win32">
+					Name="Release|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="2"
 						AdditionalIncludeDirectories=""
-						PreprocessorDefinitions=""/>
+						PreprocessorDefinitions=""
+					/>
 				</FileConfiguration>
 				<FileConfiguration
-					Name="Debug|Win32">
+					Name="Debug|Win32"
+					>
 					<Tool
 						Name="VCCLCompilerTool"
 						Optimization="0"
 						AdditionalIncludeDirectories=""
 						PreprocessorDefinitions=""
 						BasicRuntimeChecks="3"
-						BrowseInformation="1"/>
+						BrowseInformation="1"
+					/>
 				</FileConfiguration>
 			</File>
 			<Filter
 				Name="bpm"
-				Filter="">
+				>
 				<File
-					RelativePath=".\BPMDetect.cpp">
+					RelativePath=".\BPMDetect.cpp"
+					>
 				</File>
 				<File
-					RelativePath=".\PeakFinder.cpp">
+					RelativePath=".\PeakFinder.cpp"
+					>
 				</File>
 			</Filter>
 		</Filter>
 		<Filter
 			Name="Header Files"
-			Filter="h;hpp;hxx;hm;inl">
+			Filter="h;hpp;hxx;hm;inl"
+			>
 			<File
-				RelativePath="AAFilter.h">
+				RelativePath="AAFilter.h"
+				>
 			</File>
 			<File
-				RelativePath="..\..\include\BPMDetect.h">
+				RelativePath="..\..\include\BPMDetect.h"
+				>
 			</File>
 			<File
-				RelativePath="cpu_detect.h">
+				RelativePath="cpu_detect.h"
+				>
 			</File>
 			<File
-				RelativePath="..\..\include\FIFOSampleBuffer.h">
+				RelativePath="..\..\include\FIFOSampleBuffer.h"
+				>
 			</File>
 			<File
-				RelativePath="..\..\include\FIFOSamplePipe.h">
+				RelativePath="..\..\include\FIFOSamplePipe.h"
+				>
 			</File>
 			<File
-				RelativePath="FIRFilter.h">
+				RelativePath="FIRFilter.h"
+				>
 			</File>
 			<File
-				RelativePath=".\PeakFinder.h">
+				RelativePath=".\PeakFinder.h"
+				>
 			</File>
 			<File
-				RelativePath="RateTransposer.h">
+				RelativePath="RateTransposer.h"
+				>
 			</File>
 			<File
-				RelativePath="..\..\include\SoundTouch.h">
+				RelativePath="..\..\include\SoundTouch.h"
+				>
 			</File>
 			<File
-				RelativePath="..\..\include\STTypes.h">
+				RelativePath="..\..\include\STTypes.h"
+				>
 			</File>
 			<File
-				RelativePath="TDStretch.h">
+				RelativePath="TDStretch.h"
+				>
 			</File>
 		</Filter>
 	</Files>
diff --git a/source/SoundTouch/TDStretch.cpp b/source/SoundTouch/TDStretch.cpp
index e272811..f2060bc 100644
--- a/source/SoundTouch/TDStretch.cpp
+++ b/source/SoundTouch/TDStretch.cpp
@@ -212,7 +212,7 @@ void TDStretch::overlapMono(SAMPLETYPE *pOutput, const SAMPLETYPE *pInput) const
 
 void TDStretch::clearMidBuffer()
 {
-    memset(pMidBuffer, 0, 2 * sizeof(SAMPLETYPE) * overlapLength);
+    memset(pMidBuffer, 0, channels * sizeof(SAMPLETYPE) * overlapLength);
 }
 
 
@@ -265,13 +265,22 @@ int TDStretch::seekBestOverlapPosition(const SAMPLETYPE *refPos)
 // of 'ovlPos'.
 inline void TDStretch::overlap(SAMPLETYPE *pOutput, const SAMPLETYPE *pInput, uint ovlPos) const
 {
-    if (channels == 2) 
+#ifndef USE_MULTICH_ALWAYS
+    if (channels == 1)
+    {
+        // mono sound.
+        overlapMono(pOutput, pInput + ovlPos);
+    }
+    else if (channels == 2)
     {
         // stereo sound
         overlapStereo(pOutput, pInput + 2 * ovlPos);
-    } else {
-        // mono sound.
-        overlapMono(pOutput, pInput + ovlPos);
+    } 
+    else 
+#endif // USE_MULTICH_ALWAYS
+    {
+        assert(channels > 0);
+        overlapMulti(pOutput, pInput + channels * ovlPos);
     }
 }
 
@@ -458,11 +467,15 @@ void TDStretch::setChannels(int numChannels)
 {
     assert(numChannels > 0);
     if (channels == numChannels) return;
-    assert(numChannels == 1 || numChannels == 2);
+//    assert(numChannels == 1 || numChannels == 2);
 
     channels = numChannels;
     inputBuffer.setChannels(channels);
     outputBuffer.setChannels(channels);
+
+    // re-init overlap/buffer
+    overlapLength=0;
+    setParameters(sampleRate);
 }
 
 
@@ -666,6 +679,27 @@ void TDStretch::overlapStereo(short *poutput, const short *input) const
     }
 }
 
+
+// Overlaps samples in 'midBuffer' with the samples in 'input'. The 'Multi'
+// version of the routine.
+void TDStretch::overlapMulti(SAMPLETYPE *poutput, const SAMPLETYPE *input) const
+{
+    SAMPLETYPE m1=(SAMPLETYPE)0;
+    SAMPLETYPE m2;
+    int i=0;
+
+    for (m2 = (SAMPLETYPE)overlapLength; m2; m2 --)
+    {
+        for (int c = 0; c < channels; c ++)
+        {
+            poutput[i] = (input[i] * m1 + pMidBuffer[i] * m2)  / overlapLength;
+            i++;
+        }
+
+        m1++;
+    }
+}
+
 // Calculates the x having the closest 2^x value for the given value
 static int _getClosest2Power(double value)
 {
@@ -760,6 +794,34 @@ void TDStretch::overlapStereo(float *pOutput, const float *pInput) const
 }
 
 
+// Overlaps samples in 'midBuffer' with the samples in 'input'. 
+void TDStretch::overlapMulti(float *pOutput, const float *pInput) const
+{
+    int i;
+    float fScale;
+    float f1;
+    float f2;
+
+    fScale = 1.0f / (float)overlapLength;
+
+    f1 = 0;
+    f2 = 1.0f;
+
+    i=0;
+    for (int i2 = 0; i2 < overlapLength; i2 ++)
+    {
+        // note: Could optimize this slightly by taking into account that always channels > 2
+        for (int c = 0; c < channels; c ++)
+        {
+            pOutput[i] = pInput[i] * f1 + pMidBuffer[i] * f2;
+            i++;
+        }
+        f1 += fScale;
+        f2 -= fScale;
+    }
+}
+
+
 /// Calculates overlapInMsec period length in samples.
 void TDStretch::calculateOverlapLength(int overlapInMsec)
 {
diff --git a/source/SoundTouch/TDStretch.h b/source/SoundTouch/TDStretch.h
index 12ce2cf..c0f2853 100644
--- a/source/SoundTouch/TDStretch.h
+++ b/source/SoundTouch/TDStretch.h
@@ -147,6 +147,7 @@ protected:
 
     virtual void overlapStereo(SAMPLETYPE *output, const SAMPLETYPE *input) const;
     virtual void overlapMono(SAMPLETYPE *output, const SAMPLETYPE *input) const;
+    virtual void overlapMulti(SAMPLETYPE *output, const SAMPLETYPE *input) const;
 
     void clearMidBuffer();
     void overlap(SAMPLETYPE *output, const SAMPLETYPE *input, uint ovlPos) const;
