fix conflicts after merge with master
[ardour.git] / libs / ardour / audio_diskstream.cc
index 059fed8752fdab0b9eb1332395c67fa0fd7422f7..77c14de10338f07396a5caf7de59b5c0f8742ea6 100644 (file)
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2000-2006 Paul Davis 
+    Copyright (C) 2000-2006 Paul Davis
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
 #include <sys/stat.h>
 #include <sys/mman.h>
 
-#include <pbd/error.h>
-#include <glibmm/thread.h>
-#include <pbd/xml++.h>
-#include <pbd/memento_command.h>
-#include <pbd/enumwriter.h>
-#include <pbd/stacktrace.h>
-
-#include <ardour/ardour.h>
-#include <ardour/audioengine.h>
-#include <ardour/analyser.h>
-#include <ardour/audio_diskstream.h>
-#include <ardour/utils.h>
-#include <ardour/configuration.h>
-#include <ardour/audiofilesource.h>
-#include <ardour/send.h>
-#include <ardour/region_factory.h>
-#include <ardour/audioplaylist.h>
-#include <ardour/playlist_factory.h>
-#include <ardour/cycle_timer.h>
-#include <ardour/audioregion.h>
-#include <ardour/audio_port.h>
-#include <ardour/source_factory.h>
+#include "pbd/error.h"
+#include "pbd/xml++.h"
+#include "pbd/memento_command.h"
+#include "pbd/enumwriter.h"
+#include "pbd/stateful_diff_command.h"
+
+#include "ardour/analyser.h"
+#include "ardour/audio_buffer.h"
+#include "ardour/audio_diskstream.h"
+#include "ardour/audio_port.h"
+#include "ardour/audioengine.h"
+#include "ardour/audiofilesource.h"
+#include "ardour/audioplaylist.h"
+#include "ardour/audioregion.h"
+#include "ardour/butler.h"
+#include "ardour/debug.h"
+#include "ardour/io.h"
+#include "ardour/playlist_factory.h"
+#include "ardour/region_factory.h"
+#include "ardour/session.h"
+#include "ardour/session_playlists.h"
+#include "ardour/source_factory.h"
+#include "ardour/track.h"
+#include "ardour/types.h"
+#include "ardour/utils.h"
 
 #include "i18n.h"
 #include <locale.h>
@@ -66,28 +69,23 @@ gain_t* AudioDiskstream::_gain_buffer          = 0;
 
 AudioDiskstream::AudioDiskstream (Session &sess, const string &name, Diskstream::Flag flag)
        : Diskstream(sess, name, flag)
-       , deprecated_io_node(NULL)
        , channels (new ChannelList)
 {
        /* prevent any write sources from being created */
 
        in_set_state = true;
-
-       init(flag);
        use_new_playlist ();
-
        in_set_state = false;
 }
-       
+
 AudioDiskstream::AudioDiskstream (Session& sess, const XMLNode& node)
        : Diskstream(sess, node)
-       , deprecated_io_node(NULL)
        , channels (new ChannelList)
 {
        in_set_state = true;
-       init (Recordable);
+       init ();
 
-       if (set_state (node)) {
+       if (set_state (node, Stateful::loading_state_version)) {
                in_set_state = false;
                throw failed_constructor();
        }
@@ -100,10 +98,8 @@ AudioDiskstream::AudioDiskstream (Session& sess, const XMLNode& node)
 }
 
 void
-AudioDiskstream::init (Diskstream::Flag f)
+AudioDiskstream::init ()
 {
-       Diskstream::init(f);
-
        /* there are no channels at this point, so these
           two calls just get speed_buffer_size and wrap_buffer
           size setup without duplicating their code.
@@ -111,19 +107,16 @@ AudioDiskstream::init (Diskstream::Flag f)
 
        set_block_size (_session.get_block_size());
        allocate_temporary_buffers ();
-
-       add_channel (1);
-       assert(_n_channels == ChanCount(DataType::AUDIO, 1));
 }
 
 AudioDiskstream::~AudioDiskstream ()
 {
-       notify_callbacks ();
+       DEBUG_TRACE (DEBUG::Destruction, string_compose ("Audio Diskstream %1 destructor\n", _name));
 
        {
                RCUWriter<ChannelList> writer (channels);
                boost::shared_ptr<ChannelList> c = writer.get_copy();
-               
+
                for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
                        delete *chan;
                }
@@ -158,40 +151,36 @@ void
 AudioDiskstream::non_realtime_input_change ()
 {
        {
-               Glib::Mutex::Lock lm (state_lock);
+               Glib::Threads::Mutex::Lock lm (state_lock);
 
-               if (input_change_pending == NoChange) {
+               if (input_change_pending.type == IOChange::NoChange) {
                        return;
                }
 
-               {
+               if (input_change_pending.type == IOChange::ConfigurationChanged) {
                        RCUWriter<ChannelList> writer (channels);
                        boost::shared_ptr<ChannelList> c = writer.get_copy();
-                       
+
                        _n_channels.set(DataType::AUDIO, c->size());
-                       
-                       if (_io->n_inputs().n_audio() > _n_channels.n_audio()) {
-                               add_channel_to (c, _io->n_inputs().n_audio() - _n_channels.n_audio());
-                       } else if (_io->n_inputs().n_audio() < _n_channels.n_audio()) {
-                               remove_channel_from (c, _n_channels.n_audio() - _io->n_inputs().n_audio());
+
+                       if (_io->n_ports().n_audio() > _n_channels.n_audio()) {
+                               add_channel_to (c, _io->n_ports().n_audio() - _n_channels.n_audio());
+                       } else if (_io->n_ports().n_audio() < _n_channels.n_audio()) {
+                               remove_channel_from (c, _n_channels.n_audio() - _io->n_ports().n_audio());
                        }
                }
-               
-               get_input_sources ();
-               set_capture_offset ();
-               
-               if (first_input_change) {
-                       set_align_style (_persistent_alignment_style);
-                       first_input_change = false;
-               } else {
+
+               if (input_change_pending.type & IOChange::ConnectionsChanged) {
+                       get_input_sources ();
+                       set_capture_offset ();
                        set_align_style_from_io ();
                }
-               
-               input_change_pending = NoChange;
+
+               input_change_pending = IOChange::NoChange;
 
                /* implicit unlock */
        }
-       
+
        /* reset capture files */
 
        reset_write_sources (false);
@@ -199,12 +188,24 @@ AudioDiskstream::non_realtime_input_change ()
        /* now refill channel buffers */
 
        if (speed() != 1.0f || speed() != -1.0f) {
-               seek ((nframes_t) (_session.transport_frame() * (double) speed()));
+               seek ((framepos_t) (_session.transport_frame() * (double) speed()));
        } else {
                seek (_session.transport_frame());
        }
 }
 
+void
+AudioDiskstream::non_realtime_locate (framepos_t location)
+{
+       /* now refill channel buffers */
+
+       if (speed() != 1.0f || speed() != -1.0f) {
+               seek ((framepos_t) (location * (double) speed()));
+       } else {
+               seek (location);
+       }
+}
+
 void
 AudioDiskstream::get_input_sources ()
 {
@@ -212,33 +213,30 @@ AudioDiskstream::get_input_sources ()
 
        uint32_t n;
        ChannelList::iterator chan;
-       uint32_t ni = _io->n_inputs().n_audio();
+       uint32_t ni = _io->n_ports().n_audio();
        vector<string> connections;
 
        for (n = 0, chan = c->begin(); chan != c->end() && n < ni; ++chan, ++n) {
-               
+
                connections.clear ();
 
-               if (_io->input(n)->get_connections (connections) == 0) {
-               
-                       if ((*chan)->source) {
+               if (_io->nth (n)->get_connections (connections) == 0) {
+                       if (!(*chan)->source.name.empty()) {
                                // _source->disable_metering ();
                        }
-                       
-                       (*chan)->source = 0;
-                       
+                       (*chan)->source.name = string();
                } else {
-                       (*chan)->source = dynamic_cast<AudioPort*>(_session.engine().get_port_by_name (connections[0]) );
+                       (*chan)->source.name = connections[0];
                }
        }
-}              
+}
 
 int
 AudioDiskstream::find_and_use_playlist (const string& name)
 {
        boost::shared_ptr<AudioPlaylist> playlist;
-               
-       if ((playlist = boost::dynamic_pointer_cast<AudioPlaylist> (_session.playlist_by_name (name))) == 0) {
+
+       if ((playlist = boost::dynamic_pointer_cast<AudioPlaylist> (_session.playlists->by_name (name))) == 0) {
                playlist = boost::dynamic_pointer_cast<AudioPlaylist> (PlaylistFactory::create (DataType::AUDIO, _session, name));
        }
 
@@ -265,7 +263,7 @@ AudioDiskstream::use_new_playlist ()
 {
        string newname;
        boost::shared_ptr<AudioPlaylist> playlist;
-       
+
        if (!in_set_state && destructive()) {
                return 0;
        }
@@ -277,11 +275,10 @@ AudioDiskstream::use_new_playlist ()
        }
 
        if ((playlist = boost::dynamic_pointer_cast<AudioPlaylist> (PlaylistFactory::create (DataType::AUDIO, _session, newname, hidden()))) != 0) {
-               
-               playlist->set_orig_diskstream_id (id());
+
                return use_playlist (playlist);
 
-       } else { 
+       } else {
                return -1;
        }
 }
@@ -304,11 +301,10 @@ AudioDiskstream::use_copy_playlist ()
        boost::shared_ptr<AudioPlaylist> playlist;
 
        newname = Playlist::bump_name (_playlist->name(), _session);
-       
-       if ((playlist  = boost::dynamic_pointer_cast<AudioPlaylist>(PlaylistFactory::create (audio_playlist(), newname))) != 0) {
-               playlist->set_orig_diskstream_id (id());
+
+       if ((playlist = boost::dynamic_pointer_cast<AudioPlaylist>(PlaylistFactory::create (audio_playlist(), newname))) != 0) {
                return use_playlist (playlist);
-       } else { 
+       } else {
                return -1;
        }
 }
@@ -318,15 +314,22 @@ AudioDiskstream::setup_destructive_playlist ()
 {
        SourceList srcs;
        boost::shared_ptr<ChannelList> c = channels.reader();
-       
+
        for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
                srcs.push_back ((*chan)->write_source);
        }
 
        /* a single full-sized region */
 
-       boost::shared_ptr<Region> region (RegionFactory::create (srcs, 0, max_frames - srcs.front()->natural_position(), _name));
-       _playlist->add_region (region, srcs.front()->natural_position());               
+       assert (!srcs.empty ());
+
+       PropertyList plist;
+       plist.add (Properties::name, _name.val());
+       plist.add (Properties::start, 0);
+       plist.add (Properties::length, max_framepos - (max_framepos - srcs.front()->natural_position()));
+
+       boost::shared_ptr<Region> region (RegionFactory::create (srcs, plist));
+       _playlist->add_region (region, srcs.front()->natural_position());
 }
 
 void
@@ -334,7 +337,7 @@ AudioDiskstream::use_destructive_playlist ()
 {
        /* this is called from the XML-based constructor or ::set_destructive. when called,
           we already have a playlist and a region, but we need to
-          set up our sources for write. we use the sources associated 
+          set up our sources for write. we use the sources associated
           with the (presumed single, full-extent) region.
        */
 
@@ -353,7 +356,7 @@ AudioDiskstream::use_destructive_playlist ()
 
        /* be sure to stretch the region out to the maximum length */
 
-       region->set_length (max_frames - region->position(), this);
+       region->set_length (max_framepos - region->position());
 
        uint32_t n;
        ChannelList::iterator chan;
@@ -373,181 +376,66 @@ AudioDiskstream::use_destructive_playlist ()
 }
 
 void
-AudioDiskstream::check_record_status (nframes_t transport_frame, nframes_t nframes, bool can_record)
+AudioDiskstream::prepare_record_status(framepos_t capture_start_frame)
 {
-       int possibly_recording;
-       int rolling;
-       int change;
-       const int transport_rolling = 0x4;
-       const int track_rec_enabled = 0x2;
-       const int global_rec_enabled = 0x1;
-
-       /* merge together the 3 factors that affect record status, and compute
-          what has changed.
-       */
-
-       rolling = _session.transport_speed() != 0.0f;
-       possibly_recording = (rolling << 2) | (record_enabled() << 1) | can_record;
-       change = possibly_recording ^ last_possibly_recording;
-
-       if (possibly_recording == last_possibly_recording) {
-               return;
-       }
-
-       /* change state */
-
-       /* if per-track or global rec-enable turned on while the other was already on, we've started recording */
-
-       if ((change & track_rec_enabled) && record_enabled() && (!(change & global_rec_enabled) && can_record) || 
-           ((change & global_rec_enabled) && can_record && (!(change & track_rec_enabled) && record_enabled()))) {
-               
-               /* starting to record: compute first+last frames */
-
-               first_recordable_frame = transport_frame + _capture_offset;
-               last_recordable_frame = max_frames;
-               capture_start_frame = transport_frame;
-
-               if (!(last_possibly_recording & transport_rolling) && (possibly_recording & transport_rolling)) {
-
-                       /* was stopped, now rolling (and recording) */
-
-                       if (_alignment_style == ExistingMaterial) {
-                               first_recordable_frame += _session.worst_output_latency();
-                       } else {
-                               first_recordable_frame += _roll_delay;
-                       }
-
-               } else {
-
-                       /* was rolling, but record state changed */
-
-                       if (_alignment_style == ExistingMaterial) {
-
-                               if (!Config->get_punch_in()) {
-
-                                       /* manual punch in happens at the correct transport frame
-                                          because the user hit a button. but to get alignment correct 
-                                          we have to back up the position of the new region to the 
-                                          appropriate spot given the roll delay.
-                                       */
-
-                                       capture_start_frame -= _roll_delay;
-
-                                       /* XXX paul notes (august 2005): i don't know why
-                                          this is needed.
-                                       */
-
-                                       first_recordable_frame += _capture_offset;
-
-                               } else {
-
-                                       /* autopunch toggles recording at the precise
-                                          transport frame, and then the DS waits
-                                          to start recording for a time that depends
-                                          on the output latency.
-                                       */
+       if (recordable() && destructive()) {
+               boost::shared_ptr<ChannelList> c = channels.reader();
+               for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
 
-                                       first_recordable_frame += _session.worst_output_latency();
-                               }
+                       RingBufferNPT<CaptureTransition>::rw_vector transitions;
+                       (*chan)->capture_transition_buf->get_write_vector (&transitions);
 
+                       if (transitions.len[0] > 0) {
+                               transitions.buf[0]->type = CaptureStart;
+                               transitions.buf[0]->capture_val = capture_start_frame;
+                               (*chan)->capture_transition_buf->increment_write_ptr(1);
                        } else {
-
-                               if (Config->get_punch_in()) {
-                                       first_recordable_frame += _roll_delay;
-                               } else {
-                                       capture_start_frame -= _roll_delay;
-                               }
+                               // bad!
+                               fatal << X_("programming error: capture_transition_buf is full on rec start!  inconceivable!")
+                                       << endmsg;
                        }
-                       
-               }
-
-               if (recordable() && destructive()) {
-                       boost::shared_ptr<ChannelList> c = channels.reader();
-                       for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-                               
-                               RingBufferNPT<CaptureTransition>::rw_vector transvec;
-                               (*chan)->capture_transition_buf->get_write_vector(&transvec);
-                               
-                               if (transvec.len[0] > 0) {
-                                       transvec.buf[0]->type = CaptureStart;
-                                       transvec.buf[0]->capture_val = capture_start_frame;
-                                       (*chan)->capture_transition_buf->increment_write_ptr(1);
-                               }
-                               else {
-                                       // bad!
-                                       fatal << X_("programming error: capture_transition_buf is full on rec start!  inconceivable!") 
-                                             << endmsg;
-                               }
-                       }
-               }
-
-       } else if (!record_enabled() || !can_record) {
-               
-               /* stop recording */
-
-               last_recordable_frame = transport_frame + _capture_offset;
-               
-               if (_alignment_style == ExistingMaterial) {
-                       last_recordable_frame += _session.worst_output_latency();
-               } else {
-                       last_recordable_frame += _roll_delay;
                }
        }
-
-       last_possibly_recording = possibly_recording;
 }
 
+
+/** Do some record stuff [not described in this comment!]
+ *
+ *  Also:
+ *    - Setup playback_distance with the nframes, or nframes adjusted
+ *      for current varispeed, if appropriate.
+ *    - Setup current_playback_buffer in each ChannelInfo to point to data
+ *      that someone can read playback_distance worth of data from.
+ */
 int
-AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_t offset, bool can_record, bool rec_monitors_input)
+AudioDiskstream::process (BufferSet& bufs, framepos_t transport_frame, pframes_t nframes, framecnt_t& playback_distance, bool need_disk_signal)
 {
        uint32_t n;
        boost::shared_ptr<ChannelList> c = channels.reader();
        ChannelList::iterator chan;
-       int ret = -1;
-       nframes_t rec_offset = 0;
-       nframes_t rec_nframes = 0;
-       bool nominally_recording;
-       bool re = record_enabled ();
+       framecnt_t rec_offset = 0;
+       framecnt_t rec_nframes = 0;
        bool collect_playback = false;
+       bool can_record = _session.actively_recording ();
 
-       /* if we've already processed the frames corresponding to this call,
-          just return. this allows multiple routes that are taking input
-          from this diskstream to call our ::process() method, but have
-          this stuff only happen once. more commonly, it allows both
-          the AudioTrack that is using this AudioDiskstream *and* the Session
-          to call process() without problems.
-       */
+       playback_distance = 0;
 
-       if (_processed) {
+       if (!_io || !_io->active()) {
                return 0;
        }
 
-       commit_should_unlock = false;
-
-       if (!_io->active()) {
-               _processed = true;
-               return 0;
-       }
-
-       check_record_status (transport_frame, nframes, can_record);
-
-       nominally_recording = (can_record && re);
+       check_record_status (transport_frame, can_record);
 
        if (nframes == 0) {
-               _processed = true;
                return 0;
        }
 
-       /* This lock is held until the end of AudioDiskstream::commit, so these two functions
-          must always be called as a pair. The only exception is if this function
-          returns a non-zero value, in which case, ::commit should not be called.
-       */
+       Glib::Threads::Mutex::Lock sm (state_lock, Glib::Threads::TRY_LOCK);
 
-       // If we can't take the state lock return.
-       if (!state_lock.trylock()) {
+       if (!sm.locked()) {
                return 1;
-       } 
-       commit_should_unlock = true;
+       }
+
        adjust_capture_position = 0;
 
        for (chan = c->begin(); chan != c->end(); ++chan) {
@@ -555,55 +443,17 @@ AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_
                (*chan)->current_playback_buffer = 0;
        }
 
-       if (nominally_recording || (_session.get_record_enabled() && Config->get_punch_in())) {
-               OverlapType ot;
-               
-               // Safeguard against situations where process() goes haywire when autopunching and last_recordable_frame < first_recordable_frame
-               if (last_recordable_frame < first_recordable_frame) {
-                       last_recordable_frame = max_frames; 
-               }
+       // Safeguard against situations where process() goes haywire when autopunching
+       // and last_recordable_frame < first_recordable_frame
 
-               ot = coverage (first_recordable_frame, last_recordable_frame, transport_frame, transport_frame + nframes);
+       if (last_recordable_frame < first_recordable_frame) {
+               last_recordable_frame = max_framepos;
+       }
 
-               switch (ot) {
-               case OverlapNone:
-                       rec_nframes = 0;
-                       break;
-                       
-               case OverlapInternal:
-               /*     ----------    recrange
-                         |---|       transrange
-               */
-                       rec_nframes = nframes;
-                       rec_offset = 0;
-                       break;
-                       
-               case OverlapStart:
-                       /*    |--------|    recrange
-                            -----|          transrange
-                       */
-                       rec_nframes = transport_frame + nframes - first_recordable_frame;
-                       if (rec_nframes) {
-                               rec_offset = first_recordable_frame - transport_frame;
-                       }
-                       break;
-                       
-               case OverlapEnd:
-                       /*    |--------|    recrange
-                                 |--------  transrange
-                       */
-                       rec_nframes = last_recordable_frame - transport_frame;
-                       rec_offset = 0;
-                       break;
-                       
-               case OverlapExternal:
-                       /*    |--------|    recrange
-                            --------------  transrange
-                       */
-                       rec_nframes = last_recordable_frame - first_recordable_frame;
-                       rec_offset = first_recordable_frame - transport_frame;
-                       break;
-               }
+       if (record_enabled()) {
+
+               Evoral::OverlapType ot = Evoral::coverage (first_recordable_frame, last_recordable_frame, transport_frame, transport_frame + nframes);
+               calculate_record_range (ot, transport_frame, nframes, rec_nframes, rec_offset);
 
                if (rec_nframes && !was_recording) {
                        capture_captured = 0;
@@ -611,14 +461,13 @@ AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_
                }
        }
 
-
-       if (can_record && !_last_capture_regions.empty()) {
-               _last_capture_regions.clear ();
+       if (can_record && !_last_capture_sources.empty()) {
+               _last_capture_sources.clear ();
        }
 
-       if (nominally_recording || rec_nframes) {
+       if (rec_nframes) {
 
-               uint32_t limit = _io->n_inputs ().n_audio();
+               uint32_t limit = _io->n_ports ().n_audio();
 
                /* one or more ports could already have been removed from _io, but our
                   channel setup hasn't yet been updated. prevent us from trying to
@@ -628,44 +477,46 @@ AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_
                */
 
                for (n = 0, chan = c->begin(); chan != c->end() && n < limit; ++chan, ++n) {
-                       
+
                        ChannelInfo* chaninfo (*chan);
 
                        chaninfo->capture_buf->get_write_vector (&chaninfo->capture_vector);
 
-                       if (rec_nframes <= chaninfo->capture_vector.len[0]) {
-                               
+                       if (rec_nframes <= (framecnt_t) chaninfo->capture_vector.len[0]) {
+
                                chaninfo->current_capture_buffer = chaninfo->capture_vector.buf[0];
 
-                               /* note: grab the entire port buffer, but only copy what we were supposed to for recording, and use
-                                  rec_offset
+                               /* note: grab the entire port buffer, but only copy what we were supposed to
+                                  for recording, and use rec_offset
                                */
 
-                               AudioPort* const ap = _io->audio_input(n);
+                               boost::shared_ptr<AudioPort> const ap = _io->audio (n);
                                assert(ap);
-                               assert(rec_nframes <= ap->get_audio_buffer().capacity());
-                               memcpy (chaninfo->current_capture_buffer, ap->get_audio_buffer().data(rec_nframes, offset + rec_offset), sizeof (Sample) * rec_nframes);
+                               assert(rec_nframes <= (framecnt_t) ap->get_audio_buffer(nframes).capacity());
 
+                               Sample *buf = bufs.get_audio (n).data(rec_offset);
+                               memcpy (chaninfo->current_capture_buffer, buf, sizeof (Sample) * rec_nframes);
+                               
                        } else {
 
-                               nframes_t total = chaninfo->capture_vector.len[0] + chaninfo->capture_vector.len[1];
+                               framecnt_t total = chaninfo->capture_vector.len[0] + chaninfo->capture_vector.len[1];
 
                                if (rec_nframes > total) {
                                        DiskOverrun ();
-                                       goto out;
+                                       return -1;
                                }
 
-                               AudioPort* const ap = _io->audio_input(n);
+                               boost::shared_ptr<AudioPort> const ap = _io->audio (n);
                                assert(ap);
 
-                               Sample* buf = ap->get_audio_buffer().data(nframes, offset);
-                               nframes_t first = chaninfo->capture_vector.len[0];
+                               Sample *buf = bufs.get_audio (n).data(rec_offset);
+                               framecnt_t first = chaninfo->capture_vector.len[0];
 
                                memcpy (chaninfo->capture_wrap_buffer, buf, sizeof (Sample) * first);
                                memcpy (chaninfo->capture_vector.buf[0], buf, sizeof (Sample) * first);
                                memcpy (chaninfo->capture_wrap_buffer+first, buf + first, sizeof (Sample) * (rec_nframes - first));
                                memcpy (chaninfo->capture_vector.buf[1], buf + first, sizeof (Sample) * (rec_nframes - first));
-                               
+
                                chaninfo->current_capture_buffer = chaninfo->capture_wrap_buffer;
                        }
                }
@@ -673,13 +524,13 @@ AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_
        } else {
 
                if (was_recording) {
-                       finish_capture (rec_monitors_input, c);
+                       finish_capture (c);
                }
 
        }
-       
+
        if (rec_nframes) {
-               
+
                /* data will be written to disk */
 
                if (rec_nframes == nframes && rec_offset == 0) {
@@ -703,7 +554,7 @@ AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_
 
                adjust_capture_position = rec_nframes;
 
-       } else if (nominally_recording) {
+       } else if (can_record && record_enabled()) {
 
                /* can't do actual capture yet - waiting for latency effects to finish before we start*/
 
@@ -718,124 +569,172 @@ AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_
                collect_playback = true;
        }
 
-       if (collect_playback) {
-
+       if ((_track->monitoring_state () & MonitoringDisk) || collect_playback) {
+               
                /* we're doing playback */
 
-               nframes_t necessary_samples;
+               framecnt_t necessary_samples;
 
                /* no varispeed playback if we're recording, because the output .... TBD */
 
                if (rec_nframes == 0 && _actual_speed != 1.0f) {
-                       necessary_samples = (nframes_t) floor ((nframes * fabs (_actual_speed))) + 1;
+                       necessary_samples = (framecnt_t) ceil ((nframes * fabs (_actual_speed))) + 2;
                } else {
                        necessary_samples = nframes;
                }
-               
+
                for (chan = c->begin(); chan != c->end(); ++chan) {
                        (*chan)->playback_buf->get_read_vector (&(*chan)->playback_vector);
                }
 
-               n = 0;                  
+               n = 0;
+
+               /* Setup current_playback_buffer in each ChannelInfo to point to data that someone
+                  can read necessary_samples (== nframes at a transport speed of 1) worth of data
+                  from right now.
+               */
 
                for (chan = c->begin(); chan != c->end(); ++chan, ++n) {
-                       
-                       ChannelInfo* chaninfo (*chan);
 
-                       if (necessary_samples <= chaninfo->playback_vector.len[0]) {
+                       ChannelInfo* chaninfo (*chan);
 
+                       if (necessary_samples <= (framecnt_t) chaninfo->playback_vector.len[0]) {
+                               /* There are enough samples in the first part of the ringbuffer */
                                chaninfo->current_playback_buffer = chaninfo->playback_vector.buf[0];
 
                        } else {
-                               nframes_t total = chaninfo->playback_vector.len[0] + chaninfo->playback_vector.len[1];
-                               
+                               framecnt_t total = chaninfo->playback_vector.len[0] + chaninfo->playback_vector.len[1];
+
                                if (necessary_samples > total) {
+                                       cerr << _name << " Need " << necessary_samples << " total = " << total << endl;
                                        cerr << "underrun for " << _name << endl;
                                        DiskUnderrun ();
-                                       goto out;
-                                       
+                                       return -1;
+
                                } else {
+
+                                       /* We have enough samples, but not in one lump.  Coalesce the two parts
+                                          into one in playback_wrap_buffer in our ChannelInfo, and specify that
+                                          as our current_playback_buffer.
+                                       */
+
+                                       assert(wrap_buffer_size >= necessary_samples);
+
+                                       /* Copy buf[0] from playback_buf */
+                                       memcpy ((char *) chaninfo->playback_wrap_buffer,
+                                                       chaninfo->playback_vector.buf[0],
+                                                       chaninfo->playback_vector.len[0] * sizeof (Sample));
                                        
-                                       memcpy ((char *) chaninfo->playback_wrap_buffer, chaninfo->playback_vector.buf[0],
-                                               chaninfo->playback_vector.len[0] * sizeof (Sample));
-                                       memcpy (chaninfo->playback_wrap_buffer + chaninfo->playback_vector.len[0], chaninfo->playback_vector.buf[1], 
-                                               (necessary_samples - chaninfo->playback_vector.len[0]) * sizeof (Sample));
-                                       
+                                       /* Copy buf[1] from playback_buf */
+                                       memcpy (chaninfo->playback_wrap_buffer + chaninfo->playback_vector.len[0],
+                                                       chaninfo->playback_vector.buf[1],
+                                                       (necessary_samples - chaninfo->playback_vector.len[0])
+                                                                       * sizeof (Sample));
+
                                        chaninfo->current_playback_buffer = chaninfo->playback_wrap_buffer;
                                }
                        }
-               } 
+               }
 
                if (rec_nframes == 0 && _actual_speed != 1.0f && _actual_speed != -1.0f) {
-                       
-                       uint64_t phase = last_phase;
-                       int64_t phi_delta;
-                       nframes_t i = 0;
-
-                       // Linearly interpolate into the alt buffer
-                       // using 40.24 fixp maths (swh)
 
-                       if (phi != target_phi) {
-                               phi_delta = ((int64_t)(target_phi - phi)) / nframes;
-                       } else {
-                               phi_delta = 0;
-                       }
+                       interpolation.set_speed (_target_speed);
 
-                       for (chan = c->begin(); chan != c->end(); ++chan) {
-
-                               float fr;
+                       int channel = 0;
+                       for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan, ++channel) {
                                ChannelInfo* chaninfo (*chan);
-
-                               i = 0;
-                               phase = last_phase;
-
-                               for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
-                                       i = phase >> 24;
-                                       fr = (phase & 0xFFFFFF) / 16777216.0f;
-                                       chaninfo->speed_buffer[outsample] = 
-                                               chaninfo->current_playback_buffer[i] * (1.0f - fr) +
-                                               chaninfo->current_playback_buffer[i+1] * fr;
-                                       phase += phi + phi_delta;
-                               }
+                               
+                               playback_distance = interpolation.interpolate (
+                                       channel, nframes, chaninfo->current_playback_buffer, chaninfo->speed_buffer);
                                
                                chaninfo->current_playback_buffer = chaninfo->speed_buffer;
                        }
-
-                       playback_distance = i; // + 1;
-                       last_phase = (phase & 0xFFFFFF);
-
+                       
                } else {
                        playback_distance = nframes;
                }
 
-               phi = target_phi;
-
+               _speed = _target_speed;
        }
 
-       ret = 0;
+       if (need_disk_signal) {
 
-  out:
-       _processed = true;
+               /* copy data over to buffer set */
+               
+               size_t n_buffers = bufs.count().n_audio();
+               size_t n_chans = c->size();
+               gain_t scaling = 1.0f;
+               
+               if (n_chans > n_buffers) {
+                       scaling = ((float) n_buffers)/n_chans;
+               }
 
-       if (ret) {
+               for (n = 0, chan = c->begin(); chan != c->end(); ++chan, ++n) {
+                       
+                       AudioBuffer& buf (bufs.get_audio (n%n_buffers));
+                       ChannelInfo* chaninfo (*chan);
+                       
+                       if (n < n_chans) {
+                               if (scaling != 1.0f) {
+                                       buf.read_from_with_gain (chaninfo->current_playback_buffer, nframes, scaling);
+                               } else {
+                                       buf.read_from (chaninfo->current_playback_buffer, nframes);
+                               }
+                       } else {
+                               if (scaling != 1.0f) {
+                                       buf.accumulate_with_gain_from (chaninfo->current_playback_buffer, nframes, scaling);
+                               } else {
+                                       buf.accumulate_from (chaninfo->current_playback_buffer, nframes);
+                               }
+                       }
+               }
 
-               /* we're exiting with failure, so ::commit will not
-                  be called. unlock the state lock.
-               */
-               
-               commit_should_unlock = false;
-               state_lock.unlock();
-       } 
+               /* leave the MIDI count alone */
+               ChanCount cnt (DataType::AUDIO, n_chans);
+               cnt.set (DataType::MIDI, bufs.count().n_midi());
+               bufs.set_count (cnt);
+       
+               /* extra buffers will already be silent, so leave them alone */
+       }
 
-       return ret;
+       return 0;
+}
+
+frameoffset_t
+AudioDiskstream::calculate_playback_distance (pframes_t nframes)
+{
+       frameoffset_t playback_distance = nframes;
+
+       if (record_enabled()) {
+               playback_distance = nframes;
+       } else if (_actual_speed != 1.0f && _actual_speed != -1.0f) {
+               interpolation.set_speed (_target_speed);
+               boost::shared_ptr<ChannelList> c = channels.reader();
+               int channel = 0;
+               for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan, ++channel) {
+                       playback_distance = interpolation.interpolate (channel, nframes, NULL, NULL);
+               }
+       } else {
+               playback_distance = nframes;
+       }
+
+       if (_actual_speed < 0.0) {
+               return -playback_distance;
+       } else {
+               return playback_distance;
+       }
 }
 
+/** Update various things including playback_sample, read pointer on each channel's playback_buf
+ *  and write pointer on each channel's capture_buf.  Also wout whether the butler is needed.
+ *  @return true if the butler is required.
+ */
 bool
-AudioDiskstream::commit (nframes_t nframes)
+AudioDiskstream::commit (framecnt_t playback_distance)
 {
        bool need_butler = false;
 
-       if (!_io->active()) {
+       if (!_io || !_io->active()) {
                return false;
        }
 
@@ -849,38 +748,36 @@ AudioDiskstream::commit (nframes_t nframes)
        for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
 
                (*chan)->playback_buf->increment_read_ptr (playback_distance);
-               
+
                if (adjust_capture_position) {
                        (*chan)->capture_buf->increment_write_ptr (adjust_capture_position);
                }
        }
-       
+
        if (adjust_capture_position != 0) {
                capture_captured += adjust_capture_position;
                adjust_capture_position = 0;
        }
-       
+
+       if (c->empty()) {
+               return false;
+       }
+
        if (_slaved) {
-               /*if (_io && _io->active()) {*/
+               if (_io && _io->active()) {
                        need_butler = c->front()->playback_buf->write_space() >= c->front()->playback_buf->bufsize() / 2;
-               /*} else {
+               } else {
                        need_butler = false;
-               }*/
+               }
        } else {
-               /*if (_io && _io->active()) {*/
-                       need_butler = c->front()->playback_buf->write_space() >= disk_io_chunk_frames
-                               || c->front()->capture_buf->read_space() >= disk_io_chunk_frames;
-               /*} else {
-                       need_butler = c->front()->capture_buf->read_space() >= disk_io_chunk_frames;
-               }*/
-       }
-
-       if (commit_should_unlock) {
-               state_lock.unlock();
+               if (_io && _io->active()) {
+                       need_butler = ((framecnt_t) c->front()->playback_buf->write_space() >= disk_io_chunk_frames)
+                               || ((framecnt_t) c->front()->capture_buf->read_space() >= disk_io_chunk_frames);
+               } else {
+                       need_butler = ((framecnt_t) c->front()->capture_buf->read_space() >= disk_io_chunk_frames);
+               }
        }
 
-       _processed = false;
-
        return need_butler;
 }
 
@@ -888,41 +785,52 @@ void
 AudioDiskstream::set_pending_overwrite (bool yn)
 {
        /* called from audio thread, so we can use the read ptr and playback sample as we wish */
-       
-       pending_overwrite = yn;
+
+       _pending_overwrite = yn;
 
        overwrite_frame = playback_sample;
-       overwrite_offset = channels.reader()->front()->playback_buf->get_read_ptr();
+
+       boost::shared_ptr<ChannelList> c = channels.reader ();
+       if (!c->empty ()) {
+               overwrite_offset = c->front()->playback_buf->get_read_ptr();
+       }
 }
 
 int
 AudioDiskstream::overwrite_existing_buffers ()
 {
        boost::shared_ptr<ChannelList> c = channels.reader();
-       Sample* mixdown_buffer;
-       float* gain_buffer;
-       int ret = -1;
+       if (c->empty ()) {
+               _pending_overwrite = false;
+               return 0;
+       }
+
+       Sample* mixdown_buffer;
+       float* gain_buffer;
+       int ret = -1;
        bool reversed = (_visible_speed * _session.transport_speed()) < 0.0f;
 
        overwrite_queued = false;
 
        /* assume all are the same size */
-       nframes_t size = c->front()->playback_buf->bufsize();
-       
-       mixdown_buffer = new Sample[size];
-       gain_buffer = new float[size];
-       
-       /* reduce size so that we can fill the buffer correctly. */
+       framecnt_t size = c->front()->playback_buf->bufsize();
+
+       mixdown_buffer = new Sample[size];
+       gain_buffer = new float[size];
+
+       /* reduce size so that we can fill the buffer correctly (ringbuffers
+          can only handle size-1, otherwise they appear to be empty)
+       */
        size--;
-       
+
        uint32_t n=0;
-       nframes_t start;
+       framepos_t start;
 
        for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan, ++n) {
 
                start = overwrite_frame;
-               nframes_t cnt = size;
-               
+               framecnt_t cnt = size;
+
                /* to fill the buffer without resetting the playback sample, we need to
                   do it one or two chunks (normally two).
 
@@ -931,63 +839,62 @@ AudioDiskstream::overwrite_existing_buffers ()
                                       ^
                                       overwrite_offset
                    |<- second chunk->||<----------------- first chunk ------------------>|
-                  
+
                */
-               
-               nframes_t to_read = size - overwrite_offset;
 
-               if (read ((*chan)->playback_buf->buffer() + overwrite_offset, mixdown_buffer, gain_buffer, start, to_read, *chan, n, reversed)) {
+               framecnt_t to_read = size - overwrite_offset;
+
+               if (read ((*chan)->playback_buf->buffer() + overwrite_offset, mixdown_buffer, gain_buffer, start, to_read, n, reversed)) {
                        error << string_compose(_("AudioDiskstream %1: when refilling, cannot read %2 from playlist at frame %3"),
-                                        _id, size, playback_sample) << endmsg;
+                                               id(), size, playback_sample) << endmsg;
                        goto out;
                }
-                       
+
                if (cnt > to_read) {
 
                        cnt -= to_read;
-               
-                       if (read ((*chan)->playback_buf->buffer(), mixdown_buffer, gain_buffer,
-                                 start, cnt, *chan, n, reversed)) {
+
+                       if (read ((*chan)->playback_buf->buffer(), mixdown_buffer, gain_buffer, start, cnt, n, reversed)) {
                                error << string_compose(_("AudioDiskstream %1: when refilling, cannot read %2 from playlist at frame %3"),
-                                                _id, size, playback_sample) << endmsg;
+                                                       id(), size, playback_sample) << endmsg;
                                goto out;
                        }
                }
        }
 
        ret = 0;
+
   out:
-       pending_overwrite = false;
-       delete [] gain_buffer;
-       delete [] mixdown_buffer;
-       return ret;
+       _pending_overwrite = false;
+       delete [] gain_buffer;
+       delete [] mixdown_buffer;
+       return ret;
 }
 
 int
-AudioDiskstream::seek (nframes_t frame, bool complete_refill)
+AudioDiskstream::seek (framepos_t frame, bool complete_refill)
 {
        uint32_t n;
        int ret = -1;
        ChannelList::iterator chan;
        boost::shared_ptr<ChannelList> c = channels.reader();
 
-       Glib::Mutex::Lock lm (state_lock);
-       
+       Glib::Threads::Mutex::Lock lm (state_lock);
+
        for (n = 0, chan = c->begin(); chan != c->end(); ++chan, ++n) {
                (*chan)->playback_buf->reset ();
                (*chan)->capture_buf->reset ();
        }
-       
+
        /* can't rec-enable in destructive mode if transport is before start */
-       
+
        if (destructive() && record_enabled() && frame < _session.current_start_frame()) {
                disengage_record_enable ();
        }
-       
+
        playback_sample = frame;
        file_frame = frame;
-       
+
        if (complete_refill) {
                while ((ret = do_refill_with_alloc ()) > 0) ;
        } else {
@@ -998,89 +905,99 @@ AudioDiskstream::seek (nframes_t frame, bool complete_refill)
 }
 
 int
-AudioDiskstream::can_internal_playback_seek (nframes_t distance)
+AudioDiskstream::can_internal_playback_seek (framecnt_t distance)
 {
        ChannelList::iterator chan;
        boost::shared_ptr<ChannelList> c = channels.reader();
 
        for (chan = c->begin(); chan != c->end(); ++chan) {
-               if ((*chan)->playback_buf->read_space() < distance) {
+               if ((*chan)->playback_buf->read_space() < (size_t) distance) {
                        return false;
-               } 
+               }
        }
        return true;
 }
 
 int
-AudioDiskstream::internal_playback_seek (nframes_t distance)
+AudioDiskstream::internal_playback_seek (framecnt_t distance)
 {
        ChannelList::iterator chan;
        boost::shared_ptr<ChannelList> c = channels.reader();
 
        for (chan = c->begin(); chan != c->end(); ++chan) {
-               (*chan)->playback_buf->increment_read_ptr (distance);
+               (*chan)->playback_buf->increment_read_ptr (llabs(distance));
        }
 
-       first_recordable_frame += distance;
+       if (first_recordable_frame < max_framepos) {
+               first_recordable_frame += distance;
+       }
        playback_sample += distance;
-       
+
        return 0;
 }
 
+/** Read some data for 1 channel from our playlist into a buffer.
+ *  @param buf Buffer to write to.
+ *  @param start Session frame to start reading from; updated to where we end up
+ *         after the read.
+ *  @param cnt Count of samples to read.
+ *  @param reversed true if we are running backwards, otherwise false.
+ */
 int
-AudioDiskstream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer, nframes_t& start, nframes_t cnt, 
-                      ChannelInfo* channel_info, int channel, bool reversed)
+AudioDiskstream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer,
+                       framepos_t& start, framecnt_t cnt,
+                       int channel, bool reversed)
 {
-       nframes_t this_read = 0;
+       framecnt_t this_read = 0;
        bool reloop = false;
-       nframes_t loop_end = 0;
-       nframes_t loop_start = 0;
-       nframes_t loop_length = 0;
-       nframes_t offset = 0;
+       framepos_t loop_end = 0;
+       framepos_t loop_start = 0;
+       framecnt_t offset = 0;
        Location *loc = 0;
 
        /* XXX we don't currently play loops in reverse. not sure why */
 
        if (!reversed) {
 
+               framecnt_t loop_length = 0;
+
                /* Make the use of a Location atomic for this read operation.
-                  
+
                   Note: Locations don't get deleted, so all we care about
                   when I say "atomic" is that we are always pointing to
                   the same one and using a start/length values obtained
                   just once.
                */
-               
+
                if ((loc = loop_location) != 0) {
                        loop_start = loc->start();
                        loop_end = loc->end();
                        loop_length = loop_end - loop_start;
                }
-               
+
                /* if we are looping, ensure that the first frame we read is at the correct
                   position within the loop.
                */
-               
+
                if (loc && start >= loop_end) {
-                       //cerr << "start adjusted from " << start;
                        start = loop_start + ((start - loop_start) % loop_length);
-                       //cerr << "to " << start << endl;
                }
+       }
 
-               //cerr << "start is " << start << "  loopstart: " << loop_start << "  loopend: " << loop_end << endl;
+       if (reversed) {
+               start -= cnt;
        }
 
+       /* We need this while loop in case we hit a loop boundary, in which case our read from
+          the playlist must be split into more than one section.
+       */
+
        while (cnt) {
 
-               if (reversed) {
-                       start -= cnt;
-               }
-                       
                /* take any loop into account. we can't read past the end of the loop. */
 
                if (loc && (loop_end - start < cnt)) {
                        this_read = loop_end - start;
-                       //cerr << "reloop true: thisread: " << this_read << "  cnt: " << cnt << endl;
                        reloop = true;
                } else {
                        reloop = false;
@@ -1094,27 +1011,25 @@ AudioDiskstream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer,
                this_read = min(cnt,this_read);
 
                if (audio_playlist()->read (buf+offset, mixdown_buffer, gain_buffer, start, this_read, channel) != this_read) {
-                       error << string_compose(_("AudioDiskstream %1: cannot read %2 from playlist at frame %3"), _id, this_read, 
+                       error << string_compose(_("AudioDiskstream %1: cannot read %2 from playlist at frame %3"), id(), this_read,
                                         start) << endmsg;
                        return -1;
                }
 
-               _read_data_count = _playlist->read_data_count();
-               
                if (reversed) {
 
                        swap_by_ptr (buf, buf + this_read - 1);
-                       
+
                } else {
-                       
+
                        /* if we read to the end of the loop, go back to the beginning */
-                       
+
                        if (reloop) {
                                start = loop_start;
                        } else {
                                start += this_read;
                        }
-               } 
+               }
 
                cnt -= this_read;
                offset += this_read;
@@ -1130,26 +1045,29 @@ AudioDiskstream::do_refill_with_alloc ()
        float*  gain_buf = new float[disk_io_chunk_frames];
 
        int ret = _do_refill(mix_buf, gain_buf);
-       
+
        delete [] mix_buf;
        delete [] gain_buf;
 
        return ret;
 }
 
+/** Get some more data from disk and put it in our channels' playback_bufs,
+ *  if there is suitable space in them.
+ */
 int
 AudioDiskstream::_do_refill (Sample* mixdown_buffer, float* gain_buffer)
 {
        int32_t ret = 0;
-       nframes_t to_read;
+       framecnt_t to_read;
        RingBufferNPT<Sample>::rw_vector vector;
-       bool reversed = (_visible_speed * _session.transport_speed()) < 0.0f;
-       nframes_t total_space;
-       nframes_t zero_fill;
+       bool const reversed = (_visible_speed * _session.transport_speed()) < 0.0f;
+       framecnt_t total_space;
+       framecnt_t zero_fill;
        uint32_t chan_n;
        ChannelList::iterator i;
        boost::shared_ptr<ChannelList> c = channels.reader();
-       nframes_t ts;
+       framecnt_t ts;
 
        if (c->empty()) {
                return 0;
@@ -1164,8 +1082,9 @@ AudioDiskstream::_do_refill (Sample* mixdown_buffer, float* gain_buffer)
        vector.len[1] = 0;
 
        c->front()->playback_buf->get_write_vector (&vector);
-       
+
        if ((total_space = vector.len[0] + vector.len[1]) == 0) {
+               /* nowhere to write to */
                return 0;
        }
 
@@ -1173,28 +1092,32 @@ AudioDiskstream::_do_refill (Sample* mixdown_buffer, float* gain_buffer)
           this track, let the caller know so that it can arrange
           for us to be called again, ASAP.
        */
-       
-       if (total_space >= (_slaved?3:2) * disk_io_chunk_frames) {
+
+       if (total_space >= (_slaved ? 3 : 2) * disk_io_chunk_frames) {
                ret = 1;
        }
-       
-       /* if we're running close to normal speed and there isn't enough 
-          space to do disk_io_chunk_frames of I/O, then don't bother.  
-          
+
+       /* if we're running close to normal speed and there isn't enough
+          space to do disk_io_chunk_frames of I/O, then don't bother.
+
           at higher speeds, just do it because the sync between butler
           and audio thread may not be good enough.
+
+          Note: it is a design assumption that disk_io_chunk_frames is smaller
+          than the playback buffer size, so this check should never trip when
+          the playback buffer is empty.
        */
-       
+
        if ((total_space < disk_io_chunk_frames) && fabs (_actual_speed) < 2.0f) {
                return 0;
        }
-       
+
        /* when slaved, don't try to get too close to the read pointer. this
           leaves space for the buffer reversal to have something useful to
           work with.
        */
-       
-       if (_slaved && total_space < (c->front()->playback_buf->bufsize() / 2)) {
+
+       if (_slaved && total_space < (framecnt_t) (c->front()->playback_buf->bufsize() / 2)) {
                return 0;
        }
 
@@ -1209,7 +1132,7 @@ AudioDiskstream::_do_refill (Sample* mixdown_buffer, float* gain_buffer)
                        /* at start: nothing to do but fill with silence */
 
                        for (chan_n = 0, i = c->begin(); i != c->end(); ++i, ++chan_n) {
-                                       
+
                                ChannelInfo* chan (*i);
                                chan->playback_buf->get_write_vector (&vector);
                                memset (vector.buf[0], 0, sizeof(Sample) * vector.len[0]);
@@ -1223,27 +1146,26 @@ AudioDiskstream::_do_refill (Sample* mixdown_buffer, float* gain_buffer)
 
                if (file_frame < total_space) {
 
-                       /* too close to the start: read what we can, 
-                          and then zero fill the rest 
+                       /* too close to the start: read what we can,
+                          and then zero fill the rest
                        */
 
                        zero_fill = total_space - file_frame;
                        total_space = file_frame;
-                       file_frame = 0;
 
                } else {
-                       
+
                        zero_fill = 0;
                }
 
        } else {
 
-               if (file_frame == max_frames) {
+               if (file_frame == max_framepos) {
 
                        /* at end: nothing to do but fill with silence */
-                       
+
                        for (chan_n = 0, i = c->begin(); i != c->end(); ++i, ++chan_n) {
-                                       
+
                                ChannelInfo* chan (*i);
                                chan->playback_buf->get_write_vector (&vector);
                                memset (vector.buf[0], 0, sizeof(Sample) * vector.len[0]);
@@ -1254,52 +1176,52 @@ AudioDiskstream::_do_refill (Sample* mixdown_buffer, float* gain_buffer)
                        }
                        return 0;
                }
-               
-               if (file_frame > max_frames - total_space) {
+
+               if (file_frame > max_framepos - total_space) {
 
                        /* to close to the end: read what we can, and zero fill the rest */
 
-                       zero_fill = total_space - (max_frames - file_frame);
-                       total_space = max_frames - file_frame;
+                       zero_fill = total_space - (max_framepos - file_frame);
+                       total_space = max_framepos - file_frame;
 
                } else {
                        zero_fill = 0;
                }
        }
-       
-       nframes_t file_frame_tmp = 0;
+
+       framepos_t file_frame_tmp = 0;
 
        for (chan_n = 0, i = c->begin(); i != c->end(); ++i, ++chan_n) {
 
                ChannelInfo* chan (*i);
                Sample* buf1;
                Sample* buf2;
-               nframes_t len1, len2;
+               framecnt_t len1, len2;
 
                chan->playback_buf->get_write_vector (&vector);
 
-               if (vector.len[0] > disk_io_chunk_frames) {
-                       
+               if ((framecnt_t) vector.len[0] > disk_io_chunk_frames) {
+
                        /* we're not going to fill the first chunk, so certainly do not bother with the
                           other part. it won't be connected with the part we do fill, as in:
-                          
+
                           .... => writable space
                           ++++ => readable space
                           ^^^^ => 1 x disk_io_chunk_frames that would be filled
-                          
+
                           |......|+++++++++++++|...............................|
                           buf1                buf0
                                                ^^^^^^^^^^^^^^^
-                          
-                          
-                          So, just pretend that the buf1 part isn't there.                                     
-                          
+
+
+                          So, just pretend that the buf1 part isn't there.
+
                        */
-               
+
                        vector.buf[1] = 0;
                        vector.len[1] = 0;
-               
-               } 
+
+               }
 
                ts = total_space;
                file_frame_tmp = file_frame;
@@ -1312,9 +1234,11 @@ AudioDiskstream::_do_refill (Sample* mixdown_buffer, float* gain_buffer)
                to_read = min (ts, len1);
                to_read = min (to_read, disk_io_chunk_frames);
 
+               assert (to_read >= 0);
+
                if (to_read) {
 
-                       if (read (buf1, mixdown_buffer, gain_buffer, file_frame_tmp, to_read, chan, chan_n, reversed)) {
+                       if (read (buf1, mixdown_buffer, gain_buffer, file_frame_tmp, to_read, chan_n, reversed)) {
                                ret = -1;
                                goto out;
                        }
@@ -1331,26 +1255,27 @@ AudioDiskstream::_do_refill (Sample* mixdown_buffer, float* gain_buffer)
                           so read some or all of vector.len[1] as well.
                        */
 
-                       if (read (buf2, mixdown_buffer, gain_buffer, file_frame_tmp, to_read, chan, chan_n, reversed)) {
+                       if (read (buf2, mixdown_buffer, gain_buffer, file_frame_tmp, to_read, chan_n, reversed)) {
                                ret = -1;
                                goto out;
                        }
-               
+
                        chan->playback_buf->increment_write_ptr (to_read);
                }
 
                if (zero_fill) {
-                       /* do something */
+                       /* XXX: do something */
                }
 
        }
-       
+
        file_frame = file_frame_tmp;
+       assert (file_frame >= 0);
 
   out:
 
        return ret;
-}      
+}
 
 /** Flush pending data to disk.
  *
@@ -1358,20 +1283,18 @@ AudioDiskstream::_do_refill (Sample* mixdown_buffer, float* gain_buffer)
  * of data to disk. it will never write more than that.  If it writes that
  * much and there is more than that waiting to be written, it will return 1,
  * otherwise 0 on success or -1 on failure.
- * 
+ *
  * If there is less than disk_io_chunk_frames to be written, no data will be
  * written at all unless @a force_flush is true.
  */
 int
-AudioDiskstream::do_flush (Session::RunContext context, bool force_flush)
+AudioDiskstream::do_flush (RunContext /*context*/, bool force_flush)
 {
        uint32_t to_write;
        int32_t ret = 0;
        RingBufferNPT<Sample>::rw_vector vector;
        RingBufferNPT<CaptureTransition>::rw_vector transvec;
-       nframes_t total;
-
-       _write_data_count = 0;
+       framecnt_t total;
 
        transvec.buf[0] = 0;
        transvec.buf[1] = 0;
@@ -1380,7 +1303,7 @@ AudioDiskstream::do_flush (Session::RunContext context, bool force_flush)
 
        boost::shared_ptr<ChannelList> c = channels.reader();
        for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-       
+
                (*chan)->capture_buf->get_read_vector (&vector);
 
                total = vector.len[0] + vector.len[1];
@@ -1392,7 +1315,7 @@ AudioDiskstream::do_flush (Session::RunContext context, bool force_flush)
                /* if there are 2+ chunks of disk i/o possible for
                   this track, let the caller know so that it can arrange
                   for us to be called again, ASAP.
-                  
+
                   if we are forcing a flush, then if there is* any* extra
                   work, let the caller know.
 
@@ -1402,38 +1325,35 @@ AudioDiskstream::do_flush (Session::RunContext context, bool force_flush)
 
                if (total >= 2 * disk_io_chunk_frames || ((force_flush || !was_recording) && total > disk_io_chunk_frames)) {
                        ret = 1;
-               } 
+               }
+
+               to_write = min (disk_io_chunk_frames, (framecnt_t) vector.len[0]);
 
-               to_write = min (disk_io_chunk_frames, (nframes_t) vector.len[0]);
-               
                // check the transition buffer when recording destructive
                // important that we get this after the capture buf
 
                if (destructive()) {
                        (*chan)->capture_transition_buf->get_read_vector(&transvec);
                        size_t transcount = transvec.len[0] + transvec.len[1];
-                       bool have_start = false;
                        size_t ti;
 
                        for (ti=0; ti < transcount; ++ti) {
                                CaptureTransition & captrans = (ti < transvec.len[0]) ? transvec.buf[0][ti] : transvec.buf[1][ti-transvec.len[0]];
-                               
+
                                if (captrans.type == CaptureStart) {
                                        // by definition, the first data we got above represents the given capture pos
 
                                        (*chan)->write_source->mark_capture_start (captrans.capture_val);
                                        (*chan)->curr_capture_cnt = 0;
 
-                                       have_start = true;
-                               }
-                               else if (captrans.type == CaptureEnd) {
+                               } else if (captrans.type == CaptureEnd) {
 
                                        // capture end, the capture_val represents total frames in capture
 
                                        if (captrans.capture_val <= (*chan)->curr_capture_cnt + to_write) {
 
                                                // shorten to make the write a perfect fit
-                                               uint32_t nto_write = (captrans.capture_val - (*chan)->curr_capture_cnt); 
+                                               uint32_t nto_write = (captrans.capture_val - (*chan)->curr_capture_cnt);
 
                                                if (nto_write < to_write) {
                                                        ret = 1; // should we?
@@ -1441,7 +1361,7 @@ AudioDiskstream::do_flush (Session::RunContext context, bool force_flush)
                                                to_write = nto_write;
 
                                                (*chan)->write_source->mark_capture_end ();
-                                               
+
                                                // increment past this transition, but go no further
                                                ++ti;
                                                break;
@@ -1460,29 +1380,27 @@ AudioDiskstream::do_flush (Session::RunContext context, bool force_flush)
                }
 
                if ((!(*chan)->write_source) || (*chan)->write_source->write (vector.buf[0], to_write) != to_write) {
-                       error << string_compose(_("AudioDiskstream %1: cannot write to disk"), _id) << endmsg;
+                       error << string_compose(_("AudioDiskstream %1: cannot write to disk"), id()) << endmsg;
                        return -1;
                }
 
                (*chan)->capture_buf->increment_read_ptr (to_write);
                (*chan)->curr_capture_cnt += to_write;
-               
+
                if ((to_write == vector.len[0]) && (total > to_write) && (to_write < disk_io_chunk_frames) && !destructive()) {
-               
+
                        /* we wrote all of vector.len[0] but it wasn't an entire
-                          disk_io_chunk_frames of data, so arrange for some part 
+                          disk_io_chunk_frames of data, so arrange for some part
                           of vector.len[1] to be flushed to disk as well.
                        */
-                       
-                       to_write = min ((nframes_t)(disk_io_chunk_frames - to_write), (nframes_t) vector.len[1]);
+
+                       to_write = min ((framecnt_t)(disk_io_chunk_frames - to_write), (framecnt_t) vector.len[1]);
 
                        if ((*chan)->write_source->write (vector.buf[1], to_write) != to_write) {
-                               error << string_compose(_("AudioDiskstream %1: cannot write to disk"), _id) << endmsg;
+                               error << string_compose(_("AudioDiskstream %1: cannot write to disk"), id()) << endmsg;
                                return -1;
                        }
 
-                       _write_data_count += (*chan)->write_source->write_data_count();
-       
                        (*chan)->capture_buf->increment_read_ptr (to_write);
                        (*chan)->curr_capture_cnt += to_write;
                }
@@ -1493,29 +1411,29 @@ AudioDiskstream::do_flush (Session::RunContext context, bool force_flush)
 }
 
 void
-AudioDiskstream::transport_stopped (struct tm& when, time_t twhen, bool abort_capture)
+AudioDiskstream::transport_stopped_wallclock (struct tm& when, time_t twhen, bool abort_capture)
 {
        uint32_t buffer_position;
        bool more_work = true;
        int err = 0;
        boost::shared_ptr<AudioRegion> region;
-       nframes_t total_capture;
+       framecnt_t total_capture;
        SourceList srcs;
        SourceList::iterator src;
        ChannelList::iterator chan;
        vector<CaptureInfo*>::iterator ci;
        boost::shared_ptr<ChannelList> c = channels.reader();
-       uint32_t n = 0; 
+       uint32_t n = 0;
        bool mark_write_completed = false;
 
-       finish_capture (true, c);
+       finish_capture (c);
 
-       /* butler is already stopped, but there may be work to do 
+       /* butler is already stopped, but there may be work to do
           to flush remaining data to disk.
        */
 
        while (more_work && !err) {
-               switch (do_flush (Session::TransportContext, true)) {
+               switch (do_flush (TransportContext, true)) {
                case 0:
                        more_work = false;
                        break;
@@ -1528,14 +1446,14 @@ AudioDiskstream::transport_stopped (struct tm& when, time_t twhen, bool abort_ca
        }
 
        /* XXX is there anything we can do if err != 0 ? */
-       Glib::Mutex::Lock lm (capture_info_lock);
-       
+       Glib::Threads::Mutex::Lock lm (capture_info_lock);
+
        if (capture_info.empty()) {
                return;
        }
 
        if (abort_capture) {
-               
+
                if (destructive()) {
                        goto outout;
                }
@@ -1543,17 +1461,17 @@ AudioDiskstream::transport_stopped (struct tm& when, time_t twhen, bool abort_ca
                for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
 
                        if ((*chan)->write_source) {
-                               
+
                                (*chan)->write_source->mark_for_remove ();
                                (*chan)->write_source->drop_references ();
                                (*chan)->write_source.reset ();
                        }
-                       
+
                        /* new source set up in "out" below */
                }
 
                goto out;
-       } 
+       }
 
        for (total_capture = 0, ci = capture_info.begin(); ci != capture_info.end(); ++ci) {
                total_capture += (*ci)->frames;
@@ -1564,12 +1482,13 @@ AudioDiskstream::transport_stopped (struct tm& when, time_t twhen, bool abort_ca
        for (n = 0, chan = c->begin(); chan != c->end(); ++chan, ++n) {
 
                boost::shared_ptr<AudioFileSource> s = (*chan)->write_source;
-               
+
                if (s) {
                        srcs.push_back (s);
                        s->update_header (capture_info.front()->start, when, twhen);
-                       s->set_captured_for (_name);
+                       s->set_captured_for (_name.val());
                        s->mark_immutable ();
+
                        if (Config->get_auto_analyse_audio()) {
                                Analyser::queue_source_for_analysis (s, true);
                        }
@@ -1580,13 +1499,13 @@ AudioDiskstream::transport_stopped (struct tm& when, time_t twhen, bool abort_ca
 
        if (destructive()) {
 
-               /* send a signal that any UI can pick up to do the right thing. there is 
+               /* send a signal that any UI can pick up to do the right thing. there is
                   a small problem here in that a UI may need the peak data to be ready
                   for the data that was recorded and this isn't interlocked with that
                   process. this problem is deferred to the UI.
                 */
-               
-               _playlist->Modified();
+
+               _playlist->LayeringChanged(); // XXX this may not get the UI to do the right thing
 
        } else {
 
@@ -1598,61 +1517,73 @@ AudioDiskstream::transport_stopped (struct tm& when, time_t twhen, bool abort_ca
                   so that any sub-regions will obviously be
                   children of this one (later!)
                */
-               
+
                try {
-                       boost::shared_ptr<Region> rx (RegionFactory::create (srcs, c->front()->write_source->last_capture_start_frame(), total_capture, 
-                                                                            whole_file_region_name,
-                                                                            0, AudioRegion::Flag (AudioRegion::DefaultFlags|AudioRegion::Automatic|AudioRegion::WholeFile)));
+                       PropertyList plist;
+
+                       plist.add (Properties::start, c->front()->write_source->last_capture_start_frame());
+                       plist.add (Properties::length, total_capture);
+                       plist.add (Properties::name, whole_file_region_name);
+                       boost::shared_ptr<Region> rx (RegionFactory::create (srcs, plist));
+                       rx->set_automatic (true);
+                       rx->set_whole_file (true);
 
                        region = boost::dynamic_pointer_cast<AudioRegion> (rx);
                        region->special_set_position (capture_info.front()->start);
                }
-               
-               
+
+
                catch (failed_constructor& err) {
                        error << string_compose(_("%1: could not create region for complete audio file"), _name) << endmsg;
                        /* XXX what now? */
                }
-               
-               _last_capture_regions.push_back (region);
+
+               _last_capture_sources.insert (_last_capture_sources.end(), srcs.begin(), srcs.end());
 
                // cerr << _name << ": there are " << capture_info.size() << " capture_info records\n";
-               
-               XMLNode &before = _playlist->get_state();
+
+               _playlist->clear_changes ();
+               _playlist->set_capture_insertion_in_progress (true);
                _playlist->freeze ();
-               
+
                for (buffer_position = c->front()->write_source->last_capture_start_frame(), ci = capture_info.begin(); ci != capture_info.end(); ++ci) {
-                       
+
                        string region_name;
 
-                       _session.region_name (region_name, whole_file_region_name, false);
-                       
-                       // cerr << _name << ": based on ci of " << (*ci)->start << " for " << (*ci)->frames << " add region " << region_name << endl;
-                       
+                       RegionFactory::region_name (region_name, whole_file_region_name, false);
+
+                       DEBUG_TRACE (DEBUG::CaptureAlignment, string_compose ("%1 capture start @ %2 length %3 add new region %4\n",
+                                                                             _name, (*ci)->start, (*ci)->frames, region_name));
+
                        try {
-                               boost::shared_ptr<Region> rx (RegionFactory::create (srcs, buffer_position, (*ci)->frames, region_name));
+
+                               PropertyList plist;
+
+                               plist.add (Properties::start, buffer_position);
+                               plist.add (Properties::length, (*ci)->frames);
+                               plist.add (Properties::name, region_name);
+
+                               boost::shared_ptr<Region> rx (RegionFactory::create (srcs, plist));
                                region = boost::dynamic_pointer_cast<AudioRegion> (rx);
                        }
-                       
+
                        catch (failed_constructor& err) {
                                error << _("AudioDiskstream: could not create region for captured audio!") << endmsg;
                                continue; /* XXX is this OK? */
                        }
-                       
-                       region->GoingAway.connect (bind (mem_fun (*this, &Diskstream::remove_region_from_last_capture), boost::weak_ptr<Region>(region)));
-                       
-                       _last_capture_regions.push_back (region);
-                       
+
                        i_am_the_modifier++;
-                       _playlist->add_region (region, (*ci)->start);
+
+                       _playlist->add_region (region, (*ci)->start, 1, non_layered());
+                       _playlist->set_layer (region, DBL_MAX);
                        i_am_the_modifier--;
-                       
+
                        buffer_position += (*ci)->frames;
                }
 
                _playlist->thaw ();
-               XMLNode &after = _playlist->get_state();
-               _session.add_command (new MementoCommand<Playlist>(*_playlist, &before, &after));
+               _playlist->set_capture_insertion_in_progress (false);
+               _session.add_command (new StatefulDiffCommand (_playlist));
        }
 
        mark_write_completed = true;
@@ -1671,7 +1602,7 @@ AudioDiskstream::transport_stopped (struct tm& when, time_t twhen, bool abort_ca
 }
 
 void
-AudioDiskstream::transport_looped (nframes_t transport_frame)
+AudioDiskstream::transport_looped (framepos_t transport_frame)
 {
        if (was_recording) {
                // all we need to do is finish this capture, with modified capture length
@@ -1689,22 +1620,22 @@ AudioDiskstream::transport_looped (nframes_t transport_frame)
                        }
                }
 
-               finish_capture (true, c);
+               finish_capture (c);
 
                // the next region will start recording via the normal mechanism
                // we'll set the start position to the current transport pos
                // no latency adjustment or capture offset needs to be made, as that already happened the first time
                capture_start_frame = transport_frame;
                first_recordable_frame = transport_frame; // mild lie
-               last_recordable_frame = max_frames;
+               last_recordable_frame = max_framepos;
                was_recording = true;
 
                if (recordable() && destructive()) {
                        for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-                               
+
                                RingBufferNPT<CaptureTransition>::rw_vector transvec;
                                (*chan)->capture_transition_buf->get_write_vector(&transvec);
-                               
+
                                if (transvec.len[0] > 0) {
                                        transvec.buf[0]->type = CaptureStart;
                                        transvec.buf[0]->capture_val = capture_start_frame;
@@ -1712,30 +1643,32 @@ AudioDiskstream::transport_looped (nframes_t transport_frame)
                                }
                                else {
                                        // bad!
-                                       fatal << X_("programming error: capture_transition_buf is full on rec loop!  inconceivable!") 
+                                       fatal << X_("programming error: capture_transition_buf is full on rec loop!  inconceivable!")
                                              << endmsg;
                                }
-                       }
+                       }
                }
 
        }
 }
 
 void
-AudioDiskstream::finish_capture (bool rec_monitors_input, boost::shared_ptr<ChannelList> c)
+AudioDiskstream::finish_capture (boost::shared_ptr<ChannelList> c)
 {
        was_recording = false;
-       
+       first_recordable_frame = max_framepos;
+       last_recordable_frame = max_framepos;
+
        if (capture_captured == 0) {
                return;
        }
 
        if (recordable() && destructive()) {
                for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-                       
+
                        RingBufferNPT<CaptureTransition>::rw_vector transvec;
                        (*chan)->capture_transition_buf->get_write_vector(&transvec);
-                       
+
                        if (transvec.len[0] > 0) {
                                transvec.buf[0]->type = CaptureEnd;
                                transvec.buf[0]->capture_val = capture_captured;
@@ -1747,15 +1680,15 @@ AudioDiskstream::finish_capture (bool rec_monitors_input, boost::shared_ptr<Chan
                        }
                }
        }
-       
-       
+
+
        CaptureInfo* ci = new CaptureInfo;
-       
+
        ci->start =  capture_start_frame;
        ci->frames = capture_captured;
-       
-       /* XXX theoretical race condition here. Need atomic exchange ? 
-          However, the circumstances when this is called right 
+
+       /* XXX theoretical race condition here. Need atomic exchange ?
+          However, the circumstances when this is called right
           now (either on record-disable or transport_stopped)
           mean that no actual race exists. I think ...
           We now have a capture_info_lock, but it is only to be used
@@ -1769,13 +1702,13 @@ AudioDiskstream::finish_capture (bool rec_monitors_input, boost::shared_ptr<Chan
        capture_captured = 0;
 
        /* now we've finished a capture, reset first_recordable_frame for next time */
-       first_recordable_frame = max_frames;
+       first_recordable_frame = max_framepos;
 }
 
 void
 AudioDiskstream::set_record_enabled (bool yn)
 {
-       if (!recordable() || !_session.record_enabling_legal() || _io->n_inputs().n_audio() == 0) {
+       if (!recordable() || !_session.record_enabling_legal() || _io->n_ports().n_audio() == 0) {
                return;
        }
 
@@ -1785,15 +1718,6 @@ AudioDiskstream::set_record_enabled (bool yn)
                return;
        }
 
-       if (yn && channels.reader()->front()->source == 0) {
-
-               /* pick up connections not initiated *from* the IO object
-                  we're associated with.
-               */
-
-               get_input_sources ();
-       }
-
        /* yes, i know that this not proof against race conditions, but its
           good enough. i think.
        */
@@ -1804,28 +1728,37 @@ AudioDiskstream::set_record_enabled (bool yn)
                } else {
                        disengage_record_enable ();
                }
+
+               RecordEnableChanged (); /* EMIT SIGNAL */
        }
 }
 
-void
-AudioDiskstream::engage_record_enable ()
+bool
+AudioDiskstream::prep_record_enable ()
 {
+       if (!recordable() || !_session.record_enabling_legal() || _io->n_ports().n_audio() == 0) {
+               return false;
+       }
+
+       /* can't rec-enable in destructive mode if transport is before start */
+
+       if (destructive() && _session.transport_frame() < _session.current_start_frame()) {
+               return false;
+       }
+
        bool rolling = _session.transport_speed() != 0.0f;
        boost::shared_ptr<ChannelList> c = channels.reader();
 
-       g_atomic_int_set (&_record_enabled, 1);
        capturing_sources.clear ();
 
        if (Config->get_monitoring_model() == HardwareMonitoring) {
 
                for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-                       if ((*chan)->source) {
-                               (*chan)->source->ensure_monitor_input (!(Config->get_auto_input() && rolling));
-                       }
+                       (*chan)->source.request_input_monitoring (!(_session.config.get_auto_input() && rolling));
                        capturing_sources.push_back ((*chan)->write_source);
                        (*chan)->write_source->mark_streaming_write_started ();
                }
-               
+
        } else {
                for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
                        capturing_sources.push_back ((*chan)->write_source);
@@ -1833,46 +1766,33 @@ AudioDiskstream::engage_record_enable ()
                }
        }
 
-       RecordEnableChanged (); /* EMIT SIGNAL */
+       return true;
 }
 
-void
-AudioDiskstream::disengage_record_enable ()
+bool
+AudioDiskstream::prep_record_disable ()
 {
-       g_atomic_int_set (&_record_enabled, 0);
        boost::shared_ptr<ChannelList> c = channels.reader();
        if (Config->get_monitoring_model() == HardwareMonitoring) {
                for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-                       if ((*chan)->source) {
-                               (*chan)->source->ensure_monitor_input (false);
-                       }
+                       (*chan)->source.request_input_monitoring (false);
                }
        }
        capturing_sources.clear ();
-       RecordEnableChanged (); /* EMIT SIGNAL */
+
+       return true;
 }
 
 XMLNode&
 AudioDiskstream::get_state ()
 {
-       XMLNode* node = new XMLNode ("AudioDiskstream");
+       XMLNode& node (Diskstream::get_state());
        char buf[64] = "";
        LocaleGuard lg (X_("POSIX"));
-       boost::shared_ptr<ChannelList> c = channels.reader();
-
-       node->add_property ("flags", enum_2_string (_flags));
 
+       boost::shared_ptr<ChannelList> c = channels.reader();
        snprintf (buf, sizeof(buf), "%zd", c->size());
-       node->add_property ("channels", buf);
-
-       node->add_property ("playlist", _playlist->name());
-       
-       snprintf (buf, sizeof(buf), "%.12g", _visible_speed);
-       node->add_property ("speed", buf);
-
-       node->add_property("name", _name);
-       id().print (buf, sizeof (buf));
-       node->add_property("id", buf);
+       node.add_property ("channels", buf);
 
        if (!capturing_sources.empty() && _session.get_record_enabled()) {
 
@@ -1889,25 +1809,21 @@ AudioDiskstream::get_state ()
 
                Location* pi;
 
-               if (Config->get_punch_in() && ((pi = _session.locations()->auto_punch_location()) != 0)) {
-                       snprintf (buf, sizeof (buf), "%" PRIu32, pi->start());
+               if (_session.config.get_punch_in() && ((pi = _session.locations()->auto_punch_location()) != 0)) {
+                       snprintf (buf, sizeof (buf), "%" PRId64, pi->start());
                } else {
-                       snprintf (buf, sizeof (buf), "%" PRIu32, _session.transport_frame());
+                       snprintf (buf, sizeof (buf), "%" PRId64, _session.transport_frame());
                }
 
                cs_child->add_property (X_("at"), buf);
-               node->add_child_nocopy (*cs_child);
+               node.add_child_nocopy (*cs_child);
        }
 
-       if (_extra_xml) {
-               node->add_child_copy (*_extra_xml);
-       }
-
-       return* node;
+       return node;
 }
 
 int
-AudioDiskstream::set_state (const XMLNode& node)
+AudioDiskstream::set_state (const XMLNode& node, int version)
 {
        const XMLProperty* prop;
        XMLNodeList nlist = node.children();
@@ -1916,49 +1832,33 @@ AudioDiskstream::set_state (const XMLNode& node)
        XMLNode* capture_pending_node = 0;
        LocaleGuard lg (X_("POSIX"));
 
+       /* prevent write sources from being created */
+
        in_set_state = true;
 
-       for (niter = nlist.begin(); niter != nlist.end(); ++niter) {
-               if ((*niter)->name() == IO::state_node_name) {
+       for (niter = nlist.begin(); niter != nlist.end(); ++niter) {
+               if ((*niter)->name() == IO::state_node_name) {
                        deprecated_io_node = new XMLNode (**niter);
-               }
+               }
 
                if ((*niter)->name() == X_("CapturingSources")) {
                        capture_pending_node = *niter;
                }
-       }
-
-       /* prevent write sources from being created */
-       
-       in_set_state = true;
-       
-       if ((prop = node.property ("name")) != 0) {
-               _name = prop->value();
-       } 
-
-       if (deprecated_io_node) {
-               if ((prop = deprecated_io_node->property ("id")) != 0) {
-                       _id = prop->value ();
-               }
-       } else {
-               if ((prop = node.property ("id")) != 0) {
-                       _id = prop->value ();
-               }
        }
 
-       if ((prop = node.property ("flags")) != 0) {
-               _flags = Flag (string_2_enum (prop->value(), _flags));
+       if (Diskstream::set_state (node, version)) {
+               return -1;
        }
 
        if ((prop = node.property ("channels")) != 0) {
                nchans = atoi (prop->value().c_str());
        }
-       
+
        // create necessary extra channels
        // we are always constructed with one and we always need one
 
        _n_channels.set(DataType::AUDIO, channels.reader()->size());
-       
+
        if (nchans > _n_channels.n_audio()) {
 
                add_channel (nchans - _n_channels.n_audio());
@@ -1969,37 +1869,14 @@ AudioDiskstream::set_state (const XMLNode& node)
                remove_channel (_n_channels.n_audio() - nchans);
        }
 
-       if ((prop = node.property ("playlist")) == 0) {
-               return -1;
-       }
-
-       {
-               bool had_playlist = (_playlist != 0);
-       
-               if (find_and_use_playlist (prop->value())) {
-                       return -1;
-               }
-
-               if (!had_playlist) {
-                       _playlist->set_orig_diskstream_id (_id);
-               }
-               
-               if (!destructive() && capture_pending_node) {
-                       /* destructive streams have one and only one source per channel,
-                          and so they never end up in pending capture in any useful
-                          sense.
-                       */
-                       use_pending_capture_data (*capture_pending_node);
-               }
-
-       }
 
-       if ((prop = node.property ("speed")) != 0) {
-               double sp = atof (prop->value().c_str());
 
-               if (realtime_set_speed (sp, false)) {
-                       non_realtime_set_speed ();
-               }
+       if (!destructive() && capture_pending_node) {
+               /* destructive streams have one and only one source per channel,
+                  and so they never end up in pending capture in any useful
+                  sense.
+               */
+               use_pending_capture_data (*capture_pending_node);
        }
 
        in_set_state = false;
@@ -2008,10 +1885,10 @@ AudioDiskstream::set_state (const XMLNode& node)
 
        capturing_sources.clear ();
 
-       /* write sources are handled when we handle the input set 
+       /* write sources are handled when we handle the input set
           up of the IO that owns this DS (::non_realtime_input_change())
        */
-               
+
        return 0;
 }
 
@@ -2030,18 +1907,13 @@ AudioDiskstream::use_new_write_source (uint32_t n)
        }
 
        ChannelInfo* chan = (*c)[n];
-       
-       if (chan->write_source) {
-               chan->write_source->done_with_peakfile_writes ();
-               chan->write_source->set_allow_remove_if_empty (true);
-               chan->write_source.reset ();
-       }
 
        try {
-               if ((chan->write_source = _session.create_audio_source_for_session (*this, n, destructive())) == 0) {
+               if ((chan->write_source = _session.create_audio_source_for_session (
+                            n_channels().n_audio(), name(), n, destructive())) == 0) {
                        throw failed_constructor();
                }
-       } 
+       }
 
        catch (failed_constructor &err) {
                error << string_compose (_("%1:%2 new capture file not initialized correctly"), _name, n) << endmsg;
@@ -2056,25 +1928,46 @@ AudioDiskstream::use_new_write_source (uint32_t n)
        return 0;
 }
 
+list<boost::shared_ptr<Source> >
+AudioDiskstream::steal_write_sources()
+{
+       /* not possible to steal audio write sources */
+       list<boost::shared_ptr<Source> > ret;
+       return ret;
+}
+
 void
-AudioDiskstream::reset_write_sources (bool mark_write_complete, bool force)
+AudioDiskstream::reset_write_sources (bool mark_write_complete, bool /*force*/)
 {
        ChannelList::iterator chan;
        boost::shared_ptr<ChannelList> c = channels.reader();
        uint32_t n;
 
-       if (!recordable()) {
+       if (!_session.writable() || !recordable()) {
                return;
        }
-       
+
        capturing_sources.clear ();
 
        for (chan = c->begin(), n = 0; chan != c->end(); ++chan, ++n) {
+
                if (!destructive()) {
 
-                       if ((*chan)->write_source && mark_write_complete) {
-                               (*chan)->write_source->mark_streaming_write_completed ();
+                       if ((*chan)->write_source) {
+
+                               if (mark_write_complete) {
+                                       (*chan)->write_source->mark_streaming_write_completed ();
+                                       (*chan)->write_source->done_with_peakfile_writes ();
+                               }
+
+                               if ((*chan)->write_source->removable()) {
+                                       (*chan)->write_source->mark_for_remove ();
+                                       (*chan)->write_source->drop_references ();
+                               }
+
+                               (*chan)->write_source.reset ();
                        }
+
                        use_new_write_source (n);
 
                        if (record_enabled()) {
@@ -2082,13 +1975,14 @@ AudioDiskstream::reset_write_sources (bool mark_write_complete, bool force)
                        }
 
                } else {
+
                        if ((*chan)->write_source == 0) {
                                use_new_write_source (n);
                        }
                }
        }
 
-       if (destructive()) {
+       if (destructive() && !c->empty ()) {
 
                /* we now have all our write sources set up, so create the
                   playlist's single region.
@@ -2100,32 +1994,16 @@ AudioDiskstream::reset_write_sources (bool mark_write_complete, bool force)
        }
 }
 
-int
-AudioDiskstream::rename_write_sources ()
-{
-       ChannelList::iterator chan;
-       boost::shared_ptr<ChannelList> c = channels.reader();
-       uint32_t n;
-
-       for (chan = c->begin(), n = 0; chan != c->end(); ++chan, ++n) {
-               if ((*chan)->write_source != 0) {
-                       (*chan)->write_source->set_source_name (_name, destructive());
-                       /* XXX what to do if one of them fails ? */
-               }
-       }
-
-       return 0;
-}
-
 void
-AudioDiskstream::set_block_size (nframes_t nframes)
+AudioDiskstream::set_block_size (pframes_t /*nframes*/)
 {
        if (_session.get_block_size() > speed_buffer_size) {
                speed_buffer_size = _session.get_block_size();
                boost::shared_ptr<ChannelList> c = channels.reader();
 
                for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-                       if ((*chan)->speed_buffer) delete [] (*chan)->speed_buffer;
+                       if ((*chan)->speed_buffer)
+                               delete [] (*chan)->speed_buffer;
                        (*chan)->speed_buffer = new Sample[speed_buffer_size];
                }
        }
@@ -2137,21 +2015,25 @@ AudioDiskstream::allocate_temporary_buffers ()
 {
        /* make sure the wrap buffer is at least large enough to deal
           with the speeds up to 1.2, to allow for micro-variation
-          when slaving to MTC, SMPTE etc.
+          when slaving to MTC, Timecode etc.
        */
 
-       double sp = max (fabsf (_actual_speed), 1.2f);
-       nframes_t required_wrap_size = (nframes_t) floor (_session.get_block_size() * sp) + 1;
+       double const sp = max (fabsf (_actual_speed), 1.2f);
+       framecnt_t required_wrap_size = (framecnt_t) ceil (_session.get_block_size() * sp) + 2;
 
        if (required_wrap_size > wrap_buffer_size) {
 
                boost::shared_ptr<ChannelList> c = channels.reader();
 
                for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-                       if ((*chan)->playback_wrap_buffer) delete [] (*chan)->playback_wrap_buffer;
-                       (*chan)->playback_wrap_buffer = new Sample[required_wrap_size]; 
-                       if ((*chan)->capture_wrap_buffer) delete [] (*chan)->capture_wrap_buffer;
-                       (*chan)->capture_wrap_buffer = new Sample[required_wrap_size];  
+                       if ((*chan)->playback_wrap_buffer) {
+                               delete [] (*chan)->playback_wrap_buffer;
+                       }
+                       (*chan)->playback_wrap_buffer = new Sample[required_wrap_size];
+                       if ((*chan)->capture_wrap_buffer) {
+                               delete [] (*chan)->capture_wrap_buffer;
+                       }
+                       (*chan)->capture_wrap_buffer = new Sample[required_wrap_size];
                }
 
                wrap_buffer_size = required_wrap_size;
@@ -2159,15 +2041,12 @@ AudioDiskstream::allocate_temporary_buffers ()
 }
 
 void
-AudioDiskstream::monitor_input (bool yn)
+AudioDiskstream::request_input_monitoring (bool yn)
 {
        boost::shared_ptr<ChannelList> c = channels.reader();
 
        for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-               
-               if ((*chan)->source) {
-                       (*chan)->source->ensure_monitor_input (yn);
-               }
+               (*chan)->source.request_input_monitoring (yn);
        }
 }
 
@@ -2176,16 +2055,20 @@ AudioDiskstream::set_align_style_from_io ()
 {
        bool have_physical = false;
 
+       if (_alignment_choice != Automatic) {
+               return;
+       }
+
        if (_io == 0) {
                return;
        }
 
        get_input_sources ();
-       
+
        boost::shared_ptr<ChannelList> c = channels.reader();
 
        for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
-               if ((*chan)->source && (*chan)->source->flags() & JackPortIsPhysical) {
+               if ((*chan)->source.is_physical ()) {
                        have_physical = true;
                        break;
                }
@@ -2202,7 +2085,13 @@ int
 AudioDiskstream::add_channel_to (boost::shared_ptr<ChannelList> c, uint32_t how_many)
 {
        while (how_many--) {
-               c->push_back (new ChannelInfo(_session.diskstream_buffer_size(), speed_buffer_size, wrap_buffer_size));
+               c->push_back (new ChannelInfo(
+                                     _session.butler()->audio_diskstream_playback_buffer_size(),
+                                     _session.butler()->audio_diskstream_capture_buffer_size(),
+                                     speed_buffer_size, wrap_buffer_size));
+               interpolation.add_channel_to (
+                       _session.butler()->audio_diskstream_playback_buffer_size(),
+                       speed_buffer_size);
        }
 
        _n_channels.set(DataType::AUDIO, c->size());
@@ -2225,6 +2114,7 @@ AudioDiskstream::remove_channel_from (boost::shared_ptr<ChannelList> c, uint32_t
        while (how_many-- && !c->empty()) {
                delete c->back();
                c->pop_back();
+               interpolation.remove_channel_from ();
        }
 
        _n_channels.set(DataType::AUDIO, c->size());
@@ -2237,7 +2127,7 @@ AudioDiskstream::remove_channel (uint32_t how_many)
 {
        RCUWriter<ChannelList> writer (channels);
        boost::shared_ptr<ChannelList> c = writer.get_copy();
-       
+
        return remove_channel_from (c, how_many);
 }
 
@@ -2246,6 +2136,10 @@ AudioDiskstream::playback_buffer_load () const
 {
        boost::shared_ptr<ChannelList> c = channels.reader();
 
+       if (c->empty ()) {
+               return 0;
+       }
+
        return (float) ((double) c->front()->playback_buf->read_space()/
                        (double) c->front()->playback_buf->bufsize());
 }
@@ -2255,6 +2149,10 @@ AudioDiskstream::capture_buffer_load () const
 {
        boost::shared_ptr<ChannelList> c = channels.reader();
 
+       if (c->empty ()) {
+               return 0;
+       }
+
        return (float) ((double) c->front()->capture_buf->write_space()/
                        (double) c->front()->capture_buf->bufsize());
 }
@@ -2268,13 +2166,13 @@ AudioDiskstream::use_pending_capture_data (XMLNode& node)
        boost::shared_ptr<AudioFileSource> fs;
        boost::shared_ptr<AudioFileSource> first_fs;
        SourceList pending_sources;
-       nframes_t position;
+       framepos_t position;
 
        if ((prop = node.property (X_("at"))) == 0) {
                return -1;
        }
 
-       if (sscanf (prop->value().c_str(), "%" PRIu32, &position) != 1) {
+       if (sscanf (prop->value().c_str(), "%" PRIu64, &position) != 1) {
                return -1;
        }
 
@@ -2293,7 +2191,9 @@ AudioDiskstream::use_pending_capture_data (XMLNode& node)
 
                        try {
                                fs = boost::dynamic_pointer_cast<AudioFileSource> (
-                                       SourceFactory::createWritable (DataType::AUDIO, _session, prop->value(), false, _session.frame_rate()));
+                                       SourceFactory::createWritable (
+                                               DataType::AUDIO, _session,
+                                               prop->value(), false, _session.frame_rate()));
                        }
 
                        catch (failed_constructor& err) {
@@ -2304,12 +2204,12 @@ AudioDiskstream::use_pending_capture_data (XMLNode& node)
                        }
 
                        pending_sources.push_back (fs);
-                       
+
                        if (first_fs == 0) {
                                first_fs = fs;
                        }
 
-                       fs->set_captured_for (_name);
+                       fs->set_captured_for (_name.val());
                }
        }
 
@@ -2325,31 +2225,27 @@ AudioDiskstream::use_pending_capture_data (XMLNode& node)
        }
 
        boost::shared_ptr<AudioRegion> region;
-       
+
        try {
-               region = boost::dynamic_pointer_cast<AudioRegion> (RegionFactory::create (pending_sources, 0, first_fs->length(),
-                                                                                         region_name_from_path (first_fs->name(), true), 
-                                                                                         0, AudioRegion::Flag (AudioRegion::DefaultFlags|AudioRegion::Automatic|AudioRegion::WholeFile)));
-               region->special_set_position (0);
-       }
 
-       catch (failed_constructor& err) {
-               error << string_compose (_("%1: cannot create whole-file region from pending capture sources"),
-                                 _name)
-                     << endmsg;
-               
-               return -1;
-       }
+               PropertyList plist;
 
-       try {
-               region = boost::dynamic_pointer_cast<AudioRegion> (RegionFactory::create (pending_sources, 0, first_fs->length(), region_name_from_path (first_fs->name(), true)));
+               plist.add (Properties::start, 0);
+               plist.add (Properties::length, first_fs->length (first_fs->timeline_position()));
+               plist.add (Properties::name, region_name_from_path (first_fs->name(), true));
+
+               region = boost::dynamic_pointer_cast<AudioRegion> (RegionFactory::create (pending_sources, plist));
+
+               region->set_automatic (true);
+               region->set_whole_file (true);
+               region->special_set_position (0);
        }
 
        catch (failed_constructor& err) {
-               error << string_compose (_("%1: cannot create region from pending capture sources"),
-                                 _name)
-                     << endmsg;
-               
+               error << string_compose (
+                               _("%1: cannot create whole-file region from pending capture sources"),
+                               _name) << endmsg;
+
                return -1;
        }
 
@@ -2359,15 +2255,29 @@ AudioDiskstream::use_pending_capture_data (XMLNode& node)
 }
 
 int
-AudioDiskstream::set_destructive (bool yn)
+AudioDiskstream::set_non_layered (bool yn)
 {
-       bool bounce_ignored;
+       if (yn != non_layered()) {
+
+               if (yn) {
+                       _flags = Flag (_flags | NonLayered);
+               } else {
+                       _flags = Flag (_flags & ~NonLayered);
+               }
+       }
+
+       return 0;
+}
 
+int
+AudioDiskstream::set_destructive (bool yn)
+{
        if (yn != destructive()) {
-               
+
                if (yn) {
+                       bool bounce_ignored;
                        /* requestor should already have checked this and
-                          bounced if necessary and desired 
+                          bounced if necessary and desired
                        */
                        if (!can_become_destructive (bounce_ignored)) {
                                return -1;
@@ -2399,10 +2309,13 @@ AudioDiskstream::can_become_destructive (bool& requires_bounce) const
        }
 
        boost::shared_ptr<Region> first = _playlist->find_next_region (_session.current_start_frame(), Start, 1);
-       assert (first);
+       if (!first) {
+               requires_bounce = false;
+               return true;
+       }
 
        /* do the source(s) for the region cover the session start position ? */
-       
+
        if (first->position() != _session.current_start_frame()) {
                if (first->start() > _session.current_start_frame()) {
                        requires_bounce = true;
@@ -2416,8 +2329,8 @@ AudioDiskstream::can_become_destructive (bool& requires_bounce) const
 
        assert (afirst);
 
-       if (afirst->source()->used() > 1) {
-               requires_bounce = true; 
+       if (_session.playlists->source_use_count (afirst->source()) > 1) {
+               requires_bounce = true;
                return false;
        }
 
@@ -2425,10 +2338,48 @@ AudioDiskstream::can_become_destructive (bool& requires_bounce) const
        return true;
 }
 
-AudioDiskstream::ChannelInfo::ChannelInfo (nframes_t bufsize, nframes_t speed_size, nframes_t wrap_size)
+void
+AudioDiskstream::adjust_playback_buffering ()
+{
+       boost::shared_ptr<ChannelList> c = channels.reader();
+
+       for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
+               (*chan)->resize_playback (_session.butler()->audio_diskstream_playback_buffer_size());
+       }
+}
+
+void
+AudioDiskstream::adjust_capture_buffering ()
+{
+       boost::shared_ptr<ChannelList> c = channels.reader();
+
+       for (ChannelList::iterator chan = c->begin(); chan != c->end(); ++chan) {
+               (*chan)->resize_capture (_session.butler()->audio_diskstream_capture_buffer_size());
+       }
+}
+
+bool
+AudioDiskstream::ChannelSource::is_physical () const
+{
+       if (name.empty()) {
+               return false;
+       }
+
+       return AudioEngine::instance()->port_is_physical (name);
+}
+
+void
+AudioDiskstream::ChannelSource::request_input_monitoring (bool yn) const
+{
+       if (name.empty()) {
+               return;
+       }
+
+       return AudioEngine::instance()->request_input_monitoring (name, yn);
+}
+
+AudioDiskstream::ChannelInfo::ChannelInfo (framecnt_t playback_bufsize, framecnt_t capture_bufsize, framecnt_t speed_size, framecnt_t wrap_size)
 {
-       peak_power = 0.0f;
-       source = 0;
        current_capture_buffer = 0;
        current_playback_buffer = 0;
        curr_capture_cnt = 0;
@@ -2437,14 +2388,14 @@ AudioDiskstream::ChannelInfo::ChannelInfo (nframes_t bufsize, nframes_t speed_si
        playback_wrap_buffer = new Sample[wrap_size];
        capture_wrap_buffer = new Sample[wrap_size];
 
-       playback_buf = new RingBufferNPT<Sample> (bufsize);
-       capture_buf = new RingBufferNPT<Sample> (bufsize);
+       playback_buf = new RingBufferNPT<Sample> (playback_bufsize);
+       capture_buf = new RingBufferNPT<Sample> (capture_bufsize);
        capture_transition_buf = new RingBufferNPT<CaptureTransition> (256);
-       
+
        /* touch the ringbuffer buffers, which will cause
           them to be mapped into locked physical RAM if
           we're running with mlockall(). this doesn't do
-          much if we're not.  
+          much if we're not.
        */
 
        memset (playback_buf->buffer(), 0, sizeof (Sample) * playback_buf->bufsize());
@@ -2452,39 +2403,61 @@ AudioDiskstream::ChannelInfo::ChannelInfo (nframes_t bufsize, nframes_t speed_si
        memset (capture_transition_buf->buffer(), 0, sizeof (CaptureTransition) * capture_transition_buf->bufsize());
 }
 
+void
+AudioDiskstream::ChannelInfo::resize_playback (framecnt_t playback_bufsize)
+{
+       delete playback_buf;
+       playback_buf = new RingBufferNPT<Sample> (playback_bufsize);
+       memset (playback_buf->buffer(), 0, sizeof (Sample) * playback_buf->bufsize());
+}
+
+void
+AudioDiskstream::ChannelInfo::resize_capture (framecnt_t capture_bufsize)
+{
+       delete capture_buf;
+
+       capture_buf = new RingBufferNPT<Sample> (capture_bufsize);
+       memset (capture_buf->buffer(), 0, sizeof (Sample) * capture_buf->bufsize());
+}
+
 AudioDiskstream::ChannelInfo::~ChannelInfo ()
 {
-       if (write_source) {
-               write_source.reset ();
-       }
-               
-       if (speed_buffer) {
-               delete [] speed_buffer;
-               speed_buffer = 0;
-       }
+       write_source.reset ();
 
-       if (playback_wrap_buffer) {
-               delete [] playback_wrap_buffer;
-               playback_wrap_buffer = 0;
-       }
+       delete [] speed_buffer;
+       speed_buffer = 0;
 
-       if (capture_wrap_buffer) {
-               delete [] capture_wrap_buffer;
-               capture_wrap_buffer = 0;
-       }
-       
-       if (playback_buf) {
-               delete playback_buf;
-               playback_buf = 0;
-       }
+       delete [] playback_wrap_buffer;
+       playback_wrap_buffer = 0;
 
-       if (capture_buf) {
-               delete capture_buf;
-               capture_buf = 0;
-       }
+       delete [] capture_wrap_buffer;
+       capture_wrap_buffer = 0;
+
+       delete playback_buf;
+       playback_buf = 0;
+
+       delete capture_buf;
+       capture_buf = 0;
+
+       delete capture_transition_buf;
+       capture_transition_buf = 0;
+}
+
+
+bool
+AudioDiskstream::set_name (string const & name)
+{
+       Diskstream::set_name (name);
+
+       /* get a new write source so that its name reflects the new diskstream name */
+
+       boost::shared_ptr<ChannelList> c = channels.reader();
+       ChannelList::iterator i;
+       int n = 0;
 
-       if (capture_transition_buf) {
-               delete capture_transition_buf;
-               capture_transition_buf = 0;
+       for (n = 0, i = c->begin(); i != c->end(); ++i, ++n) {
+               use_new_write_source (n);
        }
+
+       return true;
 }