for (int j = 0; j < mapped->channels(); ++j) {
if (map.get (i, static_cast<dcp::Channel> (j)) > 0) {
mapped->accumulate_channel (
for (int j = 0; j < mapped->channels(); ++j) {
if (map.get (i, static_cast<dcp::Channel> (j)) > 0) {
mapped->accumulate_channel (