dcp_mapped->make_silent ();
list<pair<int, libdcp::Channel> > map = _audio_content->audio_mapping().content_to_dcp ();
for (list<pair<int, libdcp::Channel> >::iterator i = map.begin(); i != map.end(); ++i) {
dcp_mapped->make_silent ();
list<pair<int, libdcp::Channel> > map = _audio_content->audio_mapping().content_to_dcp ();
for (list<pair<int, libdcp::Channel> >::iterator i = map.begin(); i != map.end(); ++i) {