encoder: write audio in segments

I'll be honest, this probably makes no noticeable difference at all. It should be faster and more efficient, but whether that translates into any tangible improvement is yet to be seen.

app/task/export/export.cpp

@@ -99,10 +99,6 @@ bool ExportTask::Run()
                                               params_.color_transform());
   }
 
-  if (params_.audio_enabled()) {
-    audio_data_.SetParameters(audio_params());
-  }
-
   // Start render process
   TimeRangeList video_range, audio_range;
 
@@ -112,7 +108,6 @@ bool ExportTask::Run()
 
   if (params_.audio_enabled()) {
     audio_range = {range};
-    audio_data_.SetLength(range.length());
   }
 
   Render(color_manager_, video_range, audio_range, RenderMode::kOnline, nullptr,
@@ -121,13 +116,13 @@ bool ExportTask::Run()
 
   bool success = true;
 
-  if (params_.audio_enabled()) {
-    // Write audio data now
-    encoder_->WriteAudio(audio_params(), audio_data_.CreatePlaybackDevice(encoder_));
-  }
-
   encoder_->Close();
 
+  if (!encoder_->GetError().isEmpty()) {
+    SetError(encoder_->GetError());
+    success = false;
+  }
+
   delete encoder_;
 
   // If cancelled, delete the file we made, which is always a file we created since we write to a
@@ -187,7 +182,33 @@ void ExportTask::AudioDownloaded(const TimeRange &range, SampleBufferPtr samples
     adjusted_range -= params_.custom_range().in();
   }
 
-  audio_data_.WritePCM(adjusted_range, samples, QDateTime::currentMSecsSinceEpoch());
+  if (adjusted_range.in() == audio_time_) {
+    WriteAudioLoop(adjusted_range, samples);
+  } else {
+    audio_map_.insert(adjusted_range, samples);
+  }
+}
+
+void ExportTask::WriteAudioLoop(const TimeRange& time, SampleBufferPtr samples)
+{
+  encoder_->WriteAudio(samples);
+  audio_time_ = time.out();
+
+  for (auto it=audio_map_.begin(); it!=audio_map_.end(); it++) {
+    TimeRange t = it.key();
+    SampleBufferPtr s = it.value();
+
+    if (t.in() == audio_time_) {
+      // Erase from audio map since we're just about to write it
+      audio_map_.erase(it);
+
+      // Call recursively to write the next sample buffer
+      WriteAudioLoop(t, s);
+
+      // Break out of loop
+      break;
+    }
+  }
 }
 
 }