Resample.cpp

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/**********************************************************************
 
   Audacity: A Digital Audio Editor
   Audacity(R) is copyright (c) 1999-2012 Audacity Team.
   License: GPL v2 or later.  See License.txt.
 
   Resample.cpp
   Dominic Mazzoni, Rob Sykes, Vaughan Johnson
 
******************************************************************//*******************************************************************/
 
#include "Resample.h"
#include "Prefs.h"
#include "Internat.h"
#include "ComponentInterface.h"
 
#include <soxr.h>
 
Resample::Resample(const bool useBestMethod, const double dMinFactor, const double dMaxFactor)
{
   this->SetMethod(useBestMethod);
   soxr_quality_spec_t q_spec;
   if (dMinFactor == dMaxFactor)
   {
      mbWantConstRateResampling = true; // constant rate resampling
      q_spec = soxr_quality_spec("\0\1\4\6"[mMethod], 0);
   }
   else
   {
      mbWantConstRateResampling = false; // variable rate resampling
      q_spec = soxr_quality_spec(SOXR_HQ, SOXR_VR);
   }
   mHandle.reset(soxr_create(1, dMinFactor, 1, 0, 0, &q_spec, 0));
}
 
Resample::~Resample()
{
}
 
static const std::initializer_list<EnumValueSymbol> methodNames{
   { wxT("LowQuality"), XO("Low Quality (Fastest)") },
   { wxT("MediumQuality"), XO("Medium Quality") },
   { wxT("HighQuality"), XO("High Quality") },
   { wxT("BestQuality"), XO("Best Quality (Slowest)") }
};
 
static auto intChoicesMethod = {
   0, 1, 2, 3
};
 
EnumSetting< int > Resample::FastMethodSetting{
   wxT("/Quality/LibsoxrSampleRateConverterChoice"),
   methodNames,
   1,  // Medium Quality
 
   // for migrating old preferences:
   intChoicesMethod,
   wxT("/Quality/LibsoxrSampleRateConverter")
};
 
EnumSetting< int > Resample::BestMethodSetting
{
   wxT("/Quality/LibsoxrHQSampleRateConverterChoice"),
   methodNames,
   3, // Best Quality,
 
   // for migrating old preferences:
   intChoicesMethod,
   wxT("/Quality/LibsoxrHQSampleRateConverter")
};
 
std::pair<size_t, size_t>
      Resample::Process(double       factor,
                        const float *inBuffer,
                        size_t       inBufferLen,
                        bool         lastFlag,
                        float       *outBuffer,
                        size_t       outBufferLen)
{
   size_t idone, odone;
   if (mbWantConstRateResampling)
   {
      soxr_process(mHandle.get(),
            inBuffer , (lastFlag? ~inBufferLen : inBufferLen), &idone,
            outBuffer,                           outBufferLen, &odone);
   }
   else
   {
      soxr_set_io_ratio(mHandle.get(), 1/factor, 0);
 
      inBufferLen = lastFlag? ~inBufferLen : inBufferLen;
      soxr_process(mHandle.get(),
            inBuffer , inBufferLen , &idone,
            outBuffer, outBufferLen, &odone);
   }
   return { idone, odone };
}
 
void Resample::SetMethod(const bool useBestMethod)
{
   if (useBestMethod)
      mMethod = BestMethodSetting.ReadEnum();
   else
      mMethod = FastMethodSetting.ReadEnum();
}