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prepare region RMS (loudness) normalization

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This commit is contained in:
Robin Gareus 2016-07-24 20:28:56 +02:00
parent 80bd3e7279
commit 23a2cc4b71
2 changed files with 48 additions and 3 deletions
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9
libs/ardour/ardour/audioregion.h
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@ -82,8 +82,17 @@ class LIBARDOUR_API AudioRegion : public Region
gain_t scale_amplitude() const { return _scale_amplitude; }
void normalize (float, float target_in_dB = 0.0f);
/** @return the maximum (linear) amplitude of the region, or a -ve
* number if the Progress object reports that the process was cancelled.
*/
double maximum_amplitude (Progress* p = 0) const;
/** @return the maximum (rms) signal power of the region, or a -1
* if the Progress object reports that the process was cancelled.
*/
double rms (Progress* p = 0) const;
bool envelope_active () const { return _envelope_active; }
bool fade_in_active () const { return _fade_in_active; }
bool fade_out_active () const { return _fade_out_active; }

42
libs/ardour/audioregion.cc
View File

@ -1402,9 +1402,6 @@ AudioRegion::set_scale_amplitude (gain_t g)
send_change (PropertyChange (Properties::scale_amplitude));
}
/** @return the maximum (linear) amplitude of the region, or a -ve
* number if the Progress object reports that the process was cancelled.
*/
double
AudioRegion::maximum_amplitude (Progress* p) const
{
@ -1444,6 +1441,45 @@ AudioRegion::maximum_amplitude (Progress* p) const
return maxamp;
}
double
AudioRegion::rms (Progress* p) const
{
framepos_t fpos = _start;
framepos_t const fend = _start + _length;
uint32_t const n_chan = n_channels ();
double rms = 0;
framecnt_t const blocksize = 64 * 1024;
Sample buf[blocksize];
framecnt_t total = 0;
if (n_chan == 0) {
return 0;
}
while (fpos < fend) {
framecnt_t const to_read = min (fend - fpos, blocksize);
total += to_read;
for (uint32_t c = 0; c < n_chan; ++c) {
if (read_raw_internal (buf, fpos, to_read, c) != to_read) {
return 0;
}
for (framepos_t i = 0; i < to_read; ++i) {
rms += buf[i] * buf[i];
}
fpos += to_read;
if (p) {
p->set_progress (float (fpos - _start) / _length);
if (p->cancelled ()) {
return -1;
}
}
}
}
return sqrt (rms / (double)(total * n_chan));
}
/** Normalize using a given maximum amplitude and target, so that region
* _scale_amplitude becomes target / max_amplitude.
*/