| /* |
| * Copyright (C) 2010 Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of |
| * its contributors may be used to endorse or promote products derived |
| * from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
| * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "third_party/blink/renderer/platform/audio/fft_convolver.h" |
| #include "third_party/blink/renderer/platform/audio/vector_math.h" |
| |
| namespace blink { |
| |
| using namespace vector_math; |
| |
| FFTConvolver::FFTConvolver(size_t fft_size) |
| : frame_(fft_size), |
| read_write_index_(0), |
| input_buffer_(fft_size), // 2nd half of buffer is always zeroed |
| output_buffer_(fft_size), |
| last_overlap_buffer_(fft_size / 2) {} |
| |
| void FFTConvolver::Process(const FFTFrame* fft_kernel, |
| const float* source_p, |
| float* dest_p, |
| uint32_t frames_to_process) { |
| size_t half_size = FftSize() / 2; |
| |
| // framesToProcess must be an exact multiple of halfSize, |
| // or halfSize is a multiple of framesToProcess when halfSize > |
| // framesToProcess. |
| bool is_good = |
| !(half_size % frames_to_process && frames_to_process % half_size); |
| DCHECK(is_good); |
| if (!is_good) |
| return; |
| |
| size_t number_of_divisions = |
| half_size <= frames_to_process ? (frames_to_process / half_size) : 1; |
| size_t division_size = |
| number_of_divisions == 1 ? frames_to_process : half_size; |
| |
| for (size_t i = 0; i < number_of_divisions; |
| ++i, source_p += division_size, dest_p += division_size) { |
| // Copy samples to input buffer (note contraint above!) |
| float* input_p = input_buffer_.Data(); |
| |
| // Sanity check |
| bool is_copy_good1 = |
| source_p && input_p && |
| read_write_index_ + division_size <= input_buffer_.size(); |
| DCHECK(is_copy_good1); |
| if (!is_copy_good1) |
| return; |
| |
| memcpy(input_p + read_write_index_, source_p, |
| sizeof(float) * division_size); |
| |
| // Copy samples from output buffer |
| float* output_p = output_buffer_.Data(); |
| |
| // Sanity check |
| bool is_copy_good2 = |
| dest_p && output_p && |
| read_write_index_ + division_size <= output_buffer_.size(); |
| DCHECK(is_copy_good2); |
| if (!is_copy_good2) |
| return; |
| |
| memcpy(dest_p, output_p + read_write_index_, sizeof(float) * division_size); |
| read_write_index_ += division_size; |
| |
| // Check if it's time to perform the next FFT |
| if (read_write_index_ == half_size) { |
| // The input buffer is now filled (get frequency-domain version) |
| frame_.DoFFT(input_buffer_.Data()); |
| frame_.Multiply(*fft_kernel); |
| frame_.DoInverseFFT(output_buffer_.Data()); |
| |
| // Overlap-add 1st half from previous time |
| Vadd(output_buffer_.Data(), 1, last_overlap_buffer_.Data(), 1, |
| output_buffer_.Data(), 1, half_size); |
| |
| // Finally, save 2nd half of result |
| bool is_copy_good3 = output_buffer_.size() == 2 * half_size && |
| last_overlap_buffer_.size() == half_size; |
| DCHECK(is_copy_good3); |
| if (!is_copy_good3) |
| return; |
| |
| memcpy(last_overlap_buffer_.Data(), output_buffer_.Data() + half_size, |
| sizeof(float) * half_size); |
| |
| // Reset index back to start for next time |
| read_write_index_ = 0; |
| } |
| } |
| } |
| |
| void FFTConvolver::Reset() { |
| last_overlap_buffer_.Zero(); |
| read_write_index_ = 0; |
| } |
| |
| } // namespace blink |