diff options
| -rw-r--r-- | alc/effects/convolution.cpp | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/alc/effects/convolution.cpp b/alc/effects/convolution.cpp index 948966b4..bf439721 100644 --- a/alc/effects/convolution.cpp +++ b/alc/effects/convolution.cpp @@ -26,24 +26,24 @@ namespace { /* Convolution reverb is implemented using a segmented overlap-add method. The - * impulse response is broken up into multiple segments of 512 samples, and - * each segment has an FFT applied with a 1024-sample buffer (the latter half + * impulse response is broken up into multiple segments of 128 samples, and + * each segment has an FFT applied with a 256-sample buffer (the latter half * left silent) to get its frequency-domain response. The resulting response - * has its positive/non-mirrored frequencies saved (513 bins) in each segment. + * has its positive/non-mirrored frequencies saved (129 bins) in each segment. * - * Input samples are similarly broken up into 512-sample segments, with an FFT - * applied to each new incoming segment to get its 513 bins. A history of FFT'd + * Input samples are similarly broken up into 128-sample segments, with an FFT + * applied to each new incoming segment to get its 129 bins. A history of FFT'd * input segments is maintained, equal to the length of the impulse response. * * To apply the reverberation, each impulse response segment is convolved with * its paired input segment (using complex multiplies, far cheaper than FIRs), - * accumulating into a 1024-bin FFT buffer. The input history is then shifted - * to align with later impulse response segments for next time. + * accumulating into a 256-bin FFT buffer. The input history is then shifted to + * align with later impulse response segments for next time. * - * An inverse FFT is then applied to the accumulated FFT buffer to get a 1024- + * An inverse FFT is then applied to the accumulated FFT buffer to get a 256- * sample time-domain response for output, which is split in two halves. The - * first half is the 512-sample output, and the second half is a 512-sample - * (really, 511) delayed extension, which gets added to the output next time. + * first half is the 128-sample output, and the second half is a 128-sample + * (really, 127) delayed extension, which gets added to the output next time. * Convolving two time-domain responses of lengths N and M results in a time- * domain signal of length N+M-1, and this holds true regardless of the * convolution being applied in the frequency domain, so these "overflow" @@ -243,7 +243,7 @@ void ConvolutionState::setBuffer(const ALCdevice *device, const BufferStorage *b PPhaseResampler resampler; if(device->Frequency != buffer->mSampleRate) resampler.init(buffer->mSampleRate, device->Frequency); - const auto resampledCount = static_cast<ALuint>( + const auto resampledCount = static_cast<uint>( (uint64_t{buffer->mSampleLen}*device->Frequency + (buffer->mSampleRate-1)) / buffer->mSampleRate); |