diff --git a/gtk2_ardour/audio_clock.cc b/gtk2_ardour/audio_clock.cc
index f0ae7c76f4..4e29cc3c8b 100644
--- a/gtk2_ardour/audio_clock.cc
+++ b/gtk2_ardour/audio_clock.cc
@@ -1916,9 +1916,10 @@ AudioClock::bbt_frame_from_display (framepos_t pos) const
 	if (is_duration) {
 		any.bbt.bars++;
 		any.bbt.beats++;
-	}
-
-	return _session->convert_to_frames_at (pos, any);
+                return _session->any_duration_to_frames (pos, any);
+	} else {
+                return _session->convert_to_frames (any);
+        }
 }
 
 
diff --git a/gtk2_ardour/export_format_dialog.cc b/gtk2_ardour/export_format_dialog.cc
index ceea2b1082..89762be583 100644
--- a/gtk2_ardour/export_format_dialog.cc
+++ b/gtk2_ardour/export_format_dialog.cc
@@ -732,7 +732,7 @@ void
 ExportFormatDialog::update_clock (AudioClock & clock, ARDOUR::AnyTime const & time)
 {
 	// TODO position
-	clock.set (_session->convert_to_frames_at (0, time), true);
+	clock.set (_session->convert_to_frames (time), true);
 
 	AudioClock::Mode mode(AudioClock::Timecode);
 
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index 393c9d1356..7abeabd647 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -460,7 +460,8 @@ class Session : public PBD::StatefulDestructible, public PBD::ScopedConnectionLi
 	void timecode_duration (framecnt_t, Timecode::Time&) const;
 	void timecode_duration_string (char *, framecnt_t) const;
 
-	framecnt_t convert_to_frames_at (framepos_t position, AnyTime const &);
+	framecnt_t convert_to_frames (AnyTime const & position);
+        framecnt_t any_duration_to_frames (framepos_t position, AnyTime const & duration);
 
 	static PBD::Signal1<void, framepos_t> StartTimeChanged;
 	static PBD::Signal1<void, framepos_t> EndTimeChanged;
diff --git a/libs/ardour/export_format_specification.cc b/libs/ardour/export_format_specification.cc
index b85d060e2f..bf2585a281 100644
--- a/libs/ardour/export_format_specification.cc
+++ b/libs/ardour/export_format_specification.cc
@@ -49,7 +49,7 @@ ExportFormatSpecification::Time::operator= (AnyTime const & other)
 framecnt_t
 ExportFormatSpecification::Time::get_frames_at (framepos_t position, framecnt_t target_rate) const
 {
-	framecnt_t duration = session.convert_to_frames_at (position, *this);
+	framecnt_t duration = session.any_duration_to_frames (position, *this);
 	return ((double) target_rate / session.frame_rate()) * duration + 0.5;
 }
 
diff --git a/libs/ardour/session_time.cc b/libs/ardour/session_time.cc
index 7bd0ad1164..d9c612fbee 100644
--- a/libs/ardour/session_time.cc
+++ b/libs/ardour/session_time.cc
@@ -547,21 +547,21 @@ Session::jack_timebase_callback (jack_transport_state_t /*state*/,
 }
 
 ARDOUR::framecnt_t
-Session::convert_to_frames_at (framepos_t /*position*/, AnyTime const & any)
+Session::convert_to_frames (AnyTime const & position)
 {
 	double secs;
 
-	switch (any.type) {
+	switch (position.type) {
 	case AnyTime::BBT:
-		return _tempo_map->frame_time (any.bbt);
+		return _tempo_map->frame_time (position.bbt);
 		break;
 
 	case AnyTime::Timecode:
 		/* XXX need to handle negative values */
-		secs = any.timecode.hours * 60 * 60;
-		secs += any.timecode.minutes * 60;
-		secs += any.timecode.seconds;
-		secs += any.timecode.frames / timecode_frames_per_second();
+		secs = position.timecode.hours * 60 * 60;
+		secs += position.timecode.minutes * 60;
+		secs += position.timecode.seconds;
+		secs += position.timecode.frames / timecode_frames_per_second();
 		if (config.get_timecode_offset_negative()) {
 			return (framecnt_t) floor (secs * frame_rate()) - config.get_timecode_offset();
 		} else {
@@ -570,13 +570,48 @@ Session::convert_to_frames_at (framepos_t /*position*/, AnyTime const & any)
 		break;
 
 	case AnyTime::Seconds:
-		return (framecnt_t) floor (any.seconds * frame_rate());
+		return (framecnt_t) floor (position.seconds * frame_rate());
 		break;
 
 	case AnyTime::Frames:
-		return any.frames;
+		return position.frames;
 		break;
 	}
 
-	return any.frames;
+	return position.frames;
+}
+
+ARDOUR::framecnt_t
+Session::any_duration_to_frames (framepos_t position, AnyTime const & duration)
+{
+	double secs;
+
+	switch (duration.type) {
+	case AnyTime::BBT:
+		return (framecnt_t) ( _tempo_map->framepos_plus_bbt (position, duration.bbt) - position);
+		break;
+
+	case AnyTime::Timecode:
+		/* XXX need to handle negative values */
+		secs = duration.timecode.hours * 60 * 60;
+		secs += duration.timecode.minutes * 60;
+		secs += duration.timecode.seconds;
+		secs += duration.timecode.frames / timecode_frames_per_second();
+		if (config.get_timecode_offset_negative()) {
+			return (framecnt_t) floor (secs * frame_rate()) - config.get_timecode_offset();
+		} else {
+			return (framecnt_t) floor (secs * frame_rate()) + config.get_timecode_offset();
+		}
+		break;
+
+	case AnyTime::Seconds:
+                return (framecnt_t) floor (duration.seconds * frame_rate());
+		break;
+
+	case AnyTime::Frames:
+		return duration.frames;
+		break;
+	}
+
+	return duration.frames;
 }