Fix seek with respect to video/audio frame boundary alignment.

4 files changed, 14 insertions, 2 deletions

diff --git a/src/lib/audio_merger.h b/src/lib/audio_merger.h
index 2a1cc761b..f068b504e 100644
--- a/src/lib/audio_merger.h
+++ b/src/lib/audio_merger.h
@@ -37,6 +37,8 @@ public:
 	TimedAudioBuffers<T>
 	pull (T time)
 	{
+		assert (time >= _last_pull);
+		
 		TimedAudioBuffers<T> out;
 		
 		F const to_return = _t_to_f (time - _last_pull);
diff --git a/src/lib/player.cc b/src/lib/player.cc
index 56bf0767d..d60dfb6a9 100644
--- a/src/lib/player.cc
+++ b/src/lib/player.cc
@@ -351,8 +351,10 @@ Player::seek (DCPTime t, bool accurate)
 		(*i)->decoder->seek (ct, accurate);
 	}
 
-	_video_position = _audio_position = t;
-	_audio_merger.clear (t);
+	_video_position = time_round_up (t, TIME_HZ / _film->video_frame_rate());
+	_audio_position = time_round_up (t, TIME_HZ / _film->audio_frame_rate());
+
+	_audio_merger.clear (_audio_position);
 
 	if (!accurate) {
 		/* We just did an inaccurate seek, so it's likely that the next thing seen
diff --git a/src/lib/util.cc b/src/lib/util.cc
index d5a07192c..381c47a9a 100644
--- a/src/lib/util.cc
+++ b/src/lib/util.cc
@@ -915,3 +915,10 @@ fit_ratio_within (float ratio, libdcp::Size full_frame)
 	
 	return libdcp::Size (full_frame.width, rint (full_frame.width / ratio));
 }
+
+DCPTime
+time_round_up (DCPTime t, DCPTime nearest)
+{
+	DCPTime const a = t + nearest - 1;
+	return a - (a % nearest);
+}
diff --git a/src/lib/util.h b/src/lib/util.h
index 9b201a50e..892b473f7 100644
--- a/src/lib/util.h
+++ b/src/lib/util.h
@@ -119,6 +119,7 @@ struct FrameRateChange
 
 extern int dcp_audio_frame_rate (int);
 extern int stride_round_up (int, int const *, int);
+extern DCPTime time_round_up (DCPTime, DCPTime);
 extern std::multimap<std::string, std::string> read_key_value (std::istream& s);
 extern int get_required_int (std::multimap<std::string, std::string> const & kv, std::string k);
 extern float get_required_float (std::multimap<std::string, std::string> const & kv, std::string k);