Tempo ramps - correct previous commit.
[ardour.git] / libs / ardour / tempo.cc
index 151ad56d2b0c2df04d0de5b8b5b3150fc0ad5a63..b8a1007e74adbca3c1a6850986c8095a552cc65f 100644 (file)
@@ -84,6 +84,8 @@ TempoSection::TempoSection (const XMLNode& node)
        double pulse;
        uint32_t frame;
 
+       _legacy_bbt = BBT_Time (0, 0, 0);
+
        if ((prop = node.property ("start")) != 0) {
                if (sscanf (prop->value().c_str(), "%" PRIu32 "|%" PRIu32 "|%" PRIu32,
                            &bbt.bars,
@@ -92,20 +94,18 @@ TempoSection::TempoSection (const XMLNode& node)
                        /* legacy session - start used to be in bbt*/
                        _legacy_bbt = bbt;
                        pulse = -1.0;
-                       set_pulse (pulse);
+                       info << _("Legacy session detected. TempoSection XML node will be altered.") << endmsg;
                }
-       } else {
-               warning << _("TempoSection XML node has no \"start\" property") << endmsg;
        }
 
-
        if ((prop = node.property ("pulse")) != 0) {
-               if (sscanf (prop->value().c_str(), "%lf", &pulse) != 1 || pulse < 0.0) {
-                       error << _("TempoSection XML node has an illegal \"beat\" value") << endmsg;
-               } else {
-                       set_pulse (pulse);
+               if (sscanf (prop->value().c_str(), "%lf", &pulse) != 1) {
+                       error << _("TempoSection XML node has an illegal \"pulse\" value") << endmsg;
                }
        }
+
+       set_pulse (pulse);
+
        if ((prop = node.property ("frame")) != 0) {
                if (sscanf (prop->value().c_str(), "%" PRIu32, &frame) != 1) {
                        error << _("TempoSection XML node has an illegal \"frame\" value") << endmsg;
@@ -155,7 +155,11 @@ TempoSection::TempoSection (const XMLNode& node)
        }
 
        if ((prop = node.property ("lock-style")) == 0) {
-               set_position_lock_style (MusicTime);
+               if (movable()) {
+                       set_position_lock_style (MusicTime);
+               } else {
+                       set_position_lock_style (AudioTime);
+               }
        } else {
                set_position_lock_style (PositionLockStyle (string_2_enum (prop->value(), position_lock_style())));
        }
@@ -198,7 +202,7 @@ double
 TempoSection::tempo_at_frame (const framepos_t& f, const framecnt_t& frame_rate) const
 {
 
-       if (_type == Constant) {
+       if (_type == Constant || _c_func == 0.0) {
                return pulses_per_minute();
        }
 
@@ -213,7 +217,7 @@ TempoSection::tempo_at_frame (const framepos_t& f, const framecnt_t& frame_rate)
 framepos_t
 TempoSection::frame_at_tempo (const double& ppm, const double& b, const framecnt_t& frame_rate) const
 {
-       if (_type == Constant) {
+       if (_type == Constant || _c_func == 0.0) {
                return ((b - pulse())  * frames_per_pulse (frame_rate))  + frame();
        }
 
@@ -225,7 +229,7 @@ double
 TempoSection::tempo_at_pulse (const double& p) const
 {
 
-       if (_type == Constant) {
+       if (_type == Constant || _c_func == 0.0) {
                return pulses_per_minute();
        }
        double const ppm = pulse_tempo_at_pulse (p - pulse());
@@ -239,11 +243,10 @@ TempoSection::tempo_at_pulse (const double& p) const
 double
 TempoSection::pulse_at_tempo (const double& ppm, const framepos_t& f, const framecnt_t& frame_rate) const
 {
-       if (_type == Constant) {
-               double const beats = ((f - frame()) / frames_per_pulse (frame_rate)) + pulse();
-               return  beats;
+       if (_type == Constant || _c_func == 0.0) {
+               double const pulses = ((f - frame()) / frames_per_pulse (frame_rate)) + pulse();
+               return  pulses;
        }
-
        return pulse_at_pulse_tempo (ppm) + pulse();
 }
 
@@ -254,7 +257,7 @@ TempoSection::pulse_at_tempo (const double& ppm, const framepos_t& f, const fram
 double
 TempoSection::pulse_at_frame (const framepos_t& f, const framecnt_t& frame_rate) const
 {
-       if (_type == Constant) {
+       if (_type == Constant || _c_func == 0.0) {
                return ((f - frame()) / frames_per_pulse (frame_rate)) + pulse();
        }
 
@@ -269,7 +272,7 @@ TempoSection::pulse_at_frame (const framepos_t& f, const framecnt_t& frame_rate)
 framepos_t
 TempoSection::frame_at_pulse (const double& p, const framecnt_t& frame_rate) const
 {
-       if (_type == Constant) {
+       if (_type == Constant || _c_func == 0.0) {
                return (framepos_t) floor ((p - pulse()) * frames_per_pulse (frame_rate)) + frame();
        }
 
@@ -455,14 +458,13 @@ MeterSection::MeterSection (const XMLNode& node)
                        error << _("MeterSection XML node has an illegal \"start\" value") << endmsg;
                } else {
                        /* legacy session - start used to be in bbt*/
+                       info << _("Legacy session detected - MeterSection XML node will be altered.") << endmsg;
                        pulse = -1.0;
                }
-       } else {
-               error << _("MeterSection XML node has no \"start\" property") << endmsg;
        }
 
        if ((prop = node.property ("pulse")) != 0) {
-               if (sscanf (prop->value().c_str(), "%lf", &pulse) != 1 || pulse < 0.0) {
+               if (sscanf (prop->value().c_str(), "%lf", &pulse) != 1) {
                        error << _("MeterSection XML node has an illegal \"pulse\" value") << endmsg;
                }
        }
@@ -470,20 +472,20 @@ MeterSection::MeterSection (const XMLNode& node)
 
        if ((prop = node.property ("beat")) != 0) {
                if (sscanf (prop->value().c_str(), "%lf", &beat) != 1) {
-                       error << _("MeterSection XML node has an illegal \"beat\" vlue") << endmsg;
+                       error << _("MeterSection XML node has an illegal \"beat\" value") << endmsg;
                }
        }
 
        start.first = beat;
 
        if ((prop = node.property ("bbt")) == 0) {
-               error << _("MeterSection XML node has no \"bbt\" property") << endmsg;
+               warning << _("MeterSection XML node has no \"bbt\" property") << endmsg;
        } else if (sscanf (prop->value().c_str(), "%" PRIu32 "|%" PRIu32 "|%" PRIu32,
                    &bbt.bars,
                    &bbt.beats,
                    &bbt.ticks) < 3) {
                error << _("MeterSection XML node has an illegal \"bbt\" value") << endmsg;
-               //throw failed_constructor();
+               throw failed_constructor();
        }
 
        start.second = bbt;
@@ -519,19 +521,23 @@ MeterSection::MeterSection (const XMLNode& node)
                throw failed_constructor();
        }
 
-       if ((prop = node.property ("lock-style")) == 0) {
-               warning << _("MeterSection XML node has no \"lock-style\" property") << endmsg;
-               set_position_lock_style (MusicTime);
-       } else {
-               set_position_lock_style (PositionLockStyle (string_2_enum (prop->value(), position_lock_style())));
-       }
-
        if ((prop = node.property ("movable")) == 0) {
                error << _("MeterSection XML node has no \"movable\" property") << endmsg;
                throw failed_constructor();
        }
 
        set_movable (string_is_affirmative (prop->value()));
+
+       if ((prop = node.property ("lock-style")) == 0) {
+               warning << _("MeterSection XML node has no \"lock-style\" property") << endmsg;
+               if (movable()) {
+                       set_position_lock_style (MusicTime);
+               } else {
+                       set_position_lock_style (AudioTime);
+               }
+       } else {
+               set_position_lock_style (PositionLockStyle (string_2_enum (prop->value(), position_lock_style())));
+       }
 }
 
 XMLNode&
@@ -619,7 +625,7 @@ TempoMap::TempoMap (framecnt_t fr)
        BBT_Time start (1, 1, 0);
 
        TempoSection *t = new TempoSection (0.0, _default_tempo.beats_per_minute(), _default_tempo.note_type(), TempoSection::Constant);
-       MeterSection *m = new MeterSection (0.0, 0.0, start, _default_meter.divisions_per_bar(), _default_meter.note_divisor());
+       MeterSection *m = new MeterSection ((framepos_t) 0, 0.0, start, _default_meter.divisions_per_bar(), _default_meter.note_divisor());
 
        t->set_movable (false);
        m->set_movable (false);
@@ -763,6 +769,10 @@ TempoMap::do_insert (MetricSection* section)
 
                                        *(dynamic_cast<Tempo*>(*i)) = *(dynamic_cast<Tempo*>(insert_tempo));
                                        (*i)->set_position_lock_style (AudioTime);
+                                       TempoSection* t;
+                                       if ((t = dynamic_cast<TempoSection*>(*i)) != 0) {
+                                               t->set_type (insert_tempo->type());
+                                       }
                                        need_add = false;
                                } else {
                                        _metrics.erase (i);
@@ -776,7 +786,7 @@ TempoMap::do_insert (MetricSection* section)
 
                        bool const ipm = insert_meter->position_lock_style() == MusicTime;
 
-                       if ((ipm && meter->pulse() == insert_meter->pulse()) || (!ipm && meter->frame() == insert_meter->frame())) {
+                       if ((ipm && meter->beat() == insert_meter->beat()) || (!ipm && meter->frame() == insert_meter->frame())) {
 
                                if (!meter->movable()) {
 
@@ -786,11 +796,10 @@ TempoMap::do_insert (MetricSection* section)
                                         */
 
                                        *(dynamic_cast<Meter*>(*i)) = *(dynamic_cast<Meter*>(insert_meter));
-                                       (*i)->set_position_lock_style (insert_meter->position_lock_style());
+                                       (*i)->set_position_lock_style (AudioTime);
                                        need_add = false;
                                } else {
                                        _metrics.erase (i);
-
                                }
 
                                break;
@@ -814,7 +823,7 @@ TempoMap::do_insert (MetricSection* section)
 
                                if (meter) {
                                        bool const ipm = insert_meter->position_lock_style() == MusicTime;
-                                       if ((ipm && meter->pulse() > insert_meter->pulse()) || (!ipm && meter->frame() > insert_meter->frame())) {
+                                       if ((ipm && meter->beat() > insert_meter->beat()) || (!ipm && meter->frame() > insert_meter->frame())) {
                                                break;
                                        }
                                }
@@ -883,51 +892,61 @@ TempoMap::replace_tempo (const TempoSection& ts, const Tempo& tempo, const frame
        PropertyChanged (PropertyChange ());
 }
 
-void
+TempoSection*
 TempoMap::add_tempo (const Tempo& tempo, const double& pulse, ARDOUR::TempoSection::Type type)
 {
+       TempoSection* ts = 0;
        {
                Glib::Threads::RWLock::WriterLock lm (lock);
-               add_tempo_locked (tempo, pulse, true, type);
+               ts = add_tempo_locked (tempo, pulse, true, type);
        }
 
        PropertyChanged (PropertyChange ());
+
+       return ts;
 }
 
-void
+TempoSection*
 TempoMap::add_tempo (const Tempo& tempo, const framepos_t& frame, ARDOUR::TempoSection::Type type)
 {
+       TempoSection* ts = 0;
        {
                Glib::Threads::RWLock::WriterLock lm (lock);
-               add_tempo_locked (tempo, frame, true, type);
+               ts = add_tempo_locked (tempo, frame, true, type);
        }
 
 
        PropertyChanged (PropertyChange ());
+
+       return ts;
 }
 
-void
+TempoSection*
 TempoMap::add_tempo_locked (const Tempo& tempo, double pulse, bool recompute, ARDOUR::TempoSection::Type type)
 {
-       TempoSection* ts = new TempoSection (pulse, tempo.beats_per_minute(), tempo.note_type(), type);
+       TempoSection* t = new TempoSection (pulse, tempo.beats_per_minute(), tempo.note_type(), type);
 
-       do_insert (ts);
+       do_insert (t);
 
        if (recompute) {
-               solve_map (_metrics, ts, Tempo (ts->beats_per_minute(), ts->note_type()), ts->pulse());
+               solve_map (_metrics, t, t->pulse());
        }
+
+       return t;
 }
 
-void
+TempoSection*
 TempoMap::add_tempo_locked (const Tempo& tempo, framepos_t frame, bool recompute, ARDOUR::TempoSection::Type type)
 {
-       TempoSection* ts = new TempoSection (frame, tempo.beats_per_minute(), tempo.note_type(), type);
+       TempoSection* t = new TempoSection (frame, tempo.beats_per_minute(), tempo.note_type(), type);
 
-       do_insert (ts);
+       do_insert (t);
 
        if (recompute) {
-               solve_map (_metrics, ts, Tempo (ts->beats_per_minute(), ts->note_type()), ts->frame());
+               solve_map (_metrics, t, t->frame());
        }
+
+       return t;
 }
 
 void
@@ -935,18 +954,17 @@ TempoMap::replace_meter (const MeterSection& ms, const Meter& meter, const BBT_T
 {
        {
                Glib::Threads::RWLock::WriterLock lm (lock);
-               MeterSection& first (first_meter());
 
                if (ms.movable()) {
                        remove_meter_locked (ms);
                        add_meter_locked (meter, bbt_to_beats_locked (_metrics, where), where, true);
                } else {
-                       const PositionLockStyle pl = ms.position_lock_style();
+                       MeterSection& first (first_meter());
                        /* cannot move the first meter section */
                        *static_cast<Meter*>(&first) = meter;
-                       first.set_position_lock_style (pl);
-                       recompute_map (_metrics);
+                       first.set_position_lock_style (AudioTime);
                }
+               recompute_map (_metrics);
        }
 
        PropertyChanged (PropertyChange ());
@@ -960,6 +978,7 @@ TempoMap::replace_meter (const MeterSection& ms, const Meter& meter, const frame
 
                const double beat = ms.beat();
                const BBT_Time bbt = ms.bbt();
+
                if (ms.movable()) {
                        remove_meter_locked (ms);
                        add_meter_locked (meter, frame, beat, bbt, true);
@@ -976,20 +995,20 @@ TempoMap::replace_meter (const MeterSection& ms, const Meter& meter, const frame
                        first_t.set_frame (first.frame());
                        first_t.set_pulse (0.0);
                        first_t.set_position_lock_style (AudioTime);
-
-                       recompute_map (_metrics);
                }
+               recompute_map (_metrics);
        }
        PropertyChanged (PropertyChange ());
 }
 
 
-void
+MeterSection*
 TempoMap::add_meter (const Meter& meter, const double& beat, const BBT_Time& where)
 {
+       MeterSection* m = 0;
        {
                Glib::Threads::RWLock::WriterLock lm (lock);
-               add_meter_locked (meter, beat, where, true);
+               m = add_meter_locked (meter, beat, where, true);
        }
 
 
@@ -1000,14 +1019,17 @@ TempoMap::add_meter (const Meter& meter, const double& beat, const BBT_Time& whe
 #endif
 
        PropertyChanged (PropertyChange ());
+
+       return m;
 }
 
-void
+MeterSection*
 TempoMap::add_meter (const Meter& meter, const framepos_t& frame, const double& beat, const Timecode::BBT_Time& where)
 {
+       MeterSection* m = 0;
        {
                Glib::Threads::RWLock::WriterLock lm (lock);
-               add_meter_locked (meter, frame, beat, where, true);
+               m = add_meter_locked (meter, frame, beat, where, true);
        }
 
 
@@ -1018,9 +1040,11 @@ TempoMap::add_meter (const Meter& meter, const framepos_t& frame, const double&
 #endif
 
        PropertyChanged (PropertyChange ());
+
+       return m;
 }
 
-void
+MeterSection*
 TempoMap::add_meter_locked (const Meter& meter, double beat, BBT_Time where, bool recompute)
 {
        /* a new meter always starts a new bar on the first beat. so
@@ -1036,21 +1060,20 @@ TempoMap::add_meter_locked (const Meter& meter, double beat, BBT_Time where, boo
        }
        /* new meters *always* start on a beat. */
        where.ticks = 0;
-       double pulse = pulse_at_beat_locked (_metrics, beat);
-
+       const double pulse = pulse_at_beat_locked (_metrics, beat);
        MeterSection* new_meter = new MeterSection (pulse, beat, where, meter.divisions_per_bar(), meter.note_divisor());
        do_insert (new_meter);
 
        if (recompute) {
-               solve_map (_metrics, new_meter, Meter (meter.divisions_per_bar(), meter.note_divisor()), pulse);
+               solve_map (_metrics, new_meter, pulse);
        }
 
+       return new_meter;
 }
 
-void
+MeterSection*
 TempoMap::add_meter_locked (const Meter& meter, framepos_t frame, double beat, Timecode::BBT_Time where, bool recompute)
 {
-
        MeterSection* new_meter = new MeterSection (frame, beat, where, meter.divisions_per_bar(), meter.note_divisor());
 
        double pulse = pulse_at_frame_locked (_metrics, frame);
@@ -1059,9 +1082,10 @@ TempoMap::add_meter_locked (const Meter& meter, framepos_t frame, double beat, T
        do_insert (new_meter);
 
        if (recompute) {
-               solve_map (_metrics, new_meter, Meter (new_meter->divisions_per_bar(), new_meter->note_divisor()), frame);
+               solve_map (_metrics, new_meter, frame);
        }
 
+       return new_meter;
 }
 
 void
@@ -1218,7 +1242,7 @@ TempoMap::first_tempo ()
 void
 TempoMap::recompute_tempos (Metrics& metrics)
 {
-       TempoSection* prev_ts = 0;
+       TempoSection* prev_t = 0;
 
        for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
                TempoSection* t;
@@ -1227,21 +1251,26 @@ TempoMap::recompute_tempos (Metrics& metrics)
                        if (!t->active()) {
                                continue;
                        }
-                       if (prev_ts) {
+                       if (!t->movable()) {
+                               t->set_pulse (0.0);
+                               prev_t = t;
+                               continue;
+                       }
+                       if (prev_t) {
                                if (t->position_lock_style() == AudioTime) {
-                                       prev_ts->set_c_func (prev_ts->compute_c_func_frame (t->pulses_per_minute(), t->frame(), _frame_rate));
-                                       t->set_pulse (prev_ts->pulse_at_tempo (t->pulses_per_minute(), t->frame(), _frame_rate));
+                                       prev_t->set_c_func (prev_t->compute_c_func_frame (t->pulses_per_minute(), t->frame(), _frame_rate));
+                                       t->set_pulse (prev_t->pulse_at_tempo (t->pulses_per_minute(), t->frame(), _frame_rate));
 
                                } else {
-                                       prev_ts->set_c_func (prev_ts->compute_c_func_pulse (t->pulses_per_minute(), t->pulse(), _frame_rate));
-                                       t->set_frame (prev_ts->frame_at_tempo (t->pulses_per_minute(), t->pulse(), _frame_rate));
+                                       prev_t->set_c_func (prev_t->compute_c_func_pulse (t->pulses_per_minute(), t->pulse(), _frame_rate));
+                                       t->set_frame (prev_t->frame_at_tempo (t->pulses_per_minute(), t->pulse(), _frame_rate));
 
                                }
                        }
-                       prev_ts = t;
+                       prev_t = t;
                }
        }
-       prev_ts->set_c_func (0.0);
+       prev_t->set_c_func (0.0);
 }
 
 /* tempos must be positioned correctly */
@@ -1250,22 +1279,18 @@ TempoMap::recompute_meters (Metrics& metrics)
 {
        MeterSection* meter = 0;
        MeterSection* prev_m = 0;
-       uint32_t accumulated_bars = 0;
 
        for (Metrics::const_iterator mi = metrics.begin(); mi != metrics.end(); ++mi) {
                if ((meter = dynamic_cast<MeterSection*> (*mi)) != 0) {
-                       if (prev_m) {
-                               const double beats_in_m = (meter->pulse() - prev_m->pulse()) * prev_m->note_divisor();
-                               accumulated_bars += (beats_in_m + 1) / prev_m->divisions_per_bar();
-                       }
                        if (meter->position_lock_style() == AudioTime) {
                                double pulse = 0.0;
                                pair<double, BBT_Time> b_bbt;
                                if (meter->movable()) {
-                                       const double beats = ((pulse_at_frame_locked (metrics, meter->frame()) - prev_m->pulse()) * prev_m->note_divisor()) - prev_m->beat();
-                                       b_bbt = make_pair (ceil (beats), BBT_Time (accumulated_bars + 1, 1, 0));
-                                       const double true_pulse = prev_m->pulse() + (ceil (beats) - prev_m->beat()) / prev_m->note_divisor();
-                                       const double pulse_off = true_pulse - ((beats - prev_m->beat()) / prev_m->note_divisor());
+                                       const double beats = ((pulse_at_frame_locked (metrics, meter->frame()) - prev_m->pulse()) * prev_m->note_divisor());
+                                       const double floor_beats = beats - fmod (beats, prev_m->divisions_per_bar());
+                                       b_bbt = make_pair (floor_beats + prev_m->beat(), BBT_Time ((floor_beats / prev_m->divisions_per_bar()) + prev_m->bbt().bars, 1, 0));
+                                       const double true_pulse = prev_m->pulse() + (floor_beats / prev_m->note_divisor());
+                                       const double pulse_off = true_pulse - (beats / prev_m->note_divisor()) - prev_m->pulse();
                                        pulse = true_pulse - pulse_off;
                                } else {
                                        b_bbt = make_pair (0.0, BBT_Time (1, 1, 0));
@@ -1274,11 +1299,17 @@ TempoMap::recompute_meters (Metrics& metrics)
                                meter->set_pulse (pulse);
                        } else {
                                double pulse = 0.0;
+                               pair<double, BBT_Time> new_beat;
                                if (prev_m) {
-                                       pulse = prev_m->pulse() + (meter->beat() - prev_m->beat()) / prev_m->note_divisor();
+                                       pulse = prev_m->pulse() + ((meter->bbt().bars - prev_m->bbt().bars) *  prev_m->divisions_per_bar() / prev_m->note_divisor());
+                                       new_beat = make_pair (((pulse - prev_m->pulse()) * prev_m->note_divisor()) + prev_m->beat(), meter->bbt());
                                } else {
+                                       /* shouldn't happen - the first is audio-locked */
                                        pulse = pulse_at_beat_locked (metrics, meter->beat());
+                                       new_beat = make_pair (pulse, meter->bbt());
                                }
+
+                               meter->set_beat (new_beat);
                                meter->set_frame (frame_at_pulse_locked (metrics, pulse));
                                meter->set_pulse (pulse);
                        }
@@ -1286,6 +1317,7 @@ TempoMap::recompute_meters (Metrics& metrics)
                        prev_m = meter;
                }
        }
+       //dump (_metrics, std::cerr;
 }
 
 void
@@ -1314,63 +1346,6 @@ TempoMap::recompute_map (Metrics& metrics, framepos_t end)
        recompute_meters (metrics);
 }
 
-double
-TempoMap::pulse_at_beat (const double& beat) const
-{
-       Glib::Threads::RWLock::ReaderLock lm (lock);
-       return pulse_at_beat_locked (_metrics, beat);
-}
-
-double
-TempoMap::pulse_at_beat_locked (const Metrics& metrics, const double& beat) const
-{
-       MeterSection* prev_ms = 0;
-       double accumulated_beats = 0.0;
-
-       for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
-               MeterSection* m;
-               if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
-                       if (prev_ms && m->beat() > beat) {
-                               break;
-                       }
-                       accumulated_beats = m->beat();
-                       prev_ms = m;
-               }
-
-       }
-       double const ret = prev_ms->pulse() + ((beat - accumulated_beats) / prev_ms->note_divisor());
-       return ret;
-}
-
-double
-TempoMap::beat_at_pulse (const double& pulse) const
-{
-       Glib::Threads::RWLock::ReaderLock lm (lock);
-       return beat_at_pulse_locked (_metrics, pulse);
-}
-
-double
-TempoMap::beat_at_pulse_locked (const Metrics& metrics, const double& pulse) const
-{
-       MeterSection* prev_ms = 0;
-       double accumulated_beats = 0.0;
-
-       for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
-               MeterSection* m;
-               if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
-                       if (prev_ms && m->pulse() > pulse) {
-                               break;
-                       }
-                       accumulated_beats = m->beat();
-                       prev_ms = m;
-               }
-       }
-
-       double const beats_in_section = (pulse - prev_ms->pulse()) * prev_ms->note_divisor();
-
-       return beats_in_section + accumulated_beats;
-}
-
 TempoMetric
 TempoMap::metric_at (framepos_t frame, Metrics::const_iterator* last) const
 {
@@ -1430,29 +1405,142 @@ TempoMap::metric_at (BBT_Time bbt) const
        return m;
 }
 
-void
-TempoMap::bbt_time (framepos_t frame, BBT_Time& bbt)
+double
+TempoMap::pulse_at_beat_locked (const Metrics& metrics, const double& beat) const
 {
+       MeterSection* prev_m = 0;
+
+       for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
+               MeterSection* m;
+               if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
+                       if (prev_m && m->beat() > beat) {
+                               break;
+                       }
+                       prev_m = m;
+               }
 
-       if (frame < 0) {
-               bbt.bars = 1;
-               bbt.beats = 1;
-               bbt.ticks = 0;
-               warning << string_compose (_("tempo map asked for BBT time at frame %1\n"), frame) << endmsg;
-               return;
        }
+       double const ret = prev_m->pulse() + ((beat - prev_m->beat()) / prev_m->note_divisor());
+       return ret;
+}
+
+double
+TempoMap::pulse_at_beat (const double& beat) const
+{
        Glib::Threads::RWLock::ReaderLock lm (lock);
-       double const beat = beat_at_frame_locked (_metrics, frame);
+       return pulse_at_beat_locked (_metrics, beat);
+}
 
-       bbt = beats_to_bbt_locked (_metrics, beat);
+double
+TempoMap::beat_at_pulse_locked (const Metrics& metrics, const double& pulse) const
+{
+       MeterSection* prev_m = 0;
+
+       for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
+               MeterSection* m;
+               if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
+                       if (prev_m && m->pulse() > pulse) {
+                               break;
+                       }
+                       prev_m = m;
+               }
+       }
+
+       double const beats_in_section = (pulse - prev_m->pulse()) * prev_m->note_divisor();
+
+       return beats_in_section + prev_m->beat();
 }
 
 double
-TempoMap::bbt_to_beats (const Timecode::BBT_Time& bbt)
+TempoMap::beat_at_pulse (const double& pulse) const
 {
        Glib::Threads::RWLock::ReaderLock lm (lock);
+       return beat_at_pulse_locked (_metrics, pulse);
+}
 
-       return bbt_to_beats_locked (_metrics, bbt);
+double
+TempoMap::pulse_at_frame_locked (const Metrics& metrics, const framecnt_t& frame) const
+{
+       /* HOLD (at least) THE READER LOCK */
+       TempoSection* prev_t = 0;
+
+       for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
+               TempoSection* t;
+               if ((t = dynamic_cast<TempoSection*> (*i)) != 0) {
+                       if (!t->active()) {
+                               continue;
+                       }
+                       if (prev_t && t->frame() > frame) {
+                               /*the previous ts is the one containing the frame */
+                               const double ret = prev_t->pulse_at_frame (frame, _frame_rate);
+                               return ret;
+                       }
+                       prev_t = t;
+               }
+       }
+
+       /* treated as constant for this ts */
+       const double pulses_in_section = (frame - prev_t->frame()) / prev_t->frames_per_pulse (_frame_rate);
+
+       return pulses_in_section + prev_t->pulse();
+}
+
+framecnt_t
+TempoMap::frame_at_pulse_locked (const Metrics& metrics, const double& pulse) const
+{
+       /* HOLD THE READER LOCK */
+
+       const TempoSection* prev_t = 0;
+
+       for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
+               TempoSection* t;
+
+               if ((t = dynamic_cast<TempoSection*> (*i)) != 0) {
+                       if (!t->active()) {
+                               continue;
+                       }
+                       if (prev_t && t->pulse() > pulse) {
+                               return prev_t->frame_at_pulse (pulse, _frame_rate);
+                       }
+
+                       prev_t = t;
+               }
+       }
+       /* must be treated as constant, irrespective of _type */
+       double const pulses_in_section = pulse - prev_t->pulse();
+       double const dtime = pulses_in_section * prev_t->frames_per_pulse (_frame_rate);
+
+       framecnt_t const ret = (framecnt_t) floor (dtime) + prev_t->frame();
+
+       return ret;
+}
+
+double
+TempoMap::beat_at_frame_locked (const Metrics& metrics, const framecnt_t& frame) const
+{
+       const double pulse = pulse_at_frame_locked (metrics, frame);
+       return beat_at_pulse_locked (metrics, pulse);
+}
+
+double
+TempoMap::beat_at_frame (const framecnt_t& frame) const
+{
+       Glib::Threads::RWLock::ReaderLock lm (lock);
+       return beat_at_frame_locked (_metrics, frame);
+}
+
+framecnt_t
+TempoMap::frame_at_beat_locked (const Metrics& metrics, const double& beat) const
+{
+       const framecnt_t frame = frame_at_pulse_locked (metrics, pulse_at_beat_locked (metrics, beat));
+       return frame;
+}
+
+framecnt_t
+TempoMap::frame_at_beat (const double& beat) const
+{
+       Glib::Threads::RWLock::ReaderLock lm (lock);
+       return frame_at_beat_locked (_metrics, beat);
 }
 
 double
@@ -1460,78 +1548,65 @@ TempoMap::bbt_to_beats_locked (const Metrics& metrics, const Timecode::BBT_Time&
 {
        /* CALLER HOLDS READ LOCK */
 
-       double accumulated_beats = 0.0;
-       double accumulated_bars = 0.0;
-       MeterSection* prev_ms = 0;
+       MeterSection* prev_m = 0;
+
        /* because audio-locked meters have 'fake' integral beats,
           there is no pulse offset here.
        */
        for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
                MeterSection* m;
                if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
-                       double bars_to_m = 0.0;
-                       if (prev_ms) {
-                               bars_to_m = (m->beat() - prev_ms->beat()) / prev_ms->divisions_per_bar();
-                               if ((bars_to_m + accumulated_bars) > (bbt.bars - 1)) {
+                       if (prev_m) {
+                               const double bars_to_m = (m->beat() - prev_m->beat()) / prev_m->divisions_per_bar();
+                               if ((bars_to_m + (prev_m->bbt().bars - 1)) > (bbt.bars - 1)) {
                                        break;
                                }
-                               accumulated_beats = m->beat();
-                               accumulated_bars += bars_to_m;
                        }
-                       prev_ms = m;
+                       prev_m = m;
                }
        }
 
-       double const remaining_bars = (bbt.bars - 1) - accumulated_bars;
-       double const remaining_bars_in_beats = remaining_bars * prev_ms->divisions_per_bar();
-       double const ret = remaining_bars_in_beats + accumulated_beats + (bbt.beats - 1) + (bbt.ticks / BBT_Time::ticks_per_beat);
+       const double remaining_bars = bbt.bars - prev_m->bbt().bars;
+       const double remaining_bars_in_beats = remaining_bars * prev_m->divisions_per_bar();
+       const double ret = remaining_bars_in_beats + prev_m->beat() + (bbt.beats - 1) + (bbt.ticks / BBT_Time::ticks_per_beat);
 
        return ret;
 }
 
-Timecode::BBT_Time
-TempoMap::beats_to_bbt (const double& beats)
+double
+TempoMap::bbt_to_beats (const Timecode::BBT_Time& bbt)
 {
        Glib::Threads::RWLock::ReaderLock lm (lock);
-
-       return beats_to_bbt_locked (_metrics, beats);
+       return bbt_to_beats_locked (_metrics, bbt);
 }
 
 Timecode::BBT_Time
 TempoMap::beats_to_bbt_locked (const Metrics& metrics, const double& b) const
 {
        /* CALLER HOLDS READ LOCK */
-       MeterSection* prev_ms = 0;
+       MeterSection* prev_m = 0;
        const double beats = (b < 0.0) ? 0.0 : b;
-       uint32_t accumulated_bars = 0;
-       double accumulated_beats = 0.0;
 
        for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
                MeterSection* m = 0;
 
                if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
-
-                       if (prev_ms) {
-                               double const beats_to_m = m->beat() - prev_ms->beat();
-                               if (accumulated_beats + beats_to_m > beats) {
+                       if (prev_m) {
+                               if (m->beat() > beats) {
                                        /* this is the meter after the one our beat is on*/
                                        break;
                                }
-
-                               /* we need a whole number of bars. */
-                               accumulated_bars += (beats_to_m + 1) / prev_ms->divisions_per_bar();
-                               accumulated_beats += beats_to_m;
                        }
 
-                       prev_ms = m;
+                       prev_m = m;
                }
        }
 
-       double const beats_in_ms = beats - accumulated_beats;
-       uint32_t const bars_in_ms = (uint32_t) floor (beats_in_ms / prev_ms->divisions_per_bar());
-       uint32_t const total_bars = bars_in_ms + accumulated_bars;
-       double const remaining_beats = beats_in_ms - (bars_in_ms * prev_ms->divisions_per_bar());
-       double const remaining_ticks = (remaining_beats - floor (remaining_beats)) * BBT_Time::ticks_per_beat;
+       const double beats_in_ms = beats - prev_m->beat();
+       const uint32_t bars_in_ms = (uint32_t) floor (beats_in_ms / prev_m->divisions_per_bar());
+       const uint32_t total_bars = bars_in_ms + (prev_m->bbt().bars - 1);
+       const double remaining_beats = beats_in_ms - (bars_in_ms * prev_m->divisions_per_bar());
+       const double remaining_ticks = (remaining_beats - floor (remaining_beats)) * BBT_Time::ticks_per_beat;
 
        BBT_Time ret;
 
@@ -1548,7 +1623,7 @@ TempoMap::beats_to_bbt_locked (const Metrics& metrics, const double& b) const
                ret.ticks -= BBT_Time::ticks_per_beat;
        }
 
-       if (ret.beats >= prev_ms->divisions_per_bar() + 1) {
+       if (ret.beats >= prev_m->divisions_per_bar() + 1) {
                ++ret.bars;
                ret.beats = 1;
        }
@@ -1556,39 +1631,41 @@ TempoMap::beats_to_bbt_locked (const Metrics& metrics, const double& b) const
        return ret;
 }
 
+Timecode::BBT_Time
+TempoMap::beats_to_bbt (const double& beats)
+{
+       Glib::Threads::RWLock::ReaderLock lm (lock);
+       return beats_to_bbt_locked (_metrics, beats);
+}
+
 Timecode::BBT_Time
 TempoMap::pulse_to_bbt (const double& pulse)
 {
        Glib::Threads::RWLock::ReaderLock lm (lock);
-       MeterSection* prev_ms = 0;
-       uint32_t accumulated_bars = 0;
-       double accumulated_pulses = 0.0;
+       MeterSection* prev_m = 0;
 
        for (Metrics::const_iterator i = _metrics.begin(); i != _metrics.end(); ++i) {
                MeterSection* m = 0;
 
                if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
 
-                       if (prev_ms) {
-                               double const pulses_to_m = m->pulse() - prev_ms->pulse();
-                               if (accumulated_pulses + pulses_to_m > pulse) {
+                       if (prev_m) {
+                               double const pulses_to_m = m->pulse() - prev_m->pulse();
+                               if (prev_m->pulse() + pulses_to_m > pulse) {
                                        /* this is the meter after the one our beat is on*/
                                        break;
                                }
-
-                               /* we need a whole number of bars. */
-                               accumulated_pulses += pulses_to_m;
-                               accumulated_bars += ((pulses_to_m * prev_ms->note_divisor()) + 1) / prev_ms->divisions_per_bar();
                        }
 
-                       prev_ms = m;
+                       prev_m = m;
                }
        }
-       double const beats_in_ms = (pulse - prev_ms->pulse()) * prev_ms->note_divisor();
-       uint32_t const bars_in_ms = (uint32_t) floor (beats_in_ms / prev_ms->divisions_per_bar());
-       uint32_t const total_bars = bars_in_ms + accumulated_bars;
-       double const remaining_beats = beats_in_ms - (bars_in_ms * prev_ms->divisions_per_bar());
-       double const remaining_ticks = (remaining_beats - floor (remaining_beats)) * BBT_Time::ticks_per_beat;
+
+       const double beats_in_ms = (pulse - prev_m->pulse()) * prev_m->note_divisor();
+       const uint32_t bars_in_ms = (uint32_t) floor (beats_in_ms / prev_m->divisions_per_bar());
+       const uint32_t total_bars = bars_in_ms + (prev_m->bbt().bars - 1);
+       const double remaining_beats = beats_in_ms - (bars_in_ms * prev_m->divisions_per_bar());
+       const double remaining_ticks = (remaining_beats - floor (remaining_beats)) * BBT_Time::ticks_per_beat;
 
        BBT_Time ret;
 
@@ -1605,7 +1682,7 @@ TempoMap::pulse_to_bbt (const double& pulse)
                ret.ticks -= BBT_Time::ticks_per_beat;
        }
 
-       if (ret.beats >= prev_ms->divisions_per_bar() + 1) {
+       if (ret.beats >= prev_m->divisions_per_bar() + 1) {
                ++ret.bars;
                ret.beats = 1;
        }
@@ -1613,95 +1690,29 @@ TempoMap::pulse_to_bbt (const double& pulse)
        return ret;
 }
 
-double
-TempoMap::beat_at_frame (const framecnt_t& frame) const
-{
-       Glib::Threads::RWLock::ReaderLock lm (lock);
-       return beat_at_frame_locked (_metrics, frame);
-}
-
-double
-TempoMap::beat_at_frame_locked (const Metrics& metrics, const framecnt_t& frame) const
-{
-       //framecnt_t const offset_frame = frame + frame_offset_at (metrics, frame);
-       double const pulse = pulse_at_frame_locked (metrics, frame);
-
-       return beat_at_pulse_locked (metrics, pulse);
-}
-
-double
-TempoMap::pulse_at_frame_locked (const Metrics& metrics, const framecnt_t& frame) const
+void
+TempoMap::bbt_time (framepos_t frame, BBT_Time& bbt)
 {
-       /* HOLD (at least) THE READER LOCK */
-       TempoSection* prev_ts = 0;
-       double accumulated_pulses = 0.0;
 
-       for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
-               TempoSection* t;
-               if ((t = dynamic_cast<TempoSection*> (*i)) != 0) {
-                       if (!t->active()) {
-                               continue;
-                       }
-                       if (prev_ts && t->frame() > frame) {
-                               /*the previous ts is the one containing the frame */
-                               double const ret = prev_ts->pulse_at_frame (frame, _frame_rate);
-                               return ret;
-                       }
-                       accumulated_pulses = t->pulse();
-                       prev_ts = t;
-               }
+       if (frame < 0) {
+               bbt.bars = 1;
+               bbt.beats = 1;
+               bbt.ticks = 0;
+               warning << string_compose (_("tempo map asked for BBT time at frame %1\n"), frame) << endmsg;
+               return;
        }
-
-       /* treated as constant for this ts */
-       double const pulses_in_section = (frame - prev_ts->frame()) / prev_ts->frames_per_pulse (_frame_rate);
-
-       return pulses_in_section + accumulated_pulses;
-}
-
-framecnt_t
-TempoMap::frame_at_beat (const double& beat) const
-{
        Glib::Threads::RWLock::ReaderLock lm (lock);
-       return frame_at_beat_locked (_metrics, beat);
-}
+       const double beat = beat_at_frame_locked (_metrics, frame);
 
-framecnt_t
-TempoMap::frame_at_beat_locked (const Metrics& metrics, const double& beat) const
-{
-       framecnt_t const frame = frame_at_pulse_locked (metrics, pulse_at_beat_locked (metrics, beat));
-       //frameoffset_t const frame_off = frame_offset_at (metrics, frame);
-       return frame;
+       bbt = beats_to_bbt_locked (_metrics, beat);
 }
 
-framecnt_t
-TempoMap::frame_at_pulse_locked (const Metrics& metrics, const double& pulse) const
+framepos_t
+TempoMap::frame_time_locked (const Metrics& metrics, const BBT_Time& bbt) const
 {
        /* HOLD THE READER LOCK */
 
-       const TempoSection* prev_ts = 0;
-       double accumulated_pulses = 0.0;
-
-       for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
-               TempoSection* t;
-
-               if ((t = dynamic_cast<TempoSection*> (*i)) != 0) {
-                       if (!t->active()) {
-                               continue;
-                       }
-                       if (prev_ts && t->pulse() > pulse) {
-                               return prev_ts->frame_at_pulse (pulse, _frame_rate);
-                       }
-
-                       accumulated_pulses = t->pulse();
-                       prev_ts = t;
-               }
-       }
-       /* must be treated as constant, irrespective of _type */
-       double const pulses_in_section = pulse - accumulated_pulses;
-       double const dtime = pulses_in_section * prev_ts->frames_per_pulse (_frame_rate);
-
-       framecnt_t const ret = (framecnt_t) floor (dtime) + prev_ts->frame();
-
+       const framepos_t ret = frame_at_beat_locked (metrics, bbt_to_beats_locked (metrics, bbt));
        return ret;
 }
 
@@ -1717,25 +1728,14 @@ TempoMap::frame_time (const BBT_Time& bbt)
                throw std::logic_error ("beats are counted from one");
        }
        Glib::Threads::RWLock::ReaderLock lm (lock);
-       double const beat = bbt_to_beats_locked (_metrics, bbt);
-       framecnt_t const frame = frame_at_beat_locked (_metrics, beat);
-       return frame;
-}
-
-framepos_t
-TempoMap::frame_time_locked (const Metrics& metrics, const BBT_Time& bbt) const
-{
-       /* HOLD THE READER LOCK */
-
-       framepos_t const ret = frame_at_pulse_locked (metrics, pulse_at_beat_locked (metrics, bbt_to_beats_locked (metrics, bbt)));
 
-       return ret;
+       return frame_time_locked (_metrics, bbt);
 }
 
 bool
 TempoMap::check_solved (Metrics& metrics, bool by_frame)
 {
-       TempoSection* prev_ts = 0;
+       TempoSection* prev_t = 0;
 
        for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
                TempoSection* t;
@@ -1743,21 +1743,21 @@ TempoMap::check_solved (Metrics& metrics, bool by_frame)
                        if (!t->active()) {
                                continue;
                        }
-                       if (prev_ts) {
-                               if ((by_frame && t->frame() < prev_ts->frame()) || (!by_frame && t->pulse() < prev_ts->pulse())) {
+                       if (prev_t) {
+                               if ((by_frame && t->frame() < prev_t->frame()) || (!by_frame && t->pulse() < prev_t->pulse())) {
                                        return false;
                                }
 
-                               if (t->frame() == prev_ts->frame()) {
+                               if (t->frame() == prev_t->frame()) {
                                        return false;
                                }
 
-                               /* precision check ensures pulses and frames align independent of lock style.*/
-                               if (by_frame && t->frame() != prev_ts->frame_at_pulse (t->pulse(), _frame_rate)) {
+                               /* precision check ensures pulses and frames align.*/
+                               if (t->frame() != prev_t->frame_at_pulse (t->pulse(), _frame_rate)) {
                                        return false;
                                }
                        }
-                       prev_ts = t;
+                       prev_t = t;
                }
        }
 
@@ -1788,9 +1788,9 @@ TempoMap::set_active_tempos (const Metrics& metrics, const framepos_t& frame)
 }
 
 bool
-TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm, const framepos_t& frame)
+TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const framepos_t& frame)
 {
-       TempoSection* prev_ts = 0;
+       TempoSection* prev_t = 0;
        TempoSection* section_prev = 0;
        framepos_t first_m_frame = 0;
 
@@ -1805,9 +1805,9 @@ TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm
        }
        if (section->movable() && frame <= first_m_frame) {
                return false;
-       } else {
-               section->set_active (true);
        }
+
+       section->set_active (true);
        section->set_frame (frame);
 
        for (Metrics::iterator i = imaginary.begin(); i != imaginary.end(); ++i) {
@@ -1817,20 +1817,20 @@ TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm
                        if (!t->active()) {
                                continue;
                        }
-                       if (prev_ts) {
+                       if (prev_t) {
                                if (t == section) {
-                                       section_prev = prev_ts;
+                                       section_prev = prev_t;
                                        continue;
                                }
                                if (t->position_lock_style() == MusicTime) {
-                                       prev_ts->set_c_func (prev_ts->compute_c_func_pulse (t->pulses_per_minute(), t->pulse(), _frame_rate));
-                                       t->set_frame (prev_ts->frame_at_pulse (t->pulse(), _frame_rate));
+                                       prev_t->set_c_func (prev_t->compute_c_func_pulse (t->pulses_per_minute(), t->pulse(), _frame_rate));
+                                       t->set_frame (prev_t->frame_at_pulse (t->pulse(), _frame_rate));
                                } else {
-                                       prev_ts->set_c_func (prev_ts->compute_c_func_frame (t->pulses_per_minute(), t->frame(), _frame_rate));
-                                       t->set_pulse (prev_ts->pulse_at_frame (t->frame(), _frame_rate));
+                                       prev_t->set_c_func (prev_t->compute_c_func_frame (t->pulses_per_minute(), t->frame(), _frame_rate));
+                                       t->set_pulse (prev_t->pulse_at_frame (t->frame(), _frame_rate));
                                }
                        }
-                       prev_ts = t;
+                       prev_t = t;
                }
        }
 
@@ -1863,11 +1863,12 @@ TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm
        } else {
                recompute_tempos (imaginary);
        }
+
        if (check_solved (imaginary, true)) {
                recompute_meters (imaginary);
                return true;
        }
-
+#if (0)
        MetricSectionSorter cmp;
        imaginary.sort (cmp);
        if (section->position_lock_style() == MusicTime) {
@@ -1878,19 +1879,21 @@ TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm
        } else {
                recompute_tempos (imaginary);
        }
+
        if (check_solved (imaginary, true)) {
                recompute_meters (imaginary);
                return true;
        }
+#endif
        //dump (imaginary, std::cerr);
 
        return false;
 }
 
 bool
-TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm, const double& pulse)
+TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const double& pulse)
 {
-       TempoSection* prev_ts = 0;
+       TempoSection* prev_t = 0;
        TempoSection* section_prev = 0;
 
        section->set_pulse (pulse);
@@ -1901,20 +1904,25 @@ TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm
                        if (!t->active()) {
                                continue;
                        }
-                       if (prev_ts) {
+                       if (!t->movable()) {
+                               t->set_pulse (0.0);
+                               prev_t = t;
+                               continue;
+                       }
+                       if (prev_t) {
                                if (t == section) {
-                                       section_prev = prev_ts;
+                                       section_prev = prev_t;
                                        continue;
                                }
                                if (t->position_lock_style() == MusicTime) {
-                                       prev_ts->set_c_func (prev_ts->compute_c_func_pulse (t->pulses_per_minute(), t->pulse(), _frame_rate));
-                                       t->set_frame (prev_ts->frame_at_pulse (t->pulse(), _frame_rate));
+                                       prev_t->set_c_func (prev_t->compute_c_func_pulse (t->pulses_per_minute(), t->pulse(), _frame_rate));
+                                       t->set_frame (prev_t->frame_at_pulse (t->pulse(), _frame_rate));
                                } else {
-                                       prev_ts->set_c_func (prev_ts->compute_c_func_frame (t->pulses_per_minute(), t->frame(), _frame_rate));
-                                       t->set_pulse (prev_ts->pulse_at_frame (t->frame(), _frame_rate));
+                                       prev_t->set_c_func (prev_t->compute_c_func_frame (t->pulses_per_minute(), t->frame(), _frame_rate));
+                                       t->set_pulse (prev_t->pulse_at_frame (t->frame(), _frame_rate));
                                }
                        }
-                       prev_ts = t;
+                       prev_t = t;
                }
        }
        if (section_prev) {
@@ -1930,6 +1938,7 @@ TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm
        } else {
                recompute_tempos (imaginary);
        }
+
        if (check_solved (imaginary, false)) {
                recompute_meters (imaginary);
                return true;
@@ -1950,7 +1959,7 @@ TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm
                recompute_meters (imaginary);
                return true;
        }
-
+#if (0)
        MetricSectionFrameSorter fcmp;
        imaginary.sort (fcmp);
        if (section->position_lock_style() == AudioTime) {
@@ -1966,16 +1975,16 @@ TempoMap::solve_map (Metrics& imaginary, TempoSection* section, const Tempo& bpm
                recompute_meters (imaginary);
                return true;
        }
-
+#endif
        //dump (imaginary, std::cerr);
 
        return false;
 }
 
 void
-TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const Meter& mt, const framepos_t& frame)
+TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const framepos_t& frame)
 {
-       MeterSection* prev_ms = 0;
+       MeterSection* prev_m = 0;
 
        if (!section->movable()) {
                /* lock the first tempo to our first meter */
@@ -1990,77 +1999,81 @@ TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const Meter& mt,
                new_section->set_pulse (0.0);
                new_section->set_active (true);
 
-               if (solve_map (future_map, new_section, Tempo (new_section->beats_per_minute(), new_section->note_type()), frame)) {
+               if (solve_map (future_map, new_section, frame)) {
                        first_t->set_frame (frame);
                        first_t->set_pulse (0.0);
                        first_t->set_active (true);
-                       solve_map (imaginary, first_t, Tempo (first_t->beats_per_minute(), first_t->note_type()), frame);
+                       solve_map (imaginary, first_t, frame);
                } else {
                        return;
                }
        }
 
-       uint32_t accumulated_bars = 0;
-
        section->set_frame (frame);
 
        for (Metrics::iterator i = imaginary.begin(); i != imaginary.end(); ++i) {
                MeterSection* m;
                if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
-                       if (prev_ms) {
-                               const double beats_in_m = (m->pulse() - prev_ms->pulse()) * prev_ms->note_divisor();
-                               accumulated_bars += (beats_in_m + 1) / prev_ms->divisions_per_bar();
-                       }
                        if (m == section){
                                /*
                                  here we set the beat for this frame.
-                                 we're going to set it 'incorrectly' to the next integer and use this difference
-                                 to find the meter's pulse.
-                                 (meters should fall on integral beats to keep us sane)
-                                 XXX do it to the bar, you fool, not the beat!  - and don't forget to recompute_meters that way too.
+                                 we set it 'incorrectly' to the next bar's first beat
+                                 and use the delat to find the meter's pulse.
                                */
-                               double pulse = 0.0;
+                               double new_pulse = 0.0;
                                pair<double, BBT_Time> b_bbt;
-                               if (m->movable()) {
-                                       double beats = ((pulse_at_frame_locked (imaginary, frame) - prev_ms->pulse()) * prev_ms->note_divisor()) - prev_ms->beat();
-                                       b_bbt = make_pair (ceil (beats), BBT_Time (accumulated_bars + 1, 1, 0));
-                                       const double true_pulse = prev_ms->pulse() + ((ceil (beats) - prev_ms->beat()) / prev_ms->note_divisor());
-                                       const double pulse_off = true_pulse - ((beats - prev_ms->beat()) / prev_ms->note_divisor());
-                                       pulse = true_pulse - pulse_off;
+
+                               if (section->movable()) {
+                                       const double beats = ((pulse_at_frame_locked (imaginary, frame) - prev_m->pulse()) * prev_m->note_divisor());
+                                       const double floor_beats = beats - fmod (beats,  prev_m->divisions_per_bar());
+                                       b_bbt = make_pair (floor_beats + prev_m->beat(), BBT_Time ((floor_beats / prev_m->divisions_per_bar()) + prev_m->bbt().bars, 1, 0));
+                                       const double true_pulse = prev_m->pulse() + (floor_beats / prev_m->note_divisor());
+                                       const double pulse_off = true_pulse - (beats / prev_m->note_divisor()) - prev_m->pulse();
+                                       new_pulse = true_pulse - pulse_off;
                                } else {
                                        b_bbt = make_pair (0.0, BBT_Time (1, 1, 0));
                                }
-                               m->set_beat (b_bbt);
-                               m->set_pulse (pulse);
-                               prev_ms = m;
+
+                               section->set_beat (b_bbt);
+                               section->set_pulse (new_pulse);
+                               prev_m = m;
+
                                continue;
                        }
-                       if (prev_ms) {
+                       if (prev_m) {
+                               double new_pulse = 0.0;
                                if (m->position_lock_style() == MusicTime) {
-                                       const double pulse = prev_ms->pulse() + (m->beat() - prev_ms->beat()) / prev_ms->note_divisor();
-                                       m->set_frame (frame_at_pulse_locked (imaginary, pulse));
-                                       m->set_pulse (pulse);
+                                       new_pulse = prev_m->pulse() + ((m->bbt().bars - prev_m->bbt().bars) *  prev_m->divisions_per_bar() / prev_m->note_divisor());
+                                       m->set_frame (frame_at_pulse_locked (imaginary, new_pulse));
+                                       if (m->frame() > section->frame()) {
+                                               /* moving 'section' will affect later meters' beat (but not bbt).*/
+                                               pair<double, BBT_Time> new_beat (((new_pulse - prev_m->pulse()) * prev_m->note_divisor()) + prev_m->beat(), m->bbt());
+                                               m->set_beat (new_beat);
+                                       }
                                } else {
-                                       double pulse = 0.0;
                                        pair<double, BBT_Time> b_bbt;
                                        if (m->movable()) {
-                                               const double beats = ((pulse_at_frame_locked (imaginary, m->frame()) - prev_ms->pulse()) * prev_ms->note_divisor()) - prev_ms->beat();
-                                               const double true_pulse = prev_ms->pulse() + (m->beat() - prev_ms->beat()) / prev_ms->note_divisor();
-                                               const double pulse_off = true_pulse - ((beats - prev_ms->beat()) / prev_ms->note_divisor());
-                                               b_bbt = make_pair (ceil (beats), BBT_Time (accumulated_bars + 1, 1, 0));
-                                               pulse = true_pulse - pulse_off;
+                                               const double beats = ((pulse_at_frame_locked (imaginary, m->frame()) - prev_m->pulse()) * prev_m->note_divisor());
+                                               const double floor_beats = beats - fmod (beats , prev_m->divisions_per_bar());
+                                               b_bbt = make_pair (floor_beats + prev_m->beat()
+                                                                  , BBT_Time ((floor_beats / prev_m->divisions_per_bar()) + prev_m->bbt().bars, 1, 0));
+                                               const double true_pulse = prev_m->pulse() + (floor_beats / prev_m->note_divisor());
+                                               const double pulse_off = true_pulse - (beats / prev_m->note_divisor()) - prev_m->pulse();
+                                               new_pulse = true_pulse - pulse_off;
                                        } else {
                                                b_bbt = make_pair (0.0, BBT_Time (1, 1, 0));
-                                               pulse = 0.0;
+                                               new_pulse = 0.0;
                                        }
                                        m->set_beat (b_bbt);
-                                       m->set_pulse (pulse);
                                }
+                               m->set_pulse (new_pulse);
                        }
-                       prev_ms = m;
+                       prev_m = m;
                }
        }
 
+       MetricSectionFrameSorter fcmp;
+       imaginary.sort (fcmp);
        if (section->position_lock_style() == MusicTime) {
                /* we're setting the frame */
                section->set_position_lock_style (AudioTime);
@@ -2073,47 +2086,62 @@ TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const Meter& mt,
 }
 
 void
-TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const Meter& mt, const double& pulse)
+TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const double& pulse)
 {
-       MeterSection* prev_ms = 0;
-       double accumulated_beats = 0.0;
-       uint32_t accumulated_bars = 0;
+       MeterSection* prev_m = 0;
+       MeterSection* section_prev = 0;
 
        section->set_pulse (pulse);
 
        for (Metrics::iterator i = imaginary.begin(); i != imaginary.end(); ++i) {
                MeterSection* m;
                if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
-                       if (prev_ms) {
-                               double const beats_in_m = (m->pulse() - prev_ms->pulse()) * prev_ms->note_divisor();
-                               accumulated_beats += beats_in_m;
-                               accumulated_bars += (beats_in_m + 1) / prev_ms->divisions_per_bar();
-                       }
                        if (m == section){
-                               section->set_frame (frame_at_pulse_locked (imaginary, pulse));
-                               pair<double, BBT_Time> b_bbt = make_pair (accumulated_beats, BBT_Time (accumulated_bars + 1, 1, 0));
-                               section->set_beat (b_bbt);
-                               prev_ms = section;
+                               section_prev = prev_m;
                                continue;
                        }
-                       if (prev_ms) {
+                       if (prev_m) {
+                               double new_pulse = 0.0;
                                if (m->position_lock_style() == MusicTime) {
-                                       const double pulse = prev_ms->pulse() + (m->beat() - prev_ms->beat()) / prev_ms->note_divisor();
-                                       m->set_frame (frame_at_pulse_locked (imaginary, pulse));
-                                       m->set_pulse (pulse);
+                                       new_pulse = prev_m->pulse() + ((m->bbt().bars - prev_m->bbt().bars) *  prev_m->divisions_per_bar() / prev_m->note_divisor());
+                                       m->set_frame (frame_at_pulse_locked (imaginary, new_pulse));
+
+                                       if (new_pulse > section->pulse()) {
+                                               /* moving 'section' will affect later meters' beat (but not bbt).*/
+                                               pair<double, BBT_Time> new_beat (((new_pulse - prev_m->pulse()) * prev_m->note_divisor()) + prev_m->beat(), m->bbt());
+                                               m->set_beat (new_beat);
+                                       }
                                } else {
-                                       if (!m->movable()) {
-                                               pair<double, BBT_Time> b_bbt = make_pair (0.0, BBT_Time (1, 1, 0));
-                                               m->set_beat (b_bbt);
+                                       pair<double, BBT_Time> b_bbt;
+                                       if (m->movable()) {
+                                               const double beats = ((pulse_at_frame_locked (imaginary, m->frame()) - prev_m->pulse()) * prev_m->note_divisor());
+                                               const double floor_beats = beats - fmod (beats, prev_m->divisions_per_bar());
+                                               b_bbt = make_pair (floor_beats + prev_m->beat()
+                                                                  , BBT_Time ((floor_beats / prev_m->divisions_per_bar()) + prev_m->bbt().bars, 1, 0));
+                                               const double true_pulse = prev_m->pulse() + (floor_beats / prev_m->note_divisor());
+                                               const double pulse_off = true_pulse - (beats / prev_m->note_divisor()) - prev_m->pulse();
+                                               new_pulse = true_pulse - pulse_off;
+                                       } else {
+                                               b_bbt = make_pair (0.0, BBT_Time (1, 1, 0));
                                        }
-                                       const double pulse = prev_ms->pulse() + (m->beat() - prev_ms->beat()) / prev_ms->note_divisor();
-                                       m->set_pulse (pulse);
+                                       m->set_beat (b_bbt);
                                }
+                               m->set_pulse (new_pulse);
                        }
-                       prev_ms = m;
+                       prev_m = m;
                }
        }
 
+       if (section_prev) {
+               const double beats = ((pulse - section_prev->pulse()) * section_prev->note_divisor());
+               const int32_t bars = (beats + 1) / section_prev->divisions_per_bar();
+               pair<double, BBT_Time> b_bbt = make_pair (beats + section_prev->beat(), BBT_Time (bars + section_prev->bbt().bars, 1, 0));
+               section->set_beat (b_bbt);
+               section->set_frame (frame_at_pulse_locked (imaginary, pulse));
+       }
+
+       MetricSectionSorter cmp;
+       imaginary.sort (cmp);
        if (section->position_lock_style() == AudioTime) {
                /* we're setting the pulse */
                section->set_position_lock_style (MusicTime);
@@ -2125,22 +2153,24 @@ TempoMap::solve_map (Metrics& imaginary, MeterSection* section, const Meter& mt,
 }
 
 /** places a copy of _metrics into copy and returns a pointer
- *  to section's equivalent.
+ *  to section's equivalent in copy.
  */
 TempoSection*
 TempoMap::copy_metrics_and_point (Metrics& copy, TempoSection* section)
 {
        TempoSection* t;
-       TempoSection* ret = 0;
        MeterSection* m;
+       TempoSection* ret = 0;
 
        for (Metrics::iterator i = _metrics.begin(); i != _metrics.end(); ++i) {
                if ((t = dynamic_cast<TempoSection*> (*i)) != 0) {
                        if (t == section) {
                                if (t->position_lock_style() == MusicTime) {
                                        ret = new TempoSection (t->pulse(), t->beats_per_minute(), t->note_type(), t->type());
+                                       ret->set_frame (t->frame());
                                } else {
                                        ret = new TempoSection (t->frame(), t->beats_per_minute(), t->note_type(), t->type());
+                                       ret->set_pulse (t->pulse());
                                }
                                ret->set_active (t->active());
                                ret->set_movable (t->movable());
@@ -2150,8 +2180,10 @@ TempoMap::copy_metrics_and_point (Metrics& copy, TempoSection* section)
                        TempoSection* cp = 0;
                        if (t->position_lock_style() == MusicTime) {
                                cp = new TempoSection (t->pulse(), t->beats_per_minute(), t->note_type(), t->type());
+                               cp->set_frame (t->frame());
                        } else {
                                cp = new TempoSection (t->frame(), t->beats_per_minute(), t->note_type(), t->type());
+                               cp->set_pulse (t->pulse());
                        }
                        cp->set_active (t->active());
                        cp->set_movable (t->movable());
@@ -2170,12 +2202,12 @@ TempoMap::copy_metrics_and_point (Metrics& copy, TempoSection* section)
                        copy.push_back (cp);
                }
        }
-       //recompute_map (copy);
+
        return ret;
 }
 
 bool
-TempoMap::can_solve_bbt (TempoSection* ts,  const Tempo& bpm, const BBT_Time& bbt)
+TempoMap::can_solve_bbt (TempoSection* ts, const BBT_Time& bbt)
 {
        Metrics copy;
        TempoSection* new_section = 0;
@@ -2186,7 +2218,7 @@ TempoMap::can_solve_bbt (TempoSection* ts,  const Tempo& bpm, const BBT_Time& bb
        }
 
        double const beat = bbt_to_beats_locked (copy, bbt);
-       bool ret = solve_map (copy, new_section, bpm, pulse_at_beat_locked (copy, beat));
+       bool ret = solve_map (copy, new_section, pulse_at_beat_locked (copy, beat));
 
        Metrics::const_iterator d = copy.begin();
        while (d != copy.end()) {
@@ -2206,15 +2238,16 @@ TempoMap::can_solve_bbt (TempoSection* ts,  const Tempo& bpm, const BBT_Time& bb
 * @return returns - the position in frames where the new tempo section will lie.
 */
 framepos_t
-TempoMap::predict_tempo_frame (TempoSection* section, const Tempo& bpm, const BBT_Time& bbt)
+TempoMap::predict_tempo_frame (TempoSection* section, const BBT_Time& bbt)
 {
        Glib::Threads::RWLock::ReaderLock lm (lock);
        Metrics future_map;
        framepos_t ret = 0;
        TempoSection* new_section = copy_metrics_and_point (future_map, section);
 
-       double const beat = bbt_to_beats_locked (future_map, bbt);
-       if (solve_map (future_map, new_section, bpm, pulse_at_beat_locked (future_map, beat))) {
+       const double beat = bbt_to_beats_locked (future_map, bbt);
+
+       if (solve_map (future_map, new_section, pulse_at_beat_locked (future_map, beat))) {
                ret = new_section->frame();
        } else {
                ret = frame_at_beat_locked (_metrics, beat);
@@ -2229,14 +2262,14 @@ TempoMap::predict_tempo_frame (TempoSection* section, const Tempo& bpm, const BB
 }
 
 double
-TempoMap::predict_tempo_pulse (TempoSection* section, const Tempo& bpm, const framepos_t& frame)
+TempoMap::predict_tempo_pulse (TempoSection* section, const framepos_t& frame)
 {
        Glib::Threads::RWLock::ReaderLock lm (lock);
        Metrics future_map;
        double ret = 0.0;
        TempoSection* new_section = copy_metrics_and_point (future_map, section);
 
-       if (solve_map (future_map, new_section, bpm, frame)) {
+       if (solve_map (future_map, new_section, frame)) {
                ret = new_section->pulse();
        } else {
                ret = pulse_at_frame_locked (_metrics, frame);
@@ -2251,14 +2284,14 @@ TempoMap::predict_tempo_pulse (TempoSection* section, const Tempo& bpm, const fr
 }
 
 void
-TempoMap::gui_move_tempo_frame (TempoSection* ts,  const Tempo& bpm, const framepos_t& frame)
+TempoMap::gui_move_tempo_frame (TempoSection* ts, const framepos_t& frame)
 {
        Metrics future_map;
        {
                Glib::Threads::RWLock::WriterLock lm (lock);
                TempoSection* new_section = copy_metrics_and_point (future_map, ts);
-               if (solve_map (future_map, new_section, bpm, frame)) {
-                       solve_map (_metrics, ts, bpm, frame);
+               if (solve_map (future_map, new_section, frame)) {
+                       solve_map (_metrics, ts, frame);
                }
        }
 
@@ -2272,14 +2305,14 @@ TempoMap::gui_move_tempo_frame (TempoSection* ts,  const Tempo& bpm, const frame
 }
 
 void
-TempoMap::gui_move_tempo_beat (TempoSection* ts,  const Tempo& bpm, const double& beat)
+TempoMap::gui_move_tempo_beat (TempoSection* ts, const double& beat)
 {
        Metrics future_map;
        {
                Glib::Threads::RWLock::WriterLock lm (lock);
                TempoSection* new_section = copy_metrics_and_point (future_map, ts);
-               if (solve_map (future_map, new_section, bpm, pulse_at_beat_locked (future_map, beat))) {
-                       solve_map (_metrics, ts, bpm, pulse_at_beat_locked (_metrics, beat));
+               if (solve_map (future_map, new_section, pulse_at_beat_locked (future_map, beat))) {
+                       solve_map (_metrics, ts, pulse_at_beat_locked (_metrics, beat));
                }
        }
 
@@ -2293,29 +2326,29 @@ TempoMap::gui_move_tempo_beat (TempoSection* ts,  const Tempo& bpm, const double
 }
 
 void
-TempoMap::gui_move_meter (MeterSection* ms, const Meter& mt, const framepos_t&  frame)
+TempoMap::gui_move_meter (MeterSection* ms, const framepos_t&  frame)
 {
        {
                Glib::Threads::RWLock::WriterLock lm (lock);
-               solve_map (_metrics, ms, mt, frame);
+               solve_map (_metrics, ms, frame);
        }
 
        MetricPositionChanged (); // Emit Signal
 }
 
 void
-TempoMap::gui_move_meter (MeterSection* ms, const Meter& mt, const double&  beat)
+TempoMap::gui_move_meter (MeterSection* ms, const double&  beat)
 {
        {
                Glib::Threads::RWLock::WriterLock lm (lock);
-               solve_map (_metrics, ms, mt, pulse_at_beat_locked (_metrics, beat));
+               solve_map (_metrics, ms, pulse_at_beat_locked (_metrics, beat));
        }
 
        MetricPositionChanged (); // Emit Signal
 }
 
 bool
-TempoMap::gui_change_tempo (TempoSection* ts,  const Tempo& bpm)
+TempoMap::gui_change_tempo (TempoSection* ts, const Tempo& bpm)
 {
        Metrics future_map;
        bool can_solve = false;
@@ -2348,13 +2381,11 @@ TempoMap::bbt_duration_at (framepos_t pos, const BBT_Time& bbt, int dir)
 {
        Glib::Threads::RWLock::ReaderLock lm (lock);
 
-       double const tick_at_time = beat_at_frame_locked (_metrics, pos) * BBT_Time::ticks_per_beat;
-       double const bbt_ticks = bbt.ticks + (bbt.beats * BBT_Time::ticks_per_beat);
-       double const total_beats = (tick_at_time + bbt_ticks) / BBT_Time::ticks_per_beat;
-       framecnt_t const time_at_bbt = frame_at_beat_locked (_metrics, total_beats);
-       framecnt_t const ret = time_at_bbt;
+       const double tick_at_time = beat_at_frame_locked (_metrics, pos) * BBT_Time::ticks_per_beat;
+       const double bbt_ticks = bbt.ticks + (bbt.beats * BBT_Time::ticks_per_beat);
+       const double total_beats = (tick_at_time + bbt_ticks) / BBT_Time::ticks_per_beat;
 
-       return ret;
+       return frame_at_beat_locked (_metrics, total_beats);
 }
 
 framepos_t
@@ -2460,7 +2491,7 @@ TempoMap::round_to_beat_subdivision (framepos_t fr, int sub_num, RoundMode dir)
                }
        }
 
-       framepos_t const ret_frame = frame_at_beat_locked (_metrics, beats + (ticks / BBT_Time::ticks_per_beat));
+       const framepos_t ret_frame = frame_at_beat_locked (_metrics, beats + (ticks / BBT_Time::ticks_per_beat));
 
        return ret_frame;
 }
@@ -2521,7 +2552,7 @@ TempoMap::round_to_type (framepos_t frame, RoundMode dir, BBTPointType type)
 {
        Glib::Threads::RWLock::ReaderLock lm (lock);
 
-       double const beat_at_framepos = beat_at_frame_locked (_metrics, frame);
+       const double beat_at_framepos = beat_at_frame_locked (_metrics, frame);
        BBT_Time bbt (beats_to_bbt_locked (_metrics, beat_at_framepos));
 
        switch (type) {
@@ -2530,22 +2561,22 @@ TempoMap::round_to_type (framepos_t frame, RoundMode dir, BBTPointType type)
                        /* find bar previous to 'frame' */
                        bbt.beats = 1;
                        bbt.ticks = 0;
-                       return frame_time (bbt);
+                       return frame_time_locked (_metrics, bbt);
 
                } else if (dir > 0) {
                        /* find bar following 'frame' */
                        ++bbt.bars;
                        bbt.beats = 1;
                        bbt.ticks = 0;
-                       return frame_time (bbt);
+                       return frame_time_locked (_metrics, bbt);
                } else {
                        /* true rounding: find nearest bar */
-                       framepos_t raw_ft = frame_time (bbt);
+                       framepos_t raw_ft = frame_time_locked (_metrics, bbt);
                        bbt.beats = 1;
                        bbt.ticks = 0;
-                       framepos_t prev_ft = frame_time (bbt);
+                       framepos_t prev_ft = frame_time_locked (_metrics, bbt);
                        ++bbt.bars;
-                       framepos_t next_ft = frame_time (bbt);
+                       framepos_t next_ft = frame_time_locked (_metrics, bbt);
 
                        if ((raw_ft - prev_ft) > (next_ft - prev_ft) / 2) { 
                                return next_ft;
@@ -2575,7 +2606,7 @@ TempoMap::get_grid (vector<TempoMap::BBTPoint>& points,
                    framepos_t lower, framepos_t upper)
 {
        Glib::Threads::RWLock::ReaderLock lm (lock);
-       int32_t const upper_beat = (int32_t) ceil (beat_at_frame_locked (_metrics, upper));
+       const int32_t upper_beat = (int32_t) ceil (beat_at_frame_locked (_metrics, upper));
        int32_t cnt = floor (beat_at_frame_locked (_metrics, lower));
        /* although the map handles negative beats, bbt doesn't. */
        if (cnt < 0.0) {
@@ -2583,11 +2614,10 @@ TempoMap::get_grid (vector<TempoMap::BBTPoint>& points,
        }
        while (cnt <= upper_beat) {
                framecnt_t pos = frame_at_beat_locked (_metrics, cnt);
-               TempoSection const tempo = tempo_section_at_locked (pos);
-               MeterSection const meter = meter_section_at_locked (pos);
-               BBT_Time const bbt = beats_to_bbt (cnt);
-               BBTPoint point = BBTPoint (meter, tempo_at_locked (pos), pos, bbt.bars, bbt.beats, tempo.get_c_func());
-               points.push_back (point);
+               const TempoSection tempo = tempo_section_at_locked (pos);
+               const MeterSection meter = meter_section_at_locked (pos);
+               const BBT_Time bbt = beats_to_bbt (cnt);
+               points.push_back (BBTPoint (meter, tempo_at_locked (pos), pos, bbt.bars, bbt.beats, tempo.c_func()));
                ++cnt;
        }
 }
@@ -2672,7 +2702,7 @@ TempoMap::tempo_at (const framepos_t& frame) const
 const Tempo
 TempoMap::tempo_at_locked (const framepos_t& frame) const
 {
-       TempoSection* prev_ts = 0;
+       TempoSection* prev_t = 0;
 
        Metrics::const_iterator i;
 
@@ -2682,18 +2712,18 @@ TempoMap::tempo_at_locked (const framepos_t& frame) const
                        if (!t->active()) {
                                continue;
                        }
-                       if ((prev_ts) && t->frame() > frame) {
+                       if ((prev_t) && t->frame() > frame) {
                                /* t is the section past frame */
-                               double const ret = prev_ts->tempo_at_frame (frame, _frame_rate) * prev_ts->note_type();
-                               Tempo const ret_tempo (ret, prev_ts->note_type());
+                               const double ret_bpm = prev_t->tempo_at_frame (frame, _frame_rate) * prev_t->note_type();
+                               const Tempo ret_tempo (ret_bpm, prev_t->note_type());
                                return ret_tempo;
                        }
-                       prev_ts = t;
+                       prev_t = t;
                }
        }
 
-       double const ret = prev_ts->beats_per_minute();
-       Tempo const ret_tempo (ret, prev_ts->note_type ());
+       const double ret = prev_t->beats_per_minute();
+       const Tempo ret_tempo (ret, prev_t->note_type ());
 
        return ret_tempo;
 }
@@ -2708,7 +2738,6 @@ TempoMap::meter_section_at (framepos_t frame) const
 const MeterSection&
 TempoMap::meter_section_at_locked (framepos_t frame) const
 {
-       //framepos_t const frame_off = frame + frame_offset_at (_metrics, frame);
        Metrics::const_iterator i;
        MeterSection* prev = 0;
 
@@ -2743,20 +2772,82 @@ TempoMap::meter_at (framepos_t frame) const
 const MeterSection&
 TempoMap::meter_section_at (const double& beat) const
 {
-       MeterSection* prev_ms = 0;
+       MeterSection* prev_m = 0;
        Glib::Threads::RWLock::ReaderLock lm (lock);
 
        for (Metrics::const_iterator i = _metrics.begin(); i != _metrics.end(); ++i) {
                MeterSection* m;
                if ((m = dynamic_cast<MeterSection*> (*i)) != 0) {
-                       if (prev_ms && m->beat() > beat) {
+                       if (prev_m && m->beat() > beat) {
                                break;
                        }
-                       prev_ms = m;
+                       prev_m = m;
                }
 
        }
-       return *prev_ms;
+       return *prev_m;
+}
+
+void
+TempoMap::fix_legacy_session ()
+{
+       MeterSection* prev_m = 0;
+       TempoSection* prev_t = 0;
+
+       for (Metrics::iterator i = _metrics.begin(); i != _metrics.end(); ++i) {
+               MeterSection* m;
+               TempoSection* t;
+
+               if ((m = dynamic_cast<MeterSection*>(*i)) != 0) {
+                       if (!m->movable()) {
+                               pair<double, BBT_Time> bbt = make_pair (0.0, BBT_Time (1, 1, 0));
+                               m->set_beat (bbt);
+                               m->set_pulse (0.0);
+                               m->set_frame (0);
+                               m->set_position_lock_style (AudioTime);
+                               prev_m = m;
+                               continue;
+                       }
+                       if (prev_m) {
+                               pair<double, BBT_Time> start = make_pair (((m->bbt().bars - 1) * prev_m->note_divisor())
+                                                                         + (m->bbt().beats - 1)
+                                                                         + (m->bbt().ticks / BBT_Time::ticks_per_beat)
+                                                                         , m->bbt());
+                               m->set_beat (start);
+                               const double start_beat = ((m->bbt().bars - 1) * prev_m->note_divisor())
+                                       + (m->bbt().beats - 1)
+                                       + (m->bbt().ticks / BBT_Time::ticks_per_beat);
+                               m->set_pulse (start_beat / prev_m->note_divisor());
+                       }
+                       prev_m = m;
+               } else if ((t = dynamic_cast<TempoSection*>(*i)) != 0) {
+
+                       if (!t->active()) {
+                               continue;
+                       }
+
+                       if (!t->movable()) {
+                               t->set_pulse (0.0);
+                               t->set_frame (0);
+                               t->set_position_lock_style (AudioTime);
+                               prev_t = t;
+                               continue;
+                       }
+
+                       if (prev_t) {
+                               const double beat = ((t->legacy_bbt().bars - 1) * ((prev_m) ? prev_m->note_divisor() : 4.0))
+                                       + (t->legacy_bbt().beats - 1)
+                                       + (t->legacy_bbt().ticks / BBT_Time::ticks_per_beat);
+                               if (prev_m) {
+                                       t->set_pulse (beat / prev_m->note_divisor());
+                               } else {
+                                       /* really shouldn't happen but.. */
+                                       t->set_pulse (beat / 4.0);
+                               }
+                       }
+                       prev_t = t;
+               }
+       }
 }
 
 XMLNode&
@@ -2823,32 +2914,19 @@ TempoMap::set_state (const XMLNode& node, int /*version*/)
                        MetricSectionSorter cmp;
                        _metrics.sort (cmp);
                }
+
                /* check for legacy sessions where bbt was the base musical unit for tempo */
-               for (Metrics::iterator i = _metrics.begin(); i != _metrics.end(); ++i) {
-                       MeterSection* m;
+               for (Metrics::const_iterator i = _metrics.begin(); i != _metrics.end(); ++i) {
                        TempoSection* t;
-                       MeterSection* prev_ms = 0;
-                       TempoSection* prev_ts = 0;
-                       if ((m = dynamic_cast<MeterSection*>(*i)) != 0) {
-                               if (prev_ms && prev_ms->pulse() < 0.0) {
-                                       /*XX we cannot possibly make this work??. */
-                                       pair<double, BBT_Time> start = make_pair (((prev_ms->bbt().bars - 1) * prev_ms->note_divisor()) + (prev_ms->bbt().beats - 1) + (prev_ms->bbt().ticks / BBT_Time::ticks_per_beat), prev_ms->bbt());
-                                       prev_ms->set_beat (start);
-                                       const double start_pulse = ((prev_ms->bbt().bars - 1) * prev_ms->note_divisor()) + (prev_ms->bbt().beats - 1) + (prev_ms->bbt().ticks / BBT_Time::ticks_per_beat);
-                                       prev_ms->set_pulse (start_pulse);
-                               }
-                               prev_ms = m;
-                       } else if ((t = dynamic_cast<TempoSection*>(*i)) != 0) {
-                               if (!t->active()) {
-                                       continue;
-                               }
-                               if (prev_ts && prev_ts->pulse() < 0.0) {
-                                       double const start = ((prev_ts->legacy_bbt().bars - 1) * prev_ms->note_divisor()) + (prev_ts->legacy_bbt().beats - 1) + (prev_ts->legacy_bbt().ticks / BBT_Time::ticks_per_beat);
-                                       prev_ts->set_pulse (start);
+                       if ((t = dynamic_cast<TempoSection*> (*i)) != 0) {
+                               if (t->legacy_bbt().bars != 0) {
+                                       fix_legacy_session();
+                                       break;
                                }
-                               prev_ts = t;
+                               break;
                        }
                }
+
                /* check for multiple tempo/meters at the same location, which
                   ardour2 somehow allowed.
                */
@@ -2857,19 +2935,19 @@ TempoMap::set_state (const XMLNode& node, int /*version*/)
                for (Metrics::iterator i = _metrics.begin(); i != _metrics.end(); ++i) {
                        if (prev != _metrics.end()) {
                                MeterSection* ms;
-                               MeterSection* prev_ms;
+                               MeterSection* prev_m;
                                TempoSection* ts;
-                               TempoSection* prev_ts;
-                               if ((prev_ms = dynamic_cast<MeterSection*>(*prev)) != 0 && (ms = dynamic_cast<MeterSection*>(*i)) != 0) {
-                                       if (prev_ms->pulse() == ms->pulse()) {
-                                               cerr << string_compose (_("Multiple meter definitions found at %1"), prev_ms->pulse()) << endmsg;
-                                               error << string_compose (_("Multiple meter definitions found at %1"), prev_ms->pulse()) << endmsg;
+                               TempoSection* prev_t;
+                               if ((prev_m = dynamic_cast<MeterSection*>(*prev)) != 0 && (ms = dynamic_cast<MeterSection*>(*i)) != 0) {
+                                       if (prev_m->pulse() == ms->pulse()) {
+                                               cerr << string_compose (_("Multiple meter definitions found at %1"), prev_m->pulse()) << endmsg;
+                                               error << string_compose (_("Multiple meter definitions found at %1"), prev_m->pulse()) << endmsg;
                                                return -1;
                                        }
-                               } else if ((prev_ts = dynamic_cast<TempoSection*>(*prev)) != 0 && (ts = dynamic_cast<TempoSection*>(*i)) != 0) {
-                                       if (prev_ts->pulse() == ts->pulse()) {
-                                               cerr << string_compose (_("Multiple tempo definitions found at %1"), prev_ts->pulse()) << endmsg;
-                                               error << string_compose (_("Multiple tempo definitions found at %1"), prev_ts->pulse()) << endmsg;
+                               } else if ((prev_t = dynamic_cast<TempoSection*>(*prev)) != 0 && (ts = dynamic_cast<TempoSection*>(*i)) != 0) {
+                                       if (prev_t->pulse() == ts->pulse()) {
+                                               cerr << string_compose (_("Multiple tempo definitions found at %1"), prev_t->pulse()) << endmsg;
+                                               error << string_compose (_("Multiple tempo definitions found at %1"), prev_t->pulse()) << endmsg;
                                                return -1;
                                        }
                                }
@@ -2891,7 +2969,7 @@ TempoMap::dump (const Metrics& metrics, std::ostream& o) const
        Glib::Threads::RWLock::ReaderLock lm (lock, Glib::Threads::TRY_LOCK);
        const MeterSection* m;
        const TempoSection* t;
-       const TempoSection* prev_ts = 0;
+       const TempoSection* prev_t = 0;
 
        for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
 
@@ -2899,11 +2977,11 @@ TempoMap::dump (const Metrics& metrics, std::ostream& o) const
                        o << "Tempo @ " << *i << t->beats_per_minute() << " BPM (pulse = 1/" << t->note_type() << ") at " << t->pulse() << " frame= " << t->frame() << " (movable? "
                          << t->movable() << ')' << " pos lock: " << enum_2_string (t->position_lock_style()) << std::endl;
                        o << "current      : " << t->beats_per_minute() << " | " << t->pulse() << " | " << t->frame() << std::endl;
-                       if (prev_ts) {
-                               o << "previous     : " << prev_ts->beats_per_minute() << " | " << prev_ts->pulse() << " | " << prev_ts->frame() << std::endl;
-                               o << "calculated   : " << prev_ts->tempo_at_pulse (t->pulse()) *  prev_ts->note_type() << " | " << prev_ts->pulse_at_tempo (t->pulses_per_minute(), t->frame(), _frame_rate) <<  " | " << prev_ts->frame_at_tempo (t->pulses_per_minute(), t->pulse(), _frame_rate) << std::endl;
+                       if (prev_t) {
+                               o << "previous     : " << prev_t->beats_per_minute() << " | " << prev_t->pulse() << " | " << prev_t->frame() << std::endl;
+                               o << "calculated   : " << prev_t->tempo_at_pulse (t->pulse()) *  prev_t->note_type() << " | " << prev_t->pulse_at_tempo (t->pulses_per_minute(), t->frame(), _frame_rate) <<  " | " << prev_t->frame_at_tempo (t->pulses_per_minute(), t->pulse(), _frame_rate) << std::endl;
                        }
-                       prev_ts = t;
+                       prev_t = t;
                } else if ((m = dynamic_cast<const MeterSection*>(*i)) != 0) {
                        o << "Meter @ " << *i << ' ' << m->divisions_per_bar() << '/' << m->note_divisor() << " at " << m->bbt() << " frame= " << m->frame()
                          << " pulse: " << m->pulse() <<  " beat : " << m->beat() << " pos lock: " << enum_2_string (m->position_lock_style()) << " (movable? " << m->movable() << ')' << endl;