Fix missing subtitles when they start just after the start of a frame.

4 files changed, 21 insertions, 10 deletions

diff --git a/src/lib/dcpomatic_time.h b/src/lib/dcpomatic_time.h
index 204af3c1e..3d792467b 100644
--- a/src/lib/dcpomatic_time.h
+++ b/src/lib/dcpomatic_time.h
@@ -125,6 +125,10 @@ public:
 		return Time<S, O> (llrint (HZ * frames_floor(r) / r));
 	}
 
+	Time<S, O> round (double r) const {
+		return Time<S, O> (llrint (HZ * frames_round(r) / r));
+	}
+
 	double seconds () const {
 		return double (_t) / HZ;
 	}
diff --git a/src/lib/player.cc b/src/lib/player.cc
index 9ee8ab72c..ec7a93dac 100644
--- a/src/lib/player.cc
+++ b/src/lib/player.cc
@@ -658,7 +658,9 @@ Player::subtitles_for_frame (DCPTime time) const
 {
 	list<PositionImage> subtitles;
 
-	BOOST_FOREACH (PlayerSubtitles i, _active_subtitles.get_burnt (DCPTimePeriod(time, time + DCPTime::from_frames(1, _film->video_frame_rate())),  _always_burn_subtitles)) {
+	int const vfr = _film->video_frame_rate();
+
+	BOOST_FOREACH (PlayerSubtitles i, _active_subtitles.get_burnt (DCPTimePeriod(time, time + DCPTime::from_frames(1, vfr)), _always_burn_subtitles)) {
 
 		/* Image subtitles */
 		list<PositionImage> c = transform_image_subtitles (i.image);
@@ -666,7 +668,7 @@ Player::subtitles_for_frame (DCPTime time) const
 
 		/* Text subtitles (rendered to an image) */
 		if (!i.text.empty ()) {
-			list<PositionImage> s = render_subtitles (i.text, i.fonts, _video_container_size, time);
+			list<PositionImage> s = render_subtitles (i.text, i.fonts, _video_container_size, time, vfr);
 			copy (s.begin(), s.end(), back_inserter (subtitles));
 		}
 	}
diff --git a/src/lib/render_subtitles.cc b/src/lib/render_subtitles.cc
index 56343cd50..5f587c313 100644
--- a/src/lib/render_subtitles.cc
+++ b/src/lib/render_subtitles.cc
@@ -85,7 +85,7 @@ set_source_rgba (Cairo::RefPtr<Cairo::Context> context, dcp::Colour colour, floa
  *  at the same time and with the same fade in/out.
  */
 static PositionImage
-render_line (list<SubtitleString> subtitles, list<shared_ptr<Font> > fonts, dcp::Size target, DCPTime time)
+render_line (list<SubtitleString> subtitles, list<shared_ptr<Font> > fonts, dcp::Size target, DCPTime time, int frame_rate)
 {
 	/* XXX: this method can only handle italic / bold changes mid-line,
 	   nothing else yet.
@@ -242,9 +242,12 @@ render_line (list<SubtitleString> subtitles, list<shared_ptr<Font> > fonts, dcp:
 	/* Compute fade factor */
 	float fade_factor = 1;
 
-	DCPTime const fade_in_start = DCPTime::from_seconds (subtitles.front().in().as_seconds ());
+	/* Round the fade start/end to the nearest frame start.  Otherwise if a subtitle starts just after
+	   the start of a frame it will be faded out.
+	*/
+	DCPTime const fade_in_start = DCPTime::from_seconds(subtitles.front().in().as_seconds()).round(frame_rate);
 	DCPTime const fade_in_end = fade_in_start + DCPTime::from_seconds (subtitles.front().fade_up_time().as_seconds ());
-	DCPTime const fade_out_end =  DCPTime::from_seconds (subtitles.front().out().as_seconds ());
+	DCPTime const fade_out_end =  DCPTime::from_seconds (subtitles.front().out().as_seconds()).round(frame_rate);
 	DCPTime const fade_out_start = fade_out_end - DCPTime::from_seconds (subtitles.front().fade_down_time().as_seconds ());
 
 	if (fade_in_start <= time && time <= fade_in_end && fade_in_start != fade_in_end) {
@@ -347,23 +350,25 @@ render_line (list<SubtitleString> subtitles, list<shared_ptr<Font> > fonts, dcp:
 	return PositionImage (image, Position<int> (max (0, x), max (0, y)));
 }
 
-/** @param time Time of the frame that these subtitles are going on */
+/** @param time Time of the frame that these subtitles are going on.
+ *  @param frame_rate DCP frame rate.
+ */
 list<PositionImage>
-render_subtitles (list<SubtitleString> subtitles, list<shared_ptr<Font> > fonts, dcp::Size target, DCPTime time)
+render_subtitles (list<SubtitleString> subtitles, list<shared_ptr<Font> > fonts, dcp::Size target, DCPTime time, int frame_rate)
 {
 	list<SubtitleString> pending;
 	list<PositionImage> images;
 
 	BOOST_FOREACH (SubtitleString const & i, subtitles) {
 		if (!pending.empty() && fabs (i.v_position() - pending.back().v_position()) > 1e-4) {
-			images.push_back (render_line (pending, fonts, target, time));
+			images.push_back (render_line (pending, fonts, target, time, frame_rate));
 			pending.clear ();
 		}
 		pending.push_back (i);
 	}
 
 	if (!pending.empty ()) {
-		images.push_back (render_line (pending, fonts, target, time));
+		images.push_back (render_line (pending, fonts, target, time, frame_rate));
 	}
 
 	return images;
diff --git a/src/lib/render_subtitles.h b/src/lib/render_subtitles.h
index 02bf3ec65..b1239bb3d 100644
--- a/src/lib/render_subtitles.h
+++ b/src/lib/render_subtitles.h
@@ -27,5 +27,5 @@ class Font;
 
 std::string marked_up (std::list<SubtitleString> subtitles, int target_height, float fade_factor);
 std::list<PositionImage> render_subtitles (
-	std::list<SubtitleString>, std::list<boost::shared_ptr<Font> > fonts, dcp::Size, DCPTime
+	std::list<SubtitleString>, std::list<boost::shared_ptr<Font> > fonts, dcp::Size, DCPTime, int
 	);