audio: rewrote audio cache to write to contiguous segments rather than one long file

Fixes issues with PCM file placement, optimizes some audio-based timeline
and cache operations, just generally a better approach.

app/audio/audiomanager.cpp

@@ -82,16 +82,23 @@ void AudioManager::PushToOutput(const QByteArray &samples)
   emit OutputPushed(samples);
 }
 
-void AudioManager::StartOutput(const QString &filename, qint64 offset, int playback_speed)
+void AudioManager::StartOutput(AudioPlaybackCache *cache, qint64 offset, int playback_speed)
 {
+  // Create device
+  QIODevice* device = cache->CreatePlaybackDevice();
+
+  // Move to output manager's thread
+  device->moveToThread(output_manager_.thread());
+
+  // Queue to output manger in other thread
   QMetaObject::invokeMethod(&output_manager_,
                             "PullFromDevice",
                             Qt::QueuedConnection,
-                            Q_ARG(const QString&, filename),
+                            Q_ARG(QIODevice*, device),
                             Q_ARG(qint64, offset),
                             Q_ARG(int, playback_speed));
 
-  emit OutputDeviceStarted(filename, offset, playback_speed);
+  emit OutputDeviceStarted(cache, offset, playback_speed);
 }
 
 void AudioManager::StopOutput()

app/audio/audiomanager.h

@@ -30,6 +30,7 @@
 #include "common/define.h"
 #include "outputmanager.h"
 #include "render/audioparams.h"
+#include "render/audioplaybackcache.h"
 
 OLIVE_NAMESPACE_ENTER
 
@@ -57,11 +58,9 @@ public:
   void PushToOutput(const QByteArray& samples);
 
   /**
-   * @brief Start playing audio from QIODevice
-   *
-   * This takes ownership of the QIODevice and will delete it when StopOutput() is called
+   * @brief Start playing audio from AudioPlaybackCache
    */
-  void StartOutput(const QString& filename, qint64 offset, int playback_speed);
+  void StartOutput(AudioPlaybackCache* cache, qint64 offset, int playback_speed);
 
   /**
    * @brief Stop audio output immediately
@@ -86,7 +85,7 @@ signals:
 
   void OutputNotified();
 
-  void OutputDeviceStarted(const QString& filename, qint64 offset, int playback_speed);
+  void OutputDeviceStarted(AudioPlaybackCache* cache, qint64 offset, int playback_speed);
 
   void AudioParamsChanged(const AudioParams& params);
 

app/audio/outputdeviceproxy.cpp

@@ -24,11 +24,10 @@
 
 OLIVE_NAMESPACE_ENTER
 
-AudioOutputDeviceProxy::~AudioOutputDeviceProxy()
+AudioOutputDeviceProxy::AudioOutputDeviceProxy(QObject *parent) :
+  QIODevice(parent),
+  device_(nullptr)
 {
-  if (file_.isOpen()) {
-    file_.close();
-  }
 }
 
 void AudioOutputDeviceProxy::SetParameters(const AudioParams &params)
@@ -36,20 +35,23 @@ void AudioOutputDeviceProxy::SetParameters(const AudioParams &params)
   params_ = params;
 }
 
-void AudioOutputDeviceProxy::SetDevice(const QString &filename, qint64 offset, int playback_speed)
+void AudioOutputDeviceProxy::SetDevice(QIODevice* device, qint64 offset, int playback_speed)
 {
-  if (file_.isOpen()) {
-    file_.close();
+  if (device_) {
+    delete device_;
   }
 
-  file_.setFileName(filename);
+  device_ = device;
+  device_->setParent(this);
 
-  if (!file_.open(QFile::ReadOnly)) {
-    qCritical() << "Failed to open" << filename << "for audio playback";
+  if (!device_->open(QFile::ReadOnly)) {
+    qCritical() << "Failed to open IO device for audio playback";
+    delete device_;
+    device_ = nullptr;
     return;
   }
 
-  file_.seek(offset);
+  device_->seek(offset);
 
   playback_speed_ = playback_speed;
 
@@ -62,7 +64,8 @@ void AudioOutputDeviceProxy::close()
 {
   QIODevice::close();
 
-  file_.close();
+  delete device_;
+  device_ = nullptr;
 
   if (tempo_processor_.IsOpen()) {
     tempo_processor_.Close();
@@ -71,7 +74,7 @@ void AudioOutputDeviceProxy::close()
 
 qint64 AudioOutputDeviceProxy::readData(char *data, qint64 maxlen)
 {
-  if (!file_.isOpen()) {
+  if (!device_) {
     return 0;
   }
 
@@ -111,21 +114,21 @@ qint64 AudioOutputDeviceProxy::ReverseAwareRead(char *data, qint64 maxlen)
 
   if (playback_speed_ < 0) {
     // If we're reversing, we'll seek back by maxlen bytes before we read
-    new_pos = file_.pos() - maxlen;
+    new_pos = device_->pos() - maxlen;
 
     if (new_pos < 0) {
-      maxlen = file_.pos();
+      maxlen = device_->pos();
 
       new_pos = 0;
     }
 
-    file_.seek(new_pos);
+    device_->seek(new_pos);
   }
 
-  qint64 read_count = file_.read(data, maxlen);
+  qint64 read_count = device_->read(data, maxlen);
 
   if (playback_speed_ < 0) {
-    file_.seek(new_pos);
+    device_->seek(new_pos);
 
     // Reverse the samples here
     AudioManager::ReverseBuffer(data, static_cast<int>(read_count), params_.samples_to_bytes(1));

app/audio/outputdeviceproxy.h

@@ -35,13 +35,11 @@ class AudioOutputDeviceProxy : public QIODevice
 {
   Q_OBJECT
 public:
-  AudioOutputDeviceProxy() = default;
-
-  virtual ~AudioOutputDeviceProxy() override;
+  AudioOutputDeviceProxy(QObject* parent = nullptr);
 
   void SetParameters(const AudioParams& params);
 
-  void SetDevice(const QString &filename, qint64 offset, int playback_speed);
+  void SetDevice(QIODevice *device, qint64 offset, int playback_speed);
 
   virtual void close() override;
 
@@ -53,7 +51,7 @@ protected:
 private:
   qint64 ReverseAwareRead(char* data, qint64 maxlen);
 
-  QFile file_;
+  QIODevice* device_;
 
   TempoProcessor tempo_processor_;
 

app/audio/outputmanager.cpp

@@ -30,6 +30,7 @@ OLIVE_NAMESPACE_ENTER
 AudioOutputManager::AudioOutputManager(QObject *parent) :
   QObject(parent),
   output_(nullptr),
+  device_proxy_(this),
   push_device_(nullptr)
 {
 }
@@ -87,7 +88,7 @@ void AudioOutputManager::Close()
   }
 }
 
-void AudioOutputManager::PullFromDevice(const QString &filename, qint64 offset, int playback_speed)
+void AudioOutputManager::PullFromDevice(QIODevice *device, qint64 offset, int playback_speed)
 {
   if (!output_) {
     return;
@@ -99,7 +100,7 @@ void AudioOutputManager::PullFromDevice(const QString &filename, qint64 offset,
   push_samples_.clear();
 
   // Pull from the device
-  device_proxy_.SetDevice(filename, offset, playback_speed);
+  device_proxy_.SetDevice(device, offset, playback_speed);
   device_proxy_.open(QIODevice::ReadOnly);
   output_->start(&device_proxy_);
 }

app/audio/outputmanager.h

@@ -53,7 +53,7 @@ public slots:
    * This will clear any pushed samples or QIODevices currently being read and will start reading from this next time
    * the audio output requests data.
    */
-  void PullFromDevice(const QString &filename, qint64 offset, int playback_speed);
+  void PullFromDevice(QIODevice* device, qint64 offset, int playback_speed);
 
   // Queued
   void ResetToPushMode();