changespeed.cpp

Audacity是一款用於錄音和編輯聲音的、免費的開放源碼軟體。它可以執行於Mac OS X、Microsoft Windows、GNU/Linux和其它作業系統

/**********************************************************************

  Audacity: A Digital Audio Editor

  ChangeSpeed.cpp

  Vaughan Johnson, Dominic Mazzoni
  
  Change Speed effect, that affects both pitch & tempo.

**********************************************************************/

#include "ChangeSpeed.h"

#include "../Audacity.h" // for USE_LIBSAMPLERATE
#include "../Envelope.h"
#include "../Prefs.h"

#include <math.h>

#include <wx/button.h>
#include <wx/msgdlg.h> // for wxMessageBox
#include <wx/sizer.h>
#include <wx/stattext.h>
#include <wx/valtext.h>


//
// EffectChangeSpeed
//

EffectChangeSpeed::EffectChangeSpeed()
{
	// control values
	m_PercentChange = 0.0;
	m_FromVinyl = 0; 
	m_ToVinyl = 0; 
}

wxString EffectChangeSpeed::GetEffectDescription() { 
   // Note: This is useful only after change amount has been set. 
   return wxString::Format(_("Applied effect: %s %.1f%%"), 
                           this->GetEffectName().c_str(), 
									m_PercentChange); 
} 

bool EffectChangeSpeed::PromptUser()
{
   ChangeSpeedDialog dlog(this, mParent, -1, _("Change Speed"));
   dlog.m_PercentChange = m_PercentChange;
   dlog.m_FromVinyl = m_FromVinyl;
   dlog.m_ToVinyl = m_ToVinyl;
	// Don't need to call TransferDataToWindow, although other 
	//	Audacity dialogs (from which I derived this one) do it, because 
	//	ShowModal calls stuff that eventually calls wxWindowBase::OnInitDialog, 
	//	which calls dlog.TransferDataToWindow();
   dlog.CentreOnParent();
   dlog.ShowModal();

   if (!dlog.GetReturnCode())
      return false;

   m_PercentChange = dlog.m_PercentChange;
   m_FromVinyl = dlog.m_FromVinyl;
   m_ToVinyl = dlog.m_ToVinyl;

   return true;
}
bool EffectChangeSpeed::TransferParameters( Shuttle & shuttle )
{  
   shuttle.TransferDouble(wxT("Percentage"),m_PercentChange,0.0);
   return true;
}

bool EffectChangeSpeed::Process()
{
	// Similar to EffectSoundTouch::Process()

   //Iterate over each track
   TrackListIterator iter(mWaveTracks);
   WaveTrack *track = (WaveTrack *) iter.First();
   mCurTrackNum = 0;
	m_maxNewLength = 0.0;
	double curT0;
	double curT1;
   while (track) {
      //Get start and end times from track
      double trackStart = track->GetStartTime();
      double trackEnd = track->GetEndTime();

      //Set the current bounds to whichever left marker is
      //greater and whichever right marker is less:
      curT0 = mT0 < trackStart? trackStart: mT0;
      curT1 = mT1 > trackEnd? trackEnd: mT1;

      // Process only if the right marker is to the right of the left marker
      if (curT1 > curT0) {

         //Transform the marker timepoints to samples
         longSampleCount start = track->TimeToLongSamples(curT0);
         longSampleCount end = track->TimeToLongSamples(curT1);

         //ProcessOne() (implemented below) processes a single track
         if (!ProcessOne(track, start, end))
            return false;
      }
      
      //Iterate to the next track
      track = (WaveTrack *) iter.Next();
      mCurTrackNum++;
   }

	mT1 = mT0 + m_maxNewLength; // Update selection.
   return true;
}

// ProcessOne() takes a track, transforms it to bunch of buffer-blocks,
// and calls libsamplerate code on these blocks.
bool EffectChangeSpeed::ProcessOne(WaveTrack * track,
												longSampleCount start, longSampleCount end)
{
	if (track == NULL)
		return false;

	// initialization, per examples of Mixer::Mixer and
   // EffectSoundTouch::ProcessOne

   WaveTrack * outputTrack = mFactory->NewWaveTrack(track->GetSampleFormat());

   //Get the length of the selection (as double). len is
   //used simple to calculate a progress meter, so it is easier
   //to make it a double now than it is to do it later 
   double len = (double)(end - start);

   // Initiate processing buffers, most likely shorter than 
	//	the length of the selection being processed.
	sampleCount inBufferSize = track->GetMaxBlockSize();

   float * inBuffer = new float[inBufferSize];

   double factor = 100.0 / (100.0 + m_PercentChange);
	sampleCount outBufferSize = 
      (sampleCount)((factor * inBufferSize) + 10);
   float * outBuffer = new float[outBufferSize]; 

	// Set up the resampling stuff for this track.
   Resample resample(true, factor, factor);

   //Go through the track one buffer at a time. samplePos counts which
   //sample the current buffer starts at.
	bool bLoopSuccess = true;
   sampleCount blockSize;
  	longSampleCount samplePos = start;
   while (samplePos < end) {
      //Get a blockSize of samples (smaller than the size of the buffer)
      blockSize = track->GetBestBlockSize(samplePos);

      //Adjust the block size if it is the final block in the track
      if (samplePos + blockSize > end)
         blockSize = end - samplePos;

      //Get the samples from the track and put them in the buffer
      track->Get((samplePtr) inBuffer, floatSample, samplePos, blockSize);

      int inUsed;
      int outgen = resample.Process(factor,
                                    inBuffer,
                                    blockSize,
                                    ((samplePos + blockSize) >= end),
                                    &inUsed,
                                    outBuffer,
                                    outBufferSize);
      if (outgen < 0) {
			bLoopSuccess = false;
			break;
		}

      if (outgen > 0)
         outputTrack->Append((samplePtr)outBuffer, floatSample, 
                             outgen);

      // Increment samplePos
      samplePos += inUsed;

      // Update the Progress meter
      if (TrackProgress(mCurTrackNum, (samplePos - start) / len)) {
			bLoopSuccess = false;
			break;
		}
   }

	// Flush the output WaveTrack (since it's buffered, too)
	outputTrack->Flush();

   // Clean up the buffers
   delete [] inBuffer;
   delete [] outBuffer;

   // Take the output track and insert it in place of the original
   // sample data
	if (bLoopSuccess) {
		track->Clear(mT0, mT1);
		track->Paste(mT0, outputTrack);
	}

	double newLength = outputTrack->GetEndTime(); 
	if (newLength > m_maxNewLength) 
		m_maxNewLength = newLength; 

   // Delete the outputTrack now that its data is inserted in place
   delete outputTrack;

   return bLoopSuccess;
}


//----------------------------------------------------------------------------
// ChangeSpeedDialog
//----------------------------------------------------------------------------

// -99 for PERCENTCHANGE_MIN because -100% is nonsensical.
#define PERCENTCHANGE_MIN -99

#define PERCENTCHANGE_MAX 100 // warped above zero to actually go up to 400%
#define PERCENTCHANGE_SLIDER_WARP 1.30105 // warp power takes max from 100 to 400.

// the standard vinyl RPM choices
// If the percent change is not one of these ratios, the choice control gets "n/a".
#define CHOICE_33ANDATHIRD 0
#define CHOICE_45 1
#define CHOICE_78 2
#define CHOICE_NA 3 

enum {
   ID_TEXT_PERCENTCHANGE = 10001,
   ID_SLIDER_PERCENTCHANGE,
   ID_CHOICE_FROMVINYL,
   ID_CHOICE_TOVINYL,
	ID_BUTTON_PREVIEW
};


// event table for ChangeSpeedDialog

BEGIN_EVENT_TABLE(ChangeSpeedDialog, wxDialog)
    EVT_BUTTON(wxID_OK, ChangeSpeedDialog::OnOk)
    EVT_BUTTON(wxID_CANCEL, ChangeSpeedDialog::OnCancel)

    EVT_TEXT(ID_TEXT_PERCENTCHANGE, ChangeSpeedDialog::OnText_PercentChange)
    EVT_SLIDER(ID_SLIDER_PERCENTCHANGE, ChangeSpeedDialog::OnSlider_PercentChange)
    EVT_CHOICE(ID_CHOICE_FROMVINYL, ChangeSpeedDialog::OnChoice_FromVinyl)
    EVT_CHOICE(ID_CHOICE_TOVINYL, ChangeSpeedDialog::OnChoice_ToVinyl)

    EVT_BUTTON(ID_BUTTON_PREVIEW, ChangeSpeedDialog::OnPreview)
END_EVENT_TABLE()

ChangeSpeedDialog::ChangeSpeedDialog(EffectChangeSpeed * effect,
													wxWindow * parent, wxWindowID id,
													const wxString & title, 
													const wxPoint & position, 
													const wxSize & size, 
													long style)
: wxDialog(parent, id, title, position, size, style)
{
   m_bLoopDetect = false;
	m_pEffect = effect;

	// NULL out these control members because there are some cases where the 
	// event table handlers get called during this method, and those handlers that 
	// can cause trouble check for NULL.
   m_pTextCtrl_PercentChange = NULL;
   m_pSlider_PercentChange = NULL;
   m_pChoice_FromVinyl = NULL;
   m_pChoice_ToVinyl = NULL;
	
	// effect parameters
	m_PercentChange = 0.0;
	m_FromVinyl = 0; 
	m_ToVinyl = 0; 

	
	// CREATE THE CONTROLS PROGRAMMATICALLY.
	wxStaticText * pStaticText;

   wxBoxSizer * pBoxSizer_Dialog = new wxBoxSizer(wxVERTICAL);

	// heading
   pStaticText = new wxStaticText(this, -1, 
												_("Change Speed, affecting both Tempo and Pitch"),
												wxDefaultPosition, wxDefaultSize, 0);
   pBoxSizer_Dialog->Add(pStaticText, 0, wxALIGN_CENTER | wxALL, 8);

   pStaticText = new wxStaticText(this, -1, 
												_("by Vaughan Johnson && Dominic Mazzoni"),
												wxDefaultPosition, wxDefaultSize, 0);
   pBoxSizer_Dialog->Add(pStaticText, 0, wxALIGN_CENTER | wxTOP | wxLEFT | wxRIGHT, 8);

   pStaticText = new wxStaticText(this, -1, 
												_("using SampleRate, by Erik de Castro Lopo"),
												wxDefaultPosition, wxDefaultSize, 0);
   pBoxSizer_Dialog->Add(pStaticText, 0, wxALIGN_CENTER | wxBOTTOM | wxLEFT | wxRIGHT, 8);


	// percent change controls

	// Group percent controls with spacers, 
	// rather than static box, so they don't look isolated.
   pBoxSizer_Dialog->Add(0, 8, 0); // spacer

   wxBoxSizer * pBoxSizer_PercentChange = new wxBoxSizer(wxHORIZONTAL);