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Merge pull request #5303 from MerryMage/DPL2Decoder 

DPL2Decoder cleanup
This commit is contained in:
Tilka 2017-04-23 17:07:14 +01:00 committed by GitHub
parent 9090f37347 c9f50fd4ed
commit 111d92c03d
1 changed files with 46 additions and 73 deletions
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115
Source/Core/AudioCommon/DPL2Decoder.cpp
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@ -10,8 +10,9 @@
#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <string.h>
#include <numeric>
#include <vector>
#include "AudioCommon/DPL2Decoder.h"
@ -35,33 +36,17 @@ static float adapt_l_gain, adapt_r_gain, adapt_lpr_gain, adapt_lmr_gain;
static std::vector<float> lf, rf, lr, rr, cf, cr;
static float LFE_buf[256];
static unsigned int lfe_pos;
static float* filter_coefs_lfe;
static std::vector<float> filter_coefs_lfe;
static unsigned int len125;
template <class T, class _ftype_t>
static _ftype_t DotProduct(int count, const T* buf, const _ftype_t* coefficients)
template <class T>
static float DotProduct(int count, const T* buf, const std::vector<float>& coeffs, int offset)
{
int i;
float sum0 = 0.0f, sum1 = 0.0f, sum2 = 0.0f, sum3 = 0.0f;
// Unrolled loop
for (i = 0; (i + 3) < count; i += 4)
{
sum0 += buf[i + 0] * coefficients[i + 0];
sum1 += buf[i + 1] * coefficients[i + 1];
sum2 += buf[i + 2] * coefficients[i + 2];
sum3 += buf[i + 3] * coefficients[i + 3];
}
// Epilogue of unrolled loop
for (; i < count; i++)
sum0 += buf[i] * coefficients[i];
return sum0 + sum1 + sum2 + sum3;
return std::inner_product(buf, buf + count, coeffs.begin() + offset, T(0));
}
template <class T>
static T FIRFilter(const T* buf, int pos, int len, int count, const float* coefficients)
static T FIRFilter(const T* buf, int pos, int len, int count, const std::vector<float>& coeffs)
{
int count1, count2;
@ -81,9 +66,8 @@ static T FIRFilter(const T* buf, int pos, int len, int count, const float* coeff
// high part of window
const T* ptr = &buf[pos];
float r1 = DotProduct(count1, ptr, coefficients);
coefficients += count1;
float r2 = DotProduct(count2, buf, coefficients);
float r1 = DotProduct(count1, ptr, coeffs, 0);
float r2 = DotProduct(count2, buf, coeffs, count1);
return T(r1 + r2);
}
@ -94,25 +78,26 @@ static T FIRFilter(const T* buf, int pos, int len, int count, const float* coeff
// N-1
//
// n window length
// w buffer for the window parameters
// returns buffer with the window parameters
*/
static void Hamming(int n, float* w)
static std::vector<float> Hamming(int n)
{
float k = float(2 * M_PI / ((float)(n - 1))); // 2*pi/(N-1)
std::vector<float> w(n);
float k = static_cast<float>(2.0 * M_PI / (n - 1));
// Calculate window coefficients
for (int i = 0; i < n; i++)
*w++ = float(0.54 - 0.46 * cos(k * (float)i));
w[i] = static_cast<float>(0.54 - 0.46 * cos(k * i));
return w;
}
/******************************************************************************
* FIR filter design
******************************************************************************/
// FIR filter design
/* Design FIR filter using the Window method
n filter length must be odd for HP and BS filters
w buffer for the filter taps (must be n long)
fc cutoff frequencies (1 for LP and HP, 2 for BP and BS)
0 < fc < 1 where 1 <=> Fs/2
flags window and filter type as defined in filter.h
@ -120,34 +105,26 @@ variables are ored together: i.e. LP|HAMMING will give a
low pass filter designed using a hamming window
opt beta constant used only when designing using kaiser windows
returns 0 if OK, -1 if fail
returns buffer for the filter taps (will be n long)
*/
static float* DesignFIR(unsigned int* n, float* fc, float opt)
static std::vector<float> DesignFIR(unsigned int n, float fc, float opt)
{
unsigned int o = *n & 1; // Indicator for odd filter length
unsigned int end = ((*n + 1) >> 1) - o; // Loop end
const unsigned int o = n & 1; // Indicator for odd filter length
const unsigned int end = ((n + 1) >> 1) - o; // Loop end
float k1 = 2 * float(M_PI); // 2*pi*fc1
float k2 = 0.5f * (float)(1 - o); // Constant used if the filter has even length
// Cutoff frequency must be < 0.5 where 0.5 <=> Fs/2
const float fc1 = MathUtil::Clamp(fc, 0.001f, 1.0f) / 2;
const float k1 = 2 * static_cast<float>(M_PI) * fc1; // Cutoff frequency in rad/s
const float k2 = 0.5f * static_cast<float>(1 - o); // Time offset if filter has even length
float g = 0.0f; // Gain
float t1; // Temporary variables
float fc1; // Cutoff frequencies
// Sanity check
if (*n == 0)
return nullptr;
fc[0] = MathUtil::Clamp(fc[0], 0.001f, 1.0f);
float* w = (float*)calloc(sizeof(float), *n);
if (n == 0)
return {};
// Get window coefficients
Hamming(*n, w);
fc1 = *fc;
// Cutoff frequency must be < 0.5 where 0.5 <=> Fs/2
fc1 = ((fc1 <= 1.0) && (fc1 > 0.0)) ? fc1 / 2 : 0.25f;
k1 *= fc1;
std::vector<float> w = Hamming(n);
// Low pass filter
@ -164,14 +141,15 @@ static float* DesignFIR(unsigned int* n, float* fc, float opt)
// Create filter
for (u32 i = 0; i < end; i++)
{
t1 = (float)(i + 1) - k2;
w[end - i - 1] = w[*n - end + i] = float(w[end - i - 1] * sin(k1 * t1) / (M_PI * t1)); // Sinc
float t1 = static_cast<float>(i + 1) - k2;
w[end - i - 1] = w[n - end + i] =
static_cast<float>(w[end - i - 1] * sin(k1 * t1) / (M_PI * t1)); // Sinc
g += 2 * w[end - i - 1]; // Total gain in filter
}
// Normalize gain
g = 1 / g;
for (u32 i = 0; i < *n; i++)
for (u32 i = 0; i < n; i++)
w[i] *= g;
return w;
@ -197,19 +175,14 @@ static void Done()
{
OnSeek();
if (filter_coefs_lfe)
{
free(filter_coefs_lfe);
filter_coefs_lfe.clear();
}
filter_coefs_lfe = nullptr;
}
static float* CalculateCoefficients125HzLowpass(int rate)
static std::vector<float> CalculateCoefficients125HzLowpass(int rate)
{
len125 = 256;
float f = 125.0f / (rate / 2);
float* coeffs = DesignFIR(&len125, &f, 0);
std::vector<float> coeffs = DesignFIR(len125, f, 0);
static const float M3_01DB = 0.7071067812f;
for (unsigned int i = 0; i < len125; i++)
{
@ -265,10 +238,10 @@ static void MatrixDecode(const float* in, const int k, const int il, const int i
/* Matrix */
l_agc = in[il] * PassiveLock(*_adapt_l_gain);
r_agc = in[ir] * PassiveLock(*_adapt_r_gain);
_cf[k] = (l_agc + r_agc) * (float)M_SQRT1_2;
_cf[k] = (l_agc + r_agc) * static_cast<float>(M_SQRT1_2);
if (decode_rear)
{
_lr[kr] = _rr[kr] = (l_agc - r_agc) * (float)M_SQRT1_2;
_lr[kr] = _rr[kr] = (l_agc - r_agc) * static_cast<float>(M_SQRT1_2);
// Stereo rear channel is steered with the same AGC steering as
// the decoding matrix. Note this requires a fast updating AGC
// at the order of 20 ms (which is the case here).
@ -277,8 +250,8 @@ static void MatrixDecode(const float* in, const int k, const int il, const int i
}
/*** AXIS NO. 2: (Lt + Rt, Lt - Rt) -> (L, R) ***/
lpr = (in[il] + in[ir]) * (float)M_SQRT1_2;
lmr = (in[il] - in[ir]) * (float)M_SQRT1_2;
lpr = (in[il] + in[ir]) * static_cast<float>(M_SQRT1_2);
lmr = (in[il] - in[ir]) * static_cast<float>(M_SQRT1_2);
/* AGC adaption */
d_gain = fabs(lmr_unlim_gain - *_adapt_lmr_gain);
f = d_gain * (1.0f / MATAGCTRIG);
@ -288,8 +261,8 @@ static void MatrixDecode(const float* in, const int k, const int il, const int i
/* Matrix */
lpr_agc = lpr * PassiveLock(*_adapt_lpr_gain);
lmr_agc = lmr * PassiveLock(*_adapt_lmr_gain);
_lf[k] = (lpr_agc + lmr_agc) * (float)M_SQRT1_2;
_rf[k] = (lpr_agc - lmr_agc) * (float)M_SQRT1_2;
_lf[k] = (lpr_agc + lmr_agc) * static_cast<float>(M_SQRT1_2);
_rf[k] = (lpr_agc - lmr_agc) * static_cast<float>(M_SQRT1_2);
/*** CENTER FRONT CANCELLATION ***/
// A heuristic approach exploits that Lt + Rt gain contains the
@ -387,5 +360,5 @@ void DPL2Reset()
{
olddelay = -1;
oldfreq = 0;
filter_coefs_lfe = nullptr;
filter_coefs_lfe.clear();
}