shared_ptr<const AudioBuffers> ro = i->second->flush ();
if (ro->frames() > 0) {
Data (i->first, ContentAudio (ro, _positions[i->first]));
shared_ptr<const AudioBuffers> ro = i->second->flush ();
if (ro->frames() > 0) {
Data (i->first, ContentAudio (ro, _positions[i->first]));