Changes to seeking and scrubbing from Paul Licameli.

These are mostly under an EXPERIMENTAL_ #ifdef.  Also has a change for the prompt string for preferences so the displayed keybinding is adjusted when in multitool mode.

src/AudioIO.cpp

@@ -605,6 +605,8 @@ AudioIO::AudioIO()
    mMixerOutputVol = 1.0;
    mInputMixerWorks = false;
 #endif
+
+   mLastPlaybackTimeMillis = 0;
 }
 
 AudioIO::~AudioIO()
@@ -1127,7 +1129,8 @@ int AudioIO::StartStream(WaveTrackArray playbackTracks,
                          AudioIOListener* listener,
                          bool playLooped /* = false */,
                          double cutPreviewGapStart /* = 0.0 */,
-                         double cutPreviewGapLen /* = 0.0 */)
+                         double cutPreviewGapLen, /* = 0.0 */
+                         const double *pStartTime /* = 0 */)
 {
    if( IsBusy() )
       return 0;
@@ -1369,6 +1372,20 @@ int AudioIO::StartStream(WaveTrackArray playbackTracks,
    AILASetStartTime();
 #endif
 
+   if (pStartTime)
+   {
+      // Calculate the new time position
+      mTime = std::max(mT0, std::min(mT1, *pStartTime));
+      // Reset mixer positions for all playback tracks
+      unsigned numMixers = mPlaybackTracks.GetCount();
+      for (unsigned ii = 0; ii < numMixers; ++ii)
+         mPlaybackMixers[ii]->Reposition(mTime);
+      if(mTimeTrack)
+         mWarpedTime = mTimeTrack->ComputeWarpedLength(mT0, mTime);
+      else
+         mWarpedTime = mTime - mT0;
+   }
+
    // We signal the audio thread to call FillBuffers, to prime the RingBuffers
    // so that they will have data in them when the stream starts.  Having the
    // audio thread call FillBuffers here makes the code more predictable, since
@@ -3648,6 +3665,8 @@ int audacityAudioCallback(const void *inputBuffer, void *outputBuffer,
             chanCnt = 0;
          }
 
+         gAudioIO->mLastPlaybackTimeMillis = ::wxGetLocalTimeMillis();
+
          //
          // Clip output to [-1.0,+1.0] range (msmeyer)
          //

src/AudioIO.h

@@ -53,16 +53,7 @@ wxString DeviceName(const PaDeviceInfo* info);
 wxString HostName(const PaDeviceInfo* info);
 bool ValidateDeviceNames();
 
-class AUDACITY_DLL_API AudioIOListener {
+class AudioIOListener;
-public:
-   AudioIOListener() {}
-   virtual ~AudioIOListener() {}
-
-   virtual void OnAudioIORate(int rate) = 0;
-   virtual void OnAudioIOStartRecording() = 0;
-   virtual void OnAudioIOStopRecording() = 0;
-   virtual void OnAudioIONewBlockFiles(const wxString& blockFileLog) = 0;
-};
 
 #define BAD_STREAM_TIME -1000000000.0
 
@@ -113,7 +104,10 @@ class AUDACITY_DLL_API AudioIO {
                    AudioIOListener* listener,
                    bool playLooped = false,
                    double cutPreviewGapStart = 0.0,
-                   double cutPreviewGapLen = 0.0);
+                   double cutPreviewGapLen = 0.0,
+                   // May be other than t0,
+                   // but will be constrained between t0 and t1
+                   const double *pStartTime = 0);
 
    /** \brief Stop recording, playback or input monitoring.
     *
@@ -123,7 +117,7 @@ class AUDACITY_DLL_API AudioIO {
    void StopStream();
    /** \brief Move the playback / recording position of the current stream
     * by the specified amount from where it is now */
-   void SeekStream(double seconds) { mSeek = seconds; };
+   void SeekStream(double seconds) { mSeek = seconds; }
 
    /** \brief  Returns true if audio i/o is busy starting, stopping, playing,
     * or recording.
@@ -140,6 +134,8 @@ class AUDACITY_DLL_API AudioIO {
    bool IsStreamActive();
    bool IsStreamActive(int token);
 
+   wxLongLong GetLastPlaybackTime() const { return mLastPlaybackTimeMillis; }
+
 #ifdef EXPERIMENTAL_MIDI_OUT
    /** \brief Compute the current PortMidi timestamp time.
     *
@@ -517,6 +513,8 @@ private:
    volatile bool       mAudioThreadFillBuffersLoopRunning;
    volatile bool       mAudioThreadFillBuffersLoopActive;
 
+   wxLongLong          mLastPlaybackTimeMillis;
+
 #ifdef EXPERIMENTAL_MIDI_OUT
    volatile bool       mMidiThreadFillBuffersLoopRunning;
    volatile bool       mMidiThreadFillBuffersLoopActive;

src/Experimental.h

@@ -105,6 +105,12 @@
 // Paul Licameli (PRL) 5 Oct 2014
 #define EXPERIMENTAL_SPECTRAL_EDITING
 
+// Paul Licameli (PRL) 29 Nov 2014
+#define EXPERIMENTAL_SCRUBBING
+
+// Paul Licameli (PRL) 29 Nov 2014
+#define EXPERIMENTAL_IMPROVED_SEEKING
+
 // Philip Van Baren 01 July 2009
 // Replace RealFFT() and PowerSpectrum function to use (faster) RealFFTf function
 #define EXPERIMENTAL_USE_REALFFTF

src/LabelTrack.cpp

@@ -47,6 +47,7 @@ for drawing different aspects of the label and its text box.
 #include <wx/textfile.h>
 #include <wx/utils.h>
 
+#include "AudioIO.h"
 #include "LabelTrack.h"
 #include "DirManager.h"
 #include "Internat.h"

src/MixerBoard.cpp

@@ -21,6 +21,7 @@
 #include <wx/settings.h> // for wxSystemSettings::GetColour and wxSystemSettings::GetMetric
 
 #include "AColor.h"
+#include "AudioIO.h"
 #include "MixerBoard.h"
 #ifdef EXPERIMENTAL_MIDI_OUT
    #include "NoteTrack.h"

src/Project.h

@@ -25,7 +25,7 @@
 #include "UndoManager.h"
 #include "ViewInfo.h"
 #include "TrackPanelListener.h"
-#include "AudioIO.h"
+#include "AudioIOListener.h"
 #include "commands/CommandManager.h"
 #include "effects/EffectManager.h"
 #include "xml/XMLTagHandler.h"

src/TrackPanel.cpp

@@ -584,6 +584,12 @@ TrackPanel::TrackPanel(wxWindow * parent, wxWindowID id,
 
    mSelStartValid = false;
    mSelStart = 0;
+
+#ifdef EXPERIMENTAL_SCRUBBING
+   mScrubbing = false;
+   mLastScrubTime = 0;
+   mLastScrubPosition = 0;
+#endif
 }
 
 TrackPanel::~TrackPanel()
@@ -994,6 +1000,32 @@ void TrackPanel::OnTimer()
                                  (p->mLastPlayMode == loopedPlay));
    }
 
+#ifdef EXPERIMENTAL_SCRUBBING
+   if (mScrubbing
+      &&
+      gAudioIO->IsStreamActive(GetProject()->GetAudioIOToken()))
+   {
+      if (gAudioIO->GetLastPlaybackTime() < mLastScrubTime) {
+         // Allow some audio catch up
+      }
+      else {
+         wxMouseState state(::wxGetMouseState());
+         wxCoord xx = state.GetX();
+         ScreenToClient(&xx, NULL);
+         double leadPosition = PositionToTime(xx, GetLeftOffset());
+         if (mLastScrubPosition != leadPosition) {
+            wxLongLong clockTime = ::wxGetLocalTimeMillis();
+            double lagPosition = gAudioIO->GetStreamTime();
+
+            gAudioIO->SeekStream(leadPosition - lagPosition);
+
+            mLastScrubPosition = leadPosition;
+            mLastScrubTime = clockTime;
+         }
+      }
+   }
+#endif
+
    // Check whether we were playing or recording, but the stream has stopped.
    if (p->GetAudioIOToken()>0 &&
          !gAudioIO->IsStreamActive(p->GetAudioIOToken()))
@@ -1724,8 +1756,12 @@ void TrackPanel::SetCursorAndTipWhenSelectTool( Track * t,
       wxString keyStr
          (GetProject()->GetCommandManager()->GetKeyFromName(wxT("Preferences")));
       // Must compose a string that survives the function call, hence static.
+      if (keyStr.IsEmpty())
+         // No keyboard preference defined for opening Preferences dialog
+         /* i18n-hint: These are the names of a menu and a command in that menu */
+         keyStr = _("Edit, Preferences...");
       static wxString result;
-      /* i18n-hint: %s is usually replaced by "Ctrl+P" */
+      /* i18n-hint: %s is usually replaced by "Ctrl+P" for Windows/Linux, "Command+," for Mac */
       result = wxString::Format(
          _("Multi-Tool Mode: %s for Mouse and Keyboard Preferences."),
          keyStr.c_str());
@@ -1977,6 +2013,52 @@ void TrackPanel::HandleSelect(wxMouseEvent & event)
       }
 
    } else if (event.LeftUp() || event.RightUp()) {
+#ifdef EXPERIMENTAL_SCRUBBING
+      if(mScrubbing) {
+         if (gAudioIO->IsBusy()) {
+            AudacityProject *p = GetActiveProject();
+            if (p) {
+               ControlToolBar * ctb = p->GetControlToolBar();
+               ctb->StopPlaying();
+            }
+         }
+
+         if (mAdjustSelectionEdges) {
+            if (event.ShiftDown()) {
+               // Adjust time selection as if shift-left click at end
+               const double selend = PositionToTime(event.m_x, GetLeftOffset());
+               SelectionBoundary boundary = ChooseTimeBoundary(selend, false);
+               switch (boundary)
+               {
+               case SBLeft:
+                  mViewInfo->selectedRegion.setT0(selend);
+                  break;
+               case SBRight:
+                  mViewInfo->selectedRegion.setT1(selend);
+                  break;
+               default:
+                  wxASSERT(false);
+               }
+               UpdateSelectionDisplay();
+            }
+            else {
+               // Adjust time selection as if left click
+               StartSelection(event.m_x, r.x);
+               DisplaySelection();
+            }
+         }
+
+         mScrubbing = false;
+      }
+      else if (event.CmdDown()) {
+         // A control-click will set just the indicator to the clicked spot,
+         // and turn playback on -- but delayed until button up,
+         // and only if no intervening drag
+         StartOrJumpPlayback(event);
+      }
+      // Don't return yet
+#endif
+
       if (mSnapManager) {
          delete mSnapManager;
          mSnapManager = NULL;
@@ -2055,6 +2137,67 @@ void TrackPanel::HandleSelect(wxMouseEvent & event)
 }
 
 
+void TrackPanel::StartOrJumpPlayback(wxMouseEvent &event)
+{
+   AudacityProject *p = GetActiveProject();
+   if (p) {
+      double clicktime = PositionToTime(event.m_x, GetLeftOffset());
+      const double t1 = mViewInfo->selectedRegion.t1();
+      // Play to end of selection, or if that is not right of the pick, end of track
+      double endtime = clicktime < t1 ? t1 : mViewInfo->total;
+
+      //Behavior should differ depending upon whether we are
+      //currently in playback mode or not.
+
+      bool busy = gAudioIO->IsBusy();
+      if (!busy)
+      {
+         //If we aren't currently playing back, start playing back at
+         //the clicked point
+         ControlToolBar * ctb = p->GetControlToolBar();
+         //ctb->SetPlay(true);// Not needed as done in PlayPlayRegion
+         ctb->PlayPlayRegion(clicktime, endtime,false) ;
+      }
+      else
+      {
+         //If we are playing back, stop and move playback
+         //to the clicked point.
+         //This unpauses paused audio as well.  The right thing to do might be to
+         //leave it paused but move the point.  This would probably
+         //require a new method in ControlToolBar: SetPause();
+         ControlToolBar * ctb = p->GetControlToolBar();
+         ctb->StopPlaying();
+         ctb->PlayPlayRegion(clicktime,endtime,false) ;
+      }
+   }
+}
+
+
+#ifdef EXPERIMENTAL_SCRUBBING
+void TrackPanel::StartScrubbing(double position)
+{
+   AudacityProject *p = GetActiveProject();
+   if (p &&
+      // Should I make a bigger tolerance than zero?
+      mLastScrubPosition != position) {
+      ControlToolBar * ctb = p->GetControlToolBar();
+      bool busy = gAudioIO->IsBusy();
+      double maxTime = p->GetTracks()->GetEndTime();
+
+      if (busy)
+         ctb->StopPlaying();
+
+      ctb->PlayPlayRegion(0, maxTime, false, false,
+         0,
+         &position);
+      mScrubbing = true;
+      mLastScrubPosition = position;
+      mLastScrubTime = ::wxGetLocalTimeMillis();
+   }
+}
+#endif
+
+
 /// This method gets called when we're handling selection
 /// and the mouse was just clicked.
 void TrackPanel::SelectionHandleClick(wxMouseEvent & event,
@@ -2087,6 +2230,12 @@ void TrackPanel::SelectionHandleClick(wxMouseEvent & event,
 #endif
 
    if (event.ShiftDown()
+
+#ifdef EXPERIMENTAL_SCRUBBING
+       // Ctrl prevails over Shift with scrubbing enabled
+       && !event.CmdDown()
+#endif
+
 #ifdef USE_MIDI
        && !stretch
 #endif
@@ -2171,40 +2320,14 @@ void TrackPanel::SelectionHandleClick(wxMouseEvent & event,
            && !stretch
 #endif
           ) {
-      AudacityProject *p = GetActiveProject();
+#ifdef EXPERIMENTAL_SCRUBBING
-      if (p) {
+      // With scrubbing enabled, playback happens on button up, not down,
-
+      // and only if we do not start a scrub in the interim.
-         double clicktime = PositionToTime(event.m_x, GetLeftOffset());
+      mScrubbing = false;
-            const double t1 = mViewInfo->selectedRegion.t1();
+      mLastScrubPosition = PositionToTime(event.m_x, GetLeftOffset());
-            double endtime = clicktime <  t1 ? t1 : mViewInfo->total;
+#else
-
+      StartOrJumpPlayback(event);
-         //Behavior should differ depending upon whether we are
+#endif
-         //currently in playback mode or not.
-
-         bool busy = gAudioIO->IsBusy();
-         if(!busy)
-         {
-            //If we aren't currently playing back, start playing back at
-            //the clicked point
-            ControlToolBar * ctb = p->GetControlToolBar();
-            //ctb->SetPlay(true);// Not needed as done in PlayPlayRegion
-            ctb->PlayPlayRegion(clicktime, endtime,false) ;
-
-         }
-         else
-         {
-            //If we are playing back, stop and move playback
-            //to the clicked point.
-            //This unpauses paused audio as well.  The right thing to do might be to
-            //leave it paused but move the point.  This would probably
-            //require a new method in ControlToolBar: SetPause();
-            ControlToolBar * ctb = p->GetControlToolBar();
-            ctb->StopPlaying();
-            ctb->PlayPlayRegion(clicktime,endtime,false) ;
-         }
-
-      }
-
       return;
    }
    //Make sure you are within the selected track
@@ -2907,9 +3030,22 @@ void TrackPanel::SelectionHandleDrag(wxMouseEvent & event, Track *clickedTrack)
       return;
 
    // Also fuhggeddaboudit if we're not dragging and not autoscrolling.
-   if ((!event.Dragging() && !mAutoScrolling) || event.CmdDown())
+   if (!event.Dragging() && !mAutoScrolling)
       return;
 
+   if (event.CmdDown()) {
+#ifdef EXPERIMENTAL_SCRUBBING
+      if (!mScrubbing) {
+         double position = PositionToTime(event.m_x, GetLeftOffset());
+         StartScrubbing(position);
+      }
+      else
+#else
+      // Ctrl-drag has no meaning, fuhggeddaboudit
+#endif
+      return;
+   }
+
    wxRect r      = mCapturedRect;
    Track *pTrack = mCapturedTrack;
 
@@ -3091,7 +3227,8 @@ wxInt64 TrackPanel::FrequencyToPosition(double frequency,
 }
 #endif
 
-void SetIfNotNull( double * pValue, const double Value )
+template<typename T>
+inline void SetIfNotNull( T * pValue, const T Value )
 {
    if( pValue == NULL )
       return;
@@ -3099,6 +3236,43 @@ void SetIfNotNull( double * pValue, const double Value )
 }
 
 
+TrackPanel::SelectionBoundary TrackPanel::ChooseTimeBoundary
+(double selend, bool onlyWithinSnapDistance,
+ wxInt64 *pPixelDist, double *pPinValue) const
+{
+   const double t0 = mViewInfo->selectedRegion.t0();
+   const double t1 = mViewInfo->selectedRegion.t1();
+   wxInt64 pixelDist = mViewInfo->zoom * fabs(selend - t0);
+   bool chooseLeft = true;
+
+   if (mViewInfo->selectedRegion.isPoint())
+      // Special case when selection is a point, and thus left
+      // and right distances are the same
+      chooseLeft = (selend < t0);
+   else {
+      const wxInt64 rightDist = mViewInfo->zoom * fabs(selend - t1);
+      if (rightDist < pixelDist)
+         chooseLeft = false, pixelDist = rightDist;
+   }
+
+   SetIfNotNull(pPixelDist, pixelDist);
+
+   if (onlyWithinSnapDistance &&
+       pixelDist >= SELECTION_RESIZE_REGION) {
+      SetIfNotNull( pPinValue, -1.0);
+      return SBNone;
+   }
+   else if (chooseLeft) {
+      SetIfNotNull( pPinValue, t1);
+      return SBLeft;
+   }
+   else {
+      SetIfNotNull( pPinValue, t0);
+      return SBRight;
+   }
+}
+
+
 TrackPanel::SelectionBoundary TrackPanel::ChooseBoundary
 (wxMouseEvent & event, const Track *pTrack, const wxRect &rect,
 bool mayDragWidth, bool onlyWithinSnapDistance,
@@ -3110,28 +3284,19 @@ bool mayDragWidth, bool onlyWithinSnapDistance,
    // May choose no boundary if onlyWithinSnapDistance is true.
    // Otherwise choose the eligible boundary nearest the mouse click.
    const double selend = PositionToTime(event.m_x, rect.x);
+   wxInt64 pixelDist = 0;
+   SelectionBoundary boundary =
+      ChooseTimeBoundary(selend, onlyWithinSnapDistance,
+      &pixelDist, pPinValue);
+
+#ifdef EXPERIMENTAL_SPECTRAL_EDITING
    const double t0 = mViewInfo->selectedRegion.t0();
    const double t1 = mViewInfo->selectedRegion.t1();
-#ifdef EXPERIMENTAL_SPECTRAL_EDITING
    const double f0 = mViewInfo->selectedRegion.f0();
    const double f1 = mViewInfo->selectedRegion.f1();
    const double fc = mViewInfo->selectedRegion.fc();
    double ratio = 0;
-#endif
-   wxInt64 pixelDist = mViewInfo->zoom * fabs(selend - t0);
-   bool chooseLeft = true;
 
-   if (mViewInfo->selectedRegion.isPoint())
-      // Special case when selection is a point, and thus left
-      // and right distances are the same
-      chooseLeft = (selend < t0);
-   else {
-      const wxInt64 rightDist = mViewInfo->zoom * fabs(selend - t1);
-      if (rightDist < pixelDist)
-         chooseLeft = false, pixelDist = rightDist;
-   }
-
-#ifdef EXPERIMENTAL_SPECTRAL_EDITING
    bool chooseTime = true;
    bool chooseBottom = true;
    bool chooseCenter = false;
@@ -3146,14 +3311,20 @@ bool mayDragWidth, bool onlyWithinSnapDistance,
          ? FrequencyToPosition(f0, rect.y, rect.height,
                                wt->GetRate(), logF)
          : rect.y + rect.height;
-      wxInt64 verticalDist = abs(int(event.m_y - bottomSel));
       const wxInt64 topSel = (f1 >= 0)
          ? FrequencyToPosition(f1, rect.y, rect.height,
          wt->GetRate(), logF)
          : rect.y;
+      wxInt64 signedBottomDist = int(event.m_y - bottomSel);
+      wxInt64 verticalDist = abs(signedBottomDist);
+      if (bottomSel == topSel)
+         // Top and bottom are too close to resolve on screen
+         chooseBottom = (signedBottomDist >= 0);
+      else {
          const wxInt64 topDist = abs(int(event.m_y - topSel));
          if (topDist < verticalDist)
             chooseBottom = false, verticalDist = topDist;
+      }
       if (fc > 0
 #ifdef SPECTRAL_EDITING_ESC_KEY
          && mayDragWidth
@@ -3202,19 +3373,7 @@ bool mayDragWidth, bool onlyWithinSnapDistance,
    else
 #endif
    {
-      if (onlyWithinSnapDistance &&
+      return boundary;
-          pixelDist >= SELECTION_RESIZE_REGION) {
-         SetIfNotNull( pPinValue, -1.0);
-         return SBNone;
-      }
-      else if (chooseLeft) {
-         SetIfNotNull( pPinValue, t1);
-         return SBLeft;
-      }
-      else {
-         SetIfNotNull( pPinValue, t0);
-         return SBRight;
-      }
    }
 }
 
@@ -5805,8 +5964,8 @@ void TrackPanel::OnKeyDown(wxKeyEvent & event)
          else {
             // Handle ESC during frequency drag
             wxMouseState state(::wxGetMouseState());
-            wxCoord xx = state.GetX(), yy = state.GetY();
+            wxCoord yy = state.GetY();
-            ScreenToClient(&xx, &yy);
+            ScreenToClient(NULL, &yy);
             wxRect r;
             if (wt == FindTrack(state.GetX(), yy, false, false, &r)) {
                eFreqSelMode saveMode = mFreqSelMode;
@@ -7333,10 +7492,42 @@ void TrackPanel::ScrollIntoView(int x)
 
 void TrackPanel::OnCursorLeft( bool shift, bool ctrl, bool keyup )
 {
-   if( keyup )
+   // PRL:  What I found and preserved, strange though it be:
+   // During playback:  jump depends on preferences and is independent of the zoom
+   // and does not vary if the key is held
+   // Else: jump depends on the zoom and gets bigger if the key is held
+   int snapToTime = GetActiveProject()->GetSnapTo();
+   double quietSeekStepPositive = 1.0 / mViewInfo->zoom;
+   double audioSeekStepPositive = shift ? mSeekLong : mSeekShort;
+   SeekLeftOrRight
+      (true, shift, ctrl, keyup, snapToTime, true, false,
+       quietSeekStepPositive,  audioSeekStepPositive);
+}
+
+void TrackPanel::OnCursorRight(bool shift, bool ctrl, bool keyup)
+{
+   // PRL:  What I found and preserved, strange though it be:
+   // During playback:  jump depends on preferences and is independent of the zoom
+   // and does not vary if the key is held
+   // Else: jump depends on the zoom and gets bigger if the key is held
+   int snapToTime = GetActiveProject()->GetSnapTo();
+   double quietSeekStepPositive = 1.0 / mViewInfo->zoom;
+   double audioSeekStepPositive = shift ? mSeekLong : mSeekShort;
+   SeekLeftOrRight
+      (false, shift, ctrl, keyup, snapToTime, true, false,
+       quietSeekStepPositive, audioSeekStepPositive);
+}
+
+// Handle small cursor and play head movements
+void TrackPanel::SeekLeftOrRight
+(bool leftward, bool shift, bool ctrl, bool keyup,
+ int snapToTime, bool mayAccelerateQuiet, bool mayAccelerateAudio,
+ double quietSeekStepPositive, double audioSeekStepPositive)
+{
+   if (keyup)
    {
       int token = GetProject()->GetAudioIOToken();
-      if( token > 0 && gAudioIO->IsStreamActive( token ) )
+      if (token > 0 && gAudioIO->IsStreamActive(token))
       {
          return;
       }
@@ -7347,181 +7538,119 @@ void TrackPanel::OnCursorLeft( bool shift, bool ctrl, bool keyup )
 
    // If the last adjustment was very recent, we are
    // holding the key down and should move faster.
-   wxLongLong curtime = ::wxGetLocalTimeMillis();
+   const wxLongLong curtime = ::wxGetLocalTimeMillis();
-   int multiplier = 1;
+   enum { MIN_INTERVAL = 50 };
-   if( curtime - mLastSelectionAdjustment < 50 )
+   const bool fast = (curtime - mLastSelectionAdjustment < MIN_INTERVAL);
+   
+   // How much faster should the cursor move if shift is down?
+   enum { LARGER_MULTIPLIER = 4 };
+   int multiplier = (fast && mayAccelerateQuiet) ? LARGER_MULTIPLIER : 1;
+   if (leftward)
+      multiplier = -multiplier;
+
+   int token = GetProject()->GetAudioIOToken();
+
+   if (shift && ctrl)
    {
-      multiplier = 4;
-   }
       mLastSelectionAdjustment = curtime;
 
-   int snapToTime = GetActiveProject()->GetSnapTo();
+         // Contract selection
-
-   // Contract selection from the right to the left
-   if( shift && ctrl )
-   {
       // Reduce and constrain (counter-intuitive)
+      if (leftward) {
          mViewInfo->selectedRegion.setT1(
             std::max(mViewInfo->selectedRegion.t0(),
             snapToTime
-                  ? GridMove(mViewInfo->selectedRegion.t1(), -multiplier)
+               ? GridMove(mViewInfo->selectedRegion.t1(), multiplier)
-                  : mViewInfo->selectedRegion.t1() -
+               : mViewInfo->selectedRegion.t1() +
-                      multiplier / mViewInfo->zoom));
+                  multiplier * quietSeekStepPositive));
 
          // Make sure it's visible.
-      ScrollIntoView( mViewInfo->selectedRegion.t1() );
+         ScrollIntoView(mViewInfo->selectedRegion.t1());
-      Refresh( false );
       }
-   // Extend selection toward the left
+      else {
-   else if( shift )
-   {
-      // If playing, reposition a long amount of time
-      int token = GetProject()->GetAudioIOToken();
-      if( token > 0 && gAudioIO->IsStreamActive( token ) )
-      {
-         gAudioIO->SeekStream(-mSeekLong);
-         return;
-      }
-
-      // Expand and constrain
-      mViewInfo->selectedRegion.setT0(
-         std::max(0.0,
-                  snapToTime
-                  ? GridMove(mViewInfo->selectedRegion.t0(), -multiplier)
-                  : mViewInfo->selectedRegion.t0() -
-                      multiplier / mViewInfo->zoom));
-
-      // Make sure it's visible.
-      ScrollIntoView( mViewInfo->selectedRegion.t0() );
-      Refresh( false );
-   }
-   // Move the cursor toward the left
-   else
-   {
-      // If playing, reposition a short amount of time
-      int token = GetProject()->GetAudioIOToken();
-      if( token > 0 && gAudioIO->IsStreamActive( token ) )
-      {
-         gAudioIO->SeekStream(-mSeekShort);
-         return;
-      }
-
-      // Already in cursor mode?
-      if( mViewInfo->selectedRegion.isPoint() )
-      {
-         // Move and constrain
-         mViewInfo->selectedRegion.setT0(
-            std::max(0.0,
-                     snapToTime
-                     ? GridMove(mViewInfo->selectedRegion.t0(), -multiplier)
-                     : mViewInfo->selectedRegion.t0() -
-                        multiplier / mViewInfo->zoom),
-            false);
-         mViewInfo->selectedRegion.collapseToT0();
-
-         // Move the visual cursor
-         DrawCursor();
-      }
-      else
-      {
-         // Transition to cursor mode.
-         mViewInfo->selectedRegion.collapseToT0();
-         Refresh( false );
-      }
-
-      // Make sure it's visible
-      ScrollIntoView( mViewInfo->selectedRegion.t0() );
-   }
-}
-
-void TrackPanel::OnCursorRight( bool shift, bool ctrl, bool keyup )
-{
-   if( keyup )
-   {
-      int token = GetProject()->GetAudioIOToken();
-      if( token > 0 && gAudioIO->IsStreamActive( token ) )
-      {
-         return;
-      }
-
-      MakeParentModifyState(false);
-      return;
-   }
-
-   // If the last adjustment was very recent, we are
-   // holding the key down and should move faster.
-   wxLongLong curtime = ::wxGetLocalTimeMillis();
-   int multiplier = 1;
-   if( curtime - mLastSelectionAdjustment < 50 )
-   {
-      multiplier = 4;
-   }
-   mLastSelectionAdjustment = curtime;
-
-   int snapToTime = GetActiveProject()->GetSnapTo();
-
-   // Contract selection from the left to the right
-   if( shift && ctrl )
-   {
-      // Reduce and constrain (counter-intuitive)
          mViewInfo->selectedRegion.setT0(
             std::min(mViewInfo->selectedRegion.t1(),
                snapToTime
                   ? GridMove(mViewInfo->selectedRegion.t0(), multiplier)
                   : mViewInfo->selectedRegion.t0() +
-                     multiplier / mViewInfo->zoom));
+                     multiplier * quietSeekStepPositive));
 
          // Make sure new position is in view.
-      ScrollIntoView( mViewInfo->selectedRegion.t0() );
+         ScrollIntoView(mViewInfo->selectedRegion.t0());
-      Refresh( false );
       }
-   // Extend selection toward the right
+      Refresh(false);
-   else if( shift )
+   }
-   {
+   else if (token > 0 && gAudioIO->IsStreamActive(token)) {
-      // If playing, reposition a long amount of time
+#ifdef EXPERIMENTAL_IMPROVED_SEEKING
-      int token = GetProject()->GetAudioIOToken();
+      if (gAudioIO->GetLastPlaybackTime() < mLastSelectionAdjustment) {
-      if( token > 0 && gAudioIO->IsStreamActive( token ) )
+         // Allow time for the last seek to output a buffer before
-      {
+         // discarding samples again
-         gAudioIO->SeekStream(mSeekLong);
+         // Do not advance mLastSelectionAdjustment
          return;
       }
+#endif
+      mLastSelectionAdjustment = curtime;
 
+      // Ignore the multiplier for the quiet case
+      multiplier = (fast && mayAccelerateAudio) ? LARGER_MULTIPLIER : 1;
+      if (leftward)
+         multiplier = -multiplier;
+
+      // If playing, reposition
+      gAudioIO->SeekStream(multiplier * audioSeekStepPositive);
+      return;
+   }
+   else if (shift)
+   {
+      mLastSelectionAdjustment = curtime;
+
+      // Extend selection
       // Expand and constrain
-      double end = mTracks->GetEndTime();
+      if (leftward) {
-      mViewInfo->selectedRegion.setT1(
+         mViewInfo->selectedRegion.setT0(
-         std::min(end,
+            std::max(0.0,
                snapToTime
-                  ?  GridMove(mViewInfo->selectedRegion.t1(), multiplier)
+                  ? GridMove(mViewInfo->selectedRegion.t0(), multiplier)
-                  : mViewInfo->selectedRegion.t1() + multiplier/mViewInfo->zoom));
+                  : mViewInfo->selectedRegion.t0() +
+                     multiplier * quietSeekStepPositive));
 
-      // Make sure new position is in view.
+         // Make sure it's visible.
-      ScrollIntoView( mViewInfo->selectedRegion.t1() );
+         ScrollIntoView(mViewInfo->selectedRegion.t0());
-      Refresh( false );
       }
-   // Move the cursor toward the right
+      else {
-   else
-   {
-      // If playing, reposition a short amount of time
-      int token = GetProject()->GetAudioIOToken();
-      if( token > 0 && gAudioIO->IsStreamActive( token ) )
-      {
-         gAudioIO->SeekStream(mSeekShort);
-         return;
-      }
-
-      // Already in cursor mode?
-      if (mViewInfo->selectedRegion.isPoint())
-      {
-         // Move and constrain
          double end = mTracks->GetEndTime();
          mViewInfo->selectedRegion.setT1(
             std::min(end,
                snapToTime
                   ? GridMove(mViewInfo->selectedRegion.t1(), multiplier)
                   : mViewInfo->selectedRegion.t1() +
-                        multiplier / mViewInfo->zoom),
+                     multiplier * quietSeekStepPositive));
+
+         // Make sure new position is in view.
+         ScrollIntoView(mViewInfo->selectedRegion.t1());
+      }
+      Refresh(false);
+   }
+   else
+   {
+      mLastSelectionAdjustment = curtime;
+
+      // Move the cursor
+      // Already in cursor mode?
+      if (mViewInfo->selectedRegion.isPoint())
+      {
+         // Move and constrain
+         double end = mTracks->GetEndTime();
+         mViewInfo->selectedRegion.setT0(
+            std::max(0.0,
+               std::min(end,
+                  snapToTime
+                     ? GridMove(mViewInfo->selectedRegion.t0(), multiplier)
+                     : mViewInfo->selectedRegion.t0() + multiplier * quietSeekStepPositive
+               )
+            ),
             false);
-         mViewInfo->selectedRegion.collapseToT1();
+         mViewInfo->selectedRegion.collapseToT0();
 
          // Move the visual cursor
          DrawCursor();
@@ -7529,12 +7658,15 @@ void TrackPanel::OnCursorRight( bool shift, bool ctrl, bool keyup )
       else
       {
          // Transition to cursor mode.
+         if (leftward)
+            mViewInfo->selectedRegion.collapseToT0();
+         else
             mViewInfo->selectedRegion.collapseToT1();
-         Refresh( false );
+         Refresh(false);
       }
 
       // Make sure new position is in view
-      ScrollIntoView( mViewInfo->selectedRegion.t1() );
+      ScrollIntoView(mViewInfo->selectedRegion.t1());
    }
 }
 
@@ -7656,74 +7788,25 @@ void TrackPanel::OnBoundaryMove(bool left, bool boundaryContract)
 // longjump=false: Use mSeekShort; longjump=true: Use mSeekLong
 void TrackPanel::OnCursorMove(bool forward, bool jump, bool longjump )
 {
-   // If the last adjustment was very recent, we are
+   // PRL:  nobody calls this yet with !jump
-   // holding the key down and should move faster.
-   wxLongLong curtime = ::wxGetLocalTimeMillis();
-   int multiplier = 1;
-   if( curtime - mLastSelectionAdjustment < 50 )
-   {
-      multiplier = 4;
-   }
-   mLastSelectionAdjustment = curtime;
 
-   float direction = -1;
+   double positiveSeekStep;
-   if (forward) {
-      direction = 1;
-   }
-
-   float mSeek;
    if (jump) {
       if (!longjump) {
-         mSeek = mSeekShort;
+         positiveSeekStep = mSeekShort;
       } else {
-         mSeek = mSeekLong;
+         positiveSeekStep = mSeekLong;
       }
    } else {
-      mSeek = multiplier / mViewInfo->zoom;
+      positiveSeekStep = 1.0 / mViewInfo->zoom;
    }
-   mSeek *= direction;
+   bool mayAccelerate = !jump;
-
+   SeekLeftOrRight
-   // If playing, reposition a short amount of time
+      (!forward, false, false, false,
-   int token = GetProject()->GetAudioIOToken();
+       0, mayAccelerate, mayAccelerate,
-   if( token > 0 && gAudioIO->IsStreamActive( token ) )
+       positiveSeekStep, positiveSeekStep);
-   {
-      gAudioIO->SeekStream(mSeek);
-   }
-   else
-   {
-      // Already in cursor mode?
-      if( mViewInfo->selectedRegion.isPoint() )
-      {
-         // Move and constrain
-
-         double t0 = mViewInfo->selectedRegion.t0() + mSeek;
-         if( !forward && t0 < 0.0 )
-         {
-            t0 = 0.0;
-         }
-         double end = mTracks->GetEndTime();
-         if( forward && t0 > end)
-         {
-            t0 = end;
-         }
-         mViewInfo->selectedRegion.setT0(t0, false);
-         mViewInfo->selectedRegion.collapseToT0();
-
-         // Move the visual cursor
-         DrawCursor();
-      }
-      else
-      {
-         // Transition to cursor mode.
-         mViewInfo->selectedRegion.collapseToT0();
-         Refresh( false );
-      }
-
-      // Make sure it's visible
-      ScrollIntoView( mViewInfo->selectedRegion.t0() );
 
    MakeParentModifyState(false);
-   }
 }
 
 //The following methods operate controls on specified tracks,

src/TrackPanel.h

@@ -310,6 +310,10 @@ class AUDACITY_DLL_API TrackPanel:public wxPanel {
    // AS: Selection handling
    virtual void HandleSelect(wxMouseEvent & event);
    virtual void SelectionHandleDrag(wxMouseEvent &event, Track *pTrack);
+   void StartOrJumpPlayback(wxMouseEvent &event);
+#ifdef EXPERIMENTAL_SCRUBBING
+   void StartScrubbing(double position);
+#endif
    virtual void SelectionHandleClick(wxMouseEvent &event,
                                      Track* pTrack, wxRect r);
    virtual void StartSelection (int mouseXCoordinate, int trackLeftEdge);
@@ -317,6 +321,12 @@ class AUDACITY_DLL_API TrackPanel:public wxPanel {
                         Track *pTrack);
    virtual void UpdateSelectionDisplay();
 
+   // Handle small cursor and play head movements
+   void SeekLeftOrRight
+      (bool left, bool shift, bool ctrl, bool keyup,
+      int snapToTime, bool mayAccelerateQuiet, bool mayAccelerateAudio,
+      double quietSeekStepPositive, double audioSeekStepPositive);
+
 #ifdef EXPERIMENTAL_SPECTRAL_EDITING
    void StartSnappingFreqSelection (WaveTrack *pTrack);
    void MoveSnappingFreqSelection (int mouseYCoordinate,
@@ -688,6 +698,9 @@ protected:
       SBBottom, SBTop, SBCenter, SBWidth,
 #endif
    };
+   SelectionBoundary ChooseTimeBoundary
+      (double selend, bool onlyWithinSnapDistance,
+       wxInt64 *pPixelDist = NULL, double *pPinValue = NULL) const;
    SelectionBoundary ChooseBoundary
       (wxMouseEvent & event, const Track *pTrack,
        const wxRect &rect,
@@ -739,6 +752,12 @@ protected:
    int mMoveUpThreshold;
    int mMoveDownThreshold;
 
+#ifdef EXPERIMENTAL_SCRUBBING
+   bool mScrubbing;
+   wxLongLong mLastScrubTime; // milliseconds
+   double mLastScrubPosition;
+#endif
+
    wxCursor *mArrowCursor;
    wxCursor *mPencilCursor;
    wxCursor *mSelectCursor;

src/prefs/PrefsDialog.cpp

@@ -35,6 +35,7 @@
 #include "../widgets/treebook.h"
 #endif
 
+#include "../AudioIO.h"
 #include "../Experimental.h"
 #include "../Project.h"
 #include "../Prefs.h"

src/toolbars/ControlToolBar.cpp

@@ -32,6 +32,8 @@
 
 *//*******************************************************************/
 
+#include <algorithm>
+
 #include "../Audacity.h"
 #include "../Experimental.h"
 
@@ -438,7 +440,8 @@ bool ControlToolBar::IsRecordDown()
 void ControlToolBar::PlayPlayRegion(double t0, double t1,
                                     bool looped /* = false */,
                                     bool cutpreview /* = false */,
-                                    TimeTrack *timetrack /* = NULL */)
+                                    TimeTrack *timetrack /* = NULL */,
+                                    const double *pStartTime /* = NULL */)
 {
    SetPlay(true, looped, cutpreview);
 
@@ -564,7 +567,8 @@ void ControlToolBar::PlayPlayRegion(double t0, double t1,
                NoteTrackArray(),
 #endif
                timetrack, p->GetRate(), tcp0, tcp1, p, false,
-               t0, t1-t0);
+               t0, t1-t0,
+               pStartTime);
          } else
          {
             // Cannot create cut preview tracks, clean up and exit
@@ -583,7 +587,9 @@ void ControlToolBar::PlayPlayRegion(double t0, double t1,
                                        t->GetNoteTrackArray(false),
 #endif
                                        timetrack,
-                                       p->GetRate(), t0, t1, p, looped);
+                                       p->GetRate(), t0, t1, p, looped,
+                                       0, 0,
+                                       pStartTime);
       }
       if (token != 0) {
          success = true;

src/toolbars/ControlToolBar.h

@@ -67,7 +67,10 @@ class ControlToolBar:public ToolBar {
    void PlayPlayRegion(double t0, double t1,
                        bool looped = false,
                        bool cutpreview = false,
-                       TimeTrack *timetrack = NULL);
+                       TimeTrack *timetrack = NULL,
+                       // May be other than t0,
+                       // but will be constrained between t0 and t1
+                       const double *pStartTime = NULL);
    void PlayDefault();
 
    // Stop playing

src/toolbars/ToolManager.cpp

@@ -60,6 +60,7 @@
 
 #include "../AColor.h"
 #include "../AllThemeResources.h"
+#include "../AudioIO.h"
 #include "../ImageManipulation.h"
 #include "../Prefs.h"
 #include "../Project.h"

win/Projects/Audacity/Audacity.vcxproj

@@ -510,6 +510,7 @@
     <ClInclude Include="..\..\..\src\AudacityApp.h" />
     <ClInclude Include="..\..\..\src\AudacityLogger.h" />
     <ClInclude Include="..\..\..\src\AudioIO.h" />
+    <ClInclude Include="..\..\..\src\AudioIOListener.h" />
     <ClInclude Include="..\..\..\src\AutoRecovery.h" />
     <ClInclude Include="..\..\..\src\BatchCommandDialog.h" />
     <ClInclude Include="..\..\..\src\BatchCommands.h" />