Prevent clipping during the import of files from sources that have

amplitudes greater than 1 when data is being stored in files that
are clamped. e.g. when importing hot sources and resampling them
when the session file format is integer.


git-svn-id: svn://localhost/ardour2/branches/3.0@6879 d708f5d6-7413-0410-9779-e7cbd77b26cf

6 files changed, 17 insertions, 1 deletions

diff --git a/libs/ardour/ardour/audiosource.h b/libs/ardour/ardour/audiosource.h
index e78fb049d7..9677986449 100644
--- a/libs/ardour/ardour/audiosource.h
+++ b/libs/ardour/ardour/audiosource.h
@@ -100,6 +100,9 @@ class AudioSource : virtual public Source,
 	int prepare_for_peakfile_writes ();
 	void done_with_peakfile_writes (bool done = true);
 
+	/** @return true if the each source sample s must be clamped to -1 < s < 1 */
+	virtual bool clamped_at_unity () const = 0;
+
   protected:
 	static bool _build_missing_peakfiles;
 	static bool _build_peakfiles;
diff --git a/libs/ardour/ardour/importable_source.h b/libs/ardour/ardour/importable_source.h
index 801e7888a9..7df346a782 100644
--- a/libs/ardour/ardour/importable_source.h
+++ b/libs/ardour/ardour/importable_source.h
@@ -37,6 +37,8 @@ public:
 	virtual nframes_t samplerate() const = 0;
 	virtual void      seek (nframes_t pos) = 0;
 	virtual nframes64_t natural_position() const = 0;
+
+	virtual bool clamped_at_unity () const = 0;
 };
 
 }
diff --git a/libs/ardour/ardour/resampled_source.h b/libs/ardour/ardour/resampled_source.h
index efa1458152..b61303b65c 100644
--- a/libs/ardour/ardour/resampled_source.h
+++ b/libs/ardour/ardour/resampled_source.h
@@ -39,14 +39,20 @@ class ResampledImportableSource : public ImportableSource
 	uint32_t channels() const { return source->channels(); }
 	nframes_t length() const { return source->length(); }
 	nframes_t samplerate() const { return source->samplerate(); }
-	void      seek (nframes_t pos) { source->seek (pos); }
+	void      seek (nframes_t);
 	nframes64_t natural_position() const { return source->natural_position(); }
 
+	bool clamped_at_unity () const {
+		/* resampling may generate inter-sample peaks with magnitude > 1 */
+		return false;
+	}
+
 	static const uint32_t blocksize;
 
    private:
 	boost::shared_ptr<ImportableSource> source;
         float* input;
+	int _src_type;
 	SRC_STATE*	src_state;
 	SRC_DATA	src_data;
 };
diff --git a/libs/ardour/ardour/silentfilesource.h b/libs/ardour/ardour/silentfilesource.h
index 9b20f6f1b0..23128c4025 100644
--- a/libs/ardour/ardour/silentfilesource.h
+++ b/libs/ardour/ardour/silentfilesource.h
@@ -36,6 +36,8 @@ public:
 	bool destructive() const { return false; }
 	bool can_be_analysed() const { return false; }
 
+	bool clamped_at_unity() const { return false; }
+
 protected:
 	friend class SourceFactory;
 
diff --git a/libs/ardour/ardour/sndfileimportable.h b/libs/ardour/ardour/sndfileimportable.h
index 95c6d80ebb..6e308415c9 100644
--- a/libs/ardour/ardour/sndfileimportable.h
+++ b/libs/ardour/ardour/sndfileimportable.h
@@ -39,6 +39,7 @@ class SndFileImportableSource : public ImportableSource {
 	nframes_t samplerate() const;
 	void      seek (nframes_t pos);
 	nframes64_t natural_position() const;
+	bool clamped_at_unity () const;
 
    protected:
 	SF_INFO sf_info;
diff --git a/libs/ardour/ardour/sndfilesource.h b/libs/ardour/ardour/sndfilesource.h
index 19dcb13536..96f39de2c8 100644
--- a/libs/ardour/ardour/sndfilesource.h
+++ b/libs/ardour/ardour/sndfilesource.h
@@ -57,6 +57,8 @@ class SndFileSource : public AudioFileSource {
 
 	bool one_of_several_channels () const;
 
+	bool clamped_at_unity () const;
+
 	static void setup_standard_crossfades (Session const &, nframes_t sample_rate);
 	static const Source::Flag default_writable_flags;