First cut of option to strip silence from audio regions, as per mantis #1623

git-svn-id: svn://localhost/ardour2/branches/3.0@5010 d708f5d6-7413-0410-9779-e7cbd77b26cf

12 files changed, 119 insertions, 7 deletions

diff --git a/gtk2_ardour/SConscript b/gtk2_ardour/SConscript
index 0d0161d456..f09df7263a 100644
--- a/gtk2_ardour/SConscript
+++ b/gtk2_ardour/SConscript
@@ -242,6 +242,7 @@ simplerect.cc
 splash.cc
 startup.cc
 streamview.cc
+strip_silence_dialog.cc
 tape_region_view.cc
 tempo_dialog.cc
 tempo_lines.cc
diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index b129009a9c..346df2064d 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -2052,6 +2052,7 @@ Editor::add_region_context_items (StreamView* sv, boost::shared_ptr<Region> regi
 		items.push_back (SeparatorElem());
 	}
 
+	items.push_back (MenuElem (_("Strip silence..."), mem_fun (*this, &Editor::strip_region_silence)));
 	items.push_back (MenuElem (_("Reverse"), mem_fun(*this, &Editor::reverse_region)));
 	items.push_back (SeparatorElem());
 
diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 82f63792fc..167ad65b1f 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -1191,6 +1191,7 @@ class Editor : public PublicEditor
 	void audition_playlist_region_via_route (boost::shared_ptr<ARDOUR::Region>, ARDOUR::Route&);
 	void split_multichannel_region();
 	void reverse_region ();
+	void strip_region_silence ();
 	void normalize_region ();
 	void denormalize_region ();
 	void adjust_region_scale_amplitude (bool up);
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index 5826033072..66286b62f0 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -54,6 +54,7 @@
 #include "ardour/transient_detector.h"
 #include "ardour/dB.h"
 #include "ardour/quantize.h"
+#include "ardour/strip_silence.h"
 
 #include "ardour_ui.h"
 #include "editor.h"
@@ -73,6 +74,7 @@
 #include "gui_thread.h"
 #include "keyboard.h"
 #include "utils.h"
+#include "strip_silence_dialog.h"
 
 #include "i18n.h"
 
@@ -4660,6 +4662,22 @@ Editor::reverse_region ()
 	apply_filter (rev, _("reverse regions"));
 }
 
+void
+Editor::strip_region_silence ()
+{
+	if (!session) {
+		return;
+	}
+
+	StripSilenceDialog d;
+	int const r = d.run ();
+
+	if (r == Gtk::RESPONSE_OK) {
+		StripSilence s (*session, d.threshold (), d.minimum_length (), d.fade_length ());
+		apply_filter (s, _("strip silence"));
+	}
+}
+
 
 void
 Editor::quantize_region ()
@@ -4707,7 +4725,28 @@ Editor::apply_filter (Filter& filter, string command)
 			if (arv->audio_region()->apply (filter) == 0) {
 
 				XMLNode &before = playlist->get_state();
-				playlist->replace_region (arv->region(), filter.results.front(), arv->region()->position());
+
+				if (filter.results.empty ()) {
+
+					/* no regions returned; remove the old one */
+					playlist->remove_region (arv->region ());
+					
+				} else {
+
+					std::vector<boost::shared_ptr<Region> >::iterator res = filter.results.begin ();
+
+					/* first region replaces the old one */
+					playlist->replace_region (arv->region(), *res, (*res)->position());
+					++res;
+
+					/* add the rest */
+					while (res != filter.results.end()) {
+						playlist->add_region (*res, (*res)->position());
+						++res;
+					}
+					
+				}
+
 				XMLNode &after = playlist->get_state();
 				session->add_command(new MementoCommand<Playlist>(*playlist, &before, &after));
 			} else {
diff --git a/gtk2_ardour/wscript b/gtk2_ardour/wscript
index 4624440ad6..92a3650a28 100644
--- a/gtk2_ardour/wscript
+++ b/gtk2_ardour/wscript
@@ -197,6 +197,7 @@ def build(bld):
 		splash.cc
 		startup.cc
 		streamview.cc
+                strip_silence_dialog.cc
 		tape_region_view.cc
 		tempo_dialog.cc
 		tempo_lines.cc
diff --git a/libs/ardour/SConscript b/libs/ardour/SConscript
index d30c276840..27cffdff9d 100644
--- a/libs/ardour/SConscript
+++ b/libs/ardour/SConscript
@@ -159,6 +159,7 @@ sndfileimportable.cc
 sndfilesource.cc
 source.cc
 source_factory.cc
+strip_silence.cc
 svn_revision.cc
 tape_file_matcher.cc
 template_utils.cc
diff --git a/libs/ardour/ardour/audioregion.h b/libs/ardour/ardour/audioregion.h
index 917578191f..b2e2aa3eef 100644
--- a/libs/ardour/ardour/audioregion.h
+++ b/libs/ardour/ardour/audioregion.h
@@ -106,7 +106,7 @@ class AudioRegion : public Region
 	virtual nframes_t master_read_at (Sample *buf, Sample *mixdown_buf, float *gain_buf,
 			sframes_t position, nframes_t cnt, uint32_t chan_n=0) const;
 	
-	virtual nframes_t read_raw_internal (Sample*, sframes_t, nframes_t) const;
+	virtual nframes_t read_raw_internal (Sample*, sframes_t, nframes_t, int channel) const;
 
 	XMLNode& state (bool);
 	int      set_state (const XMLNode&);
@@ -162,6 +162,7 @@ class AudioRegion : public Region
 	void resume_fade_out ();
 
 	int get_transients (AnalysisFeatureList&, bool force_new = false);
+	std::list<std::pair<nframes_t, nframes_t> > find_silence (Sample, nframes_t) const;
 
   private:
 	friend class RegionFactory;
diff --git a/libs/ardour/ardour/crossfade.h b/libs/ardour/ardour/crossfade.h
index bd3ee914f9..4afa38126c 100644
--- a/libs/ardour/ardour/crossfade.h
+++ b/libs/ardour/ardour/crossfade.h
@@ -170,7 +170,7 @@ class Crossfade : public ARDOUR::AudioRegion
 	bool update ();
 
   protected:
-	nframes_t read_raw_internal (Sample*, sframes_t, nframes_t) const;	
+	nframes_t read_raw_internal (Sample*, sframes_t, nframes_t, int) const;	
 };
 
 
diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index 085296281c..b3fd239c59 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -1062,9 +1062,9 @@ AudioRegion::separate_by_channel (Session& session, vector<boost::shared_ptr<Reg
 }
 
 nframes_t
-AudioRegion::read_raw_internal (Sample* buf, sframes_t pos, nframes_t cnt) const
+AudioRegion::read_raw_internal (Sample* buf, sframes_t pos, nframes_t cnt, int channel) const
 {
-	return audio_source()->read  (buf, pos, cnt);
+	return audio_source()->read (buf, pos, cnt, channel);
 }
 
 int
@@ -1184,7 +1184,7 @@ AudioRegion::normalize_to (float target_dB)
 
 			/* read it in */
 
-			if (read_raw_internal (buf, fpos, to_read) != to_read) {
+			if (read_raw_internal (buf, fpos, to_read, 0) != to_read) {
 				return;
 			}
 			
@@ -1438,6 +1438,71 @@ then quit ardour and restart."));
 	return 0;
 }
 
+/** Find areas of `silence' within a region.
+ *
+ *  @param threshold Threshold below which signal is considered silence (as a sample value)
+ *  @param min_length Minimum length of silent period to be reported.
+ *  @return Silent periods; first of pair is the offset within the region, second is the length of the period
+ */
+
+std::list<std::pair<nframes_t, nframes_t> >
+AudioRegion::find_silence (Sample threshold, nframes_t min_length) const
+{
+	nframes_t const block_size = 64 * 1024;
+	Sample loudest[block_size];
+	Sample buf[block_size];
+	
+	nframes_t pos = _start;
+	nframes_t const end = _start + _length - 1;
+
+	std::list<std::pair<nframes_t, nframes_t> > silent_periods;
+
+	bool in_silence = false;
+	nframes_t silence_start = 0;
+	bool silence;
+
+	while (pos < end) {
+
+		nframes_t const to_read = min (end - pos, block_size);
+
+		/* fill `loudest' with the loudest absolute sample at each instant, across all channels */
+		memset (loudest, 0, sizeof (Sample) * block_size);
+		for (uint32_t n = 0; n < n_channels(); ++n) {
+
+			read_raw_internal (buf, pos, block_size, n);
+			for (nframes_t i = 0; i < block_size; ++i) {
+				loudest[i] = max (loudest[i], abs (buf[i]));
+			}
+		}
+
+		/* now look for silence */
+		for (nframes_t i = 0; i < block_size; ++i) {
+			silence = abs (loudest[i]) < threshold;
+			if (silence && !in_silence) {
+				/* non-silence to silence */
+				in_silence = true;
+				silence_start = pos + i;
+			} else if (!silence && in_silence) {
+				/* silence to non-silence */
+				in_silence = false;
+				if (pos + i - 1 - silence_start >= min_length) {
+					silent_periods.push_back (std::make_pair (silence_start, pos + i - 1));
+				}
+			}
+		}
+
+		pos += block_size;
+	}
+
+	if (in_silence && end - 1 - silence_start >= min_length) {
+		/* last block was silent, so finish off the last period */
+		silent_periods.push_back (std::make_pair (silence_start, end));
+	}
+
+	return silent_periods;
+}
+
+
 extern "C" {
 
 	int region_read_peaks_from_c (void *arg, uint32_t npeaks, uint32_t start, uint32_t cnt, intptr_t data, uint32_t n_chan, double samples_per_unit) 
diff --git a/libs/ardour/crossfade.cc b/libs/ardour/crossfade.cc
index 8aad53765a..c258a9bf73 100644
--- a/libs/ardour/crossfade.cc
+++ b/libs/ardour/crossfade.cc
@@ -271,7 +271,7 @@ Crossfade::initialize ()
 }	
 
 nframes_t 
-Crossfade::read_raw_internal (Sample* buf, sframes_t start, nframes_t cnt) const
+Crossfade::read_raw_internal (Sample* buf, sframes_t start, nframes_t cnt, int channel) const
 {
 	// FIXME: Why is this disabled?
 #if 0
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index dcca313c79..a90a2b244d 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -1638,3 +1638,4 @@ Region::invalidate_transients ()
 	_transients.clear ();
 }
 
+
diff --git a/libs/ardour/wscript b/libs/ardour/wscript
index 342ca79a0a..b087e194c2 100644
--- a/libs/ardour/wscript
+++ b/libs/ardour/wscript
@@ -198,6 +198,7 @@ def build(bld):
 		sndfilesource.cc
 		source.cc
 		source_factory.cc
+                strip_silence.cc
 		svn_revision.cc
 		tape_file_matcher.cc
 		template_utils.cc