audioregion.cc

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/*
    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
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <cmath>
#include <climits>
#include <cfloat>
#include <algorithm>

#include <set>

#include <boost/scoped_array.hpp>

#include <glibmm/threads.h>

#include "pbd/basename.h"
#include "pbd/xml++.h"
#include "pbd/stacktrace.h"
#include "pbd/enumwriter.h"
#include "pbd/convert.h"

#include "evoral/Curve.hpp"

#include "ardour/audioregion.h"
#include "ardour/session.h"
#include "ardour/dB.h"
#include "ardour/debug.h"
#include "ardour/event_type_map.h"
#include "ardour/playlist.h"
#include "ardour/audiofilesource.h"
#include "ardour/region_factory.h"
#include "ardour/runtime_functions.h"
#include "ardour/transient_detector.h"
#include "ardour/parameter_descriptor.h"
#include "ardour/progress.h"

#include "i18n.h"
#include <locale.h>

using namespace std;
using namespace ARDOUR;
using namespace PBD;

namespace ARDOUR {
        namespace Properties {
                PBD::PropertyDescriptor<bool> envelope_active;
                PBD::PropertyDescriptor<bool> default_fade_in;
                PBD::PropertyDescriptor<bool> default_fade_out;
                PBD::PropertyDescriptor<bool> fade_in_active;
                PBD::PropertyDescriptor<bool> fade_out_active;
                PBD::PropertyDescriptor<float> scale_amplitude;
                PBD::PropertyDescriptor<boost::shared_ptr<AutomationList> > fade_in;
                PBD::PropertyDescriptor<boost::shared_ptr<AutomationList> > inverse_fade_in;
                PBD::PropertyDescriptor<boost::shared_ptr<AutomationList> > fade_out;
                PBD::PropertyDescriptor<boost::shared_ptr<AutomationList> > inverse_fade_out;
                PBD::PropertyDescriptor<boost::shared_ptr<AutomationList> > envelope;
        }
}

/* Curve manipulations */

static void
reverse_curve (boost::shared_ptr<Evoral::ControlList> dst, boost::shared_ptr<const Evoral::ControlList> src)
{
        size_t len = src->back()->when;
        for (Evoral::ControlList::const_reverse_iterator it = src->rbegin(); it!=src->rend(); it++) {
                dst->fast_simple_add (len - (*it)->when, (*it)->value);
        }
}

static void
generate_inverse_power_curve (boost::shared_ptr<Evoral::ControlList> dst, boost::shared_ptr<const Evoral::ControlList> src)
{
        // calc inverse curve using sum of squares
        for (Evoral::ControlList::const_iterator it = src->begin(); it!=src->end(); ++it ) {
                float value = (*it)->value;
                value = 1 - powf(value,2);
                value = sqrtf(value);
                dst->fast_simple_add ( (*it)->when, value );
        }
}

static void
generate_db_fade (boost::shared_ptr<Evoral::ControlList> dst, double len, int num_steps, float dB_drop)
{
        dst->clear ();
        dst->fast_simple_add (0, 1);

        //generate a fade-out curve by successively applying a gain drop
        float fade_speed = dB_to_coefficient(dB_drop / (float) num_steps);
        for (int i = 1; i < (num_steps-1); i++) {
                float coeff = GAIN_COEFF_UNITY;
                for (int j = 0; j < i; j++) {
                        coeff *= fade_speed;
                }
                dst->fast_simple_add (len*(double)i/(double)num_steps, coeff);
        }

        dst->fast_simple_add (len, GAIN_COEFF_SMALL);
}

static void
merge_curves (boost::shared_ptr<Evoral::ControlList> dst, 
              boost::shared_ptr<const Evoral::ControlList> curve1, 
              boost::shared_ptr<const Evoral::ControlList> curve2)
{
        Evoral::ControlList::EventList::size_type size = curve1->size();

        //curve lengths must match for now
        if (size != curve2->size()) {
                return;
        }
        
        Evoral::ControlList::const_iterator c1 = curve1->begin();
        int count = 0;
        for (Evoral::ControlList::const_iterator c2 = curve2->begin(); c2!=curve2->end(); c2++ ) {
                float v1 = accurate_coefficient_to_dB((*c1)->value);
                float v2 = accurate_coefficient_to_dB((*c2)->value);
                
                double interp = v1 * ( 1.0-( (double)count / (double)size) );
                interp += v2 * ( (double)count / (double)size );

                interp = dB_to_coefficient(interp);
                dst->fast_simple_add ( (*c1)->when, interp );
                c1++;
                count++;
        }
}

void
AudioRegion::make_property_quarks ()
{
        Properties::envelope_active.property_id = g_quark_from_static_string (X_("envelope-active"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for envelope-active = %1\n",     Properties::envelope_active.property_id));
        Properties::default_fade_in.property_id = g_quark_from_static_string (X_("default-fade-in"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for default-fade-in = %1\n",     Properties::default_fade_in.property_id));
        Properties::default_fade_out.property_id = g_quark_from_static_string (X_("default-fade-out"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for default-fade-out = %1\n",    Properties::default_fade_out.property_id));
        Properties::fade_in_active.property_id = g_quark_from_static_string (X_("fade-in-active"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for fade-in-active = %1\n",      Properties::fade_in_active.property_id));
        Properties::fade_out_active.property_id = g_quark_from_static_string (X_("fade-out-active"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for fade-out-active = %1\n",     Properties::fade_out_active.property_id));
        Properties::scale_amplitude.property_id = g_quark_from_static_string (X_("scale-amplitude"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for scale-amplitude = %1\n",     Properties::scale_amplitude.property_id));
        Properties::fade_in.property_id = g_quark_from_static_string (X_("FadeIn"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for FadeIn = %1\n",              Properties::fade_in.property_id));
        Properties::inverse_fade_in.property_id = g_quark_from_static_string (X_("InverseFadeIn"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for InverseFadeIn = %1\n",       Properties::inverse_fade_in.property_id));
        Properties::fade_out.property_id = g_quark_from_static_string (X_("FadeOut"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for FadeOut = %1\n",             Properties::fade_out.property_id));
        Properties::inverse_fade_out.property_id = g_quark_from_static_string (X_("InverseFadeOut"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for InverseFadeOut = %1\n",      Properties::inverse_fade_out.property_id));
        Properties::envelope.property_id = g_quark_from_static_string (X_("Envelope"));
        DEBUG_TRACE (DEBUG::Properties, string_compose ("quark for Envelope = %1\n",            Properties::envelope.property_id));
}

void
AudioRegion::register_properties ()
{
        /* no need to register parent class properties */

        add_property (_envelope_active);
        add_property (_default_fade_in);
        add_property (_default_fade_out);
        add_property (_fade_in_active);
        add_property (_fade_out_active);
        add_property (_scale_amplitude);
        add_property (_fade_in);
        add_property (_inverse_fade_in);
        add_property (_fade_out);
        add_property (_inverse_fade_out);
        add_property (_envelope);
}

#define AUDIOREGION_STATE_DEFAULT \
        _envelope_active (Properties::envelope_active, false) \
        , _default_fade_in (Properties::default_fade_in, true) \
        , _default_fade_out (Properties::default_fade_out, true) \
        , _fade_in_active (Properties::fade_in_active, true) \
        , _fade_out_active (Properties::fade_out_active, true) \
        , _scale_amplitude (Properties::scale_amplitude, 1.0) \
        , _fade_in (Properties::fade_in, boost::shared_ptr<AutomationList> (new AutomationList (Evoral::Parameter (FadeInAutomation)))) \
        , _inverse_fade_in (Properties::inverse_fade_in, boost::shared_ptr<AutomationList> (new AutomationList (Evoral::Parameter (FadeInAutomation)))) \
        , _fade_out (Properties::fade_out, boost::shared_ptr<AutomationList> (new AutomationList (Evoral::Parameter (FadeOutAutomation)))) \
        , _inverse_fade_out (Properties::inverse_fade_out, boost::shared_ptr<AutomationList> (new AutomationList (Evoral::Parameter (FadeOutAutomation))))

#define AUDIOREGION_COPY_STATE(other) \
        _envelope_active (Properties::envelope_active, other->_envelope_active) \
        , _default_fade_in (Properties::default_fade_in, other->_default_fade_in) \
        , _default_fade_out (Properties::default_fade_out, other->_default_fade_out) \
        , _fade_in_active (Properties::fade_in_active, other->_fade_in_active) \
        , _fade_out_active (Properties::fade_out_active, other->_fade_out_active) \
        , _scale_amplitude (Properties::scale_amplitude, other->_scale_amplitude) \
        , _fade_in (Properties::fade_in, boost::shared_ptr<AutomationList> (new AutomationList (*other->_fade_in.val()))) \
        , _inverse_fade_in (Properties::fade_in, boost::shared_ptr<AutomationList> (new AutomationList (*other->_inverse_fade_in.val()))) \
        , _fade_out (Properties::fade_in, boost::shared_ptr<AutomationList> (new AutomationList (*other->_fade_out.val()))) \
        , _inverse_fade_out (Properties::fade_in, boost::shared_ptr<AutomationList> (new AutomationList (*other->_inverse_fade_out.val())))
/* a Session will reset these to its chosen defaults by calling AudioRegion::set_default_fade() */

void
AudioRegion::init ()
{
        register_properties ();

        suspend_property_changes();
        set_default_fades ();
        set_default_envelope ();
        resume_property_changes();

        listen_to_my_curves ();
        connect_to_analysis_changed ();
        connect_to_header_position_offset_changed ();
}

AudioRegion::AudioRegion (Session& s, framepos_t start, framecnt_t len, std::string name)
        : Region (s, start, len, name, DataType::AUDIO)
        , AUDIOREGION_STATE_DEFAULT
        , _envelope (Properties::envelope, boost::shared_ptr<AutomationList> (new AutomationList (Evoral::Parameter(EnvelopeAutomation))))
        , _automatable (s)
        , _fade_in_suspended (0)
        , _fade_out_suspended (0)
{
        init ();
        assert (_sources.size() == _master_sources.size());
}

AudioRegion::AudioRegion (const SourceList& srcs)
        : Region (srcs)
        , AUDIOREGION_STATE_DEFAULT
        , _envelope (Properties::envelope, boost::shared_ptr<AutomationList> (new AutomationList (Evoral::Parameter(EnvelopeAutomation))))
        , _automatable(srcs[0]->session())
        , _fade_in_suspended (0)
        , _fade_out_suspended (0)
{
        init ();
        assert (_sources.size() == _master_sources.size());
}

AudioRegion::AudioRegion (boost::shared_ptr<const AudioRegion> other)
        : Region (other)
        , AUDIOREGION_COPY_STATE (other)
          /* As far as I can see, the _envelope's times are relative to region position, and have nothing
             to do with sources (and hence _start).  So when we copy the envelope, we just use the supplied offset.
          */
        , _envelope (Properties::envelope, boost::shared_ptr<AutomationList> (new AutomationList (*other->_envelope.val(), 0, other->_length)))
        , _automatable (other->session())
        , _fade_in_suspended (0)
        , _fade_out_suspended (0)
{
        /* don't use init here, because we got fade in/out from the other region
        */
        register_properties ();
        listen_to_my_curves ();
        connect_to_analysis_changed ();
        connect_to_header_position_offset_changed ();

        assert(_type == DataType::AUDIO);
        assert (_sources.size() == _master_sources.size());
}

AudioRegion::AudioRegion (boost::shared_ptr<const AudioRegion> other, framecnt_t offset)
        : Region (other, offset)
        , AUDIOREGION_COPY_STATE (other)
          /* As far as I can see, the _envelope's times are relative to region position, and have nothing
             to do with sources (and hence _start).  So when we copy the envelope, we just use the supplied offset.
          */
        , _envelope (Properties::envelope, boost::shared_ptr<AutomationList> (new AutomationList (*other->_envelope.val(), offset, other->_length)))
        , _automatable (other->session())
        , _fade_in_suspended (0)
        , _fade_out_suspended (0)
{
        /* don't use init here, because we got fade in/out from the other region
        */
        register_properties ();
        listen_to_my_curves ();
        connect_to_analysis_changed ();
        connect_to_header_position_offset_changed ();

        assert(_type == DataType::AUDIO);
        assert (_sources.size() == _master_sources.size());
}

AudioRegion::AudioRegion (boost::shared_ptr<const AudioRegion> other, const SourceList& srcs)
        : Region (boost::static_pointer_cast<const Region>(other), srcs)
        , AUDIOREGION_COPY_STATE (other)
        , _envelope (Properties::envelope, boost::shared_ptr<AutomationList> (new AutomationList (*other->_envelope.val())))
        , _automatable (other->session())
        , _fade_in_suspended (0)
        , _fade_out_suspended (0)
{
        /* make-a-sort-of-copy-with-different-sources constructor (used by audio filter) */

        register_properties ();

        listen_to_my_curves ();
        connect_to_analysis_changed ();
        connect_to_header_position_offset_changed ();

        assert (_sources.size() == _master_sources.size());
}

AudioRegion::AudioRegion (SourceList& srcs)
        : Region (srcs)
        , AUDIOREGION_STATE_DEFAULT
        , _envelope (Properties::envelope, boost::shared_ptr<AutomationList> (new AutomationList(Evoral::Parameter(EnvelopeAutomation))))
        , _automatable(srcs[0]->session())
        , _fade_in_suspended (0)
        , _fade_out_suspended (0)
{
        init ();

        assert(_type == DataType::AUDIO);
        assert (_sources.size() == _master_sources.size());
}

AudioRegion::~AudioRegion ()
{
}

void
AudioRegion::post_set (const PropertyChange& /*ignored*/)
{
        if (!_sync_marked) {
                _sync_position = _start;
        }

        /* return to default fades if the existing ones are too long */

        if (_left_of_split) {
                if (_fade_in->back()->when >= _length) {
                        set_default_fade_in ();
                }
                set_default_fade_out ();
                _left_of_split = false;
        }

        if (_right_of_split) {
                if (_fade_out->back()->when >= _length) {
                        set_default_fade_out ();
                }

                set_default_fade_in ();
                _right_of_split = false;
        }

        /* If _length changed, adjust our gain envelope accordingly */
        _envelope->truncate_end (_length);
}

void
AudioRegion::connect_to_analysis_changed ()
{
        for (SourceList::const_iterator i = _sources.begin(); i != _sources.end(); ++i) {
                (*i)->AnalysisChanged.connect_same_thread (*this, boost::bind (&AudioRegion::invalidate_transients, this));
        }
}

void
AudioRegion::connect_to_header_position_offset_changed ()
{
        set<boost::shared_ptr<Source> > unique_srcs;

        for (SourceList::const_iterator i = _sources.begin(); i != _sources.end(); ++i) {

                /* connect only once to HeaderPositionOffsetChanged, even if sources are replicated
                 */

                if (unique_srcs.find (*i) == unique_srcs.end ()) {
                        unique_srcs.insert (*i);
                        boost::shared_ptr<AudioFileSource> afs = boost::dynamic_pointer_cast<AudioFileSource> (*i);
                        if (afs) {
                                afs->HeaderPositionOffsetChanged.connect_same_thread (*this, boost::bind (&AudioRegion::source_offset_changed, this));
                        }
                }
        }
}

void
AudioRegion::listen_to_my_curves ()
{
        _envelope->StateChanged.connect_same_thread (*this, boost::bind (&AudioRegion::envelope_changed, this));
        _fade_in->StateChanged.connect_same_thread (*this, boost::bind (&AudioRegion::fade_in_changed, this));
        _fade_out->StateChanged.connect_same_thread (*this, boost::bind (&AudioRegion::fade_out_changed, this));
}

void
AudioRegion::set_envelope_active (bool yn)
{
        if (envelope_active() != yn) {
                _envelope_active = yn;
                send_change (PropertyChange (Properties::envelope_active));
        }
}

ARDOUR::framecnt_t
AudioRegion::read_peaks (PeakData *buf, framecnt_t npeaks, framecnt_t offset, framecnt_t cnt, uint32_t chan_n, double frames_per_pixel) const
{
        if (chan_n >= _sources.size()) {
                return 0;
        }

        if (audio_source(chan_n)->read_peaks (buf, npeaks, offset, cnt, frames_per_pixel)) {
                return 0;
        } else {
                if (_scale_amplitude != 1.0f) {
                        for (framecnt_t n = 0; n < npeaks; ++n) {
                                buf[n].max *= _scale_amplitude;
                                buf[n].min *= _scale_amplitude;
                        }
                }
                return cnt;
        }
}

framecnt_t
AudioRegion::read (Sample* buf, framepos_t pos, framecnt_t cnt, int channel) const
{
        /* raw read, no fades, no gain, nada */
        return read_from_sources (_sources, _length, buf, _position + pos, cnt, channel);
}

framecnt_t
AudioRegion::master_read_at (Sample *buf, Sample* /*mixdown_buffer*/, float* /*gain_buffer*/,
                             framepos_t position, framecnt_t cnt, uint32_t chan_n) const
{
        /* do not read gain/scaling/fades and do not count this disk i/o in statistics */

        assert (cnt >= 0);
        return read_from_sources (
                _master_sources, _master_sources.front()->length (_master_sources.front()->timeline_position()),
                buf, position, cnt, chan_n
                );
}

framecnt_t
AudioRegion::read_at (Sample *buf, Sample *mixdown_buffer, float *gain_buffer,
                      framepos_t position,
                      framecnt_t cnt,
                      uint32_t chan_n) const
{
        /* We are reading data from this region into buf (possibly via mixdown_buffer).
           The caller has verified that we cover the desired section.
        */

        /* See doc/region_read.svg for a drawing which might help to explain
           what is going on.
        */

        assert (cnt >= 0);
        
        if (n_channels() == 0) {
                return 0;
        }

        /* WORK OUT WHERE TO GET DATA FROM */

        framecnt_t to_read;

        assert (position >= _position);
        frameoffset_t const internal_offset = position - _position;

        if (internal_offset >= _length) {
                return 0; /* read nothing */
        }

        if ((to_read = min (cnt, _length - internal_offset)) == 0) {
                return 0; /* read nothing */
        }


        /* COMPUTE DETAILS OF ANY FADES INVOLVED IN THIS READ */

        /* Amount (length) of fade in that we are dealing with in this read */
        framecnt_t fade_in_limit = 0;

        /* Offset from buf / mixdown_buffer of the start
           of any fade out that we are dealing with
        */
        frameoffset_t fade_out_offset = 0;
        
        /* Amount (length) of fade out that we are dealing with in this read */
        framecnt_t fade_out_limit = 0;

        framecnt_t fade_interval_start = 0;

        /* Fade in */
        
        if (_fade_in_active && _session.config.get_use_region_fades()) {
                
                framecnt_t fade_in_length = (framecnt_t) _fade_in->back()->when;

                /* see if this read is within the fade in */
                
                if (internal_offset < fade_in_length) {
                        fade_in_limit = min (to_read, fade_in_length - internal_offset);
                }
        }
        
        /* Fade out */
        
        if (_fade_out_active && _session.config.get_use_region_fades()) {
                
                /* see if some part of this read is within the fade out */

                /* .................        >|            REGION
                 *                           _length
                 *
                 *               {           }            FADE
                 *                           fade_out_length
                 *               ^
                 *               _length - fade_out_length
                 *
                 *      |--------------|
                 *      ^internal_offset
                 *                     ^internal_offset + to_read
                 *
                 *                     we need the intersection of [internal_offset,internal_offset+to_read] with
                 *                     [_length - fade_out_length, _length]
                 *
                 */

                fade_interval_start = max (internal_offset, _length - framecnt_t (_fade_out->back()->when));
                framecnt_t fade_interval_end = min(internal_offset + to_read, _length.val());
                
                if (fade_interval_end > fade_interval_start) {
                        /* (part of the) the fade out is in this buffer */
                        fade_out_limit = fade_interval_end - fade_interval_start;
                        fade_out_offset = fade_interval_start - internal_offset;
                }
        }

        /* READ DATA FROM THE SOURCE INTO mixdown_buffer.
           We can never read directly into buf, since it may contain data
           from a region `below' this one in the stack, and our fades (if they exist)
           may need to mix with the existing data.
        */

        if (read_from_sources (_sources, _length, mixdown_buffer, position, to_read, chan_n) != to_read) {
                return 0;
        }

        /* APPLY REGULAR GAIN CURVES AND SCALING TO mixdown_buffer */

        if (envelope_active())  {
                _envelope->curve().get_vector (internal_offset, internal_offset + to_read, gain_buffer, to_read);

                if (_scale_amplitude != 1.0f) {
                        for (framecnt_t n = 0; n < to_read; ++n) {
                                mixdown_buffer[n] *= gain_buffer[n] * _scale_amplitude;
                        }
                } else {
                        for (framecnt_t n = 0; n < to_read; ++n) {
                                mixdown_buffer[n] *= gain_buffer[n];
                        }
                }
        } else if (_scale_amplitude != 1.0f) {
                apply_gain_to_buffer (mixdown_buffer, to_read, _scale_amplitude);
        }

        /* APPLY FADES TO THE DATA IN mixdown_buffer AND MIX THE RESULTS INTO
         * buf. The key things to realize here: (1) the fade being applied is
         * (as of April 26th 2012) just the inverse of the fade in curve (2) 
         * "buf" contains data from lower regions already. So this operation
         * fades out the existing material.
         */

        if (fade_in_limit != 0) {

                if (opaque()) {
                        if (_inverse_fade_in) {

                                /* explicit inverse fade in curve (e.g. for constant
                                 * power), so we have to fetch it.
                                 */
                                
                                _inverse_fade_in->curve().get_vector (internal_offset, internal_offset + fade_in_limit, gain_buffer, fade_in_limit);
                                
                                /* Fade the data from lower layers out */
                                for (framecnt_t n = 0; n < fade_in_limit; ++n) {
                                        buf[n] *= gain_buffer[n];
                                }
                                
                                /* refill gain buffer with the fade in */
                                
                                _fade_in->curve().get_vector (internal_offset, internal_offset + fade_in_limit, gain_buffer, fade_in_limit);
                                
                        } else {
                                
                                /* no explicit inverse fade in, so just use (1 - fade
                                 * in) for the fade out of lower layers
                                 */
                                
                                _fade_in->curve().get_vector (internal_offset, internal_offset + fade_in_limit, gain_buffer, fade_in_limit);
                                
                                for (framecnt_t n = 0; n < fade_in_limit; ++n) {
                                        buf[n] *= 1 - gain_buffer[n];
                                }
                        }
                } else {
                        _fade_in->curve().get_vector (internal_offset, internal_offset + fade_in_limit, gain_buffer, fade_in_limit);
                }

                /* Mix our newly-read data in, with the fade */
                for (framecnt_t n = 0; n < fade_in_limit; ++n) {
                        buf[n] += mixdown_buffer[n] * gain_buffer[n];
                }
        }

        if (fade_out_limit != 0) {

                framecnt_t const curve_offset = fade_interval_start - (_length - _fade_out->back()->when);

                if (opaque()) {
                        if (_inverse_fade_out) {
                                
                                _inverse_fade_out->curve().get_vector (curve_offset, curve_offset + fade_out_limit, gain_buffer, fade_out_limit);
                                
                                /* Fade the data from lower levels in */
                                for (framecnt_t n = 0, m = fade_out_offset; n < fade_out_limit; ++n, ++m) {
                                        buf[m] *= gain_buffer[n];
                                }
                                
                                /* fetch the actual fade out */

                                _fade_out->curve().get_vector (curve_offset, curve_offset + fade_out_limit, gain_buffer, fade_out_limit);
                                
                        } else {

                                /* no explicit inverse fade out (which is
                                 * actually a fade in), so just use (1 - fade
                                 * out) for the fade in of lower layers
                                 */
                                
                                _fade_out->curve().get_vector (curve_offset, curve_offset + fade_out_limit, gain_buffer, fade_out_limit);
                                
                                for (framecnt_t n = 0, m = fade_out_offset; n < fade_out_limit; ++n, ++m) {
                                        buf[m] *= 1 - gain_buffer[n];
                                }
                        }
                } else {
                        _fade_out->curve().get_vector (curve_offset, curve_offset + fade_out_limit, gain_buffer, fade_out_limit);
                }

                /* Mix our newly-read data with whatever was already there,
                   with the fade out applied to our data.
                */
                for (framecnt_t n = 0, m = fade_out_offset; n < fade_out_limit; ++n, ++m) {
                        buf[m] += mixdown_buffer[m] * gain_buffer[n];
                }
        }
        
        /* MIX OR COPY THE REGION BODY FROM mixdown_buffer INTO buf */

        framecnt_t const N = to_read - fade_in_limit - fade_out_limit;
        if (N > 0) {
                if (opaque ()) {
                        DEBUG_TRACE (DEBUG::AudioPlayback, string_compose ("Region %1 memcpy into buf @ %2 + %3, from mixdown buffer @ %4 + %5, len = %6 cnt was %7\n",
                                                                           name(), buf, fade_in_limit, mixdown_buffer, fade_in_limit, N, cnt));
                        memcpy (buf + fade_in_limit, mixdown_buffer + fade_in_limit, N * sizeof (Sample));
                } else {
                        mix_buffers_no_gain (buf + fade_in_limit, mixdown_buffer + fade_in_limit, N);
                }
        }

        return to_read;
}

framecnt_t
AudioRegion::read_from_sources (SourceList const & srcs, framecnt_t limit, Sample* buf, framepos_t position, framecnt_t cnt, uint32_t chan_n) const
{
        frameoffset_t const internal_offset = position - _position;
        if (internal_offset >= limit) {
                return 0;
        }

        framecnt_t const to_read = min (cnt, limit - internal_offset);
        if (to_read == 0) {
                return 0;
        }
        
        if (chan_n < n_channels()) {

                boost::shared_ptr<AudioSource> src = boost::dynamic_pointer_cast<AudioSource> (srcs[chan_n]);
                if (src->read (buf, _start + internal_offset, to_read) != to_read) {
                        return 0; /* "read nothing" */
                }

        } else {

                /* track is N-channel, this region has fewer channels; silence the ones
                   we don't have.
                */

                if (Config->get_replicate_missing_region_channels()) {

                        /* copy an existing channel's data in for this non-existant one */

                        uint32_t channel = chan_n % n_channels();
                        boost::shared_ptr<AudioSource> src = boost::dynamic_pointer_cast<AudioSource> (srcs[channel]);

                        if (src->read (buf, _start + internal_offset, to_read) != to_read) {
                                return 0; /* "read nothing" */
                        }

                } else {
                        
                        /* use silence */
                        memset (buf, 0, sizeof (Sample) * to_read);
                }
        }

        return to_read;
}

XMLNode&
AudioRegion::get_basic_state ()
{
        XMLNode& node (Region::state ());
        char buf[64];
        LocaleGuard lg (X_("C"));

        snprintf (buf, sizeof (buf), "%u", (uint32_t) _sources.size());
        node.add_property ("channels", buf);

        return node;
}

XMLNode&
AudioRegion::state ()
{
        XMLNode& node (get_basic_state());
        XMLNode *child;
        LocaleGuard lg (X_("C"));

        child = node.add_child ("Envelope");

        bool default_env = false;

        // If there are only two points, the points are in the start of the region and the end of the region
        // so, if they are both at 1.0f, that means the default region.

        if (_envelope->size() == 2 &&
            _envelope->front()->value == GAIN_COEFF_UNITY &&
            _envelope->back()->value==GAIN_COEFF_UNITY) {
                if (_envelope->front()->when == 0 && _envelope->back()->when == _length) {
                        default_env = true;
                }
        }

        if (default_env) {
                child->add_property ("default", "yes");
        } else {
                child->add_child_nocopy (_envelope->get_state ());
        }

        child = node.add_child (X_("FadeIn"));

        if (_default_fade_in) {
                child->add_property ("default", "yes");
        } else {
                child->add_child_nocopy (_fade_in->get_state ());
        }

        if (_inverse_fade_in) {
                child = node.add_child (X_("InverseFadeIn"));
                child->add_child_nocopy (_inverse_fade_in->get_state ());
        }

        child = node.add_child (X_("FadeOut"));

        if (_default_fade_out) {
                child->add_property ("default", "yes");
        } else {
                child->add_child_nocopy (_fade_out->get_state ());
        }

        if (_inverse_fade_out) {
                child = node.add_child (X_("InverseFadeOut"));
                child->add_child_nocopy (_inverse_fade_out->get_state ());
        }

        return node;
}

int
AudioRegion::_set_state (const XMLNode& node, int version, PropertyChange& what_changed, bool send)
{
        const XMLNodeList& nlist = node.children();
        const XMLProperty *prop;
        LocaleGuard lg (X_("C"));
        boost::shared_ptr<Playlist> the_playlist (_playlist.lock());

        suspend_property_changes ();

        if (the_playlist) {
                the_playlist->freeze ();
        }


        /* this will set all our State members and stuff controlled by the Region.
           It should NOT send any changed signals - that is our responsibility.
        */

        Region::_set_state (node, version, what_changed, false);

        if ((prop = node.property ("scale-gain")) != 0) {
                float a = atof (prop->value().c_str());
                if (a != _scale_amplitude) {
                        _scale_amplitude = a;
                        what_changed.add (Properties::scale_amplitude);
                }
        }

        /* Now find envelope description and other related child items */

        _envelope->freeze ();

        for (XMLNodeConstIterator niter = nlist.begin(); niter != nlist.end(); ++niter) {
                XMLNode *child;
                XMLProperty *prop;

                child = (*niter);

                if (child->name() == "Envelope") {

                        _envelope->clear ();

                        if ((prop = child->property ("default")) != 0 || _envelope->set_state (*child, version)) {
                                set_default_envelope ();
                        }

                        _envelope->truncate_end (_length);


                } else if (child->name() == "FadeIn") {

                        _fade_in->clear ();

                        if (((prop = child->property ("default")) != 0 && string_is_affirmative (prop->value())) || (prop = child->property ("steepness")) != 0) {
                                set_default_fade_in ();
                        } else {
                                XMLNode* grandchild = child->child ("AutomationList");
                                if (grandchild) {
                                        _fade_in->set_state (*grandchild, version);
                                }
                        }

                        if ((prop = child->property ("active")) != 0) {
                                if (string_is_affirmative (prop->value())) {
                                        set_fade_in_active (true);
                                } else {
                                        set_fade_in_active (false);
                                }
                        }

                } else if (child->name() == "FadeOut") {

                        _fade_out->clear ();

                        if (((prop = child->property ("default")) != 0 && (string_is_affirmative (prop->value()))) || (prop = child->property ("steepness")) != 0) {
                                set_default_fade_out ();
                        } else {
                                XMLNode* grandchild = child->child ("AutomationList");
                                if (grandchild) {
                                        _fade_out->set_state (*grandchild, version);
                                }
                        }
                        
                        if ((prop = child->property ("active")) != 0) {
                                if (string_is_affirmative (prop->value())) {
                                        set_fade_out_active (true);
                                } else {
                                        set_fade_out_active (false);
                                }
                        }
        
                } else if ( (child->name() == "InverseFadeIn") || (child->name() == "InvFadeIn")  ) {
                        XMLNode* grandchild = child->child ("AutomationList");
                        if (grandchild) {
                                _inverse_fade_in->set_state (*grandchild, version);
                        }
                } else if ( (child->name() == "InverseFadeOut") || (child->name() == "InvFadeOut") ) {
                        XMLNode* grandchild = child->child ("AutomationList");
                        if (grandchild) {
                                _inverse_fade_out->set_state (*grandchild, version);
                        }
                }
        }

        _envelope->thaw ();
        resume_property_changes ();

        if (send) {
                send_change (what_changed);
        }

        if (the_playlist) {
                the_playlist->thaw ();
        }

        return 0;
}

int
AudioRegion::set_state (const XMLNode& node, int version)
{
        PropertyChange what_changed;
        return _set_state (node, version, what_changed, true);
}

void
AudioRegion::fade_range (framepos_t start, framepos_t end)
{
        framepos_t s, e;

        switch (coverage (start, end)) {
        case Evoral::OverlapStart:
                s = _position;
                e = end;
                set_fade_in (FadeConstantPower, e - s);
                break;
        case Evoral::OverlapEnd:
                s = start;
                e = _position + _length;
                set_fade_out (FadeConstantPower, e - s);
                break;
        case Evoral::OverlapInternal:
                /* needs addressing, perhaps. Difficult to do if we can't
                 * control one edge of the fade relative to the relevant edge
                 * of the region, which we cannot - fades are currently assumed
                 * to start/end at the start/end of the region
                 */
                break;
        default:
                return;
        }
}

void
AudioRegion::set_fade_in_shape (FadeShape shape)
{
        set_fade_in (shape, (framecnt_t) _fade_in->back()->when);
}

void
AudioRegion::set_fade_out_shape (FadeShape shape)
{
        set_fade_out (shape, (framecnt_t) _fade_out->back()->when);
}

void
AudioRegion::set_fade_in (boost::shared_ptr<AutomationList> f)
{
        _fade_in->freeze ();
        *(_fade_in.val()) = *f;
        _fade_in->thaw ();
        _default_fade_in = false;

        send_change (PropertyChange (Properties::fade_in));
}

void
AudioRegion::set_fade_in (FadeShape shape, framecnt_t len)
{
        const ARDOUR::ParameterDescriptor desc(FadeInAutomation);
        boost::shared_ptr<Evoral::ControlList> c1 (new Evoral::ControlList (FadeInAutomation, desc));
        boost::shared_ptr<Evoral::ControlList> c2 (new Evoral::ControlList (FadeInAutomation, desc));
        boost::shared_ptr<Evoral::ControlList> c3 (new Evoral::ControlList (FadeInAutomation, desc));

        _fade_in->freeze ();
        _fade_in->clear ();
        _inverse_fade_in->clear ();

        const int num_steps = 32;

        switch (shape) {
        case FadeLinear:
                _fade_in->fast_simple_add (0.0, GAIN_COEFF_SMALL);
                _fade_in->fast_simple_add (len, GAIN_COEFF_UNITY);
                reverse_curve (_inverse_fade_in.val(), _fade_in.val());
                break;

        case FadeFast:
                generate_db_fade (_fade_in.val(), len, num_steps, -60);
                reverse_curve (c1, _fade_in.val());
                _fade_in->copy_events (*c1);
                generate_inverse_power_curve (_inverse_fade_in.val(), _fade_in.val());
                break;

        case FadeSlow:
                generate_db_fade (c1, len, num_steps, -1);  // start off with a slow fade
                generate_db_fade (c2, len, num_steps, -80); // end with a fast fade
                merge_curves (_fade_in.val(), c1, c2);
                reverse_curve (c3, _fade_in.val());
                _fade_in->copy_events (*c3);
                generate_inverse_power_curve (_inverse_fade_in.val(), _fade_in.val());
                break;

        case FadeConstantPower:
                _fade_in->fast_simple_add (0.0, GAIN_COEFF_SMALL);
                for (int i = 1; i < num_steps; ++i) {
                        const float dist = i / (num_steps + 1.f);
                        _fade_in->fast_simple_add (len * dist, sin (dist * M_PI / 2.0));
                }
                _fade_in->fast_simple_add (len, GAIN_COEFF_UNITY);
                reverse_curve (_inverse_fade_in.val(), _fade_in.val());
                break;
                
        case FadeSymmetric:
                //start with a nearly linear cuve
                _fade_in->fast_simple_add (0, 1);
                _fade_in->fast_simple_add (0.5 * len, 0.6);
                //now generate a fade-out curve by successively applying a gain drop
                const double breakpoint = 0.7;  //linear for first 70%
                for (int i = 2; i < 9; ++i) {
                        const float coeff = (1.f - breakpoint) * powf (0.5, i);
                        _fade_in->fast_simple_add (len * (breakpoint + ((GAIN_COEFF_UNITY - breakpoint) * (double)i / 9.0)), coeff);
                }
                _fade_in->fast_simple_add (len, GAIN_COEFF_SMALL);
                reverse_curve (c3, _fade_in.val());
                _fade_in->copy_events (*c3);
                reverse_curve (_inverse_fade_in.val(), _fade_in.val());
                break;
        }

        _fade_in->set_interpolation(Evoral::ControlList::Curved);
        _inverse_fade_in->set_interpolation(Evoral::ControlList::Curved);

        _default_fade_in = false;
        _fade_in->thaw ();
        send_change (PropertyChange (Properties::fade_in));
}

void
AudioRegion::set_fade_out (boost::shared_ptr<AutomationList> f)
{
        _fade_out->freeze ();
        *(_fade_out.val()) = *f;
        _fade_out->thaw ();
        _default_fade_out = false;

        send_change (PropertyChange (Properties::fade_in));
}

void
AudioRegion::set_fade_out (FadeShape shape, framecnt_t len)
{
        const ARDOUR::ParameterDescriptor desc(FadeOutAutomation);
        boost::shared_ptr<Evoral::ControlList> c1 (new Evoral::ControlList (FadeOutAutomation, desc));
        boost::shared_ptr<Evoral::ControlList> c2 (new Evoral::ControlList (FadeOutAutomation, desc));

        _fade_out->freeze ();
        _fade_out->clear ();
        _inverse_fade_out->clear ();

        const int num_steps = 32;

        switch (shape) {
        case FadeLinear:
                _fade_out->fast_simple_add (0.0, GAIN_COEFF_UNITY);
                _fade_out->fast_simple_add (len, GAIN_COEFF_SMALL);
                reverse_curve (_inverse_fade_out.val(), _fade_out.val());
                break;
                
        case FadeFast: 
                generate_db_fade (_fade_out.val(), len, num_steps, -60);
                generate_inverse_power_curve (_inverse_fade_out.val(), _fade_out.val());
                break;
                
        case FadeSlow: 
                generate_db_fade (c1, len, num_steps, -1);  //start off with a slow fade
                generate_db_fade (c2, len, num_steps, -80);  //end with a fast fade
                merge_curves (_fade_out.val(), c1, c2);
                generate_inverse_power_curve (_inverse_fade_out.val(), _fade_out.val());
                break;

        case FadeConstantPower:
                //constant-power fades use a sin/cos relationship
                //the cutoff is abrupt but it has the benefit of being symmetrical
                _fade_out->fast_simple_add (0.0, GAIN_COEFF_UNITY);
                for (int i = 1; i < num_steps; ++i) {
                        const float dist = i / (num_steps + 1.f);
                        _fade_out->fast_simple_add (len * dist, cos (dist * M_PI / 2.0));
                }
                _fade_out->fast_simple_add (len, GAIN_COEFF_SMALL);
                reverse_curve (_inverse_fade_out.val(), _fade_out.val());
                break;
                
        case FadeSymmetric:
                //start with a nearly linear cuve
                _fade_out->fast_simple_add (0, 1);
                _fade_out->fast_simple_add (0.5 * len, 0.6);
                //now generate a fade-out curve by successively applying a gain drop
                const double breakpoint = 0.7;  //linear for first 70%
                for (int i = 2; i < 9; ++i) {
                        const float coeff = (1.f - breakpoint) * powf (0.5, i);
                        _fade_out->fast_simple_add (len * (breakpoint + ((GAIN_COEFF_UNITY - breakpoint) * (double)i / 9.0)), coeff);
                }
                _fade_out->fast_simple_add (len, GAIN_COEFF_SMALL);
                reverse_curve (_inverse_fade_out.val(), _fade_out.val());
                break;
        }

        _fade_out->set_interpolation(Evoral::ControlList::Curved);
        _inverse_fade_out->set_interpolation(Evoral::ControlList::Curved);

        _default_fade_out = false;
        _fade_out->thaw ();
        send_change (PropertyChange (Properties::fade_out));
}

void
AudioRegion::set_fade_in_length (framecnt_t len)
{
        if (len > _length) {
                len = _length - 1;
        }
        
        if (len < 64) {
                len = 64;
        }

        bool changed = _fade_in->extend_to (len);

        if (changed) {
                if (_inverse_fade_in) {
                        _inverse_fade_in->extend_to (len);
                }

                _default_fade_in = false;
                send_change (PropertyChange (Properties::fade_in));
        }
}

void
AudioRegion::set_fade_out_length (framecnt_t len)
{
        if (len > _length) {
                len = _length - 1;
        }

        if (len < 64) {
                len = 64;
        }

        bool changed =  _fade_out->extend_to (len);

        if (changed) {
                
                if (_inverse_fade_out) {
                        _inverse_fade_out->extend_to (len);
                }
                _default_fade_out = false;

                send_change (PropertyChange (Properties::fade_out));
        }
}

void
AudioRegion::set_fade_in_active (bool yn)
{
        if (yn == _fade_in_active) {
                return;
        }

        _fade_in_active = yn;
        send_change (PropertyChange (Properties::fade_in_active));
}

void
AudioRegion::set_fade_out_active (bool yn)
{
        if (yn == _fade_out_active) {
                return;
        }
        _fade_out_active = yn;
        send_change (PropertyChange (Properties::fade_out_active));
}

bool
AudioRegion::fade_in_is_default () const
{
        return _fade_in->size() == 2 && _fade_in->front()->when == 0 && _fade_in->back()->when == 64;
}

bool
AudioRegion::fade_out_is_default () const
{
        return _fade_out->size() == 2 && _fade_out->front()->when == 0 && _fade_out->back()->when == 64;
}

void
AudioRegion::set_default_fade_in ()
{
        _fade_in_suspended = 0;
        set_fade_in (Config->get_default_fade_shape(), 64);
}

void
AudioRegion::set_default_fade_out ()
{
        _fade_out_suspended = 0;
        set_fade_out (Config->get_default_fade_shape(), 64);
}

void
AudioRegion::set_default_fades ()
{
        set_default_fade_in ();
        set_default_fade_out ();
}

void
AudioRegion::set_default_envelope ()
{
        _envelope->freeze ();
        _envelope->clear ();
        _envelope->fast_simple_add (0, GAIN_COEFF_UNITY);
        _envelope->fast_simple_add (_length, GAIN_COEFF_UNITY);
        _envelope->thaw ();
}

void
AudioRegion::recompute_at_end ()
{
        /* our length has changed. recompute a new final point by interpolating
           based on the the existing curve.
        */

        _envelope->freeze ();
        _envelope->truncate_end (_length);
        _envelope->thaw ();

        suspend_property_changes();

        if (_left_of_split) {
                set_default_fade_out ();
                _left_of_split = false;
        } else if (_fade_out->back()->when > _length) {
                _fade_out->extend_to (_length);
                send_change (PropertyChange (Properties::fade_out));
        }

        if (_fade_in->back()->when > _length) {
                _fade_in->extend_to (_length);
                send_change (PropertyChange (Properties::fade_in));
        }

        resume_property_changes();
}

void
AudioRegion::recompute_at_start ()
{
        /* as above, but the shift was from the front */

        _envelope->truncate_start (_length);

        suspend_property_changes();

        if (_right_of_split) {
                set_default_fade_in ();
                _right_of_split = false;
        } else if (_fade_in->back()->when > _length) {
                _fade_in->extend_to (_length);
                send_change (PropertyChange (Properties::fade_in));
        }

        if (_fade_out->back()->when > _length) {
                _fade_out->extend_to (_length);
                send_change (PropertyChange (Properties::fade_out));
        }

        resume_property_changes();
}

int
AudioRegion::separate_by_channel (Session& /*session*/, vector<boost::shared_ptr<Region> >& v) const
{
        SourceList srcs;
        string new_name;
        int n = 0;

        if (_sources.size() < 2) {
                return 0;
        }

        for (SourceList::const_iterator i = _sources.begin(); i != _sources.end(); ++i) {
                srcs.clear ();
                srcs.push_back (*i);

                new_name = _name;

                if (_sources.size() == 2) {
                        if (n == 0) {
                                new_name += "-L";
                        } else {
                                new_name += "-R";
                        }
                } else {
                        new_name += '-';
                        new_name += ('0' + n + 1);
                }

                /* create a copy with just one source. prevent if from being thought of as
                   "whole file" even if it covers the entire source file(s).
                 */

                PropertyList plist;

                plist.add (Properties::start, _start.val());
                plist.add (Properties::length, _length.val());
                plist.add (Properties::name, new_name);
                plist.add (Properties::layer, layer ());

                v.push_back(RegionFactory::create (srcs, plist));
                v.back()->set_whole_file (false);

                ++n;
        }

        return 0;
}

framecnt_t
AudioRegion::read_raw_internal (Sample* buf, framepos_t pos, framecnt_t cnt, int channel) const
{
        return audio_source(channel)->read (buf, pos, cnt);
}

void
AudioRegion::set_scale_amplitude (gain_t g)
{
        boost::shared_ptr<Playlist> pl (playlist());

        _scale_amplitude = g;

        /* tell the diskstream we're in */

        if (pl) {
                pl->ContentsChanged();
        }

        /* tell everybody else */

        send_change (PropertyChange (Properties::scale_amplitude));
}

double
AudioRegion::maximum_amplitude (Progress* p) const
{
        framepos_t fpos = _start;
        framepos_t const fend = _start + _length;
        double maxamp = 0;

        framecnt_t const blocksize = 64 * 1024;
        Sample buf[blocksize];

        while (fpos < fend) {

                uint32_t n;

                framecnt_t const to_read = min (fend - fpos, blocksize);

                for (n = 0; n < n_channels(); ++n) {

                        /* read it in */

                        if (read_raw_internal (buf, fpos, to_read, n) != to_read) {
                                return 0;
                        }

                        maxamp = compute_peak (buf, to_read, maxamp);
                }

                fpos += to_read;
                if (p) {
                        p->set_progress (float (fpos - _start) / _length);
                        if (p->cancelled ()) {
                                return -1;
                        }
                }
        }

        return maxamp;
}

void
AudioRegion::normalize (float max_amplitude, float target_dB)
{
        gain_t target = dB_to_coefficient (target_dB);

        if (target == GAIN_COEFF_UNITY) {
                /* do not normalize to precisely 1.0 (0 dBFS), to avoid making it appear
                   that we may have clipped.
                */
                target -= FLT_EPSILON;
        }

        if (max_amplitude < GAIN_COEFF_SMALL) {
                /* don't even try */
                return;
        }

        if (max_amplitude == target) {
                /* we can't do anything useful */
                return;
        }

        set_scale_amplitude (target / max_amplitude);
}

void
AudioRegion::fade_in_changed ()
{
        send_change (PropertyChange (Properties::fade_in));
}

void
AudioRegion::fade_out_changed ()
{
        send_change (PropertyChange (Properties::fade_out));
}

void
AudioRegion::envelope_changed ()
{
        send_change (PropertyChange (Properties::envelope));
}

void
AudioRegion::suspend_fade_in ()
{
        if (++_fade_in_suspended == 1) {
                if (fade_in_is_default()) {
                        set_fade_in_active (false);
                }
        }
}

void
AudioRegion::resume_fade_in ()
{
        if (--_fade_in_suspended == 0 && _fade_in_suspended) {
                set_fade_in_active (true);
        }
}

void
AudioRegion::suspend_fade_out ()
{
        if (++_fade_out_suspended == 1) {
                if (fade_out_is_default()) {
                        set_fade_out_active (false);
                }
        }
}

void
AudioRegion::resume_fade_out ()
{
        if (--_fade_out_suspended == 0 &&_fade_out_suspended) {
                set_fade_out_active (true);
        }
}

bool
AudioRegion::speed_mismatch (float sr) const
{
        if (_sources.empty()) {
                /* impossible, but ... */
                return false;
        }

        float fsr = audio_source()->sample_rate();

        return fsr != sr;
}

void
AudioRegion::source_offset_changed ()
{
        /* XXX this fixes a crash that should not occur. It does occur
           becauses regions are not being deleted when a session
           is unloaded. That bug must be fixed.
        */

        if (_sources.empty()) {
                return;
        }

        boost::shared_ptr<AudioFileSource> afs = boost::dynamic_pointer_cast<AudioFileSource>(_sources.front());

        if (afs && afs->destructive()) {
                // set_start (source()->natural_position(), this);
                set_position (source()->natural_position());
        }
}

boost::shared_ptr<AudioSource>
AudioRegion::audio_source (uint32_t n) const
{
        // Guaranteed to succeed (use a static cast for speed?)
        return boost::dynamic_pointer_cast<AudioSource>(source(n));
}

int
AudioRegion::adjust_transients (frameoffset_t delta)
{
        for (AnalysisFeatureList::iterator x = _transients.begin(); x != _transients.end(); ++x) {
                (*x) = (*x) + delta;
        }

        send_change (PropertyChange (Properties::valid_transients));

        return 0;
}

int
AudioRegion::update_transient (framepos_t old_position, framepos_t new_position)
{
        for (AnalysisFeatureList::iterator x = _transients.begin(); x != _transients.end(); ++x) {
                if ((*x) == old_position) {
                        (*x) = new_position;
                        send_change (PropertyChange (Properties::valid_transients));

                        break;
                }
        }

        return 0;
}

void
AudioRegion::add_transient (framepos_t where)
{
        _transients.push_back(where);
        _valid_transients = true;

        send_change (PropertyChange (Properties::valid_transients));
}

void
AudioRegion::remove_transient (framepos_t where)
{
        _transients.remove(where);
        _valid_transients = true;

        send_change (PropertyChange (Properties::valid_transients));
}

int
AudioRegion::set_transients (AnalysisFeatureList& results)
{
        _transients.clear();
        _transients = results;
        _valid_transients = true;

        send_change (PropertyChange (Properties::valid_transients));

        return 0;
}

int
AudioRegion::get_transients (AnalysisFeatureList& results, bool force_new)
{
        boost::shared_ptr<Playlist> pl = playlist();

        if (!pl) {
                return -1;
        }

        if (_valid_transients && !force_new) {
                results = _transients;
                return 0;
        }

        SourceList::iterator s;

        for (s = _sources.begin() ; s != _sources.end(); ++s) {
                if (!(*s)->has_been_analysed()) {
                        cerr << "For " << name() << " source " << (*s)->name() << " has not been analyzed\n";
                        break;
                }
        }

        if (s == _sources.end()) {
                /* all sources are analyzed, merge data from each one */

                for (s = _sources.begin() ; s != _sources.end(); ++s) {

                        /* find the set of transients within the bounds of this region */

                        AnalysisFeatureList::iterator low = lower_bound ((*s)->transients.begin(),
                                                                         (*s)->transients.end(),
                                                                         _start);

                        AnalysisFeatureList::iterator high = upper_bound ((*s)->transients.begin(),
                                                                          (*s)->transients.end(),
                                                                          _start + _length);

                        /* and add them */

                        results.insert (results.end(), low, high);
                }

                TransientDetector::cleanup_transients (results, pl->session().frame_rate(), 3.0);

                /* translate all transients to current position */

                for (AnalysisFeatureList::iterator x = results.begin(); x != results.end(); ++x) {
                        (*x) -= _start;
                        (*x) += _position;
                }

                _transients = results;
                _valid_transients = true;

                return 0;
        }

        /* no existing/complete transient info */

        static bool analyse_dialog_shown = false; /* global per instance of Ardour */

        if (!Config->get_auto_analyse_audio()) {
                if (!analyse_dialog_shown) {
                        pl->session().Dialog (string_compose (_("\
You have requested an operation that requires audio analysis.\n\n\
You currently have \"auto-analyse-audio\" disabled, which means \
that transient data must be generated every time it is required.\n\n\
If you are doing work that will require transient data on a \
regular basis, you should probably enable \"auto-analyse-audio\" \
then quit %1 and restart.\n\n\
This dialog will not display again.  But you may notice a slight delay \
in this and future transient-detection operations.\n\
"), PROGRAM_NAME));
                        analyse_dialog_shown = true;
                }
        }

        bool existing_results = !results.empty();

        try {

                TransientDetector t (pl->session().frame_rate());

                _transients.clear ();
                _valid_transients = false;

                for (uint32_t i = 0; i < n_channels(); ++i) {

                        AnalysisFeatureList these_results;

                        t.reset ();

                        if (t.run ("", this, i, these_results)) {
                                return -1;
                        }

                        /* translate all transients to give absolute position */

                        for (AnalysisFeatureList::iterator i = these_results.begin(); i != these_results.end(); ++i) {
                                (*i) += _position;
                        }

                        /* merge */

                        _transients.insert (_transients.end(), these_results.begin(), these_results.end());
                }
        } catch (...) {
                error << string_compose(_("Transient Analysis failed for %1."), _("Audio Region")) << endmsg;
                return -1;
        }

        if (!results.empty()) {
                if (existing_results) {

                        /* merge our transients into the existing ones, then clean up
                           those.
                        */

                        results.insert (results.end(), _transients.begin(), _transients.end());
                        TransientDetector::cleanup_transients (results, pl->session().frame_rate(), 3.0);
                }

                /* make sure ours are clean too */

                TransientDetector::cleanup_transients (_transients, pl->session().frame_rate(), 3.0);

        } else {

                TransientDetector::cleanup_transients (_transients, pl->session().frame_rate(), 3.0);
                results = _transients;
        }

        _valid_transients = true;

        return 0;
}

AudioIntervalResult
AudioRegion::find_silence (Sample threshold, framecnt_t min_length, InterThreadInfo& itt) const
{
        framecnt_t const block_size = 64 * 1024;
        boost::scoped_array<Sample> loudest (new Sample[block_size]);
        boost::scoped_array<Sample> buf (new Sample[block_size]);

        framepos_t pos = _start;
        framepos_t const end = _start + _length - 1;

        AudioIntervalResult silent_periods;

        bool in_silence = false;
        frameoffset_t silence_start = 0;

        while (pos < end && !itt.cancel) {

                /* fill `loudest' with the loudest absolute sample at each instant, across all channels */
                memset (loudest.get(), 0, sizeof (Sample) * block_size);
                for (uint32_t n = 0; n < n_channels(); ++n) {

                        read_raw_internal (buf.get(), pos, block_size, n);
                        for (framecnt_t i = 0; i < block_size; ++i) {
                                loudest[i] = max (loudest[i], abs (buf[i]));
                        }
                }

                /* now look for silence */
                for (framecnt_t i = 0; i < block_size; ++i) {
                        bool const silence = abs (loudest[i]) < threshold;
                        if (silence && !in_silence) {
                                /* non-silence to silence */
                                in_silence = true;
                                silence_start = pos + i;
                        } else if (!silence && in_silence) {
                                /* silence to non-silence */
                                in_silence = false;
                                if (pos + i - 1 - silence_start >= min_length) {
                                        silent_periods.push_back (std::make_pair (silence_start, pos + i - 1));
                                }
                        }
                }

                pos += block_size;
                itt.progress = (end-pos)/(double)_length;
        }

        if (in_silence && end - 1 - silence_start >= min_length) {
                /* last block was silent, so finish off the last period */
                silent_periods.push_back (std::make_pair (silence_start, end));
        }

        itt.done = true;

        return silent_periods;
}

Evoral::Range<framepos_t>
AudioRegion::body_range () const
{
        return Evoral::Range<framepos_t> (first_frame() + _fade_in->back()->when + 1, last_frame() - _fade_out->back()->when);
}

boost::shared_ptr<Region>
AudioRegion::get_single_other_xfade_region (bool start) const
{
        boost::shared_ptr<Playlist> pl (playlist());

        if (!pl) {
                /* not currently in a playlist - xfade length is unbounded
                   (and irrelevant)
                */
                return boost::shared_ptr<AudioRegion> ();
        }

        boost::shared_ptr<RegionList> rl;

        if (start) {
                rl = pl->regions_at (position());
        } else {
                rl = pl->regions_at (last_frame());
        }
        
        RegionList::iterator i;
        boost::shared_ptr<Region> other;
        uint32_t n = 0;

        /* count and find the other region in a single pass through the list */

        for (i = rl->begin(); i != rl->end(); ++i) {
                if ((*i).get() != this) {
                        other = *i;
                }
                ++n;
        }

        if (n != 2) {
                /* zero or multiple regions stacked here - don't care about xfades */
                return boost::shared_ptr<AudioRegion> ();
        }

        return other;
}

framecnt_t
AudioRegion::verify_xfade_bounds (framecnt_t len, bool start)
{
        /* this is called from a UI to check on whether a new proposed
           length for an xfade is legal or not. it returns the legal
           length corresponding to @a len which may be shorter than or
           equal to @a len itself.
        */

        boost::shared_ptr<Region> other = get_single_other_xfade_region (start);
        framecnt_t maxlen;

        if (!other) {
                /* zero or > 2 regions here, don't care about len, but
                   it can't be longer than the region itself.
                 */
                return min (length(), len);
        }

        /* we overlap a single region. clamp the length of an xfade to
           the maximum possible duration of the overlap (if the other
           region were trimmed appropriately).
        */

        if (start) {
                maxlen = other->latest_possible_frame() - position();
        } else {
                maxlen = last_frame() - other->earliest_possible_position();
        }

        return min (length(), min (maxlen, len));
                
}