viewer: restart audio if validated during playback

Fixes #1566

app/widget/viewer/viewer.cpp

@@ -110,6 +110,11 @@ ViewerWidget::ViewerWidget(QWidget *parent) :
   connect(controls_, &PlaybackControls::TimeChanged, this, &ViewerWidget::SetTimeAndSignal);
   layout->addWidget(controls_);
 
+  // If audio is invalidated during playback, we wait some time before starting it again
+  audio_restart_timer_.setInterval(250);
+  audio_restart_timer_.setSingleShot(true);
+  connect(&audio_restart_timer_, &QTimer::timeout, this, &ViewerWidget::StartAudioOutput);
+
   // FIXME: Magic number
   SetScale(48.0);
 
@@ -186,6 +191,8 @@ void ViewerWidget::ConnectNodeEvent(ViewerOutput *n)
   connect(n, &ViewerOutput::AudioParamsChanged, this, &ViewerWidget::UpdateRendererAudioParameters);
   connect(n->video_frame_cache(), &FrameHashCache::Invalidated, this, &ViewerWidget::ViewerInvalidatedVideoRange);
   connect(n->video_frame_cache(), &FrameHashCache::Shifted, this, &ViewerWidget::ViewerShiftedRange);
+  connect(n->audio_playback_cache(), &AudioPlaybackCache::Invalidated, this, &ViewerWidget::AudioCacheInvalidated);
+  connect(n->audio_playback_cache(), &AudioPlaybackCache::Validated, this, &ViewerWidget::AudioCacheValidated);
   connect(n, &ViewerOutput::TextureInputChanged, this, &ViewerWidget::UpdateStack);
 
   VideoParams vp = n->GetVideoParams();
@@ -230,6 +237,8 @@ void ViewerWidget::DisconnectNodeEvent(ViewerOutput *n)
   disconnect(n, &ViewerOutput::AudioParamsChanged, this, &ViewerWidget::UpdateRendererAudioParameters);
   disconnect(n->video_frame_cache(), &FrameHashCache::Invalidated, this, &ViewerWidget::ViewerInvalidatedVideoRange);
   disconnect(n->video_frame_cache(), &FrameHashCache::Shifted, this, &ViewerWidget::ViewerShiftedRange);
+  disconnect(n->audio_playback_cache(), &AudioPlaybackCache::Invalidated, this, &ViewerWidget::AudioCacheInvalidated);
+  disconnect(n->audio_playback_cache(), &AudioPlaybackCache::Validated, this, &ViewerWidget::AudioCacheValidated);
   disconnect(n, &ViewerOutput::TextureInputChanged, this, &ViewerWidget::UpdateStack);
 
   ruler()->SetPlaybackCache(nullptr);
@@ -395,6 +404,17 @@ bool ViewerWidget::ShouldForceWaveform() const
       && GetConnectedNode()->GetConnectedSampleOutput().IsValid();
 }
 
+void ViewerWidget::StartAudioOutput()
+{
+  AudioPlaybackCache* audio_cache = GetConnectedNode()->audio_playback_cache();
+  if (audio_cache->GetParameters().is_valid()) {
+    AudioManager::instance()->SetOutputParams(audio_cache->GetParameters());
+    AudioManager::instance()->StartOutput(audio_cache,
+                                          audio_cache->GetParameters().time_to_bytes(GetTime()),
+                                          playback_speed_);
+  }
+}
+
 void ViewerWidget::UpdateTextureFromNode(const rational& time)
 {
   bool frame_exists_at_time = FrameExistsAtTime(time);
@@ -650,13 +670,7 @@ void ViewerWidget::FinishPlayPreprocess()
 {
   int64_t playback_start_time = ruler()->GetTime();
 
-  AudioPlaybackCache* audio_cache = GetConnectedNode()->audio_playback_cache();
-  if (audio_cache->GetParameters().is_valid()) {
-    AudioManager::instance()->SetOutputParams(audio_cache->GetParameters());
-    AudioManager::instance()->StartOutput(audio_cache,
-                                          audio_cache->GetParameters().time_to_bytes(GetTime()),
-                                          playback_speed_);
-  }
+  StartAudioOutput();
 
   playback_timer_.Start(playback_start_time, playback_speed_, timebase_dbl());
   display_widget_->ResetFPSTimer();
@@ -1263,4 +1277,21 @@ void ViewerWidget::Dropped(QDropEvent *event)
   }
 }
 
+void ViewerWidget::AudioCacheInvalidated()
+{
+  if (IsPlaying()) {
+    AudioManager::instance()->StopOutput();
+  }
+}
+
+void ViewerWidget::AudioCacheValidated()
+{
+  if (IsPlaying()) {
+    // This timer will restart audio
+    AudioManager::instance()->StopOutput();
+    audio_restart_timer_.stop();
+    audio_restart_timer_.start();
+  }
+}
+
 }

app/widget/viewer/viewer.h

@@ -245,6 +245,8 @@ private:
 
   PreviewAutoCacher auto_cacher_;
 
+  QTimer audio_restart_timer_;
+
   static QVector<ViewerWidget*> instances_;
 
 private slots:
@@ -292,6 +294,11 @@ private slots:
 
   void Dropped(QDropEvent* event);
 
+  void AudioCacheInvalidated();
+  void AudioCacheValidated();
+
+  void StartAudioOutput();
+
 };
 
 }