data->set_frames (this_time);
audio (_sndfile_content->audio_stream (), data, ContentTime::from_frames (_done, _info.samplerate));
_done += this_time;
data->set_frames (this_time);
audio (_sndfile_content->audio_stream (), data, ContentTime::from_frames (_done, _info.samplerate));
_done += this_time;