diff options
| -rw-r--r-- | core/uhjfilter.cpp | 44 | ||||
| -rw-r--r-- | core/uhjfilter.h | 6 | ||||
| -rw-r--r-- | utils/uhjdecoder.cpp | 4 |
3 files changed, 37 insertions, 17 deletions
diff --git a/core/uhjfilter.cpp b/core/uhjfilter.cpp index fad04d20..5a236d38 100644 --- a/core/uhjfilter.cpp +++ b/core/uhjfilter.cpp @@ -43,6 +43,9 @@ const PhaseShifterT<UhjEncoder::sFilterDelay*2> PShift{}; void UhjEncoder::encode(const FloatBufferSpan LeftOut, const FloatBufferSpan RightOut, const FloatBufferLine *InSamples, const size_t SamplesToDo) { + /* Given FuMa input, a +3dB boost is needed for the expected levels. */ + constexpr float sqrt2{1.41421356237f}; + ASSUME(SamplesToDo > 0); float *RESTRICT left{al::assume_aligned<16>(LeftOut.data())}; @@ -60,14 +63,14 @@ void UhjEncoder::encode(const FloatBufferSpan LeftOut, const FloatBufferSpan Rig auto miditer = mS.begin() + sFilterDelay; std::transform(winput, winput+SamplesToDo, xinput, miditer, [](const float w, const float x) noexcept -> float - { return 0.9396926f*w + 0.1855740f*x; }); + { return 0.9396926f*sqrt2*w + 0.1855740f*sqrt2*x; }); for(size_t i{0};i < SamplesToDo;++i,++miditer) *miditer += left[i] + right[i]; /* D = 0.6554516*Y */ auto sideiter = mD.begin() + sFilterDelay; std::transform(yinput, yinput+SamplesToDo, sideiter, - [](const float y) noexcept -> float { return 0.6554516f*y; }); + [](const float y) noexcept -> float { return 0.6554516f*sqrt2*y; }); for(size_t i{0};i < SamplesToDo;++i,++sideiter) *sideiter += left[i] - right[i]; @@ -75,7 +78,7 @@ void UhjEncoder::encode(const FloatBufferSpan LeftOut, const FloatBufferSpan Rig auto tmpiter = std::copy(mWXHistory.cbegin(), mWXHistory.cend(), mTemp.begin()); std::transform(winput, winput+SamplesToDo, xinput, tmpiter, [](const float w, const float x) noexcept -> float - { return -0.3420201f*w + 0.5098604f*x; }); + { return -0.3420201f*sqrt2*w + 0.5098604f*sqrt2*x; }); std::copy_n(mTemp.cbegin()+SamplesToDo, mWXHistory.size(), mWXHistory.begin()); PShift.processAccum({mD.data(), SamplesToDo}, mTemp.data()); @@ -110,23 +113,32 @@ void UhjEncoder::encode(const FloatBufferSpan LeftOut, const FloatBufferSpan Rig void UhjDecoder::decode(const al::span<BufferLine> samples, const size_t offset, const size_t samplesToDo, const size_t forwardSamples) { + /* A -3dB attenuation is needed for FuMa output. */ + constexpr float sqrt1_2{0.707106781187f}; + ASSUME(samplesToDo > 0); - /* S = Left + Right */ - for(size_t i{0};i < samplesToDo+sFilterDelay;++i) - mS[i] = samples[0][offset+i] + samples[1][offset+i]; + { + const float *RESTRICT left{al::assume_aligned<16>(samples[0].data() + offset)}; + const float *RESTRICT right{al::assume_aligned<16>(samples[1].data() + offset)}; + const float *RESTRICT t{al::assume_aligned<16>(samples[2].data() + offset)}; - /* D = Left - Right */ - for(size_t i{0};i < samplesToDo+sFilterDelay;++i) - mD[i] = samples[0][offset+i] - samples[1][offset+i]; + /* S = Left + Right */ + for(size_t i{0};i < samplesToDo+sFilterDelay;++i) + mS[i] = (left[i] + right[i]) * sqrt1_2; - /* T */ - for(size_t i{0};i < samplesToDo+sFilterDelay;++i) - mT[i] = samples[2][offset+i]; + /* D = Left - Right */ + for(size_t i{0};i < samplesToDo+sFilterDelay;++i) + mD[i] = (left[i] - right[i]) * sqrt1_2; + + /* T */ + for(size_t i{0};i < samplesToDo+sFilterDelay;++i) + mT[i] = t[i] * sqrt1_2; + } - float *RESTRICT woutput{samples[0].data() + offset}; - float *RESTRICT xoutput{samples[1].data() + offset}; - float *RESTRICT youtput{samples[2].data() + offset}; + float *RESTRICT woutput{al::assume_aligned<16>(samples[0].data() + offset)}; + float *RESTRICT xoutput{al::assume_aligned<16>(samples[1].data() + offset)}; + float *RESTRICT youtput{al::assume_aligned<16>(samples[2].data() + offset)}; /* Precompute j(0.828347*D + 0.767835*T) and store in xoutput. */ auto tmpiter = std::copy(mDTHistory.cbegin(), mDTHistory.cend(), mTemp.begin()); @@ -157,6 +169,6 @@ void UhjDecoder::decode(const al::span<BufferLine> samples, const size_t offset, float *RESTRICT zoutput{samples[3].data() + offset}; /* Z = 1.023332*Q */ for(size_t i{0};i < samplesToDo;++i) - zoutput[i] = 1.023332f*zoutput[i]; + zoutput[i] = 1.023332f*sqrt1_2*zoutput[i]; } } diff --git a/core/uhjfilter.h b/core/uhjfilter.h index c28b9510..897de2f8 100644 --- a/core/uhjfilter.h +++ b/core/uhjfilter.h @@ -49,6 +49,12 @@ struct UhjDecoder { alignas(16) std::array<float,BufferLineSize+MaxResamplerEdge + sFilterDelay*2> mTemp{}; + /** + * Decodes a 3- or 4-channel UHJ signal into a B-Format signal with FuMa + * channel ordering and scaling. For 3-channel, the 3rd channel may be + * attenuated by 'n', where 0 <= n <= 1. So 2-channel UHJ can be decoded by + * leaving the 3rd channel silent (n=0). + */ void decode(const al::span<BufferLine> samples, const size_t offset, const size_t samplesToDo, const size_t forwardSamples); diff --git a/utils/uhjdecoder.cpp b/utils/uhjdecoder.cpp index f9db4895..cda16a40 100644 --- a/utils/uhjdecoder.cpp +++ b/utils/uhjdecoder.cpp @@ -492,8 +492,10 @@ int main(int argc, char **argv) decoder->decode2(inmem.get(), decmem, got); for(size_t i{0};i < got;++i) { + /* Attenuate by -3dB for FuMa output levels. */ + constexpr float sqrt1_2{0.707106781187f}; for(size_t j{0};j < outchans;++j) - outmem[i*outchans + j] = f32AsLEBytes(decmem[j][i]); + outmem[i*outchans + j] = f32AsLEBytes(decmem[j][i] * sqrt1_2); } size_t wrote{fwrite(outmem.get(), sizeof(byte4)*outchans, got, outfile.get())}; |