committed INCOMPLETE 24bit filesource support

git-svn-id: svn://localhost/trunk/ardour2@316 d708f5d6-7413-0410-9779-e7cbd77b26cf

33 files changed, 617 insertions, 172 deletions

diff --git a/libs/ardour/SConscript b/libs/ardour/SConscript
index b1cab4bb7d..5f51e839eb 100644
--- a/libs/ardour/SConscript
+++ b/libs/ardour/SConscript
@@ -50,6 +50,7 @@ location.cc
 mtc_slave.cc
 named_selection.cc
 panner.cc
+pcm_utils.cc
 playlist.cc
 playlist_factory.cc
 plugin.cc
diff --git a/libs/ardour/ardour/audio_track.h b/libs/ardour/ardour/audio_track.h
index 030dd17a6b..0ef4c45f16 100644
--- a/libs/ardour/ardour/audio_track.h
+++ b/libs/ardour/ardour/audio_track.h
@@ -63,7 +63,7 @@ class AudioTrack : public Route
 	jack_nframes_t update_total_latency();
 	void set_latency_delay (jack_nframes_t);
 	
-	int export_stuff (vector<Sample*>& buffers, uint32_t nbufs, jack_nframes_t nframes, jack_nframes_t end_frame);
+	int export_stuff (vector<Sample*>& buffers, char * workbuf, uint32_t nbufs, jack_nframes_t nframes, jack_nframes_t end_frame);
 
 	sigc::signal<void,void*> diskstream_changed;
 
diff --git a/libs/ardour/ardour/audioplaylist.h b/libs/ardour/ardour/audioplaylist.h
index 26cce91b12..fa2aa94471 100644
--- a/libs/ardour/ardour/audioplaylist.h
+++ b/libs/ardour/ardour/audioplaylist.h
@@ -60,7 +60,7 @@ class AudioPlaylist : public ARDOUR::Playlist
 
 	void clear (bool with_delete = false, bool with_save = true);
 
-        jack_nframes_t read (Sample *dst, Sample *mixdown, float *gain_buffer, jack_nframes_t start, jack_nframes_t cnt, uint32_t chan_n=0);
+        jack_nframes_t read (Sample *dst, Sample *mixdown, float *gain_buffer, char * workbuf, jack_nframes_t start, jack_nframes_t cnt, uint32_t chan_n=0);
 
 	int set_state (const XMLNode&);
 	UndoAction get_memento() const;
diff --git a/libs/ardour/ardour/audioregion.h b/libs/ardour/ardour/audioregion.h
index 44159f73f5..fa6b3aeecc 100644
--- a/libs/ardour/ardour/audioregion.h
+++ b/libs/ardour/ardour/audioregion.h
@@ -104,13 +104,13 @@ class AudioRegion : public Region
 	jack_nframes_t read_peaks (PeakData *buf, jack_nframes_t npeaks, jack_nframes_t offset, jack_nframes_t cnt, uint32_t chan_n=0, double samples_per_unit= 1.0) const;
 
 	virtual jack_nframes_t read_at (Sample *buf, Sample *mixdown_buffer, 
-					float *gain_buffer, jack_nframes_t position, jack_nframes_t cnt, 
+					float *gain_buffer, char * workbuf, jack_nframes_t position, jack_nframes_t cnt, 
 					uint32_t chan_n = 0,
 					jack_nframes_t read_frames = 0,
 					jack_nframes_t skip_frames = 0) const;
 
 	jack_nframes_t master_read_at (Sample *buf, Sample *mixdown_buffer, 
-				       float *gain_buffer, jack_nframes_t position, jack_nframes_t cnt, uint32_t chan_n=0) const;
+				       float *gain_buffer, char * workbuf, jack_nframes_t position, jack_nframes_t cnt, uint32_t chan_n=0) const;
 
 
 	XMLNode& state (bool);
@@ -199,7 +199,7 @@ class AudioRegion : public Region
 	void rename_after_first_edit ();
 
 	jack_nframes_t _read_at (const SourceList&, Sample *buf, Sample *mixdown_buffer, 
-				 float *gain_buffer, jack_nframes_t position, jack_nframes_t cnt, 
+				 float *gain_buffer, char * workbuf, jack_nframes_t position, jack_nframes_t cnt, 
 				 uint32_t chan_n = 0,
 				 jack_nframes_t read_frames = 0,
 				 jack_nframes_t skip_frames = 0) const;
diff --git a/libs/ardour/ardour/crossfade.h b/libs/ardour/ardour/crossfade.h
index 4db833ca45..3e65e16901 100644
--- a/libs/ardour/ardour/crossfade.h
+++ b/libs/ardour/ardour/crossfade.h
@@ -87,7 +87,7 @@ class Crossfade : public Stateful, public StateManager
 	ARDOUR::AudioRegion& out() const { return *_out; }
 	
 	jack_nframes_t read_at (Sample *buf, Sample *mixdown_buffer, 
-				float *gain_buffer, jack_nframes_t position, jack_nframes_t cnt, 
+				float *gain_buffer, char * workbuf, jack_nframes_t position, jack_nframes_t cnt, 
 				uint32_t chan_n,
 				jack_nframes_t read_frames = 0,
 				jack_nframes_t skip_frames = 0);
diff --git a/libs/ardour/ardour/destructive_filesource.h b/libs/ardour/ardour/destructive_filesource.h
index bb46fdfd22..ceb049b29c 100644
--- a/libs/ardour/ardour/destructive_filesource.h
+++ b/libs/ardour/ardour/destructive_filesource.h
@@ -31,7 +31,7 @@ namespace ARDOUR {
 
 class DestructiveFileSource : public FileSource {
   public:
-	DestructiveFileSource (std::string path, jack_nframes_t rate, bool repair_first = false);
+	DestructiveFileSource (std::string path, jack_nframes_t rate, bool repair_first = false, SampleFormat samp_format=FormatInt24);
 	DestructiveFileSource (const XMLNode&, jack_nframes_t rate);
 	~DestructiveFileSource ();
 
@@ -41,7 +41,7 @@ class DestructiveFileSource : public FileSource {
 	void mark_capture_end ();
 	void clear_capture_marks();
 
-	jack_nframes_t write (Sample *src, jack_nframes_t cnt);
+	jack_nframes_t write (Sample *src, jack_nframes_t cnt, char * workbuf);
 
   private:
 	static jack_nframes_t xfade_frames;
@@ -52,10 +52,10 @@ class DestructiveFileSource : public FileSource {
 	bool          _capture_start;
 	bool          _capture_end;
 	jack_nframes_t capture_start_frame;
-	jack_nframes_t file_pos;
+	jack_nframes_t file_pos; // unit is frames
 	Sample*        xfade_buf;
 
-	jack_nframes_t crossfade (Sample* data, jack_nframes_t cnt, int dir);
+	jack_nframes_t crossfade (Sample* data, jack_nframes_t cnt, int dir, char * workbuf);
 
 };
 
diff --git a/libs/ardour/ardour/diskstream.h b/libs/ardour/ardour/diskstream.h
index 5b63cfad28..1d06c4ee49 100644
--- a/libs/ardour/ardour/diskstream.h
+++ b/libs/ardour/ardour/diskstream.h
@@ -362,10 +362,10 @@ class DiskStream : public Stateful, public sigc::trackable
 
 	/* the two central butler operations */
 
-	int do_flush (bool force = false);
-	int do_refill (Sample *mixdown_buffer, float *gain_buffer);
+	int do_flush (char * workbuf, bool force = false);
+	int do_refill (Sample *mixdown_buffer, float *gain_buffer, char *workbuf);
 
-	int read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer, jack_nframes_t& start, jack_nframes_t cnt, 
+	int read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer, char * workbuf, jack_nframes_t& start, jack_nframes_t cnt, 
 		  ChannelInfo& channel_info, int channel, bool reversed);
 
 	uint32_t i_am_the_modifier;
diff --git a/libs/ardour/ardour/filesource.h b/libs/ardour/ardour/filesource.h
index e426159014..af46596ec5 100644
--- a/libs/ardour/ardour/filesource.h
+++ b/libs/ardour/ardour/filesource.h
@@ -44,13 +44,19 @@ namespace ARDOUR {
 
 class FileSource : public Source {
   public:
-	FileSource (string path, jack_nframes_t rate, bool repair_first = false);
+	enum SampleFormat
+	{
+		FormatFloat = 0,
+		FormatInt24
+	};
+		
+	FileSource (string path, jack_nframes_t rate, bool repair_first = false, SampleFormat samp_format=FormatFloat);
 	FileSource (const XMLNode&, jack_nframes_t rate);
 	~FileSource ();
 
 	jack_nframes_t length() const { return _length; }
-	jack_nframes_t read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const;
-	jack_nframes_t write (Sample *src, jack_nframes_t cnt);
+	jack_nframes_t read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const;
+	jack_nframes_t write (Sample *src, jack_nframes_t cnt, char * workbuf);
 	void           mark_for_remove();
 	string         peak_path(string audio_path);
 	string         old_peak_path(string audio_path);
@@ -85,7 +91,9 @@ class FileSource : public Source {
 	bool           is_bwf;
 	off64_t        data_offset;
 	string        _take_id;
-
+	SampleFormat  _sample_format;
+	int           _sample_size;
+	
 	static char bwf_country_code[3];
 	static char bwf_organization_code[4];
 	static char bwf_serial_number[13];
@@ -143,8 +151,27 @@ class FileSource : public Source {
 	} header;
 
 	int init (string, bool must_exist, jack_nframes_t);
-	jack_nframes_t read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const;
-
+	jack_nframes_t read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const;
+
+	ssize_t file_write (Sample *src, jack_nframes_t framepos, jack_nframes_t cnt, char * workbuf) {
+		switch (_sample_format) {
+		case FormatInt24: return write_pcm_24(src, framepos, cnt, workbuf);
+		default: return write_float(src, framepos, cnt, workbuf);
+		};
+	}
+	
+	ssize_t file_read  (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const  {
+		switch (_sample_format) {
+		case FormatInt24: return read_pcm_24(dst, start, cnt, workbuf);
+		default: return read_float(dst, start, cnt, workbuf);
+		};
+	}
+	
+	ssize_t write_float(Sample *src, jack_nframes_t framepos, jack_nframes_t cnt, char * workbuf);
+	ssize_t read_float (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const;
+        ssize_t write_pcm_24(Sample *src, jack_nframes_t framepos, jack_nframes_t cnt, char * workbuf);
+	ssize_t read_pcm_24 (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const;
+	
 	int discover_chunks (bool silent);
 	ChunkInfo* lookup_chunk (string name);
 
diff --git a/libs/ardour/ardour/pcm_utils.h b/libs/ardour/ardour/pcm_utils.h
new file mode 100644
index 0000000000..6866e53251
--- /dev/null
+++ b/libs/ardour/ardour/pcm_utils.h
@@ -0,0 +1,42 @@
+/*
+    Copyright (C) 2006 Paul Davis , portions Erik de Castro Lopo
+
+    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.
+
+    $Id$
+*/
+
+#ifndef __ardour_pcm_utils_h__
+#define __ardour_pcm_utils_h__
+
+typedef	void	tribyte ;
+
+#define	SIZEOF_TRIBYTE	3
+
+#define BET2H_INT_PTR(x)		(((x) [0] << 24) + ((x) [1] << 16) + ((x) [2] << 8))
+#define LET2H_INT_PTR(x)		(((x) [0] << 8) + ((x) [1] << 16) + ((x) [2] << 24))
+
+
+
+void pcm_let2f_array (tribyte *src, int count, float *dest);
+void pcm_bet2f_array (tribyte *src, int count, float *dest);
+void pcm_f2let_array (float *src, tribyte *dest, int count);
+void pcm_f2let_clip_array (float *src, tribyte *dest, int count);
+void pcm_f2bet_array (const float *src, tribyte *dest, int count);
+void pcm_f2bet_clip_array (const float *src, tribyte *dest, int count);
+
+
+
+#endif
diff --git a/libs/ardour/ardour/playlist.h b/libs/ardour/ardour/playlist.h
index a5451c30d5..b0ac956d5c 100644
--- a/libs/ardour/ardour/playlist.h
+++ b/libs/ardour/ardour/playlist.h
@@ -53,7 +53,7 @@ class Playlist : public Stateful, public StateManager {
 	Playlist (const Playlist&, string name, bool hidden = false);
 	Playlist (const Playlist&, jack_nframes_t start, jack_nframes_t cnt, string name, bool hidden = false);
 
-	virtual jack_nframes_t read (Sample *dst, Sample *mixdown, float *gain_buffer, jack_nframes_t start, jack_nframes_t cnt, uint32_t chan_n=0) = 0;
+	virtual jack_nframes_t read (Sample *dst, Sample *mixdown, float *gain_buffer, char * workbuf, jack_nframes_t start, jack_nframes_t cnt, uint32_t chan_n=0) = 0;
 	virtual void clear (bool with_delete = false, bool with_save = true);
 	virtual void dump () const;
 	virtual UndoAction get_memento() const = 0;
diff --git a/libs/ardour/ardour/region.h b/libs/ardour/ardour/region.h
index e067f56f44..5af5a660c1 100644
--- a/libs/ardour/ardour/region.h
+++ b/libs/ardour/ardour/region.h
@@ -141,7 +141,7 @@ class Region : public Stateful, public StateManager
 	}
 
 	virtual jack_nframes_t read_at (Sample *buf, Sample *mixdown_buffer, 
-					float *gain_buffer, jack_nframes_t position, jack_nframes_t cnt, 
+					float *gain_buffer, char * workbuf, jack_nframes_t position, jack_nframes_t cnt, 
 					uint32_t chan_n = 0,
 					jack_nframes_t read_frames = 0,
 					jack_nframes_t skip_frames = 0) const = 0;
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index a2a62703e4..d4ca8c1ddc 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -923,6 +923,15 @@ class Session : public sigc::trackable, public Stateful
 	gain_t* gain_automation_buffer () const { return _gain_automation_buffer; }
 	pan_t** pan_automation_buffer() const { return _pan_automation_buffer; }
 
+	/* buffers for conversion */
+	enum RunContext {
+		ButlerContext = 0,
+		TransportContext,
+		ExportContext
+	};
+	
+	char *  conversion_buffer(RunContext context) { return _conversion_buffers[context]; }
+	
 	/* VST support */
 
 	static long vst_callback (AEffect* effect,
@@ -998,6 +1007,7 @@ class Session : public sigc::trackable, public Stateful
 	jack_nframes_t           last_stop_frame;
 	vector<Sample *>        _passthru_buffers;
 	vector<Sample *>        _silent_buffers;
+	map<RunContext,char*> _conversion_buffers;
 	jack_nframes_t           current_block_size;
 	jack_nframes_t          _worst_output_latency;
 	jack_nframes_t          _worst_input_latency;
diff --git a/libs/ardour/ardour/sndfilesource.h b/libs/ardour/ardour/sndfilesource.h
index 7f9712b7ec..a7583c4fe1 100644
--- a/libs/ardour/ardour/sndfilesource.h
+++ b/libs/ardour/ardour/sndfilesource.h
@@ -34,7 +34,7 @@ class SndFileSource : public Source {
 	~SndFileSource ();
 
 	jack_nframes_t length() const { return _info.frames; }
-	jack_nframes_t read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const;
+	jack_nframes_t read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const;
 	void           mark_for_remove() {} // we never remove external sndfiles 
 	string         peak_path(string audio_path);
 	string         old_peak_path(string audio_path);
@@ -54,7 +54,7 @@ class SndFileSource : public Source {
 	string  _path;
 
 	void init (const string &str, bool build_peak);
-	jack_nframes_t read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const;
+	jack_nframes_t read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const;
 };
 
 }; /* namespace EDL */
diff --git a/libs/ardour/ardour/source.h b/libs/ardour/ardour/source.h
index e9afc04f03..9772968288 100644
--- a/libs/ardour/ardour/source.h
+++ b/libs/ardour/ardour/source.h
@@ -64,11 +64,11 @@ class Source : public Stateful, public sigc::trackable
 		return _length;
 	}
 
-	virtual jack_nframes_t read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const {
+	virtual jack_nframes_t read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const {
 		return 0;
 	}
 
-	virtual jack_nframes_t write (Sample *src, jack_nframes_t cnt) {
+	virtual jack_nframes_t write (Sample *src, jack_nframes_t cnt, char * workbuf) {
 		return 0;
 	}
 
@@ -134,7 +134,7 @@ class Source : public Stateful, public sigc::trackable
 	void build_peaks_from_scratch ();
 
 	int  do_build_peak (jack_nframes_t, jack_nframes_t);
-	virtual jack_nframes_t read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const = 0;
+	virtual jack_nframes_t read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const = 0;
 	virtual string peak_path(string audio_path) = 0;
 	virtual string old_peak_path(string audio_path) = 0;
 
diff --git a/libs/ardour/audio_playlist.cc b/libs/ardour/audio_playlist.cc
index be977447b7..f6c6440ab0 100644
--- a/libs/ardour/audio_playlist.cc
+++ b/libs/ardour/audio_playlist.cc
@@ -139,7 +139,7 @@ struct RegionSortByLayer {
 };
 
 jack_nframes_t
-AudioPlaylist::read (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, jack_nframes_t start,
+AudioPlaylist::read (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, char * workbuf, jack_nframes_t start,
 		     jack_nframes_t cnt, unsigned chan_n)
 {
 	jack_nframes_t ret = cnt;
@@ -209,13 +209,13 @@ AudioPlaylist::read (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, ja
 		vector<Crossfade*>& x (relevant_xfades[*l]);
 
 		for (vector<Region*>::iterator i = r.begin(); i != r.end(); ++i) {
-			(*i)->read_at (buf, mixdown_buffer, gain_buffer, start, cnt, chan_n, read_frames, skip_frames);
+			(*i)->read_at (buf, mixdown_buffer, gain_buffer, workbuf, start, cnt, chan_n, read_frames, skip_frames);
 			_read_data_count += (*i)->read_data_count();
 		}
 		
 		for (vector<Crossfade*>::iterator i = x.begin(); i != x.end(); ++i) {
 			
-			(*i)->read_at (buf, mixdown_buffer, gain_buffer, start, cnt, chan_n);
+			(*i)->read_at (buf, mixdown_buffer, gain_buffer, workbuf, start, cnt, chan_n);
 
 			/* don't JACK up _read_data_count, since its the same data as we just
 			   read from the regions, and the OS should handle that for us.
diff --git a/libs/ardour/audio_track.cc b/libs/ardour/audio_track.cc
index dd9648c7bf..7bf8d5732f 100644
--- a/libs/ardour/audio_track.cc
+++ b/libs/ardour/audio_track.cc
@@ -768,7 +768,7 @@ AudioTrack::set_name (string str, void *src)
 }
 
 int
-AudioTrack::export_stuff (vector<Sample*>& buffers, uint32_t nbufs, jack_nframes_t start, jack_nframes_t nframes)
+AudioTrack::export_stuff (vector<Sample*>& buffers, char * workbuf, uint32_t nbufs, jack_nframes_t start, jack_nframes_t nframes)
 {
 	gain_t  gain_automation[nframes];
 	gain_t  gain_buffer[nframes];
@@ -781,7 +781,7 @@ AudioTrack::export_stuff (vector<Sample*>& buffers, uint32_t nbufs, jack_nframes
 	
 	RWLockMonitor rlock (redirect_lock, false, __LINE__, __FILE__);
 		
-	if (diskstream->playlist()->read (buffers[0], mix_buffer, gain_buffer, start, nframes) != nframes) {
+	if (diskstream->playlist()->read (buffers[0], mix_buffer, gain_buffer, workbuf, start, nframes) != nframes) {
 		return -1;
 	}
 
@@ -791,7 +791,7 @@ AudioTrack::export_stuff (vector<Sample*>& buffers, uint32_t nbufs, jack_nframes
 	++bi;
 	for (; bi != buffers.end(); ++bi, ++n) {
 		if (n < diskstream->n_channels()) {
-			if (diskstream->playlist()->read ((*bi), mix_buffer, gain_buffer, start, nframes, n) != nframes) {
+			if (diskstream->playlist()->read ((*bi), mix_buffer, gain_buffer, workbuf, start, nframes, n) != nframes) {
 				return -1;
 			}
 			b = (*bi);
diff --git a/libs/ardour/audioregion.cc b/libs/ardour/audioregion.cc
index bc14968fa7..804e378a16 100644
--- a/libs/ardour/audioregion.cc
+++ b/libs/ardour/audioregion.cc
@@ -462,22 +462,22 @@ AudioRegion::read_peaks (PeakData *buf, jack_nframes_t npeaks, jack_nframes_t of
 }
 
 jack_nframes_t
-AudioRegion::read_at (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, jack_nframes_t position, 
+AudioRegion::read_at (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, char * workbuf, jack_nframes_t position, 
 		      jack_nframes_t cnt, 
 		      uint32_t chan_n, jack_nframes_t read_frames, jack_nframes_t skip_frames) const
 {
-	return _read_at (sources, buf, mixdown_buffer, gain_buffer, position, cnt, chan_n, read_frames, skip_frames);
+	return _read_at (sources, buf, mixdown_buffer, gain_buffer, workbuf, position, cnt, chan_n, read_frames, skip_frames);
 }
 
 jack_nframes_t
-AudioRegion::master_read_at (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, jack_nframes_t position, 
+AudioRegion::master_read_at (Sample *buf, Sample *mixdown_buffer, float *gain_buffer, char * workbuf, jack_nframes_t position, 
 			     jack_nframes_t cnt, uint32_t chan_n) const
 {
-	return _read_at (master_sources, buf, mixdown_buffer, gain_buffer, position, cnt, chan_n, 0, 0);
+	return _read_at (master_sources, buf, mixdown_buffer, gain_buffer, workbuf, position, cnt, chan_n, 0, 0);
 }
 
 jack_nframes_t
-AudioRegion::_read_at (const SourceList& srcs, Sample *buf, Sample *mixdown_buffer, float *gain_buffer, 
+AudioRegion::_read_at (const SourceList& srcs, Sample *buf, Sample *mixdown_buffer, float *gain_buffer, char * workbuf,
 		       jack_nframes_t position, jack_nframes_t cnt, 
 		       uint32_t chan_n, jack_nframes_t read_frames, jack_nframes_t skip_frames) const
 {
@@ -522,7 +522,7 @@ AudioRegion::_read_at (const SourceList& srcs, Sample *buf, Sample *mixdown_buff
 
 	_read_data_count = 0;
 
-	if (srcs[chan_n]->read (mixdown_buffer, _start + internal_offset, to_read) != to_read) {
+	if (srcs[chan_n]->read (mixdown_buffer, _start + internal_offset, to_read, workbuf) != to_read) {
 		return 0; /* "read nothing" */
 	}
 
@@ -1204,7 +1204,7 @@ AudioRegion::exportme (Session& session, AudioExportSpecification& spec)
 		
 		if (spec.channels == 1) {
 
-			if (sources.front()->read (spec.dataF, _start + spec.pos, to_read) != to_read) {
+			if (sources.front()->read (spec.dataF, _start + spec.pos, to_read, 0) != to_read) {
 				goto out;
 			}
 
@@ -1214,7 +1214,7 @@ AudioRegion::exportme (Session& session, AudioExportSpecification& spec)
 
 			for (uint32_t chan = 0; chan < spec.channels; ++chan) {
 				
-				if (sources[chan]->read (buf, _start + spec.pos, to_read) != to_read) {
+				if (sources[chan]->read (buf, _start + spec.pos, to_read, 0) != to_read) {
 					goto out;
 				}
 				
@@ -1276,6 +1276,7 @@ AudioRegion::normalize_to (float target_dB)
 {
 	const jack_nframes_t blocksize = 256 * 1048;
 	Sample buf[blocksize];
+	char workbuf[blocksize * 4];
 	jack_nframes_t fpos;
 	jack_nframes_t fend;
 	jack_nframes_t to_read;
@@ -1304,7 +1305,7 @@ AudioRegion::normalize_to (float target_dB)
 
 			/* read it in */
 
-			if (source (n).read (buf, fpos, to_read) != to_read) {
+			if (source (n).read (buf, fpos, to_read, workbuf) != to_read) {
 				return;
 			}
 			
diff --git a/libs/ardour/crossfade.cc b/libs/ardour/crossfade.cc
index 8aed204d71..c23689a3a3 100644
--- a/libs/ardour/crossfade.cc
+++ b/libs/ardour/crossfade.cc
@@ -373,7 +373,7 @@ Crossfade::compute (AudioRegion& a, AudioRegion& b, CrossfadeModel model)
 
 jack_nframes_t 
 Crossfade::read_at (Sample *buf, Sample *mixdown_buffer, 
-		    float *gain_buffer, jack_nframes_t start, jack_nframes_t cnt, uint32_t chan_n,
+		    float *gain_buffer, char * workbuf, jack_nframes_t start, jack_nframes_t cnt, uint32_t chan_n,
 		    jack_nframes_t read_frames, jack_nframes_t skip_frames)
 {
 	jack_nframes_t offset;
@@ -409,8 +409,8 @@ Crossfade::read_at (Sample *buf, Sample *mixdown_buffer,
 
 	offset = start - _position;
 
-	_out->read_at (crossfade_buffer_out, mixdown_buffer, gain_buffer, start, to_write, chan_n, read_frames, skip_frames);
-	_in->read_at (crossfade_buffer_in, mixdown_buffer, gain_buffer, start, to_write, chan_n, read_frames, skip_frames);
+	_out->read_at (crossfade_buffer_out, mixdown_buffer, gain_buffer, workbuf, start, to_write, chan_n, read_frames, skip_frames);
+	_in->read_at (crossfade_buffer_in, mixdown_buffer, gain_buffer, workbuf, start, to_write, chan_n, read_frames, skip_frames);
 
 	float* fiv = new float[to_write];
 	float* fov = new float[to_write];
diff --git a/libs/ardour/destructive_filesource.cc b/libs/ardour/destructive_filesource.cc
index 6df6ff06af..8715c5f283 100644
--- a/libs/ardour/destructive_filesource.cc
+++ b/libs/ardour/destructive_filesource.cc
@@ -66,8 +66,8 @@ gain_t* DestructiveFileSource::out_coefficient = 0;
 gain_t* DestructiveFileSource::in_coefficient = 0;
 jack_nframes_t DestructiveFileSource::xfade_frames = 64;
 
-DestructiveFileSource::DestructiveFileSource (string path, jack_nframes_t rate, bool repair_first)
-	: FileSource (path, rate, repair_first)
+DestructiveFileSource::DestructiveFileSource (string path, jack_nframes_t rate, bool repair_first, SampleFormat samp_format)
+	: FileSource (path, rate, repair_first, samp_format)
 {
 	if (out_coefficient == 0) {
 		setup_standard_crossfades (rate);
@@ -118,7 +118,7 @@ int
 DestructiveFileSource::seek (jack_nframes_t frame)
 {
 //	file_pos = data_offset + (sizeof (Sample) * frame);
-	cerr << _name << " Seek to " << frame << " = " << data_offset + (sizeof (Sample) * frame) << endl;
+	cerr << _name << " Seek to " << frame << " = " << data_offset + (_sample_size * frame) << endl;
 	return 0;
 }
 
@@ -143,41 +143,37 @@ DestructiveFileSource::clear_capture_marks ()
 }	
 
 jack_nframes_t
-DestructiveFileSource::crossfade (Sample* data, jack_nframes_t cnt, int fade_in)
+DestructiveFileSource::crossfade (Sample* data, jack_nframes_t cnt, int fade_in, char * workbuf)
 {
 	jack_nframes_t xfade = min (xfade_frames, cnt);
-	jack_nframes_t xfade_bytes = xfade * sizeof (Sample);
 	jack_nframes_t nofade = cnt - xfade;
-	jack_nframes_t nofade_bytes = nofade * sizeof (Sample);
 	Sample* fade_data = 0;
-	off_t fade_position = 0;
-
+	off_t fade_position = 0; // in frames
+	ssize_t retval;
+	
 	if (fade_in) {
 		fade_position = file_pos;
 		fade_data = data;
 	} else {
-		fade_position = file_pos + nofade_bytes;
+		fade_position = file_pos + nofade;
 		fade_data = data + nofade;
 	}
 
-	if (::pread64 (fd, (char *) xfade_buf, xfade_bytes, fade_position) != (off64_t) xfade_bytes) {
-		if (errno == EAGAIN) {
+	if ((retval = file_read (xfade_buf, fade_position, xfade, workbuf)) != (ssize_t) xfade) {
+		if (retval < 0 && errno == EAGAIN) {
 			/* no data there, so no xfade */
 
 			xfade = 0;
-			xfade_bytes = 0;
 			nofade = cnt;
-			nofade_bytes = nofade * sizeof (Sample);
-
 		} else {
 			error << string_compose(_("FileSource: \"%1\" bad read (%2: %3)"), _path, errno, strerror (errno)) << endmsg;
 			return 0;
 		}
 	}
-
+	
 	if (nofade && !fade_in) {
-		cerr << "write " << nofade_bytes << " of prefade OUT data to " << file_pos << " .. " << file_pos + nofade_bytes << endl;
-		if (::pwrite64 (fd, (char *) data, nofade_bytes, file_pos) != (off64_t) nofade_bytes) {
+		cerr << "write " << nofade << " frames of prefade OUT data to " << file_pos << " .. " << file_pos + nofade << endl;
+		if (file_write (data, file_pos, nofade, workbuf) != (ssize_t) nofade) {
 			error << string_compose(_("FileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
 			return 0;
 		}
@@ -219,17 +215,18 @@ DestructiveFileSource::crossfade (Sample* data, jack_nframes_t cnt, int fade_in)
 	}
 
 	if (xfade) {
-		cerr << "write " << xfade_bytes << " of xfade  data to " << fade_position << " .. " << fade_position + xfade_bytes << endl;
-		if (::pwrite64 (fd, (char *) xfade_buf, xfade_bytes, fade_position) != (off64_t) xfade_bytes) {
+		cerr << "write " << xfade << " frames of xfade  data to " << fade_position << " .. " << fade_position + xfade << endl;
+
+		if (file_write (xfade_buf, fade_position, xfade, workbuf) != (ssize_t) xfade) {
 			error << string_compose(_("FileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
 			return 0;
 		}
 	}
 	
 	if (fade_in && nofade) {
-		cerr << "write " << nofade_bytes << " of postfade IN  data to " << file_pos + xfade_bytes << " .. " 
-		     << file_pos + xfade_bytes + nofade_bytes << endl;
-		if (::pwrite64 (fd, (char *) (data + xfade), nofade_bytes, file_pos + xfade_bytes) != (off64_t) nofade_bytes) {
+		cerr << "write " << nofade << " frames of postfade IN  data to " << file_pos + xfade << " .. " 
+		     << file_pos + xfade + nofade << endl;
+		if (file_write (data + xfade, file_pos + xfade, nofade, workbuf) != (ssize_t) nofade) {
 			error << string_compose(_("FileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
 			return 0;
 		}
@@ -239,14 +236,13 @@ DestructiveFileSource::crossfade (Sample* data, jack_nframes_t cnt, int fade_in)
 }
 
 jack_nframes_t
-DestructiveFileSource::write (Sample* data, jack_nframes_t cnt)
+DestructiveFileSource::write (Sample* data, jack_nframes_t cnt, char * workbuf)
 {
 	cerr << _name << ": write " << cnt << " to " << file_pos << " start ? " << _capture_start << " end ? " << _capture_end << endl;
 
 	{
 		LockMonitor lm (_lock, __LINE__, __FILE__);
 		
-		int32_t byte_cnt = cnt * sizeof (Sample);
 		jack_nframes_t oldlen;
 
 		if (_capture_start) {
@@ -254,11 +250,12 @@ DestructiveFileSource::write (Sample* data, jack_nframes_t cnt)
 			_capture_end = false;
 
 			/* move to the correct location place */
-			file_pos = data_offset + (capture_start_frame * sizeof (Sample));
-
-			cerr << "First byte of capture will be at " << file_pos << endl;
+			//file_pos = data_offset + (capture_start_frame * sizeof (Sample));
+			file_pos = capture_start_frame;
+			
+			cerr << "First frame of capture will be at " << file_pos << endl;
 			
-			if (crossfade (data, cnt, 1) != cnt) {
+			if (crossfade (data, cnt, 1, workbuf) != cnt) {
 				return 0;
 			}
 
@@ -266,12 +263,11 @@ DestructiveFileSource::write (Sample* data, jack_nframes_t cnt)
 			_capture_start = false;
 			_capture_end = false;
 
-			if (crossfade (data, cnt, 0) != cnt) {
+			if (crossfade (data, cnt, 0, workbuf) != cnt) {
 				return 0;
 			}
 		} else {
-			if (::pwrite64 (fd, (char *) data, byte_cnt, file_pos) != (off64_t) byte_cnt) {
-				error << string_compose(_("FileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
+			if (file_write(data, file_pos, cnt, workbuf) != (ssize_t) cnt) {
 				return 0;
 			}
 		}
@@ -280,8 +276,7 @@ DestructiveFileSource::write (Sample* data, jack_nframes_t cnt)
 		if (file_pos + cnt > _length) {
 			_length += cnt;
 		}
-		_write_data_count = byte_cnt;
-		file_pos += byte_cnt;
+		file_pos += cnt;
 
 		cerr << "at end of write, file_pos = " << file_pos << endl;
 
diff --git a/libs/ardour/diskstream.cc b/libs/ardour/diskstream.cc
index 154e085858..30f365ae32 100644
--- a/libs/ardour/diskstream.cc
+++ b/libs/ardour/diskstream.cc
@@ -992,6 +992,7 @@ DiskStream::overwrite_existing_buffers ()
 {
  	Sample* mixdown_buffer;
  	float* gain_buffer;
+	char * workbuf;
  	int ret = -1;
 	bool reversed = (_visible_speed * _session.transport_speed()) < 0.0f;
 
@@ -1002,7 +1003,8 @@ DiskStream::overwrite_existing_buffers ()
 	
  	mixdown_buffer = new Sample[size];
  	gain_buffer = new float[size];
- 
+	workbuf = new char[size*4];
+	
 	/* reduce size so that we can fill the buffer correctly. */
 	size--;
 	
@@ -1027,7 +1029,7 @@ DiskStream::overwrite_existing_buffers ()
 		
 		jack_nframes_t to_read = size - overwrite_offset;
 
-		if (read ((*chan).playback_buf->buffer() + overwrite_offset, mixdown_buffer, gain_buffer, 
+		if (read ((*chan).playback_buf->buffer() + overwrite_offset, mixdown_buffer, gain_buffer, workbuf,
 			  start, to_read, *chan, n, reversed)) {
 			error << string_compose(_("DiskStream %1: when refilling, cannot read %2 from playlist at frame %3"),
 					 _id, size, playback_sample) << endmsg;
@@ -1038,7 +1040,7 @@ DiskStream::overwrite_existing_buffers ()
 
 			cnt -= to_read;
 		
-			if (read ((*chan).playback_buf->buffer(), mixdown_buffer, gain_buffer, 
+			if (read ((*chan).playback_buf->buffer(), mixdown_buffer, gain_buffer, workbuf,
 				  start, cnt, *chan, n, reversed)) {
 				error << string_compose(_("DiskStream %1: when refilling, cannot read %2 from playlist at frame %3"),
 						 _id, size, playback_sample) << endmsg;
@@ -1053,6 +1055,7 @@ DiskStream::overwrite_existing_buffers ()
 	pending_overwrite = false;
  	delete [] gain_buffer;
  	delete [] mixdown_buffer;
+	delete [] workbuf;
  	return ret;
 }
 
@@ -1076,9 +1079,9 @@ DiskStream::seek (jack_nframes_t frame, bool complete_refill)
 	file_frame = frame;
 
 	if (complete_refill) {
-		while ((ret = do_refill (0, 0)) > 0);
+		while ((ret = do_refill (0, 0, 0)) > 0);
 	} else {
-		ret = do_refill (0, 0);
+		ret = do_refill (0, 0, 0);
 	}
 
 	return ret;
@@ -1113,8 +1116,7 @@ DiskStream::internal_playback_seek (jack_nframes_t distance)
 }
 
 int
-DiskStream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer, jack_nframes_t& start, jack_nframes_t cnt, 
-
+DiskStream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer, char * workbuf, jack_nframes_t& start, jack_nframes_t cnt, 
 		  ChannelInfo& channel_info, int channel, bool reversed)
 {
 	jack_nframes_t this_read = 0;
@@ -1171,7 +1173,7 @@ DiskStream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer, jack_
 
 		this_read = min(cnt,this_read);
 
-		if (_playlist->read (buf+offset, mixdown_buffer, gain_buffer, start, this_read, channel) != this_read) {
+		if (_playlist->read (buf+offset, mixdown_buffer, gain_buffer, workbuf, start, this_read, channel) != this_read) {
 			error << string_compose(_("DiskStream %1: cannot read %2 from playlist at frame %3"), _id, this_read, 
 					 start) << endmsg;
 			return -1;
@@ -1205,13 +1207,14 @@ DiskStream::read (Sample* buf, Sample* mixdown_buffer, float* gain_buffer, jack_
 }
 
 int
-DiskStream::do_refill (Sample* mixdown_buffer, float* gain_buffer)
+DiskStream::do_refill (Sample* mixdown_buffer, float* gain_buffer, char * workbuf)
 {
 	int32_t ret = 0;
 	jack_nframes_t to_read;
 	RingBufferNPT<Sample>::rw_vector vector;
 	bool free_mixdown;
 	bool free_gain;
+	bool free_workbuf;
 	bool reversed = (_visible_speed * _session.transport_speed()) < 0.0f;
 	jack_nframes_t total_space;
 	jack_nframes_t zero_fill;
@@ -1346,6 +1349,13 @@ DiskStream::do_refill (Sample* mixdown_buffer, float* gain_buffer)
 		free_gain = false;
 	}
 
+	if (workbuf == 0) {
+		workbuf = new char[disk_io_chunk_frames * 4];
+		free_workbuf = true;
+	} else {
+		free_workbuf = false;
+	}
+	
 	jack_nframes_t file_frame_tmp = 0;
 
 	for (chan_n = 0, i = channels.begin(); i != channels.end(); ++i, ++chan_n) {
@@ -1378,7 +1388,7 @@ DiskStream::do_refill (Sample* mixdown_buffer, float* gain_buffer)
 
 		if (to_read) {
 
-			if (read (buf1, mixdown_buffer, gain_buffer, file_frame_tmp, to_read, chan, chan_n, reversed)) {
+			if (read (buf1, mixdown_buffer, gain_buffer, workbuf, file_frame_tmp, to_read, chan, chan_n, reversed)) {
 				ret = -1;
 				goto out;
 			}
@@ -1396,7 +1406,7 @@ DiskStream::do_refill (Sample* mixdown_buffer, float* gain_buffer)
 			   so read some or all of vector.len[1] as well.
 			*/
 
-			if (read (buf2, mixdown_buffer, gain_buffer, file_frame_tmp, to_read, chan, chan_n, reversed)) {
+			if (read (buf2, mixdown_buffer, gain_buffer, workbuf, file_frame_tmp, to_read, chan, chan_n, reversed)) {
 				ret = -1;
 				goto out;
 			}
@@ -1419,12 +1429,15 @@ DiskStream::do_refill (Sample* mixdown_buffer, float* gain_buffer)
 	if (free_gain) {
 		delete [] gain_buffer;
 	}
+	if (free_workbuf) {
+		delete [] workbuf;
+	}
 
 	return ret;
 }	
 
 int
-DiskStream::do_flush (bool force_flush)
+DiskStream::do_flush (char * workbuf, bool force_flush)
 {
 	uint32_t to_write;
 	int32_t ret = 0;
@@ -1470,7 +1483,7 @@ DiskStream::do_flush (bool force_flush)
 
 		to_write = min (disk_io_chunk_frames, (jack_nframes_t) vector.len[0]);
 	
-		if ((!(*chan).write_source) || (*chan).write_source->write (vector.buf[0], to_write) != to_write) {
+		if ((!(*chan).write_source) || (*chan).write_source->write (vector.buf[0], to_write, workbuf) != to_write) {
 			error << string_compose(_("DiskStream %1: cannot write to disk"), _id) << endmsg;
 			return -1;
 		}
@@ -1486,7 +1499,7 @@ DiskStream::do_flush (bool force_flush)
 		
 			to_write = min ((jack_nframes_t)(disk_io_chunk_frames - to_write), (jack_nframes_t) vector.len[1]);
 		
-			if ((*chan).write_source->write (vector.buf[1], to_write) != to_write) {
+			if ((*chan).write_source->write (vector.buf[1], to_write, workbuf) != to_write) {
 				error << string_compose(_("DiskStream %1: cannot write to disk"), _id) << endmsg;
 				return -1;
 			}
@@ -1539,7 +1552,7 @@ DiskStream::transport_stopped (struct tm& when, time_t twhen, bool abort_capture
 	*/
 
 	while (more_work && !err) {
-		switch (do_flush (true)) {
+		switch (do_flush ( _session.conversion_buffer(Session::TransportContext), true)) {
 		case 0:
 			more_work = false;
 			break;
diff --git a/libs/ardour/filesource.cc b/libs/ardour/filesource.cc
index 780f26fed6..1f3a89557c 100644
--- a/libs/ardour/filesource.cc
+++ b/libs/ardour/filesource.cc
@@ -65,6 +65,7 @@
 #include <ardour/filesource.h>
 #include <ardour/session.h>
 #include <ardour/cycle_timer.h>
+#include <ardour/pcm_utils.h>
 
 #include "i18n.h"
 
@@ -101,10 +102,16 @@ FileSource::set_search_path (string p)
 	search_path = p;
 }
 
-FileSource::FileSource (string pathstr, jack_nframes_t rate, bool repair_first)
+FileSource::FileSource (string pathstr, jack_nframes_t rate, bool repair_first, SampleFormat samp_format)
 {
 	/* constructor used when the file cannot already exist or might be damaged */
-
+	_sample_format = samp_format;
+	if (samp_format == FormatInt24) {
+		_sample_size = 3;
+	} else {
+		_sample_size = sizeof(float);
+	}
+	
 	if (repair_first && repair (pathstr, rate)) {
 		throw failed_constructor ();
 	}
@@ -119,6 +126,9 @@ FileSource::FileSource (string pathstr, jack_nframes_t rate, bool repair_first)
 FileSource::FileSource (const XMLNode& node, jack_nframes_t rate) 
 	: Source (node)
 {
+	_sample_format = FormatFloat;
+	_sample_size = sizeof(float);
+
 	if (set_state (node)) {
 		throw failed_constructor();
 	}
@@ -558,12 +568,19 @@ FileSource::fill_header (jack_nframes_t rate)
 	memcpy (header.format.id, "fmt ", 4);
 	header.format.size = sizeof (FMTChunk) - sizeof (GenericChunk);
 
-	header.format.formatTag = 3; /* little-endian IEEE float format */
+	if (_sample_format == FormatInt24) {
+		header.format.formatTag = 1; // PCM
+		header.format.nBlockAlign = 3;
+		header.format.nBitsPerSample = 24;
+	}
+	else {
+		header.format.formatTag = 3; /* little-endian IEEE float format */
+		header.format.nBlockAlign = 4;
+		header.format.nBitsPerSample = 32;
+	}
 	header.format.nChannels = 1; /* mono */
 	header.format.nSamplesPerSec = rate;
 	header.format.nAvgBytesPerSec = rate * sizeof (Sample);
-	header.format.nBlockAlign = 4;
-	header.format.nBitsPerSample = 32;
 	
 	/* DATA */
 
@@ -788,9 +805,18 @@ FileSource::read_broadcast_data (ChunkInfo& info)
 int
 FileSource::check_header (jack_nframes_t rate, bool silent)
 {
-	if (header.format.formatTag != 3) { /* IEEE float */
+	if (header.format.formatTag == 1 && header.format.nBitsPerSample == 24) {
+		// 24 bit PCM
+		_sample_format = FormatInt24;
+		_sample_size = 3;
+	} else if (header.format.formatTag == 3) {
+		/* IEEE float */		
+		_sample_format = FormatFloat;
+		_sample_size = 4;
+	}
+	else {
 		if (!silent) {
-			error << string_compose(_("FileSource \"%1\" does not use floating point format.\n"   
+			error << string_compose(_("FileSource \"%1\" does not use valid sample format.\n"   
 					   "This is probably a programming error."), _path) << endmsg;
 		}
 		return -1;
@@ -932,73 +958,38 @@ FileSource::mark_for_remove ()
 }
 
 jack_nframes_t
-FileSource::read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const
+FileSource::read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const
 {
 	LockMonitor lm (_lock, __LINE__, __FILE__);
-	return read_unlocked (dst, start, cnt);
+	return read_unlocked (dst, start, cnt, workbuf);
 }
 
 jack_nframes_t
-FileSource::read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const
+FileSource::read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const
 {
-	int32_t byte_cnt;
-	int nread;
-
-	byte_cnt = cnt * sizeof (Sample);
-
-	if ((nread = pread (fd, (char *) dst, byte_cnt, data_offset + (start * sizeof (Sample)))) != (off64_t) byte_cnt) {
-		
-		cerr << "FileSource: \""
-		     << _path
-		     << "\" bad read at frame "
-		     << start
-		     << ", of "
-		     << cnt
-		     << " (bytes="
-		     << byte_cnt
-		     << ") frames [length = " << _length 
-		     << " eor = " << start + cnt << "] ("
-		     << strerror (errno)
-		     << ") (read "
-		     << nread / sizeof (Sample)
-		     << " (bytes=" <<nread
-		     << ")) pos was"
-		     << data_offset
-		     << '+'
-		     << start << '*' << sizeof(Sample)
-		     << " = " << data_offset + (start * sizeof(Sample))
-		     << endl;
-		
+	
+	if (file_read(dst, start, cnt, workbuf) != (ssize_t) cnt) {
 		return 0;
 	}
-
-	if (header.bigendian != WE_ARE_BIGENDIAN) {
-		swap_endian(dst, cnt);
-	}
 	
-	_read_data_count = byte_cnt;
-		
 	return cnt;
 }
 
 jack_nframes_t
-FileSource::write (Sample *data, jack_nframes_t cnt)
+FileSource::write (Sample *data, jack_nframes_t cnt, char * workbuf)
 {
 	{
 		LockMonitor lm (_lock, __LINE__, __FILE__);
 		
-		int32_t byte_cnt = cnt * sizeof (Sample);
-		int32_t byte_pos = data_offset + (_length * sizeof (Sample));
 		jack_nframes_t oldlen;
-
-		if (::pwrite64 (fd, (char *) data, byte_cnt, byte_pos) != (off64_t) byte_cnt) {
-			error << string_compose(_("FileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
+		int32_t frame_pos = _length;
+		
+		if (file_write(data, frame_pos, cnt, workbuf) != (ssize_t) cnt) {
 			return 0;
 		}
 
 		oldlen = _length;
 		_length += cnt;
-		_write_data_count = byte_cnt;
 
 		if (_build_peakfiles) {
 			PeakBuildRecord *pbr = 0;
@@ -1031,6 +1022,152 @@ FileSource::write (Sample *data, jack_nframes_t cnt)
 	return cnt;
 }
 
+ssize_t
+FileSource::write_float(Sample *data, jack_nframes_t framepos, jack_nframes_t cnt, char * workbuf)
+{
+	int32_t byte_cnt = cnt * _sample_size;
+	int32_t byte_pos = data_offset + (framepos * _sample_size);
+	ssize_t retval;
+	
+	if ((retval = ::pwrite64 (fd, (char *) data, byte_cnt, byte_pos)) != (ssize_t) byte_cnt) {
+		error << string_compose(_("FileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
+		if (retval > 0) {
+			return retval / _sample_size;
+		}
+		else {
+			return retval;
+		}
+	}
+
+	_write_data_count = byte_cnt;
+	
+	return cnt;
+}
+
+ssize_t
+FileSource::read_float (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const
+{
+	ssize_t nread;
+	ssize_t byte_cnt = (ssize_t) cnt * sizeof (Sample);
+	
+	if ((nread = pread (fd, (char *) dst, byte_cnt, data_offset + (start * _sample_size))) != byte_cnt) {
+		
+		cerr << "FileSource: \""
+		     << _path
+		     << "\" bad read at frame "
+		     << start
+		     << ", of "
+		     << cnt
+		     << " (bytes="
+		     << byte_cnt
+		     << ") frames [length = " << _length 
+		     << " eor = " << start + cnt << "] ("
+		     << strerror (errno)
+		     << ") (read "
+		     << nread / sizeof (Sample)
+		     << " (bytes=" <<nread
+		     << ")) pos was"
+		     << data_offset
+		     << '+'
+		     << start << '*' << sizeof(Sample)
+		     << " = " << data_offset + (start * sizeof(Sample))
+		     << endl;
+		
+		if (nread > 0) {
+			return nread / _sample_size;
+		}
+		else {
+			return nread;
+		}
+	}
+
+	if (header.bigendian != WE_ARE_BIGENDIAN) {
+		swap_endian(dst, cnt);
+	}
+	
+	_read_data_count = byte_cnt;
+
+	return cnt;
+}
+
+ssize_t
+FileSource::write_pcm_24(Sample *data, jack_nframes_t framepos, jack_nframes_t cnt, char * workbuf)
+{
+	int32_t byte_cnt = cnt * _sample_size;
+	int32_t byte_pos = data_offset + (framepos * _sample_size);
+	ssize_t retval;
+	
+	// convert to int24
+	if (header.bigendian) {
+		pcm_f2bet_clip_array (data, workbuf, cnt);
+	} else {
+		pcm_f2let_clip_array (data, workbuf, cnt);
+	}
+	
+	if ((retval = ::pwrite64 (fd, (char *) workbuf, byte_cnt, byte_pos)) != (ssize_t) byte_cnt) {
+		error << string_compose(_("FileSource: \"%1\" bad write (%2)"), _path, strerror (errno)) << endmsg;
+		if (retval > 0) {
+			return retval / _sample_size;
+		}
+		else {
+			return retval;
+		}
+	}
+
+	return (ssize_t) cnt;
+}
+
+ssize_t
+FileSource::read_pcm_24 (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const
+{
+	ssize_t nread;
+	ssize_t byte_cnt = (ssize_t) cnt * _sample_size;
+
+	if ((nread = pread (fd, (char *) workbuf, byte_cnt, data_offset + (start * _sample_size))) != byte_cnt) {
+		
+		cerr << "FileSource: \""
+		     << _path
+		     << "\" bad 24bit read at frame "
+		     << start
+		     << ", of "
+		     << cnt
+		     << " (bytes="
+		     << byte_cnt
+		     << ") frames [length = " << _length 
+		     << " eor = " << start + cnt << "] ("
+		     << strerror (errno)
+		     << ") (read "
+		     << nread / sizeof (Sample)
+		     << " (bytes=" <<nread
+		     << ")) pos was"
+		     << data_offset
+		     << '+'
+		     << start << '*' << sizeof(Sample)
+		     << " = " << data_offset + (start * sizeof(Sample))
+		     << endl;
+
+		if (nread > 0) {
+			return nread / _sample_size;
+		}
+		else {
+			return nread;
+		}
+	}
+
+	// convert from 24bit->float
+	
+	if (header.bigendian) {
+		pcm_bet2f_array (workbuf, cnt, dst);
+	} else {
+		pcm_let2f_array (workbuf, cnt, dst);
+	}
+	
+	_read_data_count = byte_cnt;
+
+	return (ssize_t) cnt;
+}
+
+
 bool
 FileSource::is_empty (string path)
 {
diff --git a/libs/ardour/import.cc b/libs/ardour/import.cc
index 3411481a3a..f5884a1c1d 100644
--- a/libs/ardour/import.cc
+++ b/libs/ardour/import.cc
@@ -42,7 +42,7 @@
 
 using namespace ARDOUR;
 
-#define BLOCKSIZE 2048U
+#define BLOCKSIZE 4096U
 
 int
 Session::import_audiofile (import_status& status)
@@ -53,6 +53,7 @@ Session::import_audiofile (import_status& status)
 	SF_INFO info;
 	float *data = 0;
 	Sample **channel_data = 0;
+	char * workbuf = 0;
 	long nfiles = 0;
 	long n;
 	string basepath;
@@ -147,7 +148,8 @@ Session::import_audiofile (import_status& status)
 	
 	data = new float[BLOCKSIZE * info.channels];
 	channel_data = new Sample * [ info.channels ];
-
+	workbuf = new char[BLOCKSIZE * 4];
+	
 	for (n = 0; n < info.channels; ++n) {
 		channel_data[n] = new Sample[BLOCKSIZE];
 	}
@@ -178,7 +180,7 @@ Session::import_audiofile (import_status& status)
 		/* flush to disk */
 
 		for (chn = 0; chn < info.channels; ++chn) {
-			newfiles[chn]->write (channel_data[chn], nread);
+			newfiles[chn]->write (channel_data[chn], nread, workbuf);
 		}
 
 		so_far += nread;
@@ -245,7 +247,10 @@ Session::import_audiofile (import_status& status)
 	if (data) {
 		delete [] data;
 	}
-
+	if (workbuf) {
+		delete [] workbuf;
+	}
+	
 	if (channel_data) {
 		for (n = 0; n < info.channels; ++n) {
 			delete [] channel_data[n];
diff --git a/libs/ardour/insert.cc b/libs/ardour/insert.cc
index 3b3999a848..3ef84d1481 100644
--- a/libs/ardour/insert.cc
+++ b/libs/ardour/insert.cc
@@ -599,7 +599,7 @@ PluginInsert::state (bool full)
 	node->add_property("id", string(buf));
 	if (_plugins[0]->state_node_name() == "ladspa") {
 		char buf[32];
-		snprintf (buf, 31, "%d", _plugins[0]->get_info().unique_id); 
+		snprintf (buf, 31, "%ld", _plugins[0]->get_info().unique_id); 
 		node->add_property("unique-id", string(buf));
 	}
 	node->add_property("count", string_compose("%1", _plugins.size()));
diff --git a/libs/ardour/pcm_utils.cc b/libs/ardour/pcm_utils.cc
new file mode 100644
index 0000000000..dd18fe8690
--- /dev/null
+++ b/libs/ardour/pcm_utils.cc
@@ -0,0 +1,178 @@
+/*
+    Copyright (C) 2006 Paul Davis , portions Erik de Castro Lopo
+
+    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.
+
+    $Id$
+*/
+
+#include <ardour/pcm_utils.h>
+
+#include <cmath>
+
+using namespace std;
+
+// TODO: check CPU_CLIPS_POSITIVE and CPU_CLIPS_NEGATIVE with scons
+#define CPU_CLIPS_NEGATIVE 0
+#define CPU_CLIPS_POSITIVE 0
+
+/* these routines deal with 24 bit int handling (tribytes)
+ *   originally from libsndfile, but modified.  XXX - Copyright Erik de Castro Lopo
+ */
+
+void
+pcm_let2f_array (tribyte *src, int count, float *dest)
+{
+	/* Special normfactor because tribyte value is read into an int. */
+	static const float normfact = 1.0 / ((float) 0x80000000);
+
+	unsigned char	*ucptr ;
+	int 			value ;
+
+	ucptr = ((unsigned char*) src) + 3 * count ;
+	while (--count >= 0)
+	{	ucptr -= 3 ;
+		value = LET2H_INT_PTR (ucptr) ;
+		dest [count] = ((float) value) * normfact ;
+		} ;
+} /* let2f_array */
+
+void
+pcm_bet2f_array (tribyte *src, int count, float *dest)
+{
+	/* Special normfactor because tribyte value is read into an int. */
+	static const float normfact = 1.0 / ((float) 0x80000000);
+	
+	unsigned char	*ucptr ;
+	int				value ;
+
+	
+	ucptr = ((unsigned char*) src) + 3 * count ;
+	while (--count >= 0)
+	{	ucptr -= 3 ;
+		value = BET2H_INT_PTR (ucptr) ;
+		dest [count] = ((float) value) * normfact ;
+			} ;
+} /* bet2f_array */
+
+void
+pcm_f2let_array (float *src, tribyte *dest, int count)
+{
+	static const float normfact = (1.0 * 0x7FFFFF);
+
+	unsigned char	*ucptr ;
+	int				value ;
+
+	ucptr = ((unsigned char*) dest) + 3 * count ;
+
+	while (count)
+	{	count -- ;
+		ucptr -= 3 ;
+		value = lrintf (src [count] * normfact) ;
+		ucptr [0] = value ;
+		ucptr [1] = value >> 8 ;
+		ucptr [2] = value >> 16 ;
+		} ;
+} /* f2let_array */
+
+void
+pcm_f2let_clip_array (float *src, tribyte *dest, int count)
+{
+	static const float normfact = (8.0 * 0x10000000);
+
+	unsigned char	*ucptr ;
+	float			scaled_value ;
+	int				value ;
+
+	ucptr = ((unsigned char*) dest) + 3 * count ;
+
+	while (count)
+	{	count -- ;
+		ucptr -= 3 ;
+		scaled_value = src [count] * normfact ;
+		if (CPU_CLIPS_POSITIVE == 0 && scaled_value >= (1.0 * 0x7FFFFFFF))
+		{	ucptr [0] = 0xFF ;
+			ucptr [1] = 0xFF ;
+			ucptr [2] = 0x7F ;
+			continue ;
+			} ;
+		if (CPU_CLIPS_NEGATIVE == 0 && scaled_value <= (-8.0 * 0x10000000))
+		{	ucptr [0] = 0x00 ;
+			ucptr [1] = 0x00 ;
+			ucptr [2] = 0x80 ;
+			continue ;
+			} ;
+
+		value = lrintf (scaled_value) ;
+		ucptr [0] = value >> 8 ;
+		ucptr [1] = value >> 16 ;
+		ucptr [2] = value >> 24 ;
+		} ;
+} /* f2let_clip_array */
+
+void
+pcm_f2bet_array (const float *src, tribyte *dest, int count)
+{
+	static const float normfact = (1.0 * 0x7FFFFF);
+	
+	unsigned char	*ucptr ;
+	int				value ;
+
+	ucptr = ((unsigned char*) dest) + 3 * count ;
+
+	while (--count >= 0)
+	{	ucptr -= 3 ;
+		value = lrintf (src [count] * normfact) ;
+		ucptr [0] = value >> 16 ;
+		ucptr [1] = value >> 8 ;
+		ucptr [2] = value ;
+		} ;
+} /* f2bet_array */
+
+void
+pcm_f2bet_clip_array (const float *src, tribyte *dest, int count)
+{
+	static const float normfact = (8.0 * 0x10000000);
+
+	unsigned char	*ucptr ;
+	float			scaled_value ;
+	int				value ;
+
+	ucptr = ((unsigned char*) dest) + 3 * count ;
+
+	while (--count >= 0)
+	{	ucptr -= 3 ;
+		scaled_value = src [count] * normfact ;
+		if (CPU_CLIPS_POSITIVE == 0 && scaled_value >= (1.0 * 0x7FFFFFFF))
+		{	ucptr [0] = 0x7F ;
+			ucptr [1] = 0xFF ;
+			ucptr [2] = 0xFF ;
+			continue ;
+			} ;
+		if (CPU_CLIPS_NEGATIVE == 0 && scaled_value <= (-8.0 * 0x10000000))
+		{	ucptr [0] = 0x80 ;
+			ucptr [1] = 0x00 ;
+			ucptr [2] = 0x00 ;
+			continue ;
+		} ;
+
+		value = lrint (scaled_value) ;
+		ucptr [0] = value >> 24 ;
+		ucptr [1] = value >> 16 ;
+		ucptr [2] = value >> 8 ;
+		} ;
+} /* f2bet_clip_array */
+
+//@@@@@@@
diff --git a/libs/ardour/plugin.cc b/libs/ardour/plugin.cc
index 059cf133a5..e9665908a3 100644
--- a/libs/ardour/plugin.cc
+++ b/libs/ardour/plugin.cc
@@ -273,7 +273,7 @@ Plugin::get_presets()
 	lrdf_uris* set_uris = lrdf_get_setting_uris(unique_id());
 
 	if (set_uris) {
-		for (uint32_t i = 0; i < set_uris->count; ++i) {
+		for (uint32_t i = 0; i < (uint32_t) set_uris->count; ++i) {
 			if (char* label = lrdf_get_label(set_uris->items[i])) {
 				labels.push_back(label);
 				presets[label] = set_uris->items[i];
@@ -294,10 +294,10 @@ Plugin::load_preset(const string preset_label)
 	lrdf_defaults* defs = lrdf_get_setting_values(presets[preset_label].c_str());
 
 	if (defs) {
-		for (uint32_t i = 0; i < defs->count; ++i) {
+		for (uint32_t i = 0; i < (uint32_t) defs->count; ++i) {
 			// The defs->items[i].pid < defs->count check is to work around 
 			// a bug in liblrdf that saves invalid values into the presets file.
-			if (((uint32_t) defs->items[i].pid < defs->count) && parameter_is_input (defs->items[i].pid)) {
+			if (((uint32_t) defs->items[i].pid < (uint32_t) defs->count) && parameter_is_input (defs->items[i].pid)) {
 				set_parameter(defs->items[i].pid, defs->items[i].value);
 			}
 		}
diff --git a/libs/ardour/reverse.cc b/libs/ardour/reverse.cc
index 2474e0cb8d..335dacad6e 100644
--- a/libs/ardour/reverse.cc
+++ b/libs/ardour/reverse.cc
@@ -49,6 +49,7 @@ Reverse::run (AudioRegion& region)
 	AudioRegion::SourceList::iterator si;
 	const jack_nframes_t blocksize = 256 * 1048;
 	Sample buf[blocksize];
+	char * workbuf = 0;;
 	jack_nframes_t fpos;
 	jack_nframes_t fend;
 	jack_nframes_t fstart;
@@ -61,6 +62,8 @@ Reverse::run (AudioRegion& region)
 		goto out;
 	}
 
+	workbuf = new char[blocksize * 4];
+	
 	fend = region.start() + region.length();
 	fstart = region.start();
 
@@ -82,7 +85,7 @@ Reverse::run (AudioRegion& region)
 
 			/* read it in */
 			
-			if (region.source (n).read (buf, fpos, to_read) != to_read) {
+			if (region.source (n).read (buf, fpos, to_read, workbuf) != to_read) {
 				goto out;
 			}
 			
@@ -94,7 +97,7 @@ Reverse::run (AudioRegion& region)
 			
 			/* write it out */
 
-			if ((*si)->write (buf, to_read) != to_read) {
+			if ((*si)->write (buf, to_read, workbuf) != to_read) {
 				goto out;
 			}
 		}
@@ -120,6 +123,9 @@ Reverse::run (AudioRegion& region)
 			delete *si;
 		}
 	}
-
+	if (workbuf) {
+		delete [] workbuf;
+	}
+	
 	return ret;
 }
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index b329c16cc6..e0c6c1bf7e 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -389,6 +389,10 @@ Session::~Session ()
 		free(*i);
 	}
 
+	for (map<RunContext,char*>::iterator i = _conversion_buffers.begin(); i != _conversion_buffers.end(); ++i) {
+		delete [] (i->second);
+	}
+	
 #undef TRACK_DESTRUCTION
 #ifdef TRACK_DESTRUCTION
 	cerr << "delete named selections\n";
@@ -1867,7 +1871,7 @@ void
 Session::add_diskstream (DiskStream* dstream)
 {
 	/* need to do this in case we're rolling at the time, to prevent false underruns */
-	dstream->do_refill(0, 0);
+	dstream->do_refill(0, 0, 0);
 	
 	{ 
 		RWLockMonitor lm (diskstream_lock, true, __LINE__, __FILE__);
@@ -3408,6 +3412,7 @@ Session::write_one_track (AudioTrack& track, jack_nframes_t start, jack_nframes_
 	jack_nframes_t this_chunk;
 	jack_nframes_t to_do;
 	vector<Sample*> buffers;
+	char *  workbuf = 0;
 	const jack_nframes_t chunk_size = (256 * 1024)/4;
 
 	atomic_set (&processing_prohibited, 1);
@@ -3470,18 +3475,20 @@ Session::write_one_track (AudioTrack& track, jack_nframes_t start, jack_nframes_
 #endif			
 		buffers.push_back (b);
 	}
+
+	workbuf = new char[chunk_size * 4];
 	
 	while (to_do && !itt.cancel) {
 		
 		this_chunk = min (to_do, chunk_size);
 		
-		if (track.export_stuff (buffers, nchans, start, this_chunk)) {
+		if (track.export_stuff (buffers, workbuf, nchans, start, this_chunk)) {
 			goto out;
 		}
 
 		uint32_t n = 0;
 		for (vector<Source*>::iterator src=srcs.begin(); src != srcs.end(); ++src, ++n) {
-			if ((*src)->write (buffers[n], this_chunk) != this_chunk) {
+			if ((*src)->write (buffers[n], this_chunk, workbuf) != this_chunk) {
 				goto out;
 			}
 		}
@@ -3525,6 +3532,10 @@ Session::write_one_track (AudioTrack& track, jack_nframes_t start, jack_nframes_
 		free(*i);
 	}
 
+	if (workbuf) {
+		delete [] workbuf;
+	}
+	
 	atomic_set (&processing_prohibited, 0);
 
 	itt.done = true;
diff --git a/libs/ardour/session_butler.cc b/libs/ardour/session_butler.cc
index 12a838b5dd..00a2465d9b 100644
--- a/libs/ardour/session_butler.cc
+++ b/libs/ardour/session_butler.cc
@@ -174,6 +174,8 @@ Session::butler_thread_work ()
 
 	butler_mixdown_buffer = new Sample[DiskStream::disk_io_frames()];
 	butler_gain_buffer = new gain_t[DiskStream::disk_io_frames()];
+	// this buffer is used for temp conversion purposes in filesources
+	char * conv_buffer = conversion_buffer(ButlerContext);
 
 	while (true) {
 
@@ -260,7 +262,7 @@ Session::butler_thread_work ()
 			
 			// cerr << "rah fondr " << (*i)->io()->name () << endl;
 
-			switch ((*i)->do_refill (butler_mixdown_buffer, butler_gain_buffer)) {
+			switch ((*i)->do_refill (butler_mixdown_buffer, butler_gain_buffer, conv_buffer)) {
 			case 0:
 				bytes += (*i)->read_data_count();
 				break;
@@ -303,7 +305,7 @@ Session::butler_thread_work ()
 			
 			// cerr << "write behind for " << (*i)->name () << endl;
 			
-			switch ((*i)->do_flush ()) {
+			switch ((*i)->do_flush (conv_buffer)) {
 			case 0:
 				bytes += (*i)->write_data_count();
 				break;
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index 2a8bdf2fde..45a51e813b 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -190,6 +190,10 @@ Session::first_stage_init (string fullpath, string snapshot_name)
 	pending_abort = false;
 	layer_model = MoveAddHigher;
 	xfade_model = ShortCrossfade;
+
+	/* allocate conversion buffers */
+	_conversion_buffers[ButlerContext] = new char[DiskStream::disk_io_frames() * 4];
+	_conversion_buffers[TransportContext] = new char[DiskStream::disk_io_frames() * 4];
 	
 	/* default short fade = 15ms */
 
diff --git a/libs/ardour/session_timefx.cc b/libs/ardour/session_timefx.cc
index b8f0068a91..2fae4b32c9 100644
--- a/libs/ardour/session_timefx.cc
+++ b/libs/ardour/session_timefx.cc
@@ -93,6 +93,7 @@ Session::tempoize_region (TimeStretchRequest& tsr)
 		for (uint32_t i = 0; i < sources.size(); ++i) {
 			gain_t gain_buffer[bufsize];
 			Sample buffer[bufsize];
+			char   workbuf[bufsize*4];
 			jack_nframes_t pos = 0;
 			jack_nframes_t this_read = 0;
 
@@ -106,7 +107,7 @@ Session::tempoize_region (TimeStretchRequest& tsr)
 				   not the ones currently in use, in case it's already been 
 				   subject to timefx.  */
 
-				if ((this_read = tsr.region->master_read_at (buffer, buffer, gain_buffer, pos + tsr.region->position(), this_time)) != this_time) {
+				if ((this_read = tsr.region->master_read_at (buffer, buffer, gain_buffer, workbuf, pos + tsr.region->position(), this_time)) != this_time) {
 					error << string_compose (_("tempoize: error reading data from %1"), sources[i]->name()) << endmsg;
 					goto out;
 				}
@@ -119,7 +120,7 @@ Session::tempoize_region (TimeStretchRequest& tsr)
 				st.putSamples (buffer, this_read);
 			
 				while ((this_read = st.receiveSamples (buffer, bufsize)) > 0 && tsr.running) {
-					if (sources[i]->write (buffer, this_read) != this_read) {
+					if (sources[i]->write (buffer, this_read, workbuf) != this_read) {
 						error << string_compose (_("error writing tempo-adjusted data to %1"), sources[i]->name()) << endmsg;
 						goto out;
 					}
@@ -131,7 +132,7 @@ Session::tempoize_region (TimeStretchRequest& tsr)
 			}
 		
 			while (tsr.running && (this_read = st.receiveSamples (buffer, bufsize)) > 0) {
-				if (sources[i]->write (buffer, this_read) != this_read) {
+				if (sources[i]->write (buffer, this_read, workbuf) != this_read) {
 					error << string_compose (_("error writing tempo-adjusted data to %1"), sources[i]->name()) << endmsg;
 					goto out;
 				}
diff --git a/libs/ardour/sndfilesource.cc b/libs/ardour/sndfilesource.cc
index 0baff36a3f..350a9c2ef1 100644
--- a/libs/ardour/sndfilesource.cc
+++ b/libs/ardour/sndfilesource.cc
@@ -122,13 +122,13 @@ SndFileSource::~SndFileSource ()
 }
 
 jack_nframes_t
-SndFileSource::read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const
+SndFileSource::read_unlocked (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const
 {
-	return read (dst, start, cnt);
+	return read (dst, start, cnt, workbuf);
 }
 
 jack_nframes_t
-SndFileSource::read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt) const
+SndFileSource::read (Sample *dst, jack_nframes_t start, jack_nframes_t cnt, char * workbuf) const
 {
 	int32_t nread;
 	float *ptr;
diff --git a/libs/ardour/source.cc b/libs/ardour/source.cc
index 515e8d4e9b..ee918375f6 100644
--- a/libs/ardour/source.cc
+++ b/libs/ardour/source.cc
@@ -419,7 +419,8 @@ Source::read_peaks (PeakData *peaks, jack_nframes_t npeaks, jack_nframes_t start
 	int ret = -1;
 	PeakData* staging = 0;
 	Sample* raw_staging = 0;
-
+	char * workbuf = 0;
+	
 	expected_peaks = (cnt / (double) frames_per_peak);
 	scale = npeaks/expected_peaks;
 
@@ -456,8 +457,9 @@ Source::read_peaks (PeakData *peaks, jack_nframes_t npeaks, jack_nframes_t start
 		*/
 
 		Sample* raw_staging = new Sample[cnt];
+		workbuf = new char[cnt*4];
 		
-		if (read_unlocked (raw_staging, start, cnt) != cnt) {
+		if (read_unlocked (raw_staging, start, cnt, workbuf) != cnt) {
 			error << _("cannot read sample data for unscaled peak computation") << endmsg;
 			return -1;
 		}
@@ -468,7 +470,7 @@ Source::read_peaks (PeakData *peaks, jack_nframes_t npeaks, jack_nframes_t start
 		}
 
 		delete [] raw_staging;
-		
+		delete [] workbuf;
 		return 0;
 	}
 
@@ -615,7 +617,8 @@ Source::read_peaks (PeakData *peaks, jack_nframes_t npeaks, jack_nframes_t start
 		jack_nframes_t nvisual_peaks = 0;
 		jack_nframes_t chunksize = (jack_nframes_t) min (cnt, (jack_nframes_t) 4096);
 		raw_staging = new Sample[chunksize];
-
+		workbuf = new char[chunksize *4];
+		
 		jack_nframes_t frame_pos = start;
 		double pixel_pos = floor (frame_pos / samples_per_visual_peak);
 		double next_pixel_pos = ceil (frame_pos / samples_per_visual_peak);
@@ -630,7 +633,7 @@ Source::read_peaks (PeakData *peaks, jack_nframes_t npeaks, jack_nframes_t start
 				
 				to_read = min (chunksize, (_length - current_frame));
 				
-				if ((frames_read = read_unlocked (raw_staging, current_frame, to_read)) < 0) {
+				if ((frames_read = read_unlocked (raw_staging, current_frame, to_read, workbuf)) < 0) {
 					error << string_compose(_("Source[%1]: peak read - cannot read %2 samples at offset %3")
 							 , _name, to_read, current_frame) 
 					      << endmsg;
@@ -674,6 +677,10 @@ Source::read_peaks (PeakData *peaks, jack_nframes_t npeaks, jack_nframes_t start
 		delete [] raw_staging;
 	}
 
+	if (workbuf) {
+		delete [] workbuf;
+	}
+	
 	return ret;
 }
 
@@ -743,6 +750,7 @@ Source::do_build_peak (jack_nframes_t first_frame, jack_nframes_t cnt)
 	Sample xmin, xmax;
 	uint32_t  peaki;
 	PeakData* peakbuf;
+	char * workbuf = 0;
 	jack_nframes_t frames_read;
 	jack_nframes_t frames_to_read;
 	off_t first_peak_byte;
@@ -762,11 +770,13 @@ Source::do_build_peak (jack_nframes_t first_frame, jack_nframes_t cnt)
 	peakbuf = new PeakData[(cnt/frames_per_peak)+1];
 	peaki = 0;
 
+	workbuf = new char[max(frames_per_peak, cnt) * 4];
+	
 	while (cnt) {
 
 		frames_to_read = min (frames_per_peak, cnt);
 
-		if ((frames_read = read_unlocked (buf, current_frame, frames_to_read)) != frames_to_read) {
+		if ((frames_read = read_unlocked (buf, current_frame, frames_to_read, workbuf)) != frames_to_read) {
 			error << string_compose(_("%1: could not write read raw data for peak computation (%2)"), _name, strerror (errno)) << endmsg;
 			goto out;
 		}
@@ -800,6 +810,8 @@ Source::do_build_peak (jack_nframes_t first_frame, jack_nframes_t cnt)
 
   out:
 	delete [] peakbuf;
+	if (workbuf)
+		delete [] workbuf;
 	return ret;
 }
 
diff --git a/libs/gtkmm2ext/pixscroller.cc b/libs/gtkmm2ext/pixscroller.cc
index 556fce8080..8edf0723e1 100644
--- a/libs/gtkmm2ext/pixscroller.cc
+++ b/libs/gtkmm2ext/pixscroller.cc
@@ -33,7 +33,7 @@ PixScroller::PixScroller (Adjustment& a, Pix& pix)
 	: adj (a)
 {
 	dragging = false;
-	add_events (Gdk::BUTTON_PRESS_MASK|Gdk::BUTTON_RELEASE_MASK|Gdk::POINTER_MOTION_MASK);
+	add_events (Gdk::BUTTON_PRESS_MASK|Gdk::BUTTON_RELEASE_MASK|Gdk::POINTER_MOTION_MASK|Gdk::SCROLL_MASK);
 
 	adj.signal_value_changed().connect (mem_fun (*this, &PixScroller::adjustment_changed));
 	default_value = adj.get_value();