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/render/render.cpp

@@ -57,17 +57,24 @@ bool RenderTask::Render(ColorManager* manager,
   qint64 job_time = QDateTime::currentMSecsSinceEpoch();
 
   // Queue audio jobs
-  foreach (const TimeRange& r, audio_range) {
+  foreach (const TimeRange& range, audio_range) {
     // Don't count audio progress, since it's generally a lot faster than video and is weighted at
     // 50%, which makes the progress bar look weird to the uninitiated
     //total_length += r.length().toDouble();
 
-    IncrementRunningTickets();
+    rational r = range.in();
+    while (r != range.out()) {
+      rational end = qMin(range.out(), r+1);
+      TimeRange this_range(r, end);
 
-    RenderTicketWatcher* watcher = new RenderTicketWatcher();
-    watcher->setProperty("range", QVariant::fromValue(r));
-    PrepareWatcher(watcher, &watcher_thread);
-    watcher->SetTicket(RenderManager::instance()->RenderAudio(viewer_, r, audio_params_, false));
+      RenderTicketWatcher* watcher = new RenderTicketWatcher();
+      watcher->setProperty("range", QVariant::fromValue(this_range));
+      PrepareWatcher(watcher, &watcher_thread);
+      IncrementRunningTickets();
+      watcher->SetTicket(RenderManager::instance()->RenderAudio(viewer_, this_range, audio_params_, false));
+
+      r = end;
+    }
   }
 
   // Look up hashes