modules/audio_processing/aec3/render_signal_analyzer_unittest.cc

/*
 *  Copyright (c) 2017 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 "modules/audio_processing/aec3/render_signal_analyzer.h"

#include <algorithm>
#include <array>
#include <cmath>
#include <cstddef>
#include <memory>
#include <numbers>
#include <optional>
#include <string>

#include "api/array_view.h"
#include "api/audio/echo_canceller3_config.h"
#include "modules/audio_processing/aec3/aec3_common.h"
#include "modules/audio_processing/aec3/aec3_fft.h"
#include "modules/audio_processing/aec3/block.h"
#include "modules/audio_processing/aec3/render_delay_buffer.h"
#include "modules/audio_processing/test/echo_canceller_test_tools.h"
#include "rtc_base/checks.h"
#include "rtc_base/random.h"
#include "rtc_base/strings/string_builder.h"
#include "test/gtest.h"

namespace webrtc {
namespace {

constexpr float kPi = std::numbers::pi_v<float>;

void ProduceSinusoidInNoise(int sample_rate_hz,
                            size_t sinusoid_channel,
                            float sinusoidal_frequency_hz,
                            Random* random_generator,
                            size_t* sample_counter,
                            Block* x) {
  // Fill x with low-amplitude noise.
  for (int band = 0; band < x->NumBands(); ++band) {
    for (int channel = 0; channel < x->NumChannels(); ++channel) {
      RandomizeSampleVector(random_generator, x->View(band, channel),
                            /*amplitude=*/500.f);
    }
  }
  // Produce a sinusoid of the specified frequency in the specified channel.
  for (size_t k = *sample_counter, j = 0; k < (*sample_counter + kBlockSize);
       ++k, ++j) {
    x->View(/*band=*/0, sinusoid_channel)[j] +=
        32000.f *
        std::sin(2.f * kPi * sinusoidal_frequency_hz * k / sample_rate_hz);
  }
  *sample_counter = *sample_counter + kBlockSize;
}

void RunNarrowBandDetectionTest(size_t num_channels) {
  RenderSignalAnalyzer analyzer(EchoCanceller3Config{});
  Random random_generator(42U);
  constexpr int kSampleRateHz = 48000;
  constexpr size_t kNumBands = NumBandsForRate(kSampleRateHz);
  Block x(kNumBands, num_channels);
  std::array<float, kBlockSize> x_old;
  Aec3Fft fft;
  EchoCanceller3Config config;
  std::unique_ptr<RenderDelayBuffer> render_delay_buffer(
      RenderDelayBuffer::Create(config, kSampleRateHz, num_channels));

  std::array<float, kFftLengthBy2Plus1> mask;
  x_old.fill(0.f);
  constexpr int kSinusFrequencyBin = 32;

  auto generate_sinusoid_test = [&](bool known_delay) {
    size_t sample_counter = 0;
    for (size_t k = 0; k < 100; ++k) {
      ProduceSinusoidInNoise(16000, num_channels - 1,
                             16000 / 2 * kSinusFrequencyBin / kFftLengthBy2,
                             &random_generator, &sample_counter, &x);

      render_delay_buffer->Insert(x);
      if (k == 0) {
        render_delay_buffer->Reset();
      }
      render_delay_buffer->PrepareCaptureProcessing();

      analyzer.Update(*render_delay_buffer->GetRenderBuffer(),
                      known_delay ? std::optional<size_t>(0) : std::nullopt);
    }
  };

  generate_sinusoid_test(true);
  mask.fill(1.f);
  analyzer.MaskRegionsAroundNarrowBands(&mask);
  for (int k = 0; k < static_cast<int>(mask.size()); ++k) {
    EXPECT_EQ(abs(k - kSinusFrequencyBin) <= 2 ? 0.f : 1.f, mask[k]);
  }
  EXPECT_TRUE(analyzer.PoorSignalExcitation());
  EXPECT_TRUE(static_cast<bool>(analyzer.NarrowPeakBand()));
  EXPECT_EQ(*analyzer.NarrowPeakBand(), 32);

  // Verify that no bands are detected as narrow when the delay is unknown.
  generate_sinusoid_test(false);
  mask.fill(1.f);
  analyzer.MaskRegionsAroundNarrowBands(&mask);
  std::for_each(mask.begin(), mask.end(), [](float a) { EXPECT_EQ(1.f, a); });
  EXPECT_FALSE(analyzer.PoorSignalExcitation());
}

std::string ProduceDebugText(size_t num_channels) {
  StringBuilder ss;
  ss << "number of channels: " << num_channels;
  return ss.Release();
}
}  // namespace

#if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
// Verifies that the check for non-null output parameter works.
TEST(RenderSignalAnalyzerDeathTest, NullMaskOutput) {
  RenderSignalAnalyzer analyzer(EchoCanceller3Config{});
  EXPECT_DEATH(analyzer.MaskRegionsAroundNarrowBands(nullptr), "");
}

#endif

// Verify that no narrow bands are detected in a Gaussian noise signal.
TEST(RenderSignalAnalyzer, NoFalseDetectionOfNarrowBands) {
  for (auto num_channels : {1, 2, 8}) {
    SCOPED_TRACE(ProduceDebugText(num_channels));
    RenderSignalAnalyzer analyzer(EchoCanceller3Config{});
    Random random_generator(42U);
    Block x(3, num_channels);
    std::array<float, kBlockSize> x_old;
    std::unique_ptr<RenderDelayBuffer> render_delay_buffer(
        RenderDelayBuffer::Create(EchoCanceller3Config(), 48000, num_channels));
    std::array<float, kFftLengthBy2Plus1> mask;
    x_old.fill(0.f);

    for (int k = 0; k < 100; ++k) {
      for (int band = 0; band < x.NumBands(); ++band) {
        for (int channel = 0; channel < x.NumChannels(); ++channel) {
          RandomizeSampleVector(&random_generator, x.View(band, channel));
        }
      }

      render_delay_buffer->Insert(x);
      if (k == 0) {
        render_delay_buffer->Reset();
      }
      render_delay_buffer->PrepareCaptureProcessing();

      analyzer.Update(*render_delay_buffer->GetRenderBuffer(),
                      std::optional<size_t>(0));
    }

    mask.fill(1.f);
    analyzer.MaskRegionsAroundNarrowBands(&mask);
    EXPECT_TRUE(std::all_of(mask.begin(), mask.end(),
                            [](float a) { return a == 1.f; }));
    EXPECT_FALSE(analyzer.PoorSignalExcitation());
    EXPECT_FALSE(static_cast<bool>(analyzer.NarrowPeakBand()));
  }
}

// Verify that a sinusoid signal is detected as narrow bands.
TEST(RenderSignalAnalyzer, NarrowBandDetection) {
  for (auto num_channels : {1, 2, 8}) {
    SCOPED_TRACE(ProduceDebugText(num_channels));
    RunNarrowBandDetectionTest(num_channels);
  }
}
}  // namespace webrtc