From 972a611d0302a042e9c8b9b5d4bc172296722dee Mon Sep 17 00:00:00 2001
From: Zach Pomerantz <zach@highfidelity.io>
Date: Tue, 4 Oct 2016 17:50:34 -0700
Subject: [PATCH] retain stereo on dead audio resampling

---
 libraries/audio-client/src/AudioClient.cpp    |  6 +--
 .../audio/src/MixedProcessedAudioStream.cpp   | 40 +++++++++----------
 .../audio/src/MixedProcessedAudioStream.h     |  9 +++--
 3 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/libraries/audio-client/src/AudioClient.cpp b/libraries/audio-client/src/AudioClient.cpp
index 16f4c35d21..d70730380f 100644
--- a/libraries/audio-client/src/AudioClient.cpp
+++ b/libraries/audio-client/src/AudioClient.cpp
@@ -1152,9 +1152,9 @@ bool AudioClient::outputLocalInjector(bool isStereo, AudioInjector* injector) {
 }
 
 void AudioClient::outputFormatChanged() {
-    int outputFormatChannelCountTimesSampleRate = _outputFormat.channelCount() * _outputFormat.sampleRate();
-    _outputFrameSize = AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL * outputFormatChannelCountTimesSampleRate / _desiredOutputFormat.sampleRate();
-    _receivedAudioStream.outputFormatChanged(outputFormatChannelCountTimesSampleRate);
+    _outputFrameSize = (AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL * _outputFormat.channelCount() * _outputFormat.sampleRate()) /
+        _desiredOutputFormat.sampleRate();
+    _receivedAudioStream.outputFormatChanged(_outputFormat.sampleRate(), _outputFormat.channelCount());
 }
 
 bool AudioClient::switchInputToAudioDevice(const QAudioDeviceInfo& inputDeviceInfo) {
diff --git a/libraries/audio/src/MixedProcessedAudioStream.cpp b/libraries/audio/src/MixedProcessedAudioStream.cpp
index 88a1e071ec..6820a17a47 100644
--- a/libraries/audio/src/MixedProcessedAudioStream.cpp
+++ b/libraries/audio/src/MixedProcessedAudioStream.cpp
@@ -17,27 +17,27 @@ static const int STEREO_FACTOR = 2;
 MixedProcessedAudioStream::MixedProcessedAudioStream(int numFrameSamples, int numFramesCapacity, int numStaticJitterFrames)
     : InboundAudioStream(numFrameSamples, numFramesCapacity, numStaticJitterFrames) {}
 
-void MixedProcessedAudioStream::outputFormatChanged(int outputFormatChannelCountTimesSampleRate) {
-    _outputFormatChannelsTimesSampleRate = outputFormatChannelCountTimesSampleRate;
-    int deviceOutputFrameSize = networkToDeviceSamples(AudioConstants::NETWORK_FRAME_SAMPLES_STEREO);
-    _ringBuffer.resizeForFrameSize(deviceOutputFrameSize);
+void MixedProcessedAudioStream::outputFormatChanged(int sampleRate, int channelCount) {
+    _outputSampleRate = sampleRate;
+    _outputChannelCount = channelCount;
+    int deviceOutputFrameFrames = networkToDeviceFrames(AudioConstants::NETWORK_FRAME_SAMPLES_STEREO / STEREO_FACTOR);
+    int deviceOutputFrameSamples = deviceOutputFrameFrames * STEREO_FACTOR;
+    _ringBuffer.resizeForFrameSize(deviceOutputFrameSamples);
 }
 
 int MixedProcessedAudioStream::writeDroppableSilentSamples(int silentSamples) {
-    
-    int deviceSilentSamplesWritten = InboundAudioStream::writeDroppableSilentSamples(networkToDeviceSamples(silentSamples));
-    
-    emit addedSilence(deviceToNetworkSamples(deviceSilentSamplesWritten) / STEREO_FACTOR);
-
+    int deviceSilentFrames = networkToDeviceFrames(silentSamples / STEREO_FACTOR);
+    int deviceSilentSamples = deviceSilentFrames * STEREO_FACTOR;
+    int deviceSilentSamplesWritten = InboundAudioStream::writeDroppableSilentSamples(deviceSilentSamples);
+    emit addedSilence(deviceToNetworkFrames(deviceSilentSamplesWritten / STEREO_FACTOR));
     return deviceSilentSamplesWritten;
 }
 
 int MixedProcessedAudioStream::writeLastFrameRepeatedWithFade(int samples) {
-
-    int deviceSamplesWritten = InboundAudioStream::writeLastFrameRepeatedWithFade(networkToDeviceSamples(samples));
-
-    emit addedLastFrameRepeatedWithFade(deviceToNetworkSamples(deviceSamplesWritten) / STEREO_FACTOR);
-    
+    int deviceFrames = networkToDeviceFrames(samples / STEREO_FACTOR);
+    int deviceSamples = deviceFrames * STEREO_FACTOR;
+    int deviceSamplesWritten = InboundAudioStream::writeLastFrameRepeatedWithFade(deviceSamples);
+    emit addedLastFrameRepeatedWithFade(deviceToNetworkFrames(deviceSamplesWritten / STEREO_FACTOR));
     return deviceSamplesWritten;
 }
 
@@ -60,12 +60,12 @@ int MixedProcessedAudioStream::parseAudioData(PacketType type, const QByteArray&
     return packetAfterStreamProperties.size();
 }
 
-int MixedProcessedAudioStream::networkToDeviceSamples(int networkSamples) {
-    return (quint64)networkSamples * (quint64)_outputFormatChannelsTimesSampleRate / (quint64)(STEREO_FACTOR
-                                                                                               * AudioConstants::SAMPLE_RATE);
+int MixedProcessedAudioStream::networkToDeviceFrames(int networkFrames) {
+    return ((quint64)networkFrames * _outputChannelCount * _outputSampleRate) /
+        (quint64)(STEREO_FACTOR * AudioConstants::SAMPLE_RATE);
 }
 
-int MixedProcessedAudioStream::deviceToNetworkSamples(int deviceSamples) {
-    return (quint64)deviceSamples * (quint64)(STEREO_FACTOR * AudioConstants::SAMPLE_RATE)
-        / (quint64)_outputFormatChannelsTimesSampleRate;
+int MixedProcessedAudioStream::deviceToNetworkFrames(int deviceFrames) {
+    return (quint64)deviceFrames * (quint64)(STEREO_FACTOR * AudioConstants::SAMPLE_RATE) /
+        (_outputSampleRate * _outputChannelCount);
 }
diff --git a/libraries/audio/src/MixedProcessedAudioStream.h b/libraries/audio/src/MixedProcessedAudioStream.h
index f28586f484..d89ce9f7e3 100644
--- a/libraries/audio/src/MixedProcessedAudioStream.h
+++ b/libraries/audio/src/MixedProcessedAudioStream.h
@@ -30,7 +30,7 @@ signals:
     void processSamples(const QByteArray& inputBuffer, QByteArray& outputBuffer);
 
 public:
-    void outputFormatChanged(int outputFormatChannelCountTimesSampleRate);
+    void outputFormatChanged(int sampleRate, int channelCount);
 
 protected:
     int writeDroppableSilentSamples(int silentSamples) override;
@@ -38,11 +38,12 @@ protected:
     int parseAudioData(PacketType type, const QByteArray& packetAfterStreamProperties) override;
 
 private:
-    int networkToDeviceSamples(int networkSamples);
-    int deviceToNetworkSamples(int deviceSamples);
+    int networkToDeviceFrames(int networkFrames);
+    int deviceToNetworkFrames(int deviceFrames);
 
 private:
-    int _outputFormatChannelsTimesSampleRate;
+    quint64 _outputSampleRate;
+    quint64 _outputChannelCount;
 };
 
 #endif // hifi_MixedProcessedAudioStream_h