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Revert back to using a band-splitter to increase the HF response

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Unfortunately the shelf filter causes issues due to the shelf gain magnitude
creating a varying phase offset. The splitter also creates phase offsets, but
it's consistent regardless of gain.
This commit is contained in:
Chris Robinson
2019-01-06 05:15:11 -08:00
parent d2e34e509b
commit 13056b45b0
3 changed files with 56 additions and 79 deletions
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Alc/bformatdec.cpp
+34 -51
View File
@@ -61,7 +61,7 @@ void BFormatDec::reset(const AmbDecConf *conf, bool allow_2band, ALsizei inchans
mMatrix = MatrixU{};
mDualBand = allow_2band && (conf->FreqBands == 2);
if(!mDualBand)
mSamples.resize(1);
mSamples.resize(2);
else
{
mSamples.resize(inchans * 2);
@@ -83,19 +83,14 @@ void BFormatDec::reset(const AmbDecConf *conf, bool allow_2band, ALsizei inchans
(conf->ChanMask > AMBI_1ORDER_MASK) ? 2 : 1};
{
const ALfloat (&hfscales)[MAX_AMBI_ORDER+1] = GetDecoderHFScales(out_order);
/* The specified filter gain is for the mid-point/reference gain. The
* gain at the shelf itself will be the square of that, so specify the
* square-root of the desired shelf gain.
*/
const ALfloat gain0{std::sqrt(Ambi3DDecoderHFScale[0] / hfscales[0])};
const ALfloat gain1{std::sqrt(Ambi3DDecoderHFScale[1] / hfscales[1])};
mShelf[0].setParams(BiquadType::HighShelf, gain0, xover_norm,
calc_rcpQ_from_slope(gain0, 1.0f));
mShelf[1].setParams(BiquadType::HighShelf, gain1, xover_norm,
calc_rcpQ_from_slope(gain1, 1.0f));
std::for_each(std::begin(mShelf)+2, std::end(mShelf),
std::bind(std::mem_fn(&BiquadFilter::copyParamsFrom), _1, mShelf[1]));
mUpsampler[0].Splitter.init(xover_norm);
mUpsampler[0].Gains[HF_BAND] = Ambi3DDecoderHFScale[0] / hfscales[0];
mUpsampler[0].Gains[LF_BAND] = 1.0f;
mUpsampler[1].Splitter.init(xover_norm);
mUpsampler[1].Gains[HF_BAND] = Ambi3DDecoderHFScale[1] / hfscales[1];
mUpsampler[1].Gains[LF_BAND] = 1.0f;
std::fill(std::begin(mUpsampler)+2, std::end(mUpsampler), mUpsampler[1]);
}
const bool periphonic{(conf->ChanMask&AMBI_PERIPHONIC_MASK) != 0};
@@ -154,7 +149,7 @@ void BFormatDec::reset(const ALsizei inchans, const ALfloat xover_norm, const AL
mMatrix = MatrixU{};
mDualBand = false;
mSamples.resize(1);
mSamples.resize(2);
mNumChannels = inchans;
mEnabled = std::accumulate(std::begin(chanmap), std::begin(chanmap)+chancount, 0u,
@@ -168,19 +163,14 @@ void BFormatDec::reset(const ALsizei inchans, const ALfloat xover_norm, const AL
(inchans > 3) ? 2 : 1};
{
const ALfloat (&hfscales)[MAX_AMBI_ORDER+1] = GetDecoderHFScales(out_order);
/* The specified filter gain is for the mid-point/reference gain. The
* gain at the shelf itself will be the square of that, so specify the
* square-root of the desired shelf gain.
*/
const ALfloat gain0{std::sqrt(Ambi3DDecoderHFScale[0] / hfscales[0])};
const ALfloat gain1{std::sqrt(Ambi3DDecoderHFScale[1] / hfscales[1])};
mShelf[0].setParams(BiquadType::HighShelf, gain0, xover_norm,
calc_rcpQ_from_slope(gain0, 1.0f));
mShelf[1].setParams(BiquadType::HighShelf, gain1, xover_norm,
calc_rcpQ_from_slope(gain1, 1.0f));
std::for_each(std::begin(mShelf)+2, std::end(mShelf),
std::bind(std::mem_fn(&BiquadFilter::copyParamsFrom), _1, mShelf[1]));
mUpsampler[0].Splitter.init(xover_norm);
mUpsampler[0].Gains[HF_BAND] = Ambi3DDecoderHFScale[0] / hfscales[0];
mUpsampler[0].Gains[LF_BAND] = 1.0f;
mUpsampler[1].Splitter.init(xover_norm);
mUpsampler[1].Gains[HF_BAND] = Ambi3DDecoderHFScale[1] / hfscales[1];
mUpsampler[1].Gains[LF_BAND] = 1.0f;
std::fill(std::begin(mUpsampler)+2, std::end(mUpsampler), mUpsampler[1]);
}
for(ALsizei i{0};i < chancount;i++)
@@ -233,25 +223,23 @@ void BFormatDec::process(ALfloat (*OutBuffer)[BUFFERSIZE], const ALsizei OutChan
void BFormatDec::upSample(ALfloat (*OutBuffer)[BUFFERSIZE], const ALfloat (*InSamples)[BUFFERSIZE], const ALsizei InChannels, const ALsizei SamplesToDo)
{
ASSUME(InChannels > 0);
ASSUME(SamplesToDo > 0);
/* This up-sampler leverages the differences observed in dual-band higher-
* order decoder matrices compared to first-order. For the same output
* channel configuration, the low-frequency matrix has identical
* coefficients in the shared input channels, while the high-frequency
* matrix has extra scalars applied to the W channel and X/Y/Z channels.
* Using a high-shelf filter to mix the first-order content into the
* higher-order stream, with the appropriate counter-scales applied to the
* HF response, results in the subsequent higher-order decode generating
* the same response as a first-order decode.
* Mixing the first-order content into the higher-order stream, with the
* appropriate counter-scales applied to the HF response, results in the
* subsequent higher-order decode generating the same response as a first-
* order decode.
*/
for(ALsizei i{0};i < InChannels;i++)
{
mShelf[i].process(mSamples[0].data(), InSamples[i], SamplesToDo);
const ALfloat *RESTRICT src{al::assume_aligned<16>(mSamples[0].data())};
ALfloat *dst{al::assume_aligned<16>(OutBuffer[i])};
std::transform(src, src+SamplesToDo, dst, dst, std::plus<float>{});
mUpsampler[i].Splitter.process(mSamples[HF_BAND].data(), mSamples[LF_BAND].data(),
InSamples[i], SamplesToDo);
MixRowSamples(OutBuffer[i], mUpsampler[i].Gains,
&reinterpret_cast<ALfloat(&)[BUFFERSIZE]>(mSamples[0]), sNumBands, 0, SamplesToDo);
}
}
@@ -259,29 +247,24 @@ void BFormatDec::upSample(ALfloat (*OutBuffer)[BUFFERSIZE], const ALfloat (*InSa
void AmbiUpsampler::reset(const ALsizei out_order, const ALfloat xover_norm)
{
const ALfloat (&hfscales)[MAX_AMBI_ORDER+1] = GetDecoderHFScales(out_order);
const ALfloat gain0{std::sqrt(Ambi3DDecoderHFScale[0] / hfscales[0])};
const ALfloat gain1{std::sqrt(Ambi3DDecoderHFScale[1] / hfscales[1])};
mShelf[0].setParams(BiquadType::HighShelf, gain0, xover_norm,
calc_rcpQ_from_slope(gain0, 1.0f));
mShelf[1].setParams(BiquadType::HighShelf, gain1, xover_norm,
calc_rcpQ_from_slope(gain1, 1.0f));
std::for_each(std::begin(mShelf)+2, std::end(mShelf),
std::bind(std::mem_fn(&BiquadFilter::copyParamsFrom), _1, mShelf[1]));
mInput[0].Splitter.init(xover_norm);
mInput[0].Gains[HF_BAND] = Ambi3DDecoderHFScale[0] / hfscales[0];
mInput[0].Gains[LF_BAND] = 1.0f;
mInput[1].Splitter.init(xover_norm);
mInput[1].Gains[HF_BAND] = Ambi3DDecoderHFScale[1] / hfscales[1];
mInput[1].Gains[LF_BAND] = 1.0f;
std::fill(std::begin(mInput)+2, std::end(mInput), mInput[1]);
}
void AmbiUpsampler::process(ALfloat (*OutBuffer)[BUFFERSIZE], const ALfloat (*InSamples)[BUFFERSIZE], const ALsizei InChannels, const ALsizei SamplesToDo)
{
ASSUME(SamplesToDo > 0);
ASSUME(InChannels > 0);
ASSUME(InChannels <= 4);
for(ALsizei i{0};i < InChannels;i++)
{
mShelf[i].process(mSamples, InSamples[i], SamplesToDo);
const ALfloat *RESTRICT src{al::assume_aligned<16>(mSamples)};
ALfloat *dst{al::assume_aligned<16>(OutBuffer[i])};
std::transform(src, src+SamplesToDo, dst, dst, std::plus<float>{});
mInput[i].Splitter.process(mSamples[HF_BAND], mSamples[LF_BAND], InSamples[i],
SamplesToDo);
MixRowSamples(OutBuffer[i], mInput[i].Gains, mSamples, sNumBands, 0, SamplesToDo);
}
}
Alc/bformatdec.h
+10 -5
View File
@@ -2,7 +2,6 @@
#define BFORMATDEC_H
#include "alMain.h"
#include "filters/biquad.h"
#include "filters/splitter.h"
#include "ambidefs.h"
#include "almalloc.h"
@@ -33,8 +32,10 @@ private:
std::array<ALfloat,BUFFERSIZE> *mSamplesHF;
std::array<ALfloat,BUFFERSIZE> *mSamplesLF;
/* Shelf filters used for upsampling. */
BiquadFilter mShelf[4];
struct {
BandSplitter Splitter;
ALfloat Gains[sNumBands];
} mUpsampler[4];
ALsizei mNumChannels;
ALboolean mDualBand;
@@ -58,8 +59,12 @@ public:
* with bformatdec.
*/
class AmbiUpsampler {
BiquadFilter mShelf[4];
alignas(16) ALfloat mSamples[BUFFERSIZE];
static constexpr ALsizei sNumBands{2};
struct {
BandSplitter Splitter;
ALfloat Gains[sNumBands];
} mInput[4];
alignas(16) ALfloat mSamples[sNumBands][BUFFERSIZE];
public:
void reset(const ALsizei out_order, const ALfloat xover_norm);
Alc/hrtf.cpp
+12 -23
View File
@@ -37,7 +37,7 @@
#include "alu.h"
#include "hrtf.h"
#include "alconfig.h"
#include "filters/biquad.h"
#include "filters/splitter.h"
#include "compat.h"
#include "almalloc.h"
@@ -314,16 +314,11 @@ void BuildBFormatHrtf(const HrtfEntry *Hrtf, DirectHrtfState *state, const ALsiz
std::transform(AmbiPoints, AmbiPoints+AmbiCount, idx.begin(), calc_idxs);
const ALdouble xover_norm{400.0 / Hrtf->sampleRate};
const ALsizei order_limit{OrderFromChan[NumChannels-1] + 1};
BiquadFilterR<double> shelf[MAX_AMBI_ORDER+1];
for(ALsizei o{0};o < order_limit;++o)
{
const auto g = std::sqrt(double{AmbiOrderHFGain[o]});
shelf[o].setParams(BiquadType::HighShelf, g, xover_norm, calc_rcpQ_from_slope(g, 1.0));
}
BandSplitterR<double> splitter;
splitter.init(xover_norm);
al::vector<std::array<std::array<ALdouble,2>,HRIR_LENGTH>> tmpres(NumChannels);
al::vector<std::array<ALdouble,HRIR_LENGTH>> tmpfilt(order_limit+1);
al::vector<std::array<ALdouble,HRIR_LENGTH>> tmpfilt(3);
for(ALsizei c{0};c < AmbiCount;++c)
{
const ALfloat (*fir)[2]{&Hrtf->coeffs[idx[c] * Hrtf->irSize]};
@@ -352,19 +347,16 @@ void BuildBFormatHrtf(const HrtfEntry *Hrtf, DirectHrtfState *state, const ALsiz
auto tmpfilt_iter = std::transform(fir, fir+Hrtf->irSize, tmpfilt.back().begin(),
[](const ALfloat (&ir)[2]) noexcept { return ir[0]; });
std::fill(tmpfilt_iter, tmpfilt.back().end(), 0.0);
for(ALsizei o{0};o < order_limit;++o)
{
shelf[o].clear();
shelf[o].process(tmpfilt[o].data(), tmpfilt.back().data(), HRIR_LENGTH);
}
splitter.clear();
splitter.process(tmpfilt[0].data(), tmpfilt[1].data(), tmpfilt[2].data(), HRIR_LENGTH);
/* Apply left ear response with delay. */
for(ALsizei i{0};i < NumChannels;++i)
{
const ALsizei order{OrderFromChan[i]};
const ALdouble mult{AmbiMatrix[c][i]};
const ALdouble hfgain{AmbiOrderHFGain[OrderFromChan[i]]};
for(ALsizei lidx{ldelay},j{0};lidx < HRIR_LENGTH;++lidx,++j)
tmpres[i][lidx][0] += tmpfilt[order][j] * mult;
tmpres[i][lidx][0] += (tmpfilt[0][j]*hfgain + tmpfilt[1][j]) * mult;
}
/* Extract the right HRIR and increase its per-order high-frequency
@@ -373,19 +365,16 @@ void BuildBFormatHrtf(const HrtfEntry *Hrtf, DirectHrtfState *state, const ALsiz
tmpfilt_iter = std::transform(fir, fir+Hrtf->irSize, tmpfilt.back().begin(),
[](const ALfloat (&ir)[2]) noexcept { return ir[1]; });
std::fill(tmpfilt_iter, tmpfilt.back().end(), 0.0);
for(ALsizei o{0};o < order_limit;++o)
{
shelf[o].clear();
shelf[o].process(tmpfilt[o].data(), tmpfilt.back().data(), HRIR_LENGTH);
}
splitter.clear();
splitter.process(tmpfilt[0].data(), tmpfilt[1].data(), tmpfilt[2].data(), HRIR_LENGTH);
/* Apply right ear response with delay. */
for(ALsizei i{0};i < NumChannels;++i)
{
const ALsizei order{OrderFromChan[i]};
const ALdouble mult{AmbiMatrix[c][i]};
const ALdouble hfgain{AmbiOrderHFGain[OrderFromChan[i]]};
for(ALsizei ridx{rdelay},j{0};ridx < HRIR_LENGTH;++ridx,++j)
tmpres[i][ridx][1] += tmpfilt[order][j] * mult;
tmpres[i][ridx][1] += (tmpfilt[0][j]*hfgain + tmpfilt[1][j]) * mult;
}
}
}