From 5149cb8c357630dba5253e2568b68d2ed069bcea Mon Sep 17 00:00:00 2001 From: Chris Robinson Date: Wed, 11 Oct 2023 15:56:11 -0700 Subject: Make and use a separate zconvolve method without scaling When you're doing hundreds or thousands of separate zconvolve calls into the same buffer, it's more efficient to do the multiply once at the end instead of in each call. --- alc/effects/convolution.cpp | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) (limited to 'alc/effects/convolution.cpp') diff --git a/alc/effects/convolution.cpp b/alc/effects/convolution.cpp index c7a342dc..a98a0616 100644 --- a/alc/effects/convolution.cpp +++ b/alc/effects/convolution.cpp @@ -655,11 +655,6 @@ void ConvolutionState::process(const size_t samplesToDo, const float *RESTRICT filter{mComplexData.get() + mNumConvolveSegs*ConvolveUpdateSize}; for(size_t c{0};c < chans.size();++c) { - /* The iFFT'd response is scaled up by the number of bins, so apply - * the inverse to normalize the output. - */ - static constexpr float fftscale{1.0f / float{ConvolveUpdateSize}}; - /* Convolve each input segment with its IR filter counterpart * (aligned in time). */ @@ -667,14 +662,14 @@ void ConvolutionState::process(const size_t samplesToDo, const float *RESTRICT input{&mComplexData[curseg*ConvolveUpdateSize]}; for(size_t s{curseg};s < mNumConvolveSegs;++s) { - pffft_zconvolve_accumulate(mFft.get(), input, filter, mFftBuffer.data(), fftscale); + pffft_zconvolve_accumulate(mFft.get(), input, filter, mFftBuffer.data()); input += ConvolveUpdateSize; filter += ConvolveUpdateSize; } input = mComplexData.get(); for(size_t s{0};s < curseg;++s) { - pffft_zconvolve_accumulate(mFft.get(), input, filter, mFftBuffer.data(), fftscale); + pffft_zconvolve_accumulate(mFft.get(), input, filter, mFftBuffer.data()); input += ConvolveUpdateSize; filter += ConvolveUpdateSize; } @@ -687,8 +682,12 @@ void ConvolutionState::process(const size_t samplesToDo, pffft_transform(mFft.get(), mFftBuffer.data(), mFftBuffer.data(), mFftWorkBuffer.data(), PFFFT_BACKWARD); + /* The iFFT'd response is scaled up by the number of bins, so apply + * the inverse to normalize the output. + */ + static constexpr float fftscale{1.0f / float{ConvolveUpdateSize}}; for(size_t i{0};i < ConvolveUpdateSamples;++i) - mOutput[c][i] = mFftBuffer[i] + mOutput[c][ConvolveUpdateSamples+i]; + mOutput[c][i] = (mFftBuffer[i]+mOutput[c][ConvolveUpdateSamples+i]) * fftscale; for(size_t i{0};i < ConvolveUpdateSamples;++i) mOutput[c][ConvolveUpdateSamples+i] = mFftBuffer[ConvolveUpdateSamples+i]; } -- cgit v1.2.3