+
+void
+Encoder::write_audio (shared_ptr<const AudioBuffers> data)
+{
+ if (_film->audio_channels() == 1) {
+ /* We need to switch things around so that the mono channel is on
+ the centre channel of a 5.1 set (with other channels silent).
+ */
+
+ shared_ptr<AudioBuffers> b (new AudioBuffers (6, data->frames ()));
+ b->make_silent (libdcp::LEFT);
+ b->make_silent (libdcp::RIGHT);
+ memcpy (b->data()[libdcp::CENTRE], data->data()[0], data->frames() * sizeof(float));
+ b->make_silent (libdcp::LFE);
+ b->make_silent (libdcp::LS);
+ b->make_silent (libdcp::RS);
+
+ data = b;
+ }
+
+ _writer->write (data);
+}