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linear declick

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Robin Gareus
2015-04-07 03:54:31 +02:00
parent 83519faffb
commit a306968283
1 changed files with 6 additions and 18 deletions
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24
libs/ardour/amp.cc
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@@ -210,51 +210,39 @@ Amp::apply_gain (BufferSet& bufs, framecnt_t sample_rate, framecnt_t nframes, ga
void
Amp::declick (BufferSet& bufs, framecnt_t nframes, int dir)
{
/* Similar to ::apply_gain() but skips MIDI buffers
* and use cos() Sigmoid decay with fixed initial+target values.
*/
if (nframes == 0 || bufs.count().n_total() == 0) {
return;
}
const framecnt_t declick = std::min ((framecnt_t) 128, nframes);
gain_t delta, initial, target;
double fractional_shift = -1.0/(declick-1);
double fractional_pos;
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 = 1.0;
target = 0.0;
} else {
/* fade in: add more and more of delta from initial */
delta = 1.0;
initial = 0.0;
target = 1.0;
}
/* Audio Gain */
for (BufferSet::audio_iterator i = bufs.audio_begin(); i != bufs.audio_end(); ++i) {
Sample* const buffer = i->data();
fractional_pos = 1.0;
double fractional_pos = 0.0;
for (pframes_t nx = 0; nx < declick; ++nx) {
buffer[nx] *= (initial + (delta * (0.5 + 0.5 * cos (M_PI * fractional_pos))));
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 (target == 0.0) {
if (dir < 0) {
memset (&buffer[declick], 0, sizeof (Sample) * (nframes - declick));
} else if (target != 1.0) {
apply_gain_to_buffer (&buffer[declick], nframes - declick, target);
}
}
}