Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 186 insertions, 0 deletions

diff --git a/third_party/libwebrtc/modules/audio_processing/aec3/comfort_noise_generator.cc b/third_party/libwebrtc/modules/audio_processing/aec3/comfort_noise_generator.cc
new file mode 100644
index 0000000000..de5227c089
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/aec3/comfort_noise_generator.cc
@@ -0,0 +1,186 @@
+/*
+ *  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/comfort_noise_generator.h"
+
+// Defines WEBRTC_ARCH_X86_FAMILY, used below.
+#include "rtc_base/system/arch.h"
+
+#if defined(WEBRTC_ARCH_X86_FAMILY)
+#include <emmintrin.h>
+#endif
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <cstdint>
+#include <functional>
+#include <numeric>
+
+#include "common_audio/signal_processing/include/signal_processing_library.h"
+#include "modules/audio_processing/aec3/vector_math.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+namespace {
+
+// Computes the noise floor value that matches a WGN input of noise_floor_dbfs.
+float GetNoiseFloorFactor(float noise_floor_dbfs) {
+  // kdBfsNormalization = 20.f*log10(32768.f).
+  constexpr float kdBfsNormalization = 90.30899869919436f;
+  return 64.f * powf(10.f, (kdBfsNormalization + noise_floor_dbfs) * 0.1f);
+}
+
+// Table of sqrt(2) * sin(2*pi*i/32).
+constexpr float kSqrt2Sin[32] = {
+    +0.0000000f, +0.2758994f, +0.5411961f, +0.7856950f, +1.0000000f,
+    +1.1758756f, +1.3065630f, +1.3870398f, +1.4142136f, +1.3870398f,
+    +1.3065630f, +1.1758756f, +1.0000000f, +0.7856950f, +0.5411961f,
+    +0.2758994f, +0.0000000f, -0.2758994f, -0.5411961f, -0.7856950f,
+    -1.0000000f, -1.1758756f, -1.3065630f, -1.3870398f, -1.4142136f,
+    -1.3870398f, -1.3065630f, -1.1758756f, -1.0000000f, -0.7856950f,
+    -0.5411961f, -0.2758994f};
+
+void GenerateComfortNoise(Aec3Optimization optimization,
+                          const std::array<float, kFftLengthBy2Plus1>& N2,
+                          uint32_t* seed,
+                          FftData* lower_band_noise,
+                          FftData* upper_band_noise) {
+  FftData* N_low = lower_band_noise;
+  FftData* N_high = upper_band_noise;
+
+  // Compute square root spectrum.
+  std::array<float, kFftLengthBy2Plus1> N;
+  std::copy(N2.begin(), N2.end(), N.begin());
+  aec3::VectorMath(optimization).Sqrt(N);
+
+  // Compute the noise level for the upper bands.
+  constexpr float kOneByNumBands = 1.f / (kFftLengthBy2Plus1 / 2 + 1);
+  constexpr int kFftLengthBy2Plus1By2 = kFftLengthBy2Plus1 / 2;
+  const float high_band_noise_level =
+      std::accumulate(N.begin() + kFftLengthBy2Plus1By2, N.end(), 0.f) *
+      kOneByNumBands;
+
+  // The analysis and synthesis windowing cause loss of power when
+  // cross-fading the noise where frames are completely uncorrelated
+  // (generated with random phase), hence the factor sqrt(2).
+  // This is not the case for the speech signal where the input is overlapping
+  // (strong correlation).
+  N_low->re[0] = N_low->re[kFftLengthBy2] = N_high->re[0] =
+      N_high->re[kFftLengthBy2] = 0.f;
+  for (size_t k = 1; k < kFftLengthBy2; k++) {
+    constexpr int kIndexMask = 32 - 1;
+    // Generate a random 31-bit integer.
+    seed[0] = (seed[0] * 69069 + 1) & (0x80000000 - 1);
+    // Convert to a 5-bit index.
+    int i = seed[0] >> 26;
+
+    // y = sqrt(2) * sin(a)
+    const float x = kSqrt2Sin[i];
+    // x = sqrt(2) * cos(a) = sqrt(2) * sin(a + pi/2)
+    const float y = kSqrt2Sin[(i + 8) & kIndexMask];
+
+    // Form low-frequency noise via spectral shaping.
+    N_low->re[k] = N[k] * x;
+    N_low->im[k] = N[k] * y;
+
+    // Form the high-frequency noise via simple levelling.
+    N_high->re[k] = high_band_noise_level * x;
+    N_high->im[k] = high_band_noise_level * y;
+  }
+}
+
+}  // namespace
+
+ComfortNoiseGenerator::ComfortNoiseGenerator(const EchoCanceller3Config& config,
+                                             Aec3Optimization optimization,
+                                             size_t num_capture_channels)
+    : optimization_(optimization),
+      seed_(42),
+      num_capture_channels_(num_capture_channels),
+      noise_floor_(GetNoiseFloorFactor(config.comfort_noise.noise_floor_dbfs)),
+      N2_initial_(
+          std::make_unique<std::vector<std::array<float, kFftLengthBy2Plus1>>>(
+              num_capture_channels_)),
+      Y2_smoothed_(num_capture_channels_),
+      N2_(num_capture_channels_) {
+  for (size_t ch = 0; ch < num_capture_channels_; ++ch) {
+    (*N2_initial_)[ch].fill(0.f);
+    Y2_smoothed_[ch].fill(0.f);
+    N2_[ch].fill(1.0e6f);
+  }
+}
+
+ComfortNoiseGenerator::~ComfortNoiseGenerator() = default;
+
+void ComfortNoiseGenerator::Compute(
+    bool saturated_capture,
+    rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
+        capture_spectrum,
+    rtc::ArrayView<FftData> lower_band_noise,
+    rtc::ArrayView<FftData> upper_band_noise) {
+  const auto& Y2 = capture_spectrum;
+
+  if (!saturated_capture) {
+    // Smooth Y2.
+    for (size_t ch = 0; ch < num_capture_channels_; ++ch) {
+      std::transform(Y2_smoothed_[ch].begin(), Y2_smoothed_[ch].end(),
+                     Y2[ch].begin(), Y2_smoothed_[ch].begin(),
+                     [](float a, float b) { return a + 0.1f * (b - a); });
+    }
+
+    if (N2_counter_ > 50) {
+      // Update N2 from Y2_smoothed.
+      for (size_t ch = 0; ch < num_capture_channels_; ++ch) {
+        std::transform(N2_[ch].begin(), N2_[ch].end(), Y2_smoothed_[ch].begin(),
+                       N2_[ch].begin(), [](float a, float b) {
+                         return b < a ? (0.9f * b + 0.1f * a) * 1.0002f
+                                      : a * 1.0002f;
+                       });
+      }
+    }
+
+    if (N2_initial_) {
+      if (++N2_counter_ == 1000) {
+        N2_initial_.reset();
+      } else {
+        // Compute the N2_initial from N2.
+        for (size_t ch = 0; ch < num_capture_channels_; ++ch) {
+          std::transform(N2_[ch].begin(), N2_[ch].end(),
+                         (*N2_initial_)[ch].begin(), (*N2_initial_)[ch].begin(),
+                         [](float a, float b) {
+                           return a > b ? b + 0.001f * (a - b) : a;
+                         });
+        }
+      }
+    }
+
+    for (size_t ch = 0; ch < num_capture_channels_; ++ch) {
+      for (auto& n : N2_[ch]) {
+        n = std::max(n, noise_floor_);
+      }
+      if (N2_initial_) {
+        for (auto& n : (*N2_initial_)[ch]) {
+          n = std::max(n, noise_floor_);
+        }
+      }
+    }
+  }
+
+  // Choose N2 estimate to use.
+  const auto& N2 = N2_initial_ ? (*N2_initial_) : N2_;
+
+  for (size_t ch = 0; ch < num_capture_channels_; ++ch) {
+    GenerateComfortNoise(optimization_, N2[ch], &seed_, &lower_band_noise[ch],
+                         &upper_band_noise[ch]);
+  }
+}
+
+}  // namespace webrtc