From 091c799f7691acc92bc6548624b267b73f45c9b9 Mon Sep 17 00:00:00 2001
From: Dimitri Diakopoulos <ddiakopoulos@gmail.com>
Date: Sun, 17 May 2015 22:46:20 -0700
Subject: [PATCH] implement mixing routines for basic cases

---
 examples/src/Main.cpp            | 16 +++++-----------
 include/libnyquist/PostProcess.h | 29 ++++++++++++++++++++++++-----
 src/WavEncoder.cpp               |  4 +++-
 3 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/examples/src/Main.cpp b/examples/src/Main.cpp
index fb17f0d..b085480 100644
--- a/examples/src/Main.cpp
+++ b/examples/src/Main.cpp
@@ -5,6 +5,7 @@
 #include "libnyquist/AudioDevice.h"
 #include "libnyquist/AudioDecoder.h"
 #include "libnyquist/WavEncoder.h"
+#include "libnyquist/PostProcess.h"
 
 #include <thread>
 
@@ -32,7 +33,7 @@ int main()
 		//auto result = loader.Load(fileData, "test_data/1ch/44100/8/test.wav");
 		//auto result = loader.Load(fileData, "test_data/1ch/44100/16/test.wav");
 		//auto result = loader.Load(fileData, "test_data/1ch/44100/24/test.wav");
-		//auto result = loader.Load(fileData, "test_data/1ch/44100/32/test.wav");
+		auto result = loader.Load(fileData, "test_data/1ch/44100/32/test.wav");
 		//auto result = loader.Load(fileData, "test_data/1ch/44100/64/test.wav");
 		
 		//auto result = loader.Load(fileData, "test_data/2ch/44100/8/test.wav");
@@ -47,7 +48,7 @@ int main()
 		//auto result = loader.Load(fileData, "test_data/ad_hoc/TestLaugh_44k.ogg");
 		//auto result = loader.Load(fileData, "test_data/ad_hoc/TestBeat.ogg");
 		//auto result = loader.Load(fileData, "test_data/ad_hoc/TestBeatMono.ogg");
-		auto result = loader.Load(fileData, "test_data/ad_hoc/BlockWoosh_Stereo.ogg");
+		//auto result = loader.Load(fileData, "test_data/ad_hoc/BlockWoosh_Stereo.ogg");
 		
 		//auto result = loader.Load(fileData, "test_data/ad_hoc/KittyPurr8_Stereo_Dithered.flac");
 		//auto result = loader.Load(fileData, "test_data/ad_hoc/KittyPurr16_Stereo.flac");
@@ -81,14 +82,7 @@ int main()
 	if (fileData->channelCount == 1)
 	{
 		std::vector<float> stereoCopy(fileData->samples.size() * 2);
-		
-		int m = 0;
-		for (size_t i = 0; i < stereoCopy.size(); i+=2)
-		{
-			stereoCopy[i] = fileData->samples[m];
-			stereoCopy[i+1] = fileData->samples[m];
-			m++;
-		}
+        MonoToStereo(fileData->samples.data(), stereoCopy.data(), fileData->samples.size());
 		myDevice.Play(stereoCopy);
 	}
 	else
@@ -98,7 +92,7 @@ int main()
 	}
     
     // Test wav file encoder
-    int encoderStatus = encoder.WriteFile({2, PCM_24, DITHER_NONE}, fileData, "encoded.wav");
+    int encoderStatus = encoder.WriteFile({1, PCM_24, DITHER_NONE}, fileData, "encoded.wav");
     std::cout << "Encoder Status: " << encoderStatus << std::endl;
     
 	return 0;
diff --git a/include/libnyquist/PostProcess.h b/include/libnyquist/PostProcess.h
index bf36d5a..8d3d3cd 100644
--- a/include/libnyquist/PostProcess.h
+++ b/include/libnyquist/PostProcess.h
@@ -46,13 +46,13 @@ inline void DeinterleaveStereo(T * c1, T * c2, T const * src, size_t count)
 }
 
 template<typename T>
-void InterleaveArbitrary(const T * src, T * dest, size_t numFramesPerChannel, size_t numChannels, size_t numCopyFrames)
+void InterleaveChannels(const T * src, T * dest, size_t numFramesPerChannel, size_t numChannels, size_t N)
 {
     for (size_t ch = 0; ch < numChannels; ch++)
     {
         size_t x = ch;
         const T * srcChannel = &src[ch * numFramesPerChannel];
-        for(size_t i = 0; i < numCopyFrames; i++)
+        for(size_t i = 0; i < N; i++)
         {
             dest[x] = srcChannel[i];
             x += numChannels;
@@ -61,23 +61,42 @@ void InterleaveArbitrary(const T * src, T * dest, size_t numFramesPerChannel, si
 }
 
 template<typename T>
-void DeinterleaveArbitrary(const T * src, T * dest, size_t numFramesPerChannel, size_t numChannels, size_t numCopyFrames)
+void DeinterleaveChannels(const T * src, T * dest, size_t numFramesPerChannel, size_t numChannels, size_t N)
 {
     for(size_t ch = 0; ch < numChannels; ch++)
     {
         size_t x = ch;
         T *destChannel = &dest[ch * numFramesPerChannel];
-        for (size_t i = 0; i < numCopyFrames; i++)
+        for (size_t i = 0; i < N; i++)
         {
             destChannel[i] = (T) src[x];
             x += numChannels;
         }
     }
 }
+    
+template <typename T>
+void StereoToMono(const T * src, T * dest, size_t N)
+{
+    for (size_t i = 0, j = 0; i < N; i += 2, ++j)
+    {
+        dest[j] = (src[i] + src[i + 1]) / 2.0f;
+    }
+}
+
+template <typename T>
+void MonoToStereo(const T * src, T * dest, size_t N)
+{
+    for(int i = 0, j = 0; i < N; ++i, j += 2)
+    {
+        dest[j] = src[i];
+        dest[j + 1] = src[i];
+    }
+}
 
 inline void TrimSilenceInterleaved(std::vector<float> & buffer, float v, bool fromFront, bool fromEnd)
 {
-    //@todo implement me
+    //@todo implement me!
 }
     
 } // end namespace nqr
diff --git a/src/WavEncoder.cpp b/src/WavEncoder.cpp
index 78f8de0..3eec46f 100644
--- a/src/WavEncoder.cpp
+++ b/src/WavEncoder.cpp
@@ -127,10 +127,12 @@ int WavEncoder::WriteFile(const EncoderParams p, const AudioData * d, const std:
         fout.write(reinterpret_cast<const char*>(d->samples.data()), samplesSizeInBytes);
     }
     
+
     // Padding byte
     if (isOdd(samplesSizeInBytes))
     {
-        fout.write(reinterpret_cast<const char *>(1), 1);
+        const char * zero = "";
+        fout.write(zero, 1);
     }
     
     // Find size