Check that Interop subtitle files have at least one subtitle.

It was reported on the forum that files without any <Font> or
<Subtitle> tags fail validation on EasyDCP 3.0.1 and crash
Qubemaster Pro 3.0.15.

4 files changed, 50 insertions, 1 deletions

diff --git a/src/verify.cc b/src/verify.cc
index bfa697da..8ea9ae97 100644
--- a/src/verify.cc
+++ b/src/verify.cc
@@ -687,6 +687,16 @@ verify_smpte_timed_text_asset (
 }
 
 
+/** Verify Interop subtitle-only stuff */
+void
+verify_interop_subtitle_asset(shared_ptr<const InteropSubtitleAsset> asset, vector<VerificationNote>& notes)
+{
+	if (asset->subtitles().empty()) {
+		notes.push_back({VerificationNote::Type::ERROR, VerificationNote::Code::MISSING_SUBTITLE, asset->id(), asset->file().get() });
+	}
+}
+
+
 /** Verify SMPTE subtitle-only stuff */
 void
 verify_smpte_subtitle_asset (
@@ -740,6 +750,11 @@ verify_subtitle_asset (
 		notes.push_back ({VerificationNote::Type::WARNING, VerificationNote::Code::MISSED_CHECK_OF_ENCRYPTED});
 	}
 
+	auto interop = dynamic_pointer_cast<const InteropSubtitleAsset>(asset);
+	if (interop) {
+		verify_interop_subtitle_asset(interop, notes);
+	}
+
 	auto smpte = dynamic_pointer_cast<const SMPTESubtitleAsset>(asset);
 	if (smpte) {
 		verify_smpte_timed_text_asset (smpte, reel_asset_duration, notes);
@@ -1938,6 +1953,8 @@ dcp::note_to_string (VerificationNote note)
 		return String::compose("The PKL %1 has more than one asset with the same ID", note.note().get());
 	case VerificationNote::Code::DUPLICATE_ASSET_ID_IN_ASSETMAP:
 		return String::compose("The ASSETMAP %1 has more than one asset with the same ID", note.note().get());
+	case VerificationNote::Code::MISSING_SUBTITLE:
+		return String::compose("The subtitle asset %1 has no subtitles", note.note().get());
 	}
 
 	return "";
diff --git a/src/verify.h b/src/verify.h
index e9b5c9d0..2e20bc31 100644
--- a/src/verify.h
+++ b/src/verify.h
@@ -410,7 +410,12 @@ public:
 		 *  note contains the ASSETMAP ID
 		 *  file contains the ASSETMAP filename
 		 */
-		DUPLICATE_ASSET_ID_IN_ASSETMAP
+		DUPLICATE_ASSET_ID_IN_ASSETMAP,
+		/** An Interop subtitle asset has no subtitles.
+		 *  note contains the asset ID
+		 *  file contains the asset filename
+		 */
+		MISSING_SUBTITLE
 	};
 
 	VerificationNote (Type type, Code code)
diff --git a/test/data/subs4.xml b/test/data/subs4.xml
new file mode 100644
index 00000000..5aea4c10
--- /dev/null
+++ b/test/data/subs4.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<DCSubtitle Version="1.0">
+  <SubtitleID>cab5c268-222b-41d2-88ae-6d6999441b17</SubtitleID>
+  <MovieTitle>Movie Title</MovieTitle>
+  <ReelNumber>1</ReelNumber>
+  <Language>French</Language>
+  <LoadFont Id="theFontId" URI="arial.ttf"/>
+</DCSubtitle>
diff --git a/test/verify_test.cc b/test/verify_test.cc
index 652bf12d..34dc79bc 100644
--- a/test/verify_test.cc
+++ b/test/verify_test.cc
@@ -806,6 +806,25 @@ BOOST_AUTO_TEST_CASE (verify_invalid_interop_subtitles)
 }
 
 
+BOOST_AUTO_TEST_CASE(verify_interop_subtitle_asset_with_no_subtitles)
+{
+	path const dir("build/test/verify_interop_subtitle_asset_with_no_subtitles");
+	prepare_directory(dir);
+	copy_file("test/data/subs4.xml", dir / "subs.xml");
+	auto asset = make_shared<dcp::InteropSubtitleAsset>(dir / "subs.xml");
+	auto reel_asset = make_shared<dcp::ReelInteropSubtitleAsset>(asset, dcp::Fraction(24, 1), 16 * 24, 0);
+	write_dcp_with_single_asset(dir, reel_asset, dcp::Standard::INTEROP);
+
+	check_verify_result (
+		{ dir },
+		{
+			{ dcp::VerificationNote::Type::BV21_ERROR, dcp::VerificationNote::Code::INVALID_STANDARD },
+			{ dcp::VerificationNote::Type::ERROR, dcp::VerificationNote::Code::MISSING_SUBTITLE, asset->id(), boost::filesystem::canonical(asset->file().get()) },
+		});
+
+}
+
+
 BOOST_AUTO_TEST_CASE (verify_valid_smpte_subtitles)
 {
 	path const dir("build/test/verify_valid_smpte_subtitles");