Fix false-positive duplicate format detection

Previously, stem-exports of more than 1 channel always included
the export-format, even if only one format was exported.

2 files changed, 11 insertions, 3 deletions

diff --git a/libs/ardour/export_filename.cc b/libs/ardour/export_filename.cc
index 1c8c53d117..511db44a6b 100644
--- a/libs/ardour/export_filename.cc
+++ b/libs/ardour/export_filename.cc
@@ -185,8 +185,7 @@ ExportFilename::get_path (ExportFormatSpecPtr format) const
 			&& !include_timespan
 			&& !include_channel_config
 			&& !include_channel
-			&& !include_date
-			&& !include_format_name) {
+			&& !include_date) {
 		with_timespan = true;
 	}
 
diff --git a/libs/ardour/export_handler.cc b/libs/ardour/export_handler.cc
index 3cad72c8d9..cd3d61731d 100644
--- a/libs/ardour/export_handler.cc
+++ b/libs/ardour/export_handler.cc
@@ -227,7 +227,16 @@ ExportHandler::handle_duplicate_format_extensions()
 
 	ExtCountMap counts;
 	for (ConfigMap::iterator it = timespan_bounds.first; it != timespan_bounds.second; ++it) {
-		counts[it->second.format->extension()]++;
+		if (it->second.filename->include_channel_config && it->second.channel_config) {
+			/* stem-export has multiple files in the same timestamp, but a different channel_config for each.
+			 * However channel_config is only set in ExportGraphBuilder::Encoder::init_writer()
+			 * so we cannot yet use   it->second.filename->get_path(it->second.format).
+			 * We have to explicily check uniqueness of "channel-config + extension" here:
+			 */
+			counts[it->second.channel_config->name() + it->second.format->extension()]++;
+		} else {
+			counts[it->second.format->extension()]++;
+		}
 	}
 
 	bool duplicates_found = false;