libs/ardour/strip_silence.cc

   1 /*
   2     Copyright (C) 2009-2010 Paul Davis
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #include "pbd/property_list.h"
  21
  22 #include "ardour/strip_silence.h"
  23 #include "ardour/audioregion.h"
  24 #include "ardour/region_factory.h"
  25 #include "ardour/session.h"
  26 #include "ardour/dB.h"
  27 #include "ardour/progress.h"
  28
  29 using namespace ARDOUR;
  30
  31 /** Construct a StripSilence filter.
  32  *  @param s Session.
  33  *  @param threshold Threshold below which audio is considered silence, in dBFS.
  34  *  @param minimum_length Minimum length of silence period to recognise, in samples.
  35  *  @param fade_length Length of fade in/out to apply to trimmed regions, in samples.
  36  */
  37
  38 StripSilence::StripSilence (Session & s, const AudioIntervalMap& sm, framecnt_t fade_length)
  39         : Filter (s)
  40         , _smap (sm)
  41         , _fade_length (fade_length)
  42 {
  43
  44 }
  45
  46 int
  47 StripSilence::run (boost::shared_ptr<Region> r, Progress* progress)
  48 {
  49         results.clear ();
  50
  51         /* we only operate on AudioRegions, for now, though this could be adapted to MIDI
  52            as well I guess
  53         */
  54         boost::shared_ptr<AudioRegion> region = boost::dynamic_pointer_cast<AudioRegion> (r);
  55         InterThreadInfo itt;
  56         AudioIntervalMap::const_iterator sm;
  57
  58         if (!region) {
  59                 results.push_back (r);
  60                 return -1;
  61         }
  62
  63         if ((sm = _smap.find (r)) == _smap.end()) {
  64                 results.push_back (r);
  65                 return -1;
  66         }
  67
  68         const AudioIntervalResult& silence = sm->second;
  69
  70         if (silence.size () == 1 && silence.front().first == 0 && silence.front().second == region->length() - 1) {
  71                 /* the region is all silence, so just return with nothing */
  72                 return 0;
  73         }
  74
  75         if (silence.empty()) {
  76                 /* no silence in this region */
  77                 results.push_back (region);
  78                 return 0;
  79         }
  80
  81         /* Turn the silence list into an `audible' list */
  82         AudioIntervalResult audible;
  83
  84         /* Add the possible audible section at the start of the region */
  85         AudioIntervalResult::const_iterator first_silence = silence.begin ();
  86         if (first_silence->first != region->start()) {
  87                 audible.push_back (std::make_pair (r->start(), first_silence->first));
  88         }
  89
  90         /* Add audible sections in the middle of the region */
  91         for (AudioIntervalResult::const_iterator i = silence.begin (); i != silence.end(); ++i) {
  92                 AudioIntervalResult::const_iterator j = i;
  93                 ++j;
  94
  95                 if (j != silence.end ()) {
  96                         audible.push_back (std::make_pair (i->second, j->first));
  97                 }
  98         }
  99
 100         /* Add the possible audible section at the end of the region */
 101         AudioIntervalResult::const_iterator last_silence = silence.end ();
 102         --last_silence;
 103
 104         frameoffset_t const end_of_region = r->start() + r->length();
 105
 106         if (last_silence->second != end_of_region - 1) {
 107                 audible.push_back (std::make_pair (last_silence->second, end_of_region - 1));
 108         }
 109
 110         int n = 0;
 111         int const N = audible.size ();
 112
 113         for (AudioIntervalResult::const_iterator i = audible.begin(); i != audible.end(); ++i) {
 114
 115                 PBD::PropertyList plist;
 116                 boost::shared_ptr<AudioRegion> copy;
 117
 118                 plist.add (Properties::length, i->second - i->first);
 119                 plist.add (Properties::position, r->position() + (i->first - r->start()));
 120
 121                 copy = boost::dynamic_pointer_cast<AudioRegion> (
 122                         RegionFactory::create (region, (i->first - r->start()), plist)
 123                         );
 124
 125                 copy->set_name (RegionFactory::new_region_name (region->name ()));
 126
 127                 framecnt_t const f = std::min (_fade_length, (i->second - i->first));
 128
 129                 copy->set_fade_in_active (true);
 130                 copy->set_fade_in (FadeLinear, f);
 131                 copy->set_fade_out (FadeLinear, f);
 132                 results.push_back (copy);
 133
 134                 if (progress && (n <= N)) {
 135                         progress->set_progress (float (n) / N);
 136                 }
 137         }
 138
 139         return 0;
 140 }