audacia/src/Resample.cpp

109 lines
3.0 KiB
C++

/**********************************************************************
Audacity: A Digital Audio Editor
Audacity(R) is copyright (c) 1999-2012 Audacity Team.
License: GPL v2. See License.txt.
Resample.cpp
Dominic Mazzoni, Rob Sykes, Vaughan Johnson
******************************************************************//**
\class Resample
\brief Interface to libsoxr.
This class abstracts the interface to different resampling libraries:
libsoxr, written by Rob Sykes. LGPL.
Since Audacity always does resampling on mono streams that are
contiguous in memory, this class doesn't support multiple channels
or some of the other optional features of some of these resamplers.
*//*******************************************************************/
#include "Resample.h"
#include "Prefs.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()
{
}
int Resample::GetNumMethods() { return 4; }
wxString Resample::GetMethodName(int index)
{
static char const * const soxr_method_names[] = {
"Low Quality (Fastest)", "Medium Quality", "High Quality", "Best Quality (Slowest)"
};
return wxString(wxString::FromAscii(soxr_method_names[index]));
}
const wxString Resample::GetFastMethodKey()
{
return wxT("/Quality/LibsoxrSampleRateConverter");
}
const wxString Resample::GetBestMethodKey()
{
return wxT("/Quality/LibsoxrHQSampleRateConverter");
}
int Resample::GetFastMethodDefault() {return 1;}
int Resample::GetBestMethodDefault() {return 3;}
std::pair<size_t, size_t>
Resample::Process(double factor,
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 = gPrefs->Read(GetBestMethodKey(), GetBestMethodDefault());
else
mMethod = gPrefs->Read(GetFastMethodKey(), GetFastMethodDefault());
}