Move bformatdec to core

1 files changed, 263 insertions, 0 deletions

diff --git a/core/bformatdec.cpp b/core/bformatdec.cpp
new file mode 100644
index 00000000..6bf85ec9
--- /dev/null
+++ b/core/bformatdec.cpp
@@ -0,0 +1,263 @@
+
+#include "config.h"
+
+#include "bformatdec.h"
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <utility>
+
+#include "almalloc.h"
+#include "ambdec.h"
+#include "filters/splitter.h"
+#include "front_stablizer.h"
+#include "math_defs.h"
+#include "mixer.h"
+#include "opthelpers.h"
+
+
+namespace {
+
+inline auto& GetAmbiScales(AmbDecScale scaletype) noexcept
+{
+    if(scaletype == AmbDecScale::FuMa) return AmbiScale::FromFuMa();
+    if(scaletype == AmbDecScale::SN3D) return AmbiScale::FromSN3D();
+    return AmbiScale::FromN3D();
+}
+
+} // namespace
+
+
+BFormatDec::BFormatDec(const AmbDecConf *conf, const bool allow_2band, const size_t inchans,
+    const uint srate, const uint (&chanmap)[MAX_OUTPUT_CHANNELS],
+    std::unique_ptr<FrontStablizer> stablizer)
+    : mStablizer{std::move(stablizer)}, mDualBand{allow_2band && (conf->FreqBands == 2)}
+    , mChannelDec{inchans}
+{
+    const bool periphonic{(conf->ChanMask&AmbiPeriphonicMask) != 0};
+    auto&& coeff_scale = GetAmbiScales(conf->CoeffScale);
+
+    if(!mDualBand)
+    {
+        for(size_t j{0},k{0};j < mChannelDec.size();++j)
+        {
+            const size_t acn{periphonic ? j : AmbiIndex::FromACN2D()[j]};
+            if(!(conf->ChanMask&(1u<<acn))) continue;
+            const size_t order{AmbiIndex::OrderFromChannel()[acn]};
+            const float gain{conf->HFOrderGain[order] / coeff_scale[acn]};
+            for(size_t i{0u};i < conf->NumSpeakers;++i)
+            {
+                const size_t chanidx{chanmap[i]};
+                mChannelDec[j].mGains.Single[chanidx] = conf->Matrix[i][k] * gain;
+            }
+            ++k;
+        }
+    }
+    else
+    {
+        mChannelDec[0].mXOver.init(conf->XOverFreq / static_cast<float>(srate));
+        for(size_t j{1};j < mChannelDec.size();++j)
+            mChannelDec[j].mXOver = mChannelDec[0].mXOver;
+
+        const float ratio{std::pow(10.0f, conf->XOverRatio / 40.0f)};
+        for(size_t j{0},k{0};j < mChannelDec.size();++j)
+        {
+            const size_t acn{periphonic ? j : AmbiIndex::FromACN2D()[j]};
+            if(!(conf->ChanMask&(1u<<acn))) continue;
+            const size_t order{AmbiIndex::OrderFromChannel()[acn]};
+            const float hfGain{conf->HFOrderGain[order] * ratio / coeff_scale[acn]};
+            const float lfGain{conf->LFOrderGain[order] / ratio / coeff_scale[acn]};
+            for(size_t i{0u};i < conf->NumSpeakers;++i)
+            {
+                const size_t chanidx{chanmap[i]};
+                mChannelDec[j].mGains.Dual[sHFBand][chanidx] = conf->HFMatrix[i][k] * hfGain;
+                mChannelDec[j].mGains.Dual[sLFBand][chanidx] = conf->LFMatrix[i][k] * lfGain;
+            }
+            ++k;
+        }
+    }
+}
+
+BFormatDec::BFormatDec(const size_t inchans, const al::span<const ChannelDec> coeffs,
+    const al::span<const ChannelDec> coeffslf, std::unique_ptr<FrontStablizer> stablizer)
+    : mStablizer{std::move(stablizer)}, mDualBand{!coeffslf.empty()}, mChannelDec{inchans}
+{
+    if(!mDualBand)
+    {
+        for(size_t j{0};j < mChannelDec.size();++j)
+        {
+            float *outcoeffs{mChannelDec[j].mGains.Single};
+            for(const ChannelDec &incoeffs : coeffs)
+                *(outcoeffs++) = incoeffs[j];
+        }
+    }
+    else
+    {
+        for(size_t j{0};j < mChannelDec.size();++j)
+        {
+            float *outcoeffs{mChannelDec[j].mGains.Dual[sHFBand]};
+            for(const ChannelDec &incoeffs : coeffs)
+                *(outcoeffs++) = incoeffs[j];
+
+            outcoeffs = mChannelDec[j].mGains.Dual[sLFBand];
+            for(const ChannelDec &incoeffs : coeffslf)
+                *(outcoeffs++) = incoeffs[j];
+        }
+    }
+}
+
+
+void BFormatDec::process(const al::span<FloatBufferLine> OutBuffer,
+    const FloatBufferLine *InSamples, const size_t SamplesToDo)
+{
+    ASSUME(SamplesToDo > 0);
+
+    if(mDualBand)
+    {
+        const al::span<float> hfSamples{mSamples[sHFBand].data(), SamplesToDo};
+        const al::span<float> lfSamples{mSamples[sLFBand].data(), SamplesToDo};
+        for(auto &chandec : mChannelDec)
+        {
+            chandec.mXOver.process({InSamples->data(), SamplesToDo}, hfSamples.data(),
+                lfSamples.data());
+            MixSamples(hfSamples, OutBuffer, chandec.mGains.Dual[sHFBand],
+                chandec.mGains.Dual[sHFBand], 0, 0);
+            MixSamples(lfSamples, OutBuffer, chandec.mGains.Dual[sLFBand],
+                chandec.mGains.Dual[sLFBand], 0, 0);
+            ++InSamples;
+        }
+    }
+    else
+    {
+        for(auto &chandec : mChannelDec)
+        {
+            MixSamples({InSamples->data(), SamplesToDo}, OutBuffer, chandec.mGains.Single,
+                chandec.mGains.Single, 0, 0);
+            ++InSamples;
+        }
+    }
+}
+
+void BFormatDec::processStablize(const al::span<FloatBufferLine> OutBuffer,
+    const FloatBufferLine *InSamples, const size_t lidx, const size_t ridx, const size_t cidx,
+    const size_t SamplesToDo)
+{
+    ASSUME(SamplesToDo > 0);
+
+    /* Move the existing direct L/R signal out so it doesn't get processed by
+     * the stablizer. Add a delay to it so it stays aligned with the stablizer
+     * delay.
+     */
+    float *RESTRICT mid{al::assume_aligned<16>(mStablizer->MidDirect.data())};
+    float *RESTRICT side{al::assume_aligned<16>(mStablizer->Side.data())};
+    for(size_t i{0};i < SamplesToDo;++i)
+    {
+        mid[FrontStablizer::DelayLength+i] = OutBuffer[lidx][i] + OutBuffer[ridx][i];
+        side[FrontStablizer::DelayLength+i] = OutBuffer[lidx][i] - OutBuffer[ridx][i];
+    }
+    std::fill_n(OutBuffer[lidx].begin(), SamplesToDo, 0.0f);
+    std::fill_n(OutBuffer[ridx].begin(), SamplesToDo, 0.0f);
+
+    /* Decode the B-Format input to OutBuffer. */
+    process(OutBuffer, InSamples, SamplesToDo);
+
+    /* Apply a delay to all channels, except the front-left and front-right, so
+     * they maintain correct timing.
+     */
+    const size_t NumChannels{OutBuffer.size()};
+    for(size_t i{0u};i < NumChannels;i++)
+    {
+        if(i == lidx || i == ridx)
+            continue;
+
+        auto &DelayBuf = mStablizer->DelayBuf[i];
+        auto buffer_end = OutBuffer[i].begin() + SamplesToDo;
+        if LIKELY(SamplesToDo >= FrontStablizer::DelayLength)
+        {
+            auto delay_end = std::rotate(OutBuffer[i].begin(),
+                buffer_end - FrontStablizer::DelayLength, buffer_end);
+            std::swap_ranges(OutBuffer[i].begin(), delay_end, DelayBuf.begin());
+        }
+        else
+        {
+            auto delay_start = std::swap_ranges(OutBuffer[i].begin(), buffer_end,
+                DelayBuf.begin());
+            std::rotate(DelayBuf.begin(), delay_start, DelayBuf.end());
+        }
+    }
+
+    /* Include the side signal for what was just decoded. */
+    for(size_t i{0};i < SamplesToDo;++i)
+        side[FrontStablizer::DelayLength+i] += OutBuffer[lidx][i] - OutBuffer[ridx][i];
+
+    /* Combine the delayed mid signal with the decoded mid signal. Note that
+     * the samples are stored and combined in reverse, so the newest samples
+     * are at the front and the oldest at the back.
+     */
+    al::span<float> tmpbuf{mStablizer->TempBuf.data(), SamplesToDo+FrontStablizer::DelayLength};
+    auto tmpiter = tmpbuf.begin() + SamplesToDo;
+    std::copy(mStablizer->MidDelay.cbegin(), mStablizer->MidDelay.cend(), tmpiter);
+    for(size_t i{0};i < SamplesToDo;++i)
+        *--tmpiter = OutBuffer[lidx][i] + OutBuffer[ridx][i];
+    /* Save the newest samples for next time. */
+    std::copy_n(tmpbuf.cbegin(), mStablizer->MidDelay.size(), mStablizer->MidDelay.begin());
+
+    /* Apply an all-pass on the reversed signal, then reverse the samples to
+     * get the forward signal with a reversed phase shift. The future samples
+     * are included with the all-pass to reduce the error in the output
+     * samples (the smaller the delay, the more error is introduced).
+     */
+    mStablizer->MidFilter.applyAllpass(tmpbuf);
+    tmpbuf = tmpbuf.subspan<FrontStablizer::DelayLength>();
+    std::reverse(tmpbuf.begin(), tmpbuf.end());
+
+    /* Now apply the band-splitter, combining its phase shift with the reversed
+     * phase shift, restoring the original phase on the split signal.
+     */
+    mStablizer->MidFilter.process(tmpbuf, mStablizer->MidHF.data(), mStablizer->MidLF.data());
+
+    /* This pans the separate low- and high-frequency signals between being on
+     * the center channel and the left+right channels. The low-frequency signal
+     * is panned 1/3rd toward center and the high-frequency signal is panned
+     * 1/4th toward center. These values can be tweaked.
+     */
+    const float cos_lf{std::cos(1.0f/3.0f * (al::MathDefs<float>::Pi()*0.5f))};
+    const float cos_hf{std::cos(1.0f/4.0f * (al::MathDefs<float>::Pi()*0.5f))};
+    const float sin_lf{std::sin(1.0f/3.0f * (al::MathDefs<float>::Pi()*0.5f))};
+    const float sin_hf{std::sin(1.0f/4.0f * (al::MathDefs<float>::Pi()*0.5f))};
+    for(size_t i{0};i < SamplesToDo;i++)
+    {
+        const float m{mStablizer->MidLF[i]*cos_lf + mStablizer->MidHF[i]*cos_hf + mid[i]};
+        const float c{mStablizer->MidLF[i]*sin_lf + mStablizer->MidHF[i]*sin_hf};
+        const float s{side[i]};
+
+        /* The generated center channel signal adds to the existing signal,
+         * while the modified left and right channels replace.
+         */
+        OutBuffer[lidx][i] = (m + s) * 0.5f;
+        OutBuffer[ridx][i] = (m - s) * 0.5f;
+        OutBuffer[cidx][i] += c * 0.5f;
+    }
+    /* Move the delayed mid/side samples to the front for next time. */
+    auto mid_end = mStablizer->MidDirect.cbegin() + SamplesToDo;
+    std::copy(mid_end, mid_end+FrontStablizer::DelayLength, mStablizer->MidDirect.begin());
+    auto side_end = mStablizer->Side.cbegin() + SamplesToDo;
+    std::copy(side_end, side_end+FrontStablizer::DelayLength, mStablizer->Side.begin());
+}
+
+
+std::unique_ptr<BFormatDec> BFormatDec::Create(const AmbDecConf *conf, const bool allow_2band,
+    const size_t inchans, const uint srate, const uint (&chanmap)[MAX_OUTPUT_CHANNELS],
+    std::unique_ptr<FrontStablizer> stablizer)
+{
+    return std::unique_ptr<BFormatDec>{new(FamCount(inchans))
+        BFormatDec{conf, allow_2band, inchans, srate, chanmap, std::move(stablizer)}};
+}
+std::unique_ptr<BFormatDec> BFormatDec::Create(const size_t inchans,
+    const al::span<const ChannelDec> coeffs, const al::span<const ChannelDec> coeffslf,
+    std::unique_ptr<FrontStablizer> stablizer)
+{
+    return std::unique_ptr<BFormatDec>{new(FamCount(inchans))
+        BFormatDec{inchans, coeffs, coeffslf, std::move(stablizer)}};
+}