diff --git a/gtk2_ardour/automation_line.cc b/gtk2_ardour/automation_line.cc
index 136bb70d23..d6c4f54f99 100644
--- a/gtk2_ardour/automation_line.cc
+++ b/gtk2_ardour/automation_line.cc
@@ -1392,3 +1392,9 @@ AutomationLine::set_offset (timecnt_t const & off)
 	_offset = off;
 	reset ();
 }
+
+void
+AutomationLine::set_distance_measure_origin (timepos_t const & pos)
+{
+	_distance_measure.set_origin (pos);
+}
diff --git a/gtk2_ardour/editor_export_audio.cc b/gtk2_ardour/editor_export_audio.cc
index 08110c2ee1..0fac6abcbd 100644
--- a/gtk2_ardour/editor_export_audio.cc
+++ b/gtk2_ardour/editor_export_audio.cc
@@ -479,10 +479,10 @@ Editor::write_audio_range (AudioPlaylist& playlist, const ChanCount& count, list
 {
 	boost::shared_ptr<AudioFileSource> fs;
 	const samplepos_t chunk_size = 4096;
-	timecnt_t nframes;
+	samplecnt_t nframes;
 	Sample buf[chunk_size];
 	gain_t gain_buffer[chunk_size];
-	timepos_t pos;
+	samplepos_t pos;
 	char s[PATH_MAX+1];
 	uint32_t cnt;
 	string path;
@@ -531,18 +531,18 @@ Editor::write_audio_range (AudioPlaylist& playlist, const ChanCount& count, list
 
 	for (list<TimelineRange>::iterator i = range.begin(); i != range.end();) {
 
-		nframes = (*i).length();
-		pos = (*i).start();
+		nframes = (*i).length().samples();
+		pos = (*i).start().samples();
 
-		while (nframes.positive()) {
+		while (nframes) {
 
-			timecnt_t this_time = min (nframes, timecnt_t (chunk_size));
+			timecnt_t this_time = timecnt_t (min (nframes, chunk_size));
 
 			for (uint32_t n=0; n < channels; ++n) {
 
 				fs = sources[n];
 
-				if (playlist.read (buf, buf, gain_buffer, pos, this_time, n) != this_time) {
+				if (playlist.read (buf, buf, gain_buffer, timepos_t (pos), this_time, n) != this_time) {
 					break;
 				}
 
@@ -551,8 +551,8 @@ Editor::write_audio_range (AudioPlaylist& playlist, const ChanCount& count, list
 				}
 			}
 
-			nframes -= this_time;
-			pos += this_time;
+			nframes -= this_time.samples();
+			pos += this_time.samples();
 		}
 
 		list<TimelineRange>::iterator tmp = i;
@@ -562,11 +562,11 @@ Editor::write_audio_range (AudioPlaylist& playlist, const ChanCount& count, list
 
 			/* fill gaps with silence */
 
-			nframes = (*i).end().distance ((*tmp).start());
+			nframes = (*i).end().distance ((*tmp).start()).samples();
 
-			while (nframes.positive()) {
+			while (nframes) {
 
-				timecnt_t this_time = min (nframes, timecnt_t (chunk_size));
+				timecnt_t this_time = timecnt_t (min (nframes, chunk_size));
 				memset (buf, 0, sizeof (Sample) * this_time.samples());
 
 				for (uint32_t n=0; n < channels; ++n) {
@@ -577,7 +577,7 @@ Editor::write_audio_range (AudioPlaylist& playlist, const ChanCount& count, list
 					}
 				}
 
-				nframes -= this_time;
+				nframes -= this_time.samples();
 			}
 		}
 
diff --git a/libs/ardour/location.cc b/libs/ardour/location.cc
index f5dde17804..8078352980 100644
--- a/libs/ardour/location.cc
+++ b/libs/ardour/location.cc
@@ -61,6 +61,7 @@ PBD::Signal1<void,Location*> Location::end_changed;
 PBD::Signal1<void,Location*> Location::start_changed;
 PBD::Signal1<void,Location*> Location::flags_changed;
 PBD::Signal1<void,Location*> Location::lock_changed;
+PBD::Signal1<void,Location*> Location::position_time_domain_changed;
 PBD::Signal1<void,Location*> Location::changed;
 
 Location::Location (Session& s)
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index 25b9fa9164..b6652e2bdd 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -82,6 +82,7 @@ namespace ARDOUR {
 		PBD::PropertyDescriptor<uint64_t> layering_index;
 		PBD::PropertyDescriptor<std::string> tags;
 		PBD::PropertyDescriptor<bool> contents;
+		PBD::PropertyDescriptor<Temporal::TimeDomain> time_domain;
 	}
 }
 
@@ -571,6 +572,20 @@ Region::special_set_position (timepos_t const & pos)
 	_position = pos;
 }
 
+void
+Region::set_position_time_domain (Temporal::TimeDomain ps)
+{
+	if (_position.val().time_domain() != ps) {
+
+		boost::shared_ptr<Playlist> pl (playlist());
+
+#warning NUTEMPO are we going to allow this operation?
+		// _position.call().set_time_domain (ps);
+
+		send_change (Properties::time_domain);
+	}
+}
+
 void
 Region::recompute_position_from_time_domain ()
 {
@@ -598,7 +613,7 @@ Region::update_after_tempo_map_change (bool send)
 
 	PropertyChange what_changed;
 
-#warning NUTEMPO THINKME make this more nuanced ... nothing may have changed and maybe we don't need this at all
+#warning NUTEMPO THINKME make this more nuanced ... nothing may have changed and maybe we do not need this at all
 
 	what_changed.add (Properties::start);
 	what_changed.add (Properties::length);
diff --git a/libs/temporal/timeline.cc b/libs/temporal/timeline.cc
index 7057e5ec3c..b50aca7c4f 100644
--- a/libs/temporal/timeline.cc
+++ b/libs/temporal/timeline.cc
@@ -219,6 +219,100 @@ timecnt_t::to_string () const
 	return ss.str();
 }
 
+timecnt_t
+timecnt_t::operator+ (timecnt_t const & other) const
+{
+	if (time_domain() == AudioTime) {
+		if (other.time_domain() == AudioTime) {
+			/* both audio, just add and use an arbitrary position */
+			return timecnt_t (_distance + other.distance(), _position);
+		} else {
+			return timecnt_t (_distance + other.samples(), _position);
+		}
+	}
+
+	return timecnt_t (beats() + other.beats(), _position);
+}
+
+timecnt_t
+timecnt_t::operator- (timecnt_t const & other) const
+{
+	if (time_domain() == AudioTime) {
+		if (other.time_domain() == AudioTime) {
+			return timecnt_t (_distance - other.distance(), _position);
+		} else {
+			return timecnt_t (_distance - other.samples(), _position);
+		}
+	}
+
+	return timecnt_t (beats() - other.beats(), _position);
+}
+
+timecnt_t &
+timecnt_t::operator+= (timecnt_t const & other)
+{
+	if (time_domain() == AudioTime) {
+		if (other.time_domain() == AudioTime) {
+			_distance += other.distance();
+		} else {
+			_distance += other.samples();
+		}
+	} else {
+		_distance += other.ticks ();
+	}
+
+	return *this;
+}
+
+timecnt_t
+timecnt_t::operator+ (timepos_t const & other) const
+{
+	if (time_domain() == AudioTime) {
+		if (other.time_domain() == AudioTime) {
+			/* both audio, just add and use an arbitrary position */
+			return timecnt_t (_distance + other.val(), _position);
+		} else {
+			return timecnt_t (_distance + other.samples(), _position);
+		}
+	}
+
+	return timecnt_t (beats() + other.beats(), _position);
+}
+
+timecnt_t
+timecnt_t::operator- (timepos_t const & other) const
+{
+	if (time_domain() == AudioTime) {
+		if (other.time_domain() == AudioTime) {
+			return timecnt_t (_distance - other.val(), _position);
+		} else {
+			return timecnt_t (_distance - other.samples(), _position);
+		}
+	}
+
+	return timecnt_t (beats() - other.beats(), _position);
+}
+
+timecnt_t &
+timecnt_t::operator-= (timecnt_t const & other)
+{
+	if (time_domain() == other.time_domain()) {
+		_distance -= other.distance();
+	} else if (time_domain() == AudioTime) {
+		_distance -= other.samples();
+	} else {
+		_distance -= other.ticks ();
+	}
+
+	return *this;
+}
+
+timecnt_t
+timecnt_t::operator- () const
+{
+	return timecnt_t (-_distance, _position);
+}
+
 /* timepos */
 
 timepos_t::timepos_t (timecnt_t const & t)
@@ -239,6 +333,46 @@ timepos_t::operator= (timecnt_t const & t)
 	return *this;
 }
 
+bool
+timepos_t::operator< (timecnt_t const & t) const
+{
+	if (time_domain() == AudioTime) {
+		return superclocks() < t.superclocks();
+	}
+
+	return beats() < t.beats ();
+}
+
+bool
+timepos_t::operator> (timecnt_t const & t) const
+{
+	if (time_domain() == AudioTime) {
+		return superclocks() > t.superclocks();
+	}
+
+	return beats() > t.beats ();
+}
+
+bool
+timepos_t::operator<= (timecnt_t const & t) const
+{
+	if (time_domain() == AudioTime) {
+		return superclocks() <= t.superclocks();
+	}
+
+	return beats() <= t.beats ();
+}
+
+bool
+timepos_t::operator>= (timecnt_t const & t) const
+{
+	if (time_domain() == AudioTime) {
+		return superclocks() >= t.superclocks();
+	}
+
+	return beats() >= t.beats ();
+}
+
 void
 timepos_t::set_superclock (superclock_t s)
 {
@@ -386,6 +520,34 @@ timepos_t::earlier (Temporal::Beats const & b) const
 	return timepos_t (bb - b);
 }
 
+timepos_t
+timepos_t::earlier (Temporal::BBT_Offset const & offset) const
+{
+	TempoMap::SharedPtr tm (TempoMap::use());
+
+	if (is_superclock()) {
+		return timepos_t (tm->superclock_at (tm->bbt_walk (tm->bbt_at (superclocks()), -offset)));
+	}
+
+	return timepos_t (tm->bbtwalk_to_quarters (beats(), -offset));
+}
+
+
+timepos_t &
+timepos_t::shift_earlier (Temporal::BBT_Offset const & offset)
+{
+	TempoMap::SharedPtr tm (TempoMap::use());
+
+	if (is_superclock()) {
+		v = build (false, (tm->superclock_at (tm->bbt_walk (tm->bbt_at (superclocks()), -offset))));
+	} else {
+		v = build (true, tm->bbtwalk_to_quarters (beats(), -offset).to_ticks());
+	}
+
+	return *this;
+}
+
+
 timepos_t
 timepos_t::earlier (timepos_t const & other) const
 {
@@ -405,6 +567,46 @@ timepos_t::earlier (timecnt_t const & distance) const
 	return earlier (distance.beats());
 }
 
+bool
+timepos_t::expensive_lt (timepos_t const & other) const
+{
+	if (time_domain() == AudioTime) {
+		return superclocks() < other.superclocks();
+	}
+
+	return beats() < other.beats ();
+}
+
+bool
+timepos_t::expensive_gt (timepos_t const & other) const
+{
+	if (time_domain() == AudioTime) {
+		return superclocks() < other.superclocks();
+	}
+
+	return beats() > other.beats ();
+}
+
+bool
+timepos_t::expensive_lte (timepos_t const & other) const
+{
+	if (time_domain() == AudioTime) {
+		return superclocks() < other.superclocks();
+	}
+
+	return beats() <= other.beats ();
+}
+
+bool
+timepos_t::expensive_gte (timepos_t const & other) const
+{
+	if (time_domain() == AudioTime) {
+		return superclocks() < other.superclocks();
+	}
+
+	return beats() >= other.beats ();
+}
+
 /* */
 
 timepos_t &
@@ -446,6 +648,19 @@ timepos_t::shift_earlier (Temporal::Beats const & b)
 
 /* */
 
+timepos_t &
+timepos_t::operator+= (Temporal::BBT_Offset const & offset)
+{
+	TempoMap::SharedPtr tm (TempoMap::use());
+	if (is_beats()) {
+		v = build (true, tm->bbtwalk_to_quarters (beats(), offset));
+	} else {
+		v = build (false, tm->superclock_at (tm->bbt_walk (tm->bbt_at (superclocks()), offset)));
+	}
+
+	return *this;
+}
+
 timepos_t &
 timepos_t::operator+=(Temporal::Beats const & b)
 {