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/*
Copyright (C) 2009 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 "ardour/strip_silence.h"
#include "ardour/audioregion.h"
#include "ardour/region_factory.h"
#include "ardour/session.h"
#include "ardour/dB.h"
using namespace ARDOUR;
/** Construct a StripSilence filter.
* @param s Session.
* @param threshold Threshold below which audio is considered silence, in dBFS.
* @param minimum_length Minimum length of silence period to recognise, in samples.
* @param fade_length Length of fade in/out to apply to trimmed regions, in samples.
*/
StripSilence::StripSilence (Session & s, double threshold, nframes_t minimum_length, nframes_t fade_length)
: Filter (s), _threshold (threshold), _minimum_length (minimum_length), _fade_length (fade_length)
{
}
int
StripSilence::run (boost::shared_ptr<Region> r)
{
results.clear ();
/* we only operate on AudioRegions, for now, though this could be adapted to MIDI
as well I guess */
boost::shared_ptr<AudioRegion> region = boost::dynamic_pointer_cast<AudioRegion> (r);
if (!region) {
results.push_back (r);
return -1;
}
/* find periods of silence in the region */
std::list<std::pair<frameoffset_t, framecnt_t> > const silence =
region->find_silence (dB_to_coefficient (_threshold), _minimum_length);
if (silence.size () == 1 && silence.front().first == 0 && silence.front().second == region->length() - 1) {
/* the region is all silence, so just return with nothing */
return 0;
}
if (silence.empty()) {
/* no silence in this region */
results.push_back (region);
return 0;
}
std::list<std::pair<framepos_t, framecnt_t > >::const_iterator s = silence.begin ();
framepos_t const pos = region->position ();
framepos_t const end = region->start () + region->length() - 1;
framepos_t const start = region->start ();
region = boost::dynamic_pointer_cast<AudioRegion> (RegionFactory::create (region));
region->set_name (session.new_region_name (region->name ()));
boost::shared_ptr<AudioRegion> last_region = region;
results.push_back (region);
if (s->first == 0) {
/* the region starts with some silence */
/* we must set length to an intermediate value here, otherwise the call
** to set_start will fail */
region->set_length (region->length() - s->second + _fade_length, 0);
region->set_start (start + s->second - _fade_length, 0);
region->set_position (pos + s->second - _fade_length, 0);
region->set_fade_in_active (true);
region->set_fade_in (AudioRegion::Linear, _fade_length);
s++;
}
while (s != silence.end()) {
/* trim the end of this region */
region->trim_end (pos + s->first + _fade_length, 0);
region->set_fade_out_active (true);
region->set_fade_out (AudioRegion::Linear, _fade_length);
/* make a new region and trim its start */
region = boost::dynamic_pointer_cast<AudioRegion> (RegionFactory::create (region));
region->set_name (session.new_region_name (region->name ()));
last_region = region;
assert (region);
results.push_back (region);
/* set length here for the same reasons as above */
region->set_length (region->length() - s->second + _fade_length, 0);
region->set_start (start + s->second - _fade_length, 0);
region->set_position (pos + s->second - _fade_length, 0);
region->set_fade_in_active (true);
region->set_fade_in (AudioRegion::Linear, _fade_length);
s++;
}
if (silence.back().second == end) {
/* the last region we created is zero-sized, so just remove it */
results.pop_back ();
} else {
/* finish off the last region */
last_region->trim_end (end, 0);
}
return 0;
}
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