Don't write <Language> tags to SMPTE subs unless we know the language,

as "Unknown" is an invalid value and <Language> is optional in SMPTE.

diff --git a/src/lib/reel_writer.cc b/src/lib/reel_writer.cc
index e34874a14ca91c7bed111c0c8759fcdb368d21d1..d699adfba0e7ae52e05082712382f188b3530101 100644 (file)
--- a/src/lib/reel_writer.cc
+++ b/src/lib/reel_writer.cc
@@ -566,19 +566,22 @@ ReelWriter::write (PlayerText subs, TextType type, optional<DCPTextTrack> track,
 
        if (!asset) {
                string lang = _film->subtitle_language ();
-               if (lang.empty ()) {
-                       lang = "Unknown";
-               }
                if (_film->interop ()) {
                        shared_ptr<dcp::InteropSubtitleAsset> s (new dcp::InteropSubtitleAsset ());
                        s->set_movie_title (_film->name ());
-                       s->set_language (lang);
+                       if (lang.empty()) {
+                               s->set_language ("Unknown");
+                       } else {
+                               s->set_language (lang);
+                       }
                        s->set_reel_number (raw_convert<string> (_reel_index + 1));
                        asset = s;
                } else {
                        shared_ptr<dcp::SMPTESubtitleAsset> s (new dcp::SMPTESubtitleAsset ());
                        s->set_content_title_text (_film->name ());
-                       s->set_language (lang);
+                       if (!lang.empty()) {
+                               s->set_language (lang);
+                       }
                        s->set_edit_rate (dcp::Fraction (_film->video_frame_rate (), 1));
                        s->set_reel_number (_reel_index + 1);
                        s->set_time_code_rate (_film->video_frame_rate ());