Make source length a dynamic thing.

Update MIDI region length (actually and visually) when position changes.


git-svn-id: svn://localhost/ardour2/branches/3.0@4644 d708f5d6-7413-0410-9779-e7cbd77b26cf

21 files changed, 132 insertions, 65 deletions

diff --git a/libs/ardour/analyser.cc b/libs/ardour/analyser.cc
index 28eeeb190c..6d2392eb20 100644
--- a/libs/ardour/analyser.cc
+++ b/libs/ardour/analyser.cc
@@ -95,7 +95,7 @@ Analyser::work ()
 
 		boost::shared_ptr<AudioFileSource> afs = boost::dynamic_pointer_cast<AudioFileSource> (src);
 
-		if (afs && afs->length()) {
+		if (afs && afs->length(afs->timeline_position())) {
 			analyse_audio_file_source (afs);
 		}
 	}
@@ -116,4 +116,3 @@ Analyser::analyse_audio_file_source (boost::shared_ptr<AudioFileSource> src)
 
 }
 
-		
diff --git a/libs/ardour/ardour/audiosource.h b/libs/ardour/ardour/audiosource.h
index 08435bf3b1..4f2ad0eee1 100644
--- a/libs/ardour/ardour/audiosource.h
+++ b/libs/ardour/ardour/audiosource.h
@@ -54,6 +54,9 @@ class AudioSource : virtual public Source,
 
 	nframes64_t readable_length() const { return _length; }
 	uint32_t    n_channels()      const { return 1; }
+	
+	sframes_t length (sframes_t pos) const;
+	void      update_length (sframes_t pos, sframes_t cnt);
 
 	virtual nframes_t available_peaks (double zoom) const;
 
@@ -108,6 +111,7 @@ class AudioSource : virtual public Source,
 	static bool _build_missing_peakfiles;
 	static bool _build_peakfiles;
 
+	sframes_t            _length;
 	bool                 _peaks_built;
 	mutable Glib::Mutex  _peaks_ready_lock;
 	Glib::ustring         peakpath;
diff --git a/libs/ardour/ardour/crossfade.h b/libs/ardour/ardour/crossfade.h
index 2b893478d4..4ad2ab551d 100644
--- a/libs/ardour/ardour/crossfade.h
+++ b/libs/ardour/ardour/crossfade.h
@@ -129,7 +129,7 @@ class Crossfade : public ARDOUR::AudioRegion
 	AutomationList& fade_in() { return _fade_in; } 
 	AutomationList& fade_out() { return _fade_out; }
 
-	nframes_t set_length (nframes_t);
+	nframes_t set_xfade_length (nframes_t);
 
 	bool is_dependent() const { return true; }
 	bool depends_on (boost::shared_ptr<Region> other) const { 
diff --git a/libs/ardour/ardour/midi_region.h b/libs/ardour/ardour/midi_region.h
index 0760fb7268..9f4041060e 100644
--- a/libs/ardour/ardour/midi_region.h
+++ b/libs/ardour/ardour/midi_region.h
@@ -115,6 +115,8 @@ class MidiRegion : public Region
 
 	void recompute_at_start ();
 	void recompute_at_end ();
+	
+	void set_position_internal (nframes_t pos, bool allow_bbt_recompute);
 
 	void switch_source(boost::shared_ptr<Source> source);
 
diff --git a/libs/ardour/ardour/midi_source.h b/libs/ardour/ardour/midi_source.h
index ec454803dc..0c18b096bd 100644
--- a/libs/ardour/ardour/midi_source.h
+++ b/libs/ardour/ardour/midi_source.h
@@ -69,6 +69,9 @@ class MidiSource : virtual public Source
 
 	virtual void append_event_unlocked_frames(const Evoral::Event<nframes_t>& ev,
 			sframes_t position) = 0;
+	
+	virtual sframes_t length (sframes_t pos) const;
+	virtual void      update_length (sframes_t pos, sframes_t cnt);
 
 	virtual void mark_streaming_midi_write_started (NoteMode mode, sframes_t start_time);
 	virtual void mark_streaming_write_started ();
@@ -118,15 +121,18 @@ class MidiSource : virtual public Source
 			sframes_t position,
 			nframes_t cnt) = 0;
 	
-	std::string         _captured_for;
-	mutable uint32_t    _read_data_count;  ///< modified in read()
-	mutable uint32_t    _write_data_count; ///< modified in write()
+	std::string      _captured_for;
+	mutable uint32_t _read_data_count;  ///< modified in read()
+	mutable uint32_t _write_data_count; ///< modified in write()
 	
 	boost::shared_ptr<MidiModel> _model;
 	bool                         _writing;
 	
 	mutable Evoral::Sequence<double>::const_iterator _model_iter;
-	mutable sframes_t                                _last_read_end;
+	
+	mutable double    _length_beats;
+	mutable sframes_t _last_read_end;
+	sframes_t         _last_write_end;
 
   private:
 	bool file_changed (std::string path);
diff --git a/libs/ardour/ardour/region.h b/libs/ardour/ardour/region.h
index a4ce35b61b..2696c7da91 100644
--- a/libs/ardour/ardour/region.h
+++ b/libs/ardour/ardour/region.h
@@ -120,6 +120,8 @@ class Region
 	nframes_t length()    const { return _length; }
 	layer_t   layer ()    const { return _layer; }
 
+	sframes_t source_length(uint32_t n) const;
+
 	/* these two are valid ONLY during a StateChanged signal handler */
 
 	nframes_t last_position() const { return _last_position; }
@@ -288,7 +290,7 @@ class Region
 	void send_change (Change);
 
 	void trim_to_internal (nframes_t position, nframes_t length, void *src);
-	void set_position_internal (nframes_t pos, bool allow_bbt_recompute);
+	virtual void set_position_internal (nframes_t pos, bool allow_bbt_recompute);
 
 	bool copied() const { return _flags & Copied; }
 	void maybe_uncopy ();
diff --git a/libs/ardour/ardour/source.h b/libs/ardour/ardour/source.h
index 36d7e1fe96..7905debbcc 100644
--- a/libs/ardour/ardour/source.h
+++ b/libs/ardour/ardour/source.h
@@ -61,7 +61,8 @@ class Source : public SessionObject, public boost::noncopyable
 	time_t timestamp() const { return _timestamp; }
 	void stamp (time_t when) { _timestamp = when; }
 	
-	sframes_t length() const { return _length; }
+	virtual sframes_t length (sframes_t pos) const = 0;
+	virtual void      update_length (sframes_t pos, sframes_t cnt) = 0;
 	
 	virtual const Glib::ustring& path() const = 0;
 
@@ -104,10 +105,8 @@ class Source : public SessionObject, public boost::noncopyable
 	std::string get_transients_path() const;
 	int load_transients (const std::string&);
 	
-	void update_length (sframes_t pos, sframes_t cnt);
-	
-	int64_t timeline_position() const { return _timeline_position; }
-	virtual void set_timeline_position (int64_t pos);
+	sframes_t    timeline_position() const { return _timeline_position; }
+	virtual void set_timeline_position (sframes_t pos);
 	
 	void set_allow_remove_if_empty (bool yn);
 	
@@ -118,8 +117,7 @@ class Source : public SessionObject, public boost::noncopyable
 	DataType            _type;
 	Flag                _flags;
 	time_t              _timestamp;
-	sframes_t           _length;
-	int64_t             _timeline_position;
+	sframes_t           _timeline_position;
 	bool                _analysed;
 	mutable Glib::Mutex _lock;
 	mutable Glib::Mutex _analysis_lock;
diff --git a/libs/ardour/audio_diskstream.cc b/libs/ardour/audio_diskstream.cc
index ed8027ec59..e08118c0fc 100644
--- a/libs/ardour/audio_diskstream.cc
+++ b/libs/ardour/audio_diskstream.cc
@@ -2373,9 +2373,9 @@ AudioDiskstream::use_pending_capture_data (XMLNode& node)
 	
 	try {
 		region = boost::dynamic_pointer_cast<AudioRegion> (RegionFactory::create (
-				pending_sources, 0, first_fs->length(),
-			  region_name_from_path (first_fs->name(), true), 0,
-			  Region::Flag (Region::DefaultFlags|Region::Automatic|Region::WholeFile)));
+				pending_sources, 0, first_fs->length(first_fs->timeline_position()),
+				region_name_from_path (first_fs->name(), true), 0,
+				Region::Flag (Region::DefaultFlags|Region::Automatic|Region::WholeFile)));
 		region->special_set_position (0);
 	}
 
@@ -2389,7 +2389,7 @@ AudioDiskstream::use_pending_capture_data (XMLNode& node)
 
 	try {
 		region = boost::dynamic_pointer_cast<AudioRegion> (RegionFactory::create (
-				pending_sources, 0, first_fs->length(),
+				pending_sources, 0, first_fs->length(first_fs->timeline_position()),
 				region_name_from_path (first_fs->name(), true)));
 	}
 
diff --git a/libs/ardour/audio_track.cc b/libs/ardour/audio_track.cc
index df648bc055..2e1a266577 100644
--- a/libs/ardour/audio_track.cc
+++ b/libs/ardour/audio_track.cc
@@ -897,10 +897,11 @@ AudioTrack::freeze (InterThreadInfo& itt)
 
 	/* create a new region from all filesources, keep it private */
 
-	boost::shared_ptr<Region> region (RegionFactory::create (srcs, 0, srcs[0]->length(), 
-								 region_name, 0, 
-								 (Region::Flag) (Region::WholeFile|Region::DefaultFlags),
-								 false));
+	boost::shared_ptr<Region> region (RegionFactory::create (srcs, 0,
+			srcs[0]->length(srcs[0]->timeline_position()), 
+			region_name, 0,
+			(Region::Flag) (Region::WholeFile|Region::DefaultFlags),
+			false));
 
 	new_playlist->set_orig_diskstream_id (diskstream->id());
 	new_playlist->add_region (region, _session.current_start_frame());
diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index aafa67e7d3..3ea00deb59 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -348,14 +348,18 @@ AudioRegion::read_at (Sample *buf, Sample *mixdown_buffer, float *gain_buffer,
 		nframes_t read_frames, nframes_t skip_frames) const
 {
 	/* regular diskstream/butler read complete with fades etc */
-	return _read_at (_sources, _length, buf, mixdown_buffer, gain_buffer, file_position, cnt, chan_n, read_frames, skip_frames, ReadOps (~0));
+	return _read_at (_sources, _length, buf, mixdown_buffer, gain_buffer,
+			file_position, cnt, chan_n, read_frames, skip_frames, ReadOps (~0));
 }
 
 nframes_t
 AudioRegion::master_read_at (Sample *buf, Sample *mixdown_buffer, float *gain_buffer,
 		sframes_t position, nframes_t cnt, uint32_t chan_n) const
 {
-	return _read_at (_master_sources, _master_sources.front()->length(), buf, mixdown_buffer, gain_buffer, position, cnt, chan_n, 0, 0);
+	return _read_at (_master_sources,
+			_master_sources.front()->length(_master_sources.front()->timeline_position()),
+			buf, mixdown_buffer, gain_buffer,
+			position, cnt, chan_n, 0, 0);
 }
 
 nframes_t
diff --git a/libs/ardour/audiosource.cc b/libs/ardour/audiosource.cc
index 15f35bf1f1..24ca406b38 100644
--- a/libs/ardour/audiosource.cc
+++ b/libs/ardour/audiosource.cc
@@ -57,6 +57,7 @@ bool AudioSource::_build_peakfiles = false;
 
 AudioSource::AudioSource (Session& s, ustring name)
 	: Source (s, DataType::AUDIO, name)
+	, _length (0)
 {
 	_peaks_built = false;
 	_peak_byte_max = 0;
@@ -70,6 +71,7 @@ AudioSource::AudioSource (Session& s, ustring name)
 
 AudioSource::AudioSource (Session& s, const XMLNode& node) 
 	: Source (s, node)
+	, _length (0)
 {
 	
 	_peaks_built = false;
@@ -125,6 +127,21 @@ AudioSource::set_state (const XMLNode& node)
 	return 0;
 }
 
+sframes_t
+AudioSource::length (sframes_t pos) const
+{
+	return _length;
+}
+
+void
+AudioSource::update_length (sframes_t pos, sframes_t cnt)
+{
+	if (pos + cnt > _length) {
+		_length = pos + cnt;
+	}
+}
+
+
 /***********************************************************************
   PEAK FILE STUFF
  ***********************************************************************/
@@ -211,7 +228,7 @@ AudioSource::initialize_peakfile (bool newfile, ustring audio_path)
 		
 		/* we found it in the peaks dir, so check it out */
 		
-		if (statbuf.st_size == 0 || ((nframes_t) statbuf.st_size < ((length() / _FPP) * sizeof (PeakData)))) {
+		if (statbuf.st_size == 0 || ((nframes_t) statbuf.st_size < ((length(_timeline_position) / _FPP) * sizeof (PeakData)))) {
 			// empty
 			_peaks_built = false;
 		} else {
@@ -895,10 +912,8 @@ AudioSource::file_changed (ustring path)
 nframes_t
 AudioSource::available_peaks (double zoom_factor) const
 {
-	off_t end;
-
 	if (zoom_factor < _FPP) {
-		return length(); // peak data will come from the audio file
+		return length(_timeline_position); // peak data will come from the audio file
 	} 
 	
 	/* peak data comes from peakfile, but the filesize might not represent
@@ -907,7 +922,7 @@ AudioSource::available_peaks (double zoom_factor) const
 	   but _peak_byte_max only monotonically increases after initialization.
 	*/
 
-	end = _peak_byte_max;
+	off_t end = _peak_byte_max;
 
 	return (end/sizeof(PeakData)) * _FPP;
 }
diff --git a/libs/ardour/crossfade.cc b/libs/ardour/crossfade.cc
index 5d180ceccc..9d10f1d1cc 100644
--- a/libs/ardour/crossfade.cc
+++ b/libs/ardour/crossfade.cc
@@ -187,7 +187,7 @@ Crossfade::Crossfade (boost::shared_ptr<Crossfade> orig, boost::shared_ptr<Audio
 	layer_relation = (int32_t) (_in->layer() - _out->layer());
 
 	// Let's make sure the fade isn't too long
-	set_length(_length);
+	set_xfade_length(_length);
 }
 
 
@@ -869,16 +869,16 @@ Crossfade::set_follow_overlap (bool yn)
 	_follow_overlap = yn;
 
 	if (!yn) {
-		set_length (_short_xfade_length);
+		set_xfade_length (_short_xfade_length);
 	} else {
-		set_length (_out->first_frame() + _out->length() - _in->first_frame());
+		set_xfade_length (_out->first_frame() + _out->length() - _in->first_frame());
 	}
 
 	StateChanged (FollowOverlapChanged);
 }
 
 nframes_t
-Crossfade::set_length (nframes_t len)
+Crossfade::set_xfade_length (nframes_t len)
 {
 	nframes_t limit = 0;
 
diff --git a/libs/ardour/file_source.cc b/libs/ardour/file_source.cc
index ed9c80338a..649fc6156b 100644
--- a/libs/ardour/file_source.cc
+++ b/libs/ardour/file_source.cc
@@ -77,13 +77,12 @@ FileSource::removable () const
 {
 	return (_flags & Removable)
 		&& (   (_flags & RemoveAtDestroy)
-			|| ((_flags & RemovableIfEmpty) && length() == 0));
+			|| ((_flags & RemovableIfEmpty) && length(timeline_position()) == 0));
 }
 
 int
 FileSource::init (const ustring& pathstr, bool must_exist)
 {
-	_length = 0;
 	_timeline_position = 0;
 
 	if (!find (_type, pathstr, must_exist, _file_is_new, _channel)) {
diff --git a/libs/ardour/midi_region.cc b/libs/ardour/midi_region.cc
index 5eea77ebca..a30b837c5f 100644
--- a/libs/ardour/midi_region.cc
+++ b/libs/ardour/midi_region.cc
@@ -116,6 +116,19 @@ MidiRegion::~MidiRegion ()
 {
 }
 
+void
+MidiRegion::set_position_internal (nframes_t pos, bool allow_bbt_recompute)
+{
+	BeatsFramesConverter old_converter(_session, _position - _start);
+	double length_beats = old_converter.from(_length);
+
+	Region::set_position_internal(pos, allow_bbt_recompute);
+	
+	BeatsFramesConverter new_converter(_session, pos - _start);
+
+	set_length(new_converter.to(length_beats), 0);
+}
+
 nframes_t
 MidiRegion::read_at (MidiRingBuffer<nframes_t>& out, sframes_t position, nframes_t dur, uint32_t chan_n, NoteMode mode) const
 {
diff --git a/libs/ardour/midi_source.cc b/libs/ardour/midi_source.cc
index bb5179d2bb..7cb8cbb83e 100644
--- a/libs/ardour/midi_source.cc
+++ b/libs/ardour/midi_source.cc
@@ -54,7 +54,9 @@ MidiSource::MidiSource (Session& s, string name, Source::Flag flags)
 	, _read_data_count(0)
 	, _write_data_count(0)
 	, _writing (false)
+	, _length_beats(0.0)
 	, _last_read_end(0)
+	, _last_write_end(0)
 {
 }
 
@@ -63,7 +65,9 @@ MidiSource::MidiSource (Session& s, const XMLNode& node)
 	, _read_data_count(0)
 	, _write_data_count(0)
 	, _writing (false)
+	, _length_beats(0.0)
 	, _last_read_end(0)
+	, _last_write_end(0)
 {
 	_read_data_count = 0;
 	_write_data_count = 0;
@@ -101,6 +105,19 @@ MidiSource::set_state (const XMLNode& node)
 	return 0;
 }
 
+sframes_t
+MidiSource::length (sframes_t pos) const
+{
+	BeatsFramesConverter converter(_session, pos);
+	return converter.to(_length_beats);
+}
+
+void
+MidiSource::update_length (sframes_t pos, sframes_t cnt)
+{
+	// You're not the boss of me!
+}
+
 void
 MidiSource::invalidate ()
 {
@@ -150,7 +167,9 @@ nframes_t
 MidiSource::midi_write (MidiRingBuffer<nframes_t>& dst, sframes_t position, nframes_t cnt)
 {
 	Glib::Mutex::Lock lm (_lock);
-	return write_unlocked (dst, position, cnt);
+	const nframes_t ret = write_unlocked (dst, position, cnt);
+	_last_write_end = position + cnt;
+	return ret;
 }
 
 bool
@@ -172,17 +191,21 @@ MidiSource::mark_streaming_midi_write_started (NoteMode mode, sframes_t start_fr
 		_model->set_note_mode(mode);
 		_model->start_write();
 	}
-	
+
+	_last_write_end = start_frame;
 	_writing = true;
 }
 
 void
 MidiSource::mark_streaming_write_started ()
 {
+	sframes_t start_frame = _session.transport_frame();
+
 	if (_model) {
 		_model->start_write();
 	}
 
+	_last_write_end = start_frame;
 	_writing = true;
 }
 
@@ -190,7 +213,7 @@ void
 MidiSource::mark_streaming_write_completed ()
 {
 	if (_model) {
-		_model->end_write(false); // FIXME: param?
+		_model->end_write(false);
 	}
 
 	_writing = false;
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index 70e9eba9ba..cae564832d 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -1534,6 +1534,12 @@ Region::source_equivalent (boost::shared_ptr<const Region> other) const
 	return true;
 }
 
+sframes_t
+Region::source_length(uint32_t n) const
+{
+	return _sources[n]->length(_position - _start);
+}
+
 bool
 Region::verify_length (nframes_t len)
 {
@@ -1544,7 +1550,7 @@ Region::verify_length (nframes_t len)
 	nframes_t maxlen = 0;
 
 	for (uint32_t n=0; n < _sources.size(); ++n) {
-		maxlen = max (maxlen, (nframes_t)_sources[n]->length() - _start);
+		maxlen = max (maxlen, (nframes_t)source_length(n) - _start);
 	}
 	
 	len = min (len, maxlen);
@@ -1562,7 +1568,7 @@ Region::verify_start_and_length (nframes_t new_start, nframes_t& new_length)
 	nframes_t maxlen = 0;
 
 	for (uint32_t n=0; n < _sources.size(); ++n) {
-		maxlen = max (maxlen, (nframes_t)_sources[n]->length() - new_start);
+		maxlen = max (maxlen, (nframes_t)source_length(n) - new_start);
 	}
 
 	new_length = min (new_length, maxlen);
@@ -1578,7 +1584,7 @@ Region::verify_start (nframes_t pos)
 	}
 
 	for (uint32_t n=0; n < _sources.size(); ++n) {
-		if (pos > _sources[n]->length() - _length) {
+		if (pos > source_length(n) - _length) {
 			return false;
 		}
 	}
@@ -1593,8 +1599,8 @@ Region::verify_start_mutable (nframes_t& new_start)
 	}
 
 	for (uint32_t n=0; n < _sources.size(); ++n) {
-		if (new_start > _sources[n]->length() - _length) {
-			new_start = _sources[n]->length() - _length;
+		if (new_start > source_length(n) - _length) {
+			new_start = source_length(n) - _length;
 		}
 	}
 	return true;
diff --git a/libs/ardour/region_factory.cc b/libs/ardour/region_factory.cc
index 742a65962e..0de20bfcac 100644
--- a/libs/ardour/region_factory.cc
+++ b/libs/ardour/region_factory.cc
@@ -109,7 +109,7 @@ RegionFactory::create (boost::shared_ptr<Region> region, const SourceList& srcs,
 	*/
 
 	if ((other = boost::dynamic_pointer_cast<AudioRegion>(region)) != 0) {
-		AudioRegion* ar = new AudioRegion (other, srcs, srcs.front()->length(), name, layer, flags);
+		AudioRegion* ar = new AudioRegion (other, srcs, srcs.front()->length(srcs.front()->timeline_position()), name, layer, flags);
 		boost::shared_ptr<AudioRegion> arp (ar);
 		boost::shared_ptr<Region> ret (boost::static_pointer_cast<Region> (arp));
 		if (announce) {
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index e55167ff08..b9144aa3b6 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -4087,8 +4087,9 @@ Session::write_one_track (AudioTrack& track, nframes_t start, nframes_t end,
 
 		/* construct a region to represent the bounced material */
 
-		result = RegionFactory::create (srcs, 0, srcs.front()->length(), 
-						region_name_from_path (srcs.front()->name(), true));
+		result = RegionFactory::create (srcs, 0,
+				srcs.front()->length(srcs.front()->timeline_position()), 
+				region_name_from_path (srcs.front()->name(), true));
 	}
 
   out:
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 3f9a481340..beacb192f1 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -995,7 +995,7 @@ Session::state(bool full_state)
 			boost::shared_ptr<AudioFileSource> fs;
 			if ((fs = boost::dynamic_pointer_cast<AudioFileSource> (siter->second)) != 0) {
 				if (!fs->destructive()) {
-					if (fs->length() == 0) {
+					if (fs->length(fs->timeline_position()) == 0) {
 						continue;
 					}
 				}
@@ -2560,7 +2560,7 @@ Session::cleanup_sources (Session::cleanup_report& rep)
 		   capture files.
 		*/
 
- 		if (!i->second->used() && i->second->length() > 0) {
+ 		if (!i->second->used() && i->second->length(i->second->timeline_position()) > 0) {
 			dead_sources.push_back (i->second);
 			i->second->GoingAway();
 		} 
diff --git a/libs/ardour/smf_source.cc b/libs/ardour/smf_source.cc
index 7e707b1821..74ee1fd680 100644
--- a/libs/ardour/smf_source.cc
+++ b/libs/ardour/smf_source.cc
@@ -182,16 +182,17 @@ SMFSource::write_unlocked (MidiRingBuffer<nframes_t>& src, sframes_t position, n
 		_model->start_write();
 	}
 
-	Evoral::MIDIEvent<nframes_t> ev(0, 0.0, 4, NULL, true);
+	Evoral::MIDIEvent<nframes_t> ev;
 
 	while (true) {
 		bool ret = src.peek_time(&time);
-		if (!ret || time - position > _length + dur) {
+		if (!ret || time > _last_write_end + dur) {
 			break;
 		}
 
 		ret = src.read_prefix(&time, &type, &size);
 		if (!ret) {
+			cerr << "ERROR: Unable to read event prefix, corrupt MIDI ring buffer" << endl;
 			break;
 		}
 
@@ -227,10 +228,7 @@ SMFSource::write_unlocked (MidiRingBuffer<nframes_t>& src, sframes_t position, n
 	Evoral::SMF::flush();
 	free(buf);
 
-	const sframes_t oldlen = _length;
-	update_length(oldlen, dur);
-
-	ViewDataRangeReady(position + oldlen, dur); /* EMIT SIGNAL */
+	ViewDataRangeReady(position + _last_write_end, dur); /* EMIT SIGNAL */
 
 	return dur;
 }
@@ -254,6 +252,8 @@ SMFSource::append_event_unlocked_beats (const Evoral::Event<double>& ev)
 		return;
 	}
 	
+	_length_beats = max(_length_beats, ev.time());
+	
 	const double delta_time_beats   = ev.time() - _last_ev_time_beats;
 	const uint32_t delta_time_ticks = (uint32_t)lrint(delta_time_beats * (double)ppqn());
 
@@ -287,6 +287,8 @@ SMFSource::append_event_unlocked_frames (const Evoral::Event<nframes_t>& ev, sfr
 	
 	BeatsFramesConverter converter(_session, position);
 	
+	_length_beats = max(_length_beats, converter.from(ev.time()));
+	
 	const sframes_t delta_time_frames = ev.time() - _last_ev_time_frames;
 	const double    delta_time_beats  = converter.from(delta_time_frames);
 	const uint32_t  delta_time_ticks  = (uint32_t)(lrint(delta_time_beats * (double)ppqn()));
@@ -405,6 +407,8 @@ SMFSource::load_model (bool lock, bool force_reload)
 			scratch_size = ev.size();
 		}
 		ev.size() = scratch_size; // ensure read_event only allocates if necessary
+		
+		_length_beats = max(_length_beats, ev.time());
 	}
 
 	set_default_controls_interpolation();
diff --git a/libs/ardour/source.cc b/libs/ardour/source.cc
index 5c2ac132e1..61ace5a72b 100644
--- a/libs/ardour/source.cc
+++ b/libs/ardour/source.cc
@@ -54,7 +54,6 @@ Source::Source (Session& s, DataType type, const string& name, Flag flags)
 {
 	_analysed = false;
 	_timestamp = 0;
-	_length = 0;
 	_in_use = 0;
 }
 
@@ -65,7 +64,6 @@ Source::Source (Session& s, const XMLNode& node)
 	, _timeline_position(0)
 {
 	_timestamp = 0;
-	_length = 0;
 	_analysed = false;
 	_in_use = 0;
 
@@ -140,14 +138,6 @@ Source::set_state (const XMLNode& node)
 }
 
 void
-Source::update_length (sframes_t pos, sframes_t cnt)
-{
-	if (pos + cnt > _length) {
-		_length = pos + cnt;
-	}
-}
-
-void
 Source::add_playlist (boost::shared_ptr<Playlist> pl)
 {
 	std::pair<PlaylistMap::iterator,bool> res;