Add experimental Qt audio renderer

app/app.pro

@@ -89,6 +89,7 @@ SOURCES += \
     streaming/session.cpp \
     streaming/audio/audio.cpp \
     streaming/audio/renderers/sdlaud.cpp \
+    streaming/audio/renderers/qtaud.cpp \
     gui/computermodel.cpp \
     gui/appmodel.cpp \
     streaming/streamutils.cpp \
@@ -107,6 +108,7 @@ HEADERS += \
     streaming/session.hpp \
     streaming/audio/renderers/renderer.h \
     streaming/audio/renderers/sdl.h \
+    streaming/audio/renderers/qtaud.h \
     gui/computermodel.h \
     gui/appmodel.h \
     streaming/video/decoder.h \

app/streaming/audio/audio.cpp

@@ -1,6 +1,7 @@
 #include "../session.hpp"
 #include "renderers/renderer.h"
 #include "renderers/sdl.h"
+#include "renderers/qtaud.h"
 
 #include <Limelight.h>
 

app/streaming/audio/renderers/qtaud.cpp

@@ -0,0 +1,94 @@
+#include "qtaud.h"
+
+#include <QDebug>
+
+QtAudioRenderer::QtAudioRenderer()
+    : m_AudioOutput(nullptr),
+      m_OutputDevice(nullptr)
+{
+
+}
+
+QtAudioRenderer::~QtAudioRenderer()
+{
+    delete m_AudioOutput;
+}
+
+bool QtAudioRenderer::prepareForPlayback(const OPUS_MULTISTREAM_CONFIGURATION* opusConfig)
+{
+    QAudioFormat format;
+
+    // testAudio() assumes this sample rate
+    Q_ASSERT(opusConfig->sampleRate == 48000);
+
+    format.setSampleRate(opusConfig->sampleRate);
+    format.setChannelCount(opusConfig->channelCount);
+    format.setSampleSize(16);
+    format.setSampleType(QAudioFormat::SignedInt);
+    format.setCodec("audio/pcm");
+
+    m_AudioOutput = new QAudioOutput(format);
+
+    m_AudioOutput->setBufferSize(SAMPLES_PER_FRAME * 2);
+
+    qInfo() << "Audio stream buffer:" << m_AudioOutput->bufferSize() << "bytes";
+
+    m_OutputDevice = m_AudioOutput->start();
+    if (m_OutputDevice == nullptr) {
+        qWarning() << "Audio start failed:" << m_AudioOutput->error();
+        return false;
+    }
+
+    return true;
+}
+
+void QtAudioRenderer::submitAudio(short* audioBuffer, int audioSize)
+{
+    m_OutputDevice->write((const char *)audioBuffer, audioSize);
+}
+
+bool QtAudioRenderer::testAudio(int audioConfiguration)
+{
+    QAudioFormat format;
+
+    format.setSampleRate(48000);
+    format.setSampleSize(16);
+    format.setSampleType(QAudioFormat::SignedInt);
+    format.setCodec("audio/pcm");
+
+    switch (audioConfiguration) {
+    case AUDIO_CONFIGURATION_STEREO:
+        format.setChannelCount(2);
+        break;
+    case AUDIO_CONFIGURATION_51_SURROUND:
+        format.setChannelCount(6);
+        break;
+    default:
+        Q_ASSERT(false);
+        return false;
+    }
+
+    if (QAudioDeviceInfo::defaultOutputDevice().isFormatSupported(format)) {
+        qInfo() << "Audio test successful with" << format.channelCount() << "channels";
+        return true;
+    }
+    else {
+        qWarning() << "Audio test failed with" << format.channelCount() << "channels";
+        return false;
+    }
+}
+
+int QtAudioRenderer::detectAudioConfiguration()
+{
+    int preferredChannelCount = QAudioDeviceInfo::defaultOutputDevice().preferredFormat().channelCount();
+
+    qInfo() << "Audio output device prefers" << preferredChannelCount << "channel configuration";
+
+    // We can better downmix 5.1 to quad than we can upmix stereo
+    if (preferredChannelCount > 2) {
+        return AUDIO_CONFIGURATION_51_SURROUND;
+    }
+    else {
+        return AUDIO_CONFIGURATION_STEREO;
+    }
+}

app/streaming/audio/renderers/qtaud.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include "renderer.h"
+#include <QAudioOutput>
+
+class QtAudioRenderer : public IAudioRenderer
+{
+public:
+    QtAudioRenderer();
+
+    virtual ~QtAudioRenderer();
+
+    virtual bool prepareForPlayback(const OPUS_MULTISTREAM_CONFIGURATION* opusConfig);
+
+    virtual void submitAudio(short* audioBuffer, int audioSize);
+
+    virtual bool testAudio(int audioConfiguration);
+
+    virtual int detectAudioConfiguration();
+
+private:
+    QAudioOutput* m_AudioOutput;
+    QIODevice* m_OutputDevice;
+};