| /* |
| * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. |
| * |
| * Use of this source code is governed by a BSD-style license |
| * that can be found in the LICENSE file in the root of the source |
| * tree. An additional intellectual property rights grant can be found |
| * in the file PATENTS. All contributing project authors may |
| * be found in the AUTHORS file in the root of the source tree. |
| */ |
| |
| #include "common_audio/signal_processing/include/real_fft.h" |
| #include "common_audio/signal_processing/include/signal_processing_library.h" |
| #include "test/gtest.h" |
| |
| namespace webrtc { |
| namespace { |
| |
| // FFT order. |
| const int kOrder = 5; |
| // Lengths for real FFT's time and frequency bufffers. |
| // For N-point FFT, the length requirements from API are N and N+2 respectively. |
| const int kTimeDataLength = 1 << kOrder; |
| const int kFreqDataLength = (1 << kOrder) + 2; |
| // For complex FFT's time and freq buffer. The implementation requires |
| // 2*N 16-bit words. |
| const int kComplexFftDataLength = 2 << kOrder; |
| // Reference data for time signal. |
| const int16_t kRefData[kTimeDataLength] = { |
| 11739, 6848, -8688, 31980, -30295, 25242, 27085, 19410, |
| -26299, 15607, -10791, 11778, -23819, 14498, -25772, 10076, |
| 1173, 6848, -8688, 31980, -30295, 2522, 27085, 19410, |
| -2629, 5607, -3, 1178, -23819, 1498, -25772, 10076}; |
| |
| TEST(RealFFTTest, CreateFailsOnBadInput) { |
| RealFFT* fft = WebRtcSpl_CreateRealFFT(11); |
| EXPECT_TRUE(fft == nullptr); |
| fft = WebRtcSpl_CreateRealFFT(-1); |
| EXPECT_TRUE(fft == nullptr); |
| } |
| |
| TEST(RealFFTTest, RealAndComplexMatch) { |
| int i = 0; |
| int j = 0; |
| int16_t real_fft_time[kTimeDataLength] = {0}; |
| int16_t real_fft_freq[kFreqDataLength] = {0}; |
| // One common buffer for complex FFT's time and frequency data. |
| int16_t complex_fft_buff[kComplexFftDataLength] = {0}; |
| |
| // Prepare the inputs to forward FFT's. |
| memcpy(real_fft_time, kRefData, sizeof(kRefData)); |
| for (i = 0, j = 0; i < kTimeDataLength; i += 1, j += 2) { |
| complex_fft_buff[j] = kRefData[i]; |
| complex_fft_buff[j + 1] = 0; // Insert zero's to imaginary parts. |
| } |
| |
| // Create and run real forward FFT. |
| RealFFT* fft = WebRtcSpl_CreateRealFFT(kOrder); |
| EXPECT_TRUE(fft != nullptr); |
| EXPECT_EQ(0, WebRtcSpl_RealForwardFFT(fft, real_fft_time, real_fft_freq)); |
| |
| // Run complex forward FFT. |
| WebRtcSpl_ComplexBitReverse(complex_fft_buff, kOrder); |
| EXPECT_EQ(0, WebRtcSpl_ComplexFFT(complex_fft_buff, kOrder, 1)); |
| |
| // Verify the results between complex and real forward FFT. |
| for (i = 0; i < kFreqDataLength; i++) { |
| EXPECT_EQ(real_fft_freq[i], complex_fft_buff[i]); |
| } |
| |
| // Prepare the inputs to inverse real FFT. |
| // We use whatever data in complex_fft_buff[] since we don't care |
| // about data contents. Only kFreqDataLength 16-bit words are copied |
| // from complex_fft_buff to real_fft_freq since remaining words (2nd half) |
| // are conjugate-symmetric to the first half in theory. |
| memcpy(real_fft_freq, complex_fft_buff, sizeof(real_fft_freq)); |
| |
| // Run real inverse FFT. |
| int real_scale = WebRtcSpl_RealInverseFFT(fft, real_fft_freq, real_fft_time); |
| EXPECT_GE(real_scale, 0); |
| |
| // Run complex inverse FFT. |
| WebRtcSpl_ComplexBitReverse(complex_fft_buff, kOrder); |
| int complex_scale = WebRtcSpl_ComplexIFFT(complex_fft_buff, kOrder, 1); |
| |
| // Verify the results between complex and real inverse FFT. |
| // They are not bit-exact, since complex IFFT doesn't produce |
| // exactly conjugate-symmetric data (between first and second half). |
| EXPECT_EQ(real_scale, complex_scale); |
| for (i = 0, j = 0; i < kTimeDataLength; i += 1, j += 2) { |
| EXPECT_LE(abs(real_fft_time[i] - complex_fft_buff[j]), 1); |
| } |
| |
| WebRtcSpl_FreeRealFFT(fft); |
| } |
| |
| } // namespace |
| } // namespace webrtc |