Fix black frames when raising frame rate by a lot (#2993).

2 files changed, 39 insertions, 4 deletions

diff --git a/src/lib/player.cc b/src/lib/player.cc
index fd99e7732..4c988c804 100644
--- a/src/lib/player.cc
+++ b/src/lib/player.cc
@@ -997,7 +997,16 @@ Player::emit_video_until(DCPTime time)
 		emit_video(to_do.first, to_do.second);
 	};
 
-	auto const age_threshold = one_video_frame() * 2;
+	auto film = _film.lock();
+	DCPOMATIC_ASSERT(film);
+
+	auto const age_threshold = [this, film](pair<shared_ptr<PlayerVideo>, dcpomatic::DCPTime> video) {
+		if (auto content = video.first->content().lock()) {
+			return one_video_frame() * (std::ceil(film->video_frame_rate() / content->video_frame_rate().get_value_or(24)) + 1);
+		} else {
+			return one_video_frame() * 2;
+		}
+	};
 
 	while (_next_video_time.get_value_or({}) < time) {
 		auto left = _last_video[Eyes::LEFT];
@@ -1010,12 +1019,12 @@ Player::emit_video_until(DCPTime time)
 			left.first &&
 			right.first &&
 			(!both.first || (left.second >= both.second && right.second >= both.second)) &&
-			(left.second - next) < age_threshold &&
-			(right.second - next) < age_threshold
+			(left.second - next) < age_threshold(left) &&
+			(right.second - next) < age_threshold(right)
 		   ) {
 			frame(left.first, next);
 			frame(right.first, next);
-		} else if (both.first && (both.second - next) < age_threshold) {
+		} else if (both.first && (both.second - next) < age_threshold(both)) {
 			frame(both.first, next);
 			LOG_DEBUG_PLAYER("Content %1 selected for DCP %2 (age %3)", to_string(both.second), to_string(next), to_string(both.second - next));
 		} else {
diff --git a/test/player_test.cc b/test/player_test.cc
index eb49bc4df..60b365eb1 100644
--- a/test/player_test.cc
+++ b/test/player_test.cc
@@ -731,3 +731,29 @@ BOOST_AUTO_TEST_CASE(unmapped_audio_does_not_raise_buffer_error)
 	butler.rethrow();
 }
 
+
+BOOST_AUTO_TEST_CASE(frames_are_copied_correctly_for_low_frame_rates)
+{
+	auto content = content_factory("test/data/flat_red.png");
+	auto film = new_test_film("frames_are_copied_correctly_for_low_frame_rates", content);
+
+	content[0]->set_video_frame_rate(film, 10);
+	film->set_video_frame_rate(30);
+
+	Player player(film, Image::Alignment::COMPACT, false);
+	Butler butler(film, player, AudioMapping(), 2, bind(PlayerVideo::force, AV_PIX_FMT_RGB24), VideoRange::FULL, Image::Alignment::PADDED, true, false, Butler::Audio::ENABLED);
+
+	/* Check that only red frames come out - previously there would be some black ones mixed in */
+	for (auto i = 0; i < 24; ++i) {
+		auto frame = butler.get_video(Butler::Behaviour::BLOCKING);
+		auto image = frame.first->image([](AVPixelFormat) { return AV_PIX_FMT_RGB24; }, VideoRange::FULL, false);
+		for (int y = 0; y < image->size().height; ++y) {
+			uint8_t const* p = image->data()[0] + image->stride()[0] * y;
+			for (int x = 0; x < image->size().width; ++x) {
+				BOOST_REQUIRE_EQUAL(p[0], 255);
+				BOOST_REQUIRE_EQUAL(p[1], 0);
+				BOOST_REQUIRE_EQUAL(p[2], 0);
+			}
+		}
+	}
+}