+ DCPOMATIC_ASSERT (audio);
+
+ int const afr = _film->audio_frame_rate();
+
+ DCPTime const end = time + DCPTime::from_frames(audio->frames(), afr);
+
+ /* The audio we get might span a reel boundary, and if so we have to write it in bits */
+
+ DCPTime t = time;
+ while (t < end) {
+
+ if (_audio_reel == _reels.end ()) {
+ /* This audio is off the end of the last reel; ignore it */
+ return;
+ }
+
+ if (end <= _audio_reel->period().to) {
+ /* Easy case: we can write all the audio to this reel */
+ _audio_reel->write (audio);
+ t = end;
+ } else {
+ /* Split the audio into two and write the first part */
+ DCPTime part_lengths[2] = {
+ _audio_reel->period().to - t,
+ end - _audio_reel->period().to
+ };
+
+ Frame part_frames[2] = {
+ part_lengths[0].frames_ceil(afr),
+ part_lengths[1].frames_ceil(afr)
+ };
+
+ if (part_frames[0]) {
+ shared_ptr<AudioBuffers> part (new AudioBuffers (audio->channels(), part_frames[0]));
+ part->copy_from (audio.get(), part_frames[0], 0, 0);
+ _audio_reel->write (part);
+ }
+
+ if (part_frames[1]) {
+ shared_ptr<AudioBuffers> part (new AudioBuffers (audio->channels(), part_frames[1]));
+ part->copy_from (audio.get(), part_frames[1], part_frames[0], 0);
+ audio = part;
+ } else {
+ audio.reset ();
+ }
+
+ ++_audio_reel;
+ t += part_lengths[0];
+ }