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Update amp.cc to use gain_t for maths (no more double)

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Also tweak threshold for LPF, assume gain-differences < 10-e5 as
no-change
This commit is contained in:
Robin Gareus
2017-07-24 01:56:25 +02:00
parent 4ff6ed0f22
commit 30f85faa49
1 changed files with 28 additions and 30 deletions
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58
libs/ardour/amp.cc
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@@ -35,8 +35,7 @@
using namespace ARDOUR;
using namespace PBD;
// used for low-pass filter denormal protection
#define GAIN_COEFF_TINY (1e-10) // -200dB
#define GAIN_COEFF_DELTA (1e-5)
Amp::Amp (Session& s, const std::string& name, boost::shared_ptr<GainControl> gc, bool control_midi_also)
: Processor(s, "Amp")
@@ -103,9 +102,8 @@ Amp::run (BufferSet& bufs, framepos_t /*start_frame*/, framepos_t /*end_frame*/,
}
}
const double a = 156.825 / _session.nominal_frame_rate(); // 25 Hz LPF; see Amp::apply_gain for details
double lpf = _current_gain;
const gain_t a = 156.825f / (gain_t)_session.nominal_frame_rate(); // 25 Hz LPF; see Amp::apply_gain for details
gain_t lpf = _current_gain;
for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
Sample* const sp = i->data();
@@ -116,7 +114,7 @@ Amp::run (BufferSet& bufs, framepos_t /*start_frame*/, framepos_t /*end_frame*/,
}
}
if (fabs (lpf) < GAIN_COEFF_TINY) {
if (fabsf (lpf) < GAIN_COEFF_SMALL) {
_current_gain = GAIN_COEFF_ZERO;
} else {
_current_gain = lpf;
@@ -124,20 +122,20 @@ Amp::run (BufferSet& bufs, framepos_t /*start_frame*/, framepos_t /*end_frame*/,
} else { /* manual (scalar) gain */
gain_t const dg = _gain_control->get_value();
gain_t const target_gain = _gain_control->get_value();
if (_current_gain != dg) {
if (fabsf (_current_gain - target_gain) >= GAIN_COEFF_DELTA) {
_current_gain = Amp::apply_gain (bufs, _session.nominal_frame_rate(), nframes, _current_gain, dg, _midi_amp);
_current_gain = Amp::apply_gain (bufs, _session.nominal_frame_rate(), nframes, _current_gain, target_gain, _midi_amp);
/* see note in PluginInsert::connect_and_run ()
* set_value_unchecked() won't emit a signal since the value is effectively unchanged
*/
_gain_control->Changed (false, PBD::Controllable::NoGroup);
} else if (_current_gain != GAIN_COEFF_UNITY) {
} else if (target_gain != GAIN_COEFF_UNITY) {
/* gain has not changed, but its non-unity */
_current_gain = target_gain;
if (_midi_amp) {
/* don't Trim midi velocity -- only relevant for Midi on Audio tracks */
@@ -157,6 +155,9 @@ Amp::run (BufferSet& bufs, framepos_t /*start_frame*/, framepos_t /*end_frame*/,
for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
apply_gain_to_buffer (i->data(), nframes, _current_gain);
}
} else {
/* unity target gain */
_current_gain = target_gain;
}
}
@@ -166,7 +167,7 @@ Amp::run (BufferSet& bufs, framepos_t /*start_frame*/, framepos_t /*end_frame*/,
gain_t
Amp::apply_gain (BufferSet& bufs, framecnt_t sample_rate, framecnt_t nframes, gain_t initial, gain_t target, bool midi_amp)
{
/** Apply a (potentially) declicked gain to the buffers of @a bufs */
/** Apply a (potentially) declicked gain to the buffers of @a bufs */
gain_t rv = target;
if (nframes == 0 || bufs.count().n_total() == 0) {
@@ -211,7 +212,7 @@ Amp::apply_gain (BufferSet& bufs, framecnt_t sample_rate, framecnt_t nframes, ga
/* 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
const gain_t a = 156.825f / (gain_t)sample_rate; // 25 Hz LPF
for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
Sample* const buffer = i->data();
@@ -225,8 +226,7 @@ Amp::apply_gain (BufferSet& bufs, framecnt_t sample_rate, framecnt_t nframes, ga
rv = lpf;
}
}
if (fabsf (rv - target) < GAIN_COEFF_TINY) return target;
if (fabsf (rv) < GAIN_COEFF_TINY) return GAIN_COEFF_ZERO;
if (fabsf (rv - target) < GAIN_COEFF_DELTA) return target;
return rv;
}
@@ -244,11 +244,11 @@ Amp::declick (BufferSet& bufs, framecnt_t nframes, int dir)
if (dir < 0) {
/* fade out: remove more and more of delta from initial */
delta = -1.0;
initial = GAIN_COEFF_UNITY;
initial = GAIN_COEFF_UNITY;
} else {
/* fade in: add more and more of delta from initial */
delta = 1.0;
initial = GAIN_COEFF_ZERO;
initial = GAIN_COEFF_ZERO;
}
/* Audio Gain */
@@ -265,7 +265,7 @@ Amp::declick (BufferSet& bufs, framecnt_t nframes, int dir)
/* 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));
memset (&buffer[declick], 0, sizeof (Sample) * (nframes - declick));
}
}
}
@@ -275,7 +275,7 @@ Amp::declick (BufferSet& bufs, framecnt_t nframes, int dir)
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
/* Apply a (potentially) declicked gain to the contents of @a buf
* -- used by MonitorProcessor::run()
*/
@@ -289,17 +289,16 @@ Amp::apply_gain (AudioBuffer& buf, framecnt_t sample_rate, framecnt_t nframes, g
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
Sample* const buffer = buf.data();
const gain_t a = 156.825f / (gain_t)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;
gain_t 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;
if (fabsf (lpf - target) < GAIN_COEFF_DELTA) return target;
return lpf;
}
@@ -352,9 +351,9 @@ 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);
memset (buf.data(), 0, sizeof (Sample) * nframes);
} else if (target != GAIN_COEFF_UNITY) {
apply_gain_to_buffer (buf.data(), nframes, target);
apply_gain_to_buffer (buf.data(), nframes, target);
}
}
@@ -419,7 +418,6 @@ Amp::visible() const
* gain automationc curves. Must be called before setup_gain_automation,
* and must be called with process lock held.
*/
void
Amp::set_gain_automation_buffer (gain_t* g)
{