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Simplify some pitch shifter scaling calculations

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This commit is contained in:
Chris Robinson 2020-11-08 07:59:14 -08:00
parent db6d6d68b4
commit 54e4346f50
1 changed files with 7 additions and 8 deletions
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15
alc/effects/pshifter.cpp
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@ -192,11 +192,10 @@ void PshifterState::process(const size_t samplesToDo, const al::span<const Float
/* Get deviation from bin frequency from the +/- Pi interval */
tmp /= expected;
/* Compute the k-th partials' true frequency, twice the amplitude
* for maintain the gain (because half of bins are used) and store
* amplitude and true frequency in analysis buffer.
/* Compute the k-th partials' true frequency and store the
* amplitude and true frequency in the analysis buffer.
*/
mAnalysisBuffer[k].Amplitude = 2.0 * amplitude;
mAnalysisBuffer[k].Amplitude = amplitude;
mAnalysisBuffer[k].Frequency = (static_cast<double>(k) + tmp) * freq_per_bin;
/* Store the actual phase[k] for the next frame. */
@ -207,11 +206,11 @@ void PshifterState::process(const size_t samplesToDo, const al::span<const Float
* accumulating the amplitudes of overlapping frequency bins.
*/
std::fill(mSynthesisBuffer.begin(), mSynthesisBuffer.end(), FrequencyBin{});
for(size_t k{0u};k < STFT_HALF_SIZE+1;k++)
const size_t bin_count{minz(STFT_HALF_SIZE+1,
(((STFT_HALF_SIZE+1)<<MixerFracBits) - (MixerFracOne>>1))/mPitchShiftI)};
for(size_t k{0u};k < bin_count;k++)
{
const size_t j{(k*mPitchShiftI + (MixerFracOne>>1)) >> MixerFracBits};
if(j >= STFT_HALF_SIZE+1) break;
mSynthesisBuffer[j].Amplitude += mAnalysisBuffer[k].Amplitude;
mSynthesisBuffer[j].Frequency = mAnalysisBuffer[k].Frequency * mPitchShift;
}
@ -237,7 +236,7 @@ void PshifterState::process(const size_t samplesToDo, const al::span<const Float
*/
inverse_fft(mFftBuffer);
for(size_t k{0u};k < STFT_SIZE;k++)
mOutputAccum[k] += HannWindow[k]*mFftBuffer[k].real() * (2.0/STFT_SIZE/OVERSAMP);
mOutputAccum[k] += HannWindow[k]*mFftBuffer[k].real() * (4.0/OVERSAMP/STFT_SIZE);
/* Shift FIFO and accumulator. */
fifo_iter = std::copy(mFIFO.begin()+STFT_STEP, mFIFO.end(), mFIFO.begin());