amp.cc

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/*
    Copyright (C) 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 <iostream>
#include <cstring>
#include <cmath>
#include <algorithm>

#include "evoral/Curve.hpp"

#include "ardour/amp.h"
#include "ardour/audio_buffer.h"
#include "ardour/buffer_set.h"
#include "ardour/midi_buffer.h"
#include "ardour/rc_configuration.h"
#include "ardour/session.h"

#include "i18n.h"

using namespace ARDOUR;
using namespace PBD;

// used for low-pass filter denormal protection
#define GAIN_COEFF_TINY (1e-10) // -200dB

Amp::Amp (Session& s, std::string type)
        : Processor(s, "Amp")
        , _apply_gain(true)
        , _apply_gain_automation(false)
        , _current_gain(GAIN_COEFF_UNITY)
        , _current_automation_frame (INT64_MAX)
        , _gain_automation_buffer(0)
        , _type (type)
        , _midi_amp (type != "trim")
{
        Evoral::Parameter p (_type == "trim" ? TrimAutomation : GainAutomation);
        boost::shared_ptr<AutomationList> gl (new AutomationList (p));
        _gain_control = boost::shared_ptr<GainControl> (new GainControl ((_type == "trim") ? X_("trimcontrol") : X_("gaincontrol"), s, this, p, gl));
        _gain_control->set_flags (Controllable::GainLike);

        add_control(_gain_control);
}

std::string
Amp::display_name() const
{
        return _("Fader");
}

bool
Amp::can_support_io_configuration (const ChanCount& in, ChanCount& out)
{
        out = in;
        return true;
}

bool
Amp::configure_io (ChanCount in, ChanCount out)
{
        if (out != in) { // always 1:1
                return false;
        }

        return Processor::configure_io (in, out);
}

void
Amp::run (BufferSet& bufs, framepos_t /*start_frame*/, framepos_t /*end_frame*/, pframes_t nframes, bool)
{
        if (!_active && !_pending_active) {
                return;
        }

        if (_apply_gain) {

                if (_apply_gain_automation) {

                        gain_t* gab = _gain_automation_buffer;
                        assert (gab);

                        if (_midi_amp) {
                                for (BufferSet::midi_iterator i = bufs.midi_begin(); i != bufs.midi_end(); ++i) {
                                        MidiBuffer& mb (*i);
                                        for (MidiBuffer::iterator m = mb.begin(); m != mb.end(); ++m) {
                                                Evoral::MIDIEvent<MidiBuffer::TimeType> ev = *m;
                                                if (ev.is_note_on()) {
                                                        assert(ev.time() >= 0 && ev.time() < nframes);
                                                        ev.scale_velocity (fabsf (gab[ev.time()]));
                                                }
                                        }
                                }
                        }


                        const double a = 156.825 / _session.nominal_frame_rate(); // 25 Hz LPF; see Amp::apply_gain for details
                        double lpf = _current_gain;

                        for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
                                Sample* const sp = i->data();
                                lpf = _current_gain;
                                for (pframes_t nx = 0; nx < nframes; ++nx) {
                                        sp[nx] *= lpf;
                                        lpf += a * (gab[nx] - lpf);
                                }
                        }

                        if (fabs (lpf) < GAIN_COEFF_TINY) {
                                _current_gain = GAIN_COEFF_ZERO;
                        } else {
                                _current_gain = lpf;
                        }

                } else { /* manual (scalar) gain */

                        gain_t const dg = _gain_control->user_double();

                        if (_current_gain != dg) {

                                _current_gain = Amp::apply_gain (bufs, _session.nominal_frame_rate(), nframes, _current_gain, dg, _midi_amp);

                        } else if (_current_gain != GAIN_COEFF_UNITY) {

                                /* gain has not changed, but its non-unity */

                                if (_midi_amp) {
                                        /* don't Trim midi velocity -- only relevant for Midi on Audio tracks */
                                        for (BufferSet::midi_iterator i = bufs.midi_begin(); i != bufs.midi_end(); ++i) {

                                                MidiBuffer& mb (*i);

                                                for (MidiBuffer::iterator m = mb.begin(); m != mb.end(); ++m) {
                                                        Evoral::MIDIEvent<MidiBuffer::TimeType> ev = *m;
                                                        if (ev.is_note_on()) {
                                                                ev.scale_velocity (fabsf (_current_gain));
                                                        }
                                                }
                                        }
                                }

                                for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
                                        apply_gain_to_buffer (i->data(), nframes, _current_gain);
                                }
                        }
                }
        }

        _active = _pending_active;
}

gain_t
Amp::apply_gain (BufferSet& bufs, framecnt_t sample_rate, framecnt_t nframes, gain_t initial, gain_t target, bool midi_amp)
{
        gain_t rv = target;

        if (nframes == 0 || bufs.count().n_total() == 0) {
                return initial;
        }

        // if we don't need to declick, defer to apply_simple_gain
        if (initial == target) {
                apply_simple_gain (bufs, nframes, target);
                return target;
        }

        /* MIDI Gain */
        if (midi_amp) {
                /* don't Trim midi velocity -- only relevant for Midi on Audio tracks */
                for (BufferSet::midi_iterator i = bufs.midi_begin(); i != bufs.midi_end(); ++i) {

                        gain_t  delta;
                        if (target < initial) {
                                /* fade out: remove more and more of delta from initial */
                                delta = -(initial - target);
                        } else {
                                /* fade in: add more and more of delta from initial */
                                delta = target - initial;
                        }

                        MidiBuffer& mb (*i);

                        for (MidiBuffer::iterator m = mb.begin(); m != mb.end(); ++m) {
                                Evoral::MIDIEvent<MidiBuffer::TimeType> ev = *m;

                                if (ev.is_note_on()) {
                                        const gain_t scale = delta * (ev.time()/(double) nframes);
                                        ev.scale_velocity (fabsf (initial+scale));
                                }
                        }
                }
        }

        /* Audio Gain */

        /* Low pass filter coefficient: 1.0 - e^(-2.0 * π * f / 48000) f in Hz.
         * for f << SR,  approx a ~= 6.2 * f / SR;
         */
        const double a = 156.825 / sample_rate; // 25 Hz LPF

        for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
                Sample* const buffer = i->data();
                double lpf = initial;

                for (pframes_t nx = 0; nx < nframes; ++nx) {
                        buffer[nx] *= lpf;
                        lpf += a * (target - lpf);
                }
                if (i == bufs.audio_begin()) {
                        rv = lpf;
                }
        }
        if (fabsf (rv - target) < GAIN_COEFF_TINY) return target;
        if (fabsf (rv) < GAIN_COEFF_TINY) return GAIN_COEFF_ZERO;
        return rv;
}

void
Amp::declick (BufferSet& bufs, framecnt_t nframes, int dir)
{
        if (nframes == 0 || bufs.count().n_total() == 0) {
                return;
        }

        const framecnt_t declick = std::min ((framecnt_t) 512, nframes);
        const double     fractional_shift = 1.0 / declick ;
        gain_t           delta, initial;

        if (dir < 0) {
                /* fade out: remove more and more of delta from initial */
                delta = -1.0;
                initial = GAIN_COEFF_UNITY;
        } else {
                /* fade in: add more and more of delta from initial */
                delta = 1.0;
                initial = GAIN_COEFF_ZERO;
        }

        /* Audio Gain */
        for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
                Sample* const buffer = i->data();

                double fractional_pos = 0.0;

                for (pframes_t nx = 0; nx < declick; ++nx) {
                        buffer[nx] *= initial + (delta * fractional_pos);
                        fractional_pos += fractional_shift;
                }

                /* now ensure the rest of the buffer has the target value applied, if necessary. */
                if (declick != nframes) {
                        if (dir < 0) {
                                memset (&buffer[declick], 0, sizeof (Sample) * (nframes - declick));
                        }
                }
        }
}


gain_t
Amp::apply_gain (AudioBuffer& buf, framecnt_t sample_rate, framecnt_t nframes, gain_t initial, gain_t target)
{
        /* Apply a (potentially) declicked gain to the contents of @a buf
         * -- used by MonitorProcessor::run()
         */

        if (nframes == 0) {
                return initial;
        }

        // if we don't need to declick, defer to apply_simple_gain
        if (initial == target) {
                apply_simple_gain (buf, nframes, target);
                return target;
        }

        Sample* const buffer = buf.data();
        const double a = 156.825 / sample_rate; // 25 Hz LPF, see [other] Amp::apply_gain() above for details

        double lpf = initial;
        for (pframes_t nx = 0; nx < nframes; ++nx) {
                buffer[nx] *= lpf;
                lpf += a * (target - lpf);
        }

        if (fabs (lpf - target) < GAIN_COEFF_TINY) return target;
        if (fabs (lpf) < GAIN_COEFF_TINY) return GAIN_COEFF_ZERO;
        return lpf;
}

void
Amp::apply_simple_gain (BufferSet& bufs, framecnt_t nframes, gain_t target, bool midi_amp)
{
        if (fabsf (target) < GAIN_COEFF_SMALL) {

                if (midi_amp) {
                        /* don't Trim midi velocity -- only relevant for Midi on Audio tracks */
                        for (BufferSet::midi_iterator i = bufs.midi_begin(); i != bufs.midi_end(); ++i) {
                                MidiBuffer& mb (*i);

                                for (MidiBuffer::iterator m = mb.begin(); m != mb.end(); ++m) {
                                        Evoral::MIDIEvent<MidiBuffer::TimeType> ev = *m;
                                        if (ev.is_note_on()) {
                                                ev.set_velocity (0);
                                        }
                                }
                        }
                }

                for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
                        memset (i->data(), 0, sizeof (Sample) * nframes);
                }

        } else if (target != GAIN_COEFF_UNITY) {

                if (midi_amp) {
                        /* don't Trim midi velocity -- only relevant for Midi on Audio tracks */
                        for (BufferSet::midi_iterator i = bufs.midi_begin(); i != bufs.midi_end(); ++i) {
                                MidiBuffer& mb (*i);

                                for (MidiBuffer::iterator m = mb.begin(); m != mb.end(); ++m) {
                                        Evoral::MIDIEvent<MidiBuffer::TimeType> ev = *m;
                                        if (ev.is_note_on()) {
                                                ev.scale_velocity (fabsf (target));
                                        }
                                }
                        }
                }

                for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
                        apply_gain_to_buffer (i->data(), nframes, target);
                }
        }
}

void
Amp::apply_simple_gain (AudioBuffer& buf, framecnt_t nframes, gain_t target)
{
        if (fabsf (target) < GAIN_COEFF_SMALL) {
                memset (buf.data(), 0, sizeof (Sample) * nframes);
        } else if (target != GAIN_COEFF_UNITY) {
                apply_gain_to_buffer (buf.data(), nframes, target);
        }
}

void
Amp::inc_gain (gain_t factor, void *src)
{
        float desired_gain = _gain_control->user_double();

        if (fabsf (desired_gain) < GAIN_COEFF_SMALL) {
                // really?! what's the idea here?
                set_gain (0.000001f + (0.000001f * factor), src);
        } else {
                set_gain (desired_gain + (desired_gain * factor), src);
        }
}

void
Amp::set_gain (gain_t val, void *)
{
        _gain_control->set_value (val);
}

XMLNode&
Amp::state (bool full_state)
{
        XMLNode& node (Processor::state (full_state));
        node.add_property("type", _type);
        node.add_child_nocopy (_gain_control->get_state());

        return node;
}

int
Amp::set_state (const XMLNode& node, int version)
{
        XMLNode* gain_node;

        Processor::set_state (node, version);

        if ((gain_node = node.child (Controllable::xml_node_name.c_str())) != 0) {
                _gain_control->set_state (*gain_node, version);
        }

        return 0;
}

void
Amp::GainControl::set_value (double val)
{
        AutomationControl::set_value (std::max (std::min (val, (double)_desc.upper), (double)_desc.lower));
        _amp->session().set_dirty ();
}

double
Amp::GainControl::internal_to_interface (double v) const
{
        if (_desc.type == GainAutomation) {
                return gain_to_slider_position (v);
        } else {
                return (accurate_coefficient_to_dB (v) - lower_db) / range_db;
        }
}

double
Amp::GainControl::interface_to_internal (double v) const
{
        if (_desc.type == GainAutomation) {
                return slider_position_to_gain (v);
        } else {
                return dB_to_coefficient (lower_db + v * range_db);
        }
}

double
Amp::GainControl::internal_to_user (double v) const
{
        return accurate_coefficient_to_dB (v);
}

double
Amp::GainControl::user_to_internal (double u) const
{
        return dB_to_coefficient (u);
}

std::string
Amp::GainControl::get_user_string () const
{
        char theBuf[32]; sprintf( theBuf, _("%3.1f dB"), accurate_coefficient_to_dB (get_value()));
        return std::string(theBuf);
}

void
Amp::setup_gain_automation (framepos_t start_frame, framepos_t end_frame, framecnt_t nframes)
{
        Glib::Threads::Mutex::Lock am (control_lock(), Glib::Threads::TRY_LOCK);

        if (am.locked()
            && (_session.transport_rolling() || _session.bounce_processing())
            && _gain_control->automation_playback())
        {
                assert (_gain_automation_buffer);
                _apply_gain_automation = _gain_control->list()->curve().rt_safe_get_vector (
                        start_frame, end_frame, _gain_automation_buffer, nframes);
                if (start_frame != _current_automation_frame) {
                        _current_gain = _gain_automation_buffer[0];
                }
                _current_automation_frame = end_frame;
        } else {
                _apply_gain_automation = false;
                _current_automation_frame = INT64_MAX;
        }
}

bool
Amp::visible() const
{
        return true;
}

std::string
Amp::value_as_string (boost::shared_ptr<AutomationControl> ac) const
{
        if (ac == _gain_control) {
                char buffer[32];
                snprintf (buffer, sizeof (buffer), _("%.2fdB"), ac->internal_to_user (ac->get_value ()));
                return buffer;
        }

        return Automatable::value_as_string (ac);
}

void
Amp::set_gain_automation_buffer (gain_t* g)
{
        _gain_automation_buffer = g;
}