diff options
Diffstat (limited to 'alc/uhjfilter.cpp')
| -rw-r--r-- | alc/uhjfilter.cpp | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/alc/uhjfilter.cpp b/alc/uhjfilter.cpp index 00d7dad3..9c0692c4 100644 --- a/alc/uhjfilter.cpp +++ b/alc/uhjfilter.cpp @@ -44,18 +44,21 @@ std::array<float,Uhj2Encoder::sFilterSize> GenerateFilter() */ constexpr complex_d c0{0.0, 1.0}; constexpr complex_d c1{0.0, -1.0}; - constexpr size_t half_size{32768}; + constexpr size_t fft_size{65536}; + constexpr size_t half_size{fft_size / 2}; - /* Generate a frequency domain impulse with a +90 degree phase offset. Keep - * the mirrored frequencies clear for converting to the time domain. + /* Generate a frequency domain impulse with a +90 degree phase offset. + * Reconstruct the mirrored frequencies to convert to the time domain. */ - auto fftBuffer = std::vector<complex_d>(half_size*2, complex_d{}); + auto fftBuffer = std::vector<complex_d>(fft_size, complex_d{}); for(size_t i{0};i < half_size;i += 2) { fftBuffer[i ] = c0; fftBuffer[i+1] = c1; } fftBuffer[half_size] = c0; + for(size_t i{half_size+1};i < fft_size;++i) + fftBuffer[i] = std::conj(fftBuffer[fft_size - i]); complex_fft(fftBuffer, 1.0); /* Reverse and truncate the filter to a usable size, and store only the @@ -65,7 +68,7 @@ std::array<float,Uhj2Encoder::sFilterSize> GenerateFilter() auto fftiter = fftBuffer.data() + half_size + (Uhj2Encoder::sFilterSize-1); for(float &coeff : ret) { - coeff = static_cast<float>(fftiter->real() / (half_size+1)); + coeff = static_cast<float>(fftiter->real() / double{fft_size}); fftiter -= 2; } return ret; |