don't always rebuild peakfiles for compound regions
[ardour.git] / libs / ardour / audiosource.cc
index 5fcabb0c774127b45607cbca6c852841cf9777a9..de6c5edfec9e5d781f4a663648c9227a84812431 100644 (file)
@@ -38,6 +38,7 @@
 #include "pbd/pthread_utils.h"
 
 #include "ardour/audiosource.h"
+#include "ardour/audio_diskstream.h"
 #include "ardour/cycle_timer.h"
 #include "ardour/session.h"
 #include "ardour/transient_detector.h"
 using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
-using Glib::ustring;
 
+Glib::StaticMutex AudioSource::_level_buffer_lock = GLIBMM_STATIC_MUTEX_INIT;
+vector<boost::shared_ptr<Sample> > AudioSource::_mixdown_buffers;
+vector<boost::shared_ptr<gain_t> > AudioSource::_gain_buffers;
+size_t AudioSource::_working_buffers_size = 0;
 bool AudioSource::_build_missing_peakfiles = false;
 
 /** true if we want peakfiles (e.g. if we are displaying a GUI) */
@@ -57,13 +61,13 @@ bool AudioSource::_build_peakfiles = false;
 
 #define _FPP 256
 
-AudioSource::AudioSource (Session& s, ustring name)
+AudioSource::AudioSource (Session& s, string name)
        : Source (s, DataType::AUDIO, name)
        , _length (0)
 {
        _peaks_built = false;
        _peak_byte_max = 0;
-       peakfile = -1;
+       _peakfile_descriptor = 0;
        _read_data_count = 0;
        _write_data_count = 0;
        peak_leftover_cnt = 0;
@@ -78,7 +82,7 @@ AudioSource::AudioSource (Session& s, const XMLNode& node)
 
        _peaks_built = false;
        _peak_byte_max = 0;
-       peakfile = -1;
+       _peakfile_descriptor = 0;
        _read_data_count = 0;
        _write_data_count = 0;
        peak_leftover_cnt = 0;
@@ -98,10 +102,7 @@ AudioSource::~AudioSource ()
                cerr << "AudioSource destroyed with leftover peak data pending" << endl;
        }
 
-       if (peakfile >= 0) {
-               ::close (peakfile);
-       }
-
+       delete _peakfile_descriptor;
        delete [] peak_leftovers;
 }
 
@@ -129,14 +130,20 @@ AudioSource::set_state (const XMLNode& node, int /*version*/)
        return 0;
 }
 
-sframes_t
-AudioSource::length (sframes_t /*pos*/) const
+bool
+AudioSource::empty () const
+{
+        return _length == 0;
+}
+
+framecnt_t
+AudioSource::length (framepos_t /*pos*/) const
 {
        return _length;
 }
 
 void
-AudioSource::update_length (sframes_t pos, sframes_t cnt)
+AudioSource::update_length (framepos_t pos, framecnt_t cnt)
 {
        if (pos + cnt > _length) {
                _length = pos + cnt;
@@ -148,18 +155,24 @@ AudioSource::update_length (sframes_t pos, sframes_t cnt)
   PEAK FILE STUFF
  ***********************************************************************/
 
+/** Checks to see if peaks are ready.  If so, we return true.  If not, we return false, and
+ *  things are set up so that doThisWhenReady is called when the peaks are ready.
+ *  A new PBD::ScopedConnection is created for the associated connection and written to
+ *  *connect_here_if_not.
+ *
+ *  @param doThisWhenReady Function to call when peaks are ready (if they are not already).
+ *  @param connect_here_if_not Address to write new ScopedConnection to.
+ *  @param event_loop Event loop for doThisWhenReady to be called in.
+ */
 bool
-AudioSource::peaks_ready (boost::function<void()> doThisWhenReady, Connection& connect_here_if_not) const
+AudioSource::peaks_ready (boost::function<void()> doThisWhenReady, ScopedConnection** connect_here_if_not, EventLoop* event_loop) const
 {
        bool ret;
        Glib::Mutex::Lock lm (_peaks_ready_lock);
 
-       /* check to see if the peak data is ready. if not
-          connect the slot while still holding the lock.
-       */
-
        if (!(ret = _peaks_built)) {
-               PeaksReady.connect (connect_here_if_not, doThisWhenReady);
+               *connect_here_if_not = new ScopedConnection;
+               PeaksReady.connect (**connect_here_if_not, MISSING_INVALIDATOR, doThisWhenReady, event_loop);
        }
 
        return ret;
@@ -183,13 +196,13 @@ AudioSource::touch_peakfile ()
 }
 
 int
-AudioSource::rename_peakfile (ustring newpath)
+AudioSource::rename_peakfile (string newpath)
 {
        /* caller must hold _lock */
 
-       ustring oldpath = peakpath;
+       string oldpath = peakpath;
 
-       if (access (oldpath.c_str(), F_OK) == 0) {
+       if (Glib::file_test (oldpath, Glib::FILE_TEST_EXISTS)) {
                if (rename (oldpath.c_str(), newpath.c_str()) != 0) {
                        error << string_compose (_("cannot rename peakfile for %1 from %2 to %3 (%4)"), _name, oldpath, newpath, strerror (errno)) << endmsg;
                        return -1;
@@ -202,7 +215,7 @@ AudioSource::rename_peakfile (ustring newpath)
 }
 
 int
-AudioSource::initialize_peakfile (bool newfile, ustring audio_path)
+AudioSource::initialize_peakfile (bool newfile, string audio_path)
 {
        struct stat statbuf;
 
@@ -230,7 +243,7 @@ AudioSource::initialize_peakfile (bool newfile, ustring audio_path)
 
                /* we found it in the peaks dir, so check it out */
 
-               if (statbuf.st_size == 0 || ((nframes_t) statbuf.st_size < ((length(_timeline_position) / _FPP) * sizeof (PeakData)))) {
+               if (statbuf.st_size == 0 || (statbuf.st_size < (off_t) ((length(_timeline_position) / _FPP) * sizeof (PeakData)))) {
                        // empty
                        _peaks_built = false;
                } else {
@@ -239,8 +252,14 @@ AudioSource::initialize_peakfile (bool newfile, ustring audio_path)
                        int err = stat (audio_path.c_str(), &stat_file);
 
                        if (err) {
-                               _peaks_built = false;
-                               _peak_byte_max = 0;
+
+                               /* no audio path - nested source or we can't
+                                  read it or ... whatever, use the peakfile as-is.
+                               */
+
+                               _peaks_built = true;
+                               _peak_byte_max = statbuf.st_size;
+
                        } else {
 
                                /* allow 6 seconds slop on checking peak vs. file times because of various
@@ -265,15 +284,15 @@ AudioSource::initialize_peakfile (bool newfile, ustring audio_path)
        return 0;
 }
 
-nframes_t
-AudioSource::read (Sample *dst, sframes_t start, nframes_t cnt, int /*channel*/) const
+framecnt_t
+AudioSource::read (Sample *dst, framepos_t start, framecnt_t cnt, int /*channel*/) const
 {
        Glib::Mutex::Lock lm (_lock);
        return read_unlocked (dst, start, cnt);
 }
 
-nframes_t
-AudioSource::write (Sample *dst, nframes_t cnt)
+framecnt_t
+AudioSource::write (Sample *dst, framecnt_t cnt)
 {
        Glib::Mutex::Lock lm (_lock);
        /* any write makes the fill not removable */
@@ -282,7 +301,7 @@ AudioSource::write (Sample *dst, nframes_t cnt)
 }
 
 int
-AudioSource::read_peaks (PeakData *peaks, nframes_t npeaks, sframes_t start, nframes_t cnt, double samples_per_visual_peak) const
+AudioSource::read_peaks (PeakData *peaks, framecnt_t npeaks, framepos_t start, framecnt_t cnt, double samples_per_visual_peak) const
 {
        return read_peaks_with_fpp (peaks, npeaks, start, cnt, samples_per_visual_peak, _FPP);
 }
@@ -292,8 +311,8 @@ AudioSource::read_peaks (PeakData *peaks, nframes_t npeaks, sframes_t start, nfr
  */
 
 int
-AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t start, nframes_t cnt,
-                                 double samples_per_visual_peak, nframes_t samples_per_file_peak) const
+AudioSource::read_peaks_with_fpp (PeakData *peaks, framecnt_t npeaks, framepos_t start, framecnt_t cnt,
+                                 double samples_per_visual_peak, framecnt_t samples_per_file_peak) const
 {
        Glib::Mutex::Lock lm (_lock);
        double scale;
@@ -302,11 +321,13 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
        PeakData::PeakDatum xmin;
        int32_t to_read;
        uint32_t nread;
-       nframes_t zero_fill = 0;
+       framecnt_t zero_fill = 0;
        int ret = -1;
        PeakData* staging = 0;
        Sample* raw_staging = 0;
-       int _peakfile = -1;
+
+       FdFileDescriptor* peakfile_descriptor = new FdFileDescriptor (peakpath, false, 0664);
+       int peakfile_fd = -1;
 
        expected_peaks = (cnt / (double) samples_per_file_peak);
        scale = npeaks/expected_peaks;
@@ -329,8 +350,8 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
        if (cnt > _length - start) {
                // cerr << "too close to end @ " << _length << " given " << start << " + " << cnt << endl;
                cnt = _length - start;
-               nframes_t old = npeaks;
-               npeaks = min ((nframes_t) floor (cnt / samples_per_visual_peak), npeaks);
+               framecnt_t old = npeaks;
+               npeaks = min ((framecnt_t) floor (cnt / samples_per_visual_peak), npeaks);
                zero_fill = old - npeaks;
        }
 
@@ -352,11 +373,12 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
                        return -1;
                }
 
-               for (nframes_t i = 0; i < npeaks; ++i) {
+               for (framecnt_t i = 0; i < npeaks; ++i) {
                        peaks[i].max = raw_staging[i];
                        peaks[i].min = raw_staging[i];
                }
 
+               delete peakfile_descriptor;
                delete [] raw_staging;
                return 0;
        }
@@ -367,8 +389,9 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
 
                /* open, read, close */
 
-               if ((_peakfile = ::open (peakpath.c_str(), O_RDONLY, 0664)) < 0) {
+               if ((peakfile_fd = peakfile_descriptor->allocate ()) < 0) {
                        error << string_compose(_("AudioSource: cannot open peakpath (a) \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
+                       delete peakfile_descriptor;
                        return -1;
                }
 
@@ -376,8 +399,8 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
                cerr << "DIRECT PEAKS\n";
 #endif
 
-               nread = ::pread (_peakfile, peaks, sizeof (PeakData)* npeaks, first_peak_byte);
-               close (_peakfile);
+               nread = ::pread (peakfile_fd, peaks, sizeof (PeakData)* npeaks, first_peak_byte);
+               delete peakfile_descriptor;
 
                if (nread != sizeof (PeakData) * npeaks) {
                        cerr << "AudioSource["
@@ -392,6 +415,7 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
                             << first_peak_byte
                             << ')'
                             << endl;
+                       delete peakfile_descriptor;
                        return -1;
                }
 
@@ -399,11 +423,12 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
                        memset (&peaks[npeaks], 0, sizeof (PeakData) * zero_fill);
                }
 
+               delete peakfile_descriptor;
                return 0;
        }
 
 
-       nframes_t tnp;
+       framecnt_t tnp;
 
        if (scale < 1.0) {
 
@@ -420,20 +445,20 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
                    to avoid confusion, I'll refer to the requested peaks as visual_peaks and the peakfile peaks as stored_peaks
                */
 
-               const uint32_t chunksize = (uint32_t) min (expected_peaks, 65536.0);
-
+               const framecnt_t chunksize = (framecnt_t) min (expected_peaks, 65536.0);
+               
                staging = new PeakData[chunksize];
 
                /* compute the rounded up frame position  */
 
-               nframes_t current_frame = start;
-               nframes_t current_stored_peak = (nframes_t) ceil (current_frame / (double) samples_per_file_peak);
-               uint32_t       next_visual_peak  = (uint32_t) ceil (current_frame / samples_per_visual_peak);
-               double         next_visual_peak_frame = next_visual_peak * samples_per_visual_peak;
-               uint32_t       stored_peak_before_next_visual_peak = (nframes_t) next_visual_peak_frame / samples_per_file_peak;
-               uint32_t       nvisual_peaks = 0;
-               uint32_t       stored_peaks_read = 0;
-               uint32_t       i = 0;
+               framepos_t current_frame = start;
+               framepos_t current_stored_peak = (framepos_t) ceil (current_frame / (double) samples_per_file_peak);
+               framepos_t next_visual_peak  = (framepos_t) ceil (current_frame / samples_per_visual_peak);
+               double     next_visual_peak_frame = next_visual_peak * samples_per_visual_peak;
+               framepos_t stored_peak_before_next_visual_peak = (framepos_t) next_visual_peak_frame / samples_per_file_peak;
+               framecnt_t nvisual_peaks = 0;
+               framecnt_t stored_peaks_read = 0;
+               framecnt_t i = 0;
 
                /* handle the case where the initial visual peak is on a pixel boundary */
 
@@ -441,8 +466,10 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
 
                /* open ... close during out: handling */
 
-               if ((_peakfile = ::open (peakpath.c_str(), O_RDONLY, 0664)) < 0) {
+               if ((peakfile_fd = peakfile_descriptor->allocate ()) < 0) {
                        error << string_compose(_("AudioSource: cannot open peakpath (b) \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
+                       delete peakfile_descriptor;
+                       delete [] staging;
                        return 0;
                }
 
@@ -451,17 +478,17 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
                        if (i == stored_peaks_read) {
 
                                uint32_t       start_byte = current_stored_peak * sizeof(PeakData);
-                               tnp = min ((nframes_t)(_length/samples_per_file_peak - current_stored_peak), (nframes_t) expected_peaks);
+                               tnp = min ((framecnt_t)(_length/samples_per_file_peak - current_stored_peak), (framecnt_t) expected_peaks);
                                to_read = min (chunksize, tnp);
 
 #ifdef DEBUG_READ_PEAKS
                                cerr << "read " << sizeof (PeakData) * to_read << " from peakfile @ " << start_byte << endl;
 #endif
 
-                               if ((nread = ::pread (_peakfile, staging, sizeof (PeakData) * to_read, start_byte))
+                               if ((nread = ::pread (peakfile_fd, staging, sizeof (PeakData) * to_read, start_byte))
                                    != sizeof (PeakData) * to_read) {
 
-                                       off_t fend = lseek (_peakfile, 0, SEEK_END);
+                                       off_t fend = lseek (peakfile_fd, 0, SEEK_END);
 
                                        cerr << "AudioSource["
                                             << _name
@@ -526,14 +553,14 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
                   data on the fly.
                */
 
-               nframes_t frames_read = 0;
-               nframes_t current_frame = start;
-               nframes_t i = 0;
-               nframes_t nvisual_peaks = 0;
-               nframes_t chunksize = (nframes_t) min (cnt, (nframes_t) 4096);
+               framecnt_t frames_read = 0;
+               framepos_t current_frame = start;
+               framecnt_t i = 0;
+               framecnt_t nvisual_peaks = 0;
+               framecnt_t chunksize = (framecnt_t) min (cnt, (framecnt_t) 4096);
                raw_staging = new Sample[chunksize];
 
-               nframes_t frame_pos = start;
+               framepos_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);
                double pixels_per_frame = 1.0 / samples_per_visual_peak;
@@ -545,24 +572,32 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
 
                        if (i == frames_read) {
 
-                               to_read = min (chunksize, nframes_t(_length - current_frame));
+                               to_read = min (chunksize, (framecnt_t)(_length - current_frame));
 
-                               if (to_read == 0) {
-                                       /* XXX ARGH .. out by one error ... need to figure out why this happens
-                                          and fix it rather than do this band-aid move.
-                                       */
-                                       zero_fill = npeaks - nvisual_peaks;
-                                       npeaks -= zero_fill;
-                                       break;
-                               }
-
-                               if ((frames_read = read_unlocked (raw_staging, current_frame, to_read)) == 0) {
-                                       error << string_compose(_("AudioSource[%1]: peak read - cannot read %2 samples at offset %3 of %4 (%5)"),
-                                                               _name, to_read, current_frame, _length, strerror (errno))
-                                             << endmsg;
-                                       goto out;
-                               }
+                               if (current_frame >= _length) {
 
+                                        /* hmm, error condition - we've reached the end of the file
+                                           without generating all the peak data. cook up a zero-filled
+                                           data buffer and then use it. this is simpler than
+                                           adjusting zero_fill and npeaks and then breaking out of
+                                           this loop early
+                                       */
+                                        
+                                        memset (raw_staging, 0, sizeof (Sample) * chunksize);
+                                        
+                                } else {
+                                        
+                                        to_read = min (chunksize, (_length - current_frame));
+                                        
+                                        
+                                        if ((frames_read = read_unlocked (raw_staging, current_frame, to_read)) == 0) {
+                                                error << string_compose(_("AudioSource[%1]: peak read - cannot read %2 samples at offset %3 of %4 (%5)"),
+                                                                        _name, to_read, current_frame, _length, strerror (errno))
+                                                      << endmsg;
+                                                goto out;
+                                        }
+                                }
+                                
                                i = 0;
                        }
 
@@ -592,9 +627,7 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
        }
 
   out:
-       if (_peakfile >= 0) {
-               close (_peakfile);
-       }
+       delete peakfile_descriptor;
 
        delete [] staging;
        delete [] raw_staging;
@@ -611,12 +644,9 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, nframes_t npeaks, sframes_t s
 int
 AudioSource::build_peaks_from_scratch ()
 {
-       nframes_t current_frame;
-       nframes_t cnt;
        Sample* buf = 0;
-       nframes_t frames_read;
-       nframes_t frames_to_read;
-       const nframes_t bufsize = 65536; // 256kB per disk read for mono data is about ideal
+
+       const framecnt_t bufsize = 65536; // 256kB per disk read for mono data is about ideal
 
        int ret = -1;
 
@@ -629,14 +659,16 @@ AudioSource::build_peaks_from_scratch ()
                        goto out;
                }
 
-               current_frame = 0;
-               cnt = _length;
+               framecnt_t current_frame = 0;
+               framecnt_t cnt = _length;
+
                _peaks_built = false;
                buf = new Sample[bufsize];
 
                while (cnt) {
 
-                       frames_to_read = min (bufsize, cnt);
+                       framecnt_t frames_to_read = min (bufsize, cnt);
+                       framecnt_t frames_read;
 
                        if ((frames_read = read_unlocked (buf, current_frame, frames_to_read)) != frames_to_read) {
                                error << string_compose(_("%1: could not write read raw data for peak computation (%2)"), _name, strerror (errno)) << endmsg;
@@ -658,13 +690,7 @@ AudioSource::build_peaks_from_scratch ()
                }
 
                done_with_peakfile_writes ((cnt == 0));
-       }
-
-       {
-               Glib::Mutex::Lock lm (_peaks_ready_lock);
-
-               if (_peaks_built) {
-                       PeaksReady (); /* EMIT SIGNAL */
+               if (cnt == 0) {
                        ret = 0;
                }
        }
@@ -682,7 +708,8 @@ AudioSource::build_peaks_from_scratch ()
 int
 AudioSource::prepare_for_peakfile_writes ()
 {
-       if ((peakfile = ::open (peakpath.c_str(), O_RDWR|O_CREAT, 0664)) < 0) {
+       _peakfile_descriptor = new FdFileDescriptor (peakpath, true, 0664);
+       if ((_peakfile_fd = _peakfile_descriptor->allocate()) < 0) {
                error << string_compose(_("AudioSource: cannot open peakpath (c) \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg;
                return -1;
        }
@@ -697,37 +724,38 @@ AudioSource::done_with_peakfile_writes (bool done)
        }
 
        if (done) {
+               Glib::Mutex::Lock lm (_peaks_ready_lock);
                _peaks_built = true;
+               PeaksReady (); /* EMIT SIGNAL */
        }
 
-       if (peakfile >= 0) {
-               close (peakfile);
-               peakfile = -1;
-       }
+       delete _peakfile_descriptor;
+       _peakfile_descriptor = 0;
 }
 
+/** @param first_frame Offset from the source start of the first frame to process */
 int
-AudioSource::compute_and_write_peaks (Sample* buf, sframes_t first_frame, nframes_t cnt,
-               bool force, bool intermediate_peaks_ready)
+AudioSource::compute_and_write_peaks (Sample* buf, framecnt_t first_frame, framecnt_t cnt,
+                                     bool force, bool intermediate_peaks_ready)
 {
        return compute_and_write_peaks (buf, first_frame, cnt, force, intermediate_peaks_ready, _FPP);
 }
 
 int
-AudioSource::compute_and_write_peaks (Sample* buf, sframes_t first_frame, nframes_t cnt,
-               bool force, bool intermediate_peaks_ready, nframes_t fpp)
+AudioSource::compute_and_write_peaks (Sample* buf, framecnt_t first_frame, framecnt_t cnt,
+                                     bool force, bool intermediate_peaks_ready, framecnt_t fpp)
 {
        Sample* buf2 = 0;
-       nframes_t to_do;
+       framecnt_t to_do;
        uint32_t  peaks_computed;
        PeakData* peakbuf = 0;
        int ret = -1;
-       nframes_t current_frame;
-       nframes_t frames_done;
+       framepos_t current_frame;
+       framecnt_t frames_done;
        const size_t blocksize = (128 * 1024);
        off_t first_peak_byte;
 
-       if (peakfile < 0) {
+       if (_peakfile_descriptor == 0) {
                prepare_for_peakfile_writes ();
        }
 
@@ -748,7 +776,7 @@ AudioSource::compute_and_write_peaks (Sample* buf, sframes_t first_frame, nframe
 
                        off_t byte = (peak_leftover_frame / fpp) * sizeof (PeakData);
 
-                       if (::pwrite (peakfile, &x, sizeof (PeakData), byte) != sizeof (PeakData)) {
+                       if (::pwrite (_peakfile_fd, &x, sizeof (PeakData), byte) != sizeof (PeakData)) {
                                error << string_compose(_("%1: could not write peak file data (%2)"), _name, strerror (errno)) << endmsg;
                                goto out;
                        }
@@ -827,7 +855,7 @@ AudioSource::compute_and_write_peaks (Sample* buf, sframes_t first_frame, nframe
                        break;
                }
 
-               nframes_t this_time = min (fpp, to_do);
+               framecnt_t this_time = min (fpp, to_do);
 
                peakbuf[peaks_computed].max = buf[0];
                peakbuf[peaks_computed].min = buf[0];
@@ -851,16 +879,16 @@ AudioSource::compute_and_write_peaks (Sample* buf, sframes_t first_frame, nframe
                   less than BLOCKSIZE bytes.  only call ftruncate if we'll make the file larger.
                */
 
-               off_t endpos = lseek (peakfile, 0, SEEK_END);
+               off_t endpos = lseek (_peakfile_fd, 0, SEEK_END);
                off_t target_length = blocksize * ((first_peak_byte + blocksize + 1) / blocksize);
 
                if (endpos < target_length) {
-                       ftruncate (peakfile, target_length);
+                       (void) ftruncate (_peakfile_fd, target_length);
                        /* error doesn't actually matter though, so continue on without testing */
                }
        }
 
-       if (::pwrite (peakfile, peakbuf, sizeof (PeakData) * peaks_computed, first_peak_byte) != (ssize_t) (sizeof (PeakData) * peaks_computed)) {
+       if (::pwrite (_peakfile_fd, peakbuf, sizeof (PeakData) * peaks_computed, first_peak_byte) != (ssize_t) (sizeof (PeakData) * peaks_computed)) {
                error << string_compose(_("%1: could not write peak file data (%2)"), _name, strerror (errno)) << endmsg;
                goto out;
        }
@@ -887,7 +915,7 @@ AudioSource::compute_and_write_peaks (Sample* buf, sframes_t first_frame, nframe
 void
 AudioSource::truncate_peakfile ()
 {
-       if (peakfile < 0) {
+       if (_peakfile_descriptor == 0) {
                error << string_compose (_("programming error: %1"), "AudioSource::truncate_peakfile() called without open peakfile descriptor")
                      << endmsg;
                return;
@@ -895,14 +923,14 @@ AudioSource::truncate_peakfile ()
 
        /* truncate the peakfile down to its natural length if necessary */
 
-       off_t end = lseek (peakfile, 0, SEEK_END);
+       off_t end = lseek (_peakfile_fd, 0, SEEK_END);
 
        if (end > _peak_byte_max) {
-               ftruncate (peakfile, _peak_byte_max);
+               (void) ftruncate (_peakfile_fd, _peak_byte_max);
        }
 }
 
-nframes_t
+framecnt_t
 AudioSource::available_peaks (double zoom_factor) const
 {
        if (zoom_factor < _FPP) {
@@ -920,3 +948,64 @@ AudioSource::available_peaks (double zoom_factor) const
        return (end/sizeof(PeakData)) * _FPP;
 }
 
+void
+AudioSource::dec_read_data_count (framecnt_t cnt)
+{
+        uint32_t val = cnt * sizeof (Sample);
+
+        if (val < _read_data_count) {
+                _read_data_count -= val;
+        } else { 
+                _read_data_count = 0;
+        }
+}
+
+void
+AudioSource::mark_streaming_write_completed ()
+{
+       Glib::Mutex::Lock lm (_peaks_ready_lock);
+
+       if (_peaks_built) {
+               PeaksReady (); /* EMIT SIGNAL */
+       }
+}
+
+void
+AudioSource::allocate_working_buffers (framecnt_t framerate)
+{
+       Glib::Mutex::Lock lm (_level_buffer_lock);
+       
+       
+       /* Note: we don't need any buffers allocated until
+          a level 1 audiosource is created, at which
+          time we'll call ::ensure_buffers_for_level()
+          with the right value and do the right thing.
+       */
+       
+       if (!_mixdown_buffers.empty()) {
+               ensure_buffers_for_level_locked ( _mixdown_buffers.size(), framerate);
+       }
+}
+
+void
+AudioSource::ensure_buffers_for_level (uint32_t level, framecnt_t frame_rate) 
+{
+       Glib::Mutex::Lock lm (_level_buffer_lock);
+       ensure_buffers_for_level_locked (level, frame_rate);
+}
+
+void
+AudioSource::ensure_buffers_for_level_locked (uint32_t level, framecnt_t frame_rate) 
+{
+       framecnt_t nframes = (framecnt_t) floor (Config->get_audio_playback_buffer_seconds() * frame_rate);
+
+       _mixdown_buffers.clear ();
+       _gain_buffers.clear ();
+
+       cerr << "Allocating nested buffers for level " << level << endl;
+
+       while (_mixdown_buffers.size() < level) {
+               _mixdown_buffers.push_back (boost::shared_ptr<Sample> (new Sample[nframes]));
+               _gain_buffers.push_back (boost::shared_ptr<gain_t> (new gain_t[nframes]));
+       }
+}