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Diffstat (limited to 'third_party/libwebrtc/modules/audio_processing/agc2/interpolated_gain_curve.h')
| -rw-r--r-- | third_party/libwebrtc/modules/audio_processing/agc2/interpolated_gain_curve.h | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/agc2/interpolated_gain_curve.h b/third_party/libwebrtc/modules/audio_processing/agc2/interpolated_gain_curve.h new file mode 100644 index 0000000000..8dd3e48f21 --- /dev/null +++ b/third_party/libwebrtc/modules/audio_processing/agc2/interpolated_gain_curve.h @@ -0,0 +1,152 @@ +/* + * Copyright (c) 2018 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. + */ + +#ifndef MODULES_AUDIO_PROCESSING_AGC2_INTERPOLATED_GAIN_CURVE_H_ +#define MODULES_AUDIO_PROCESSING_AGC2_INTERPOLATED_GAIN_CURVE_H_ + +#include <array> + +#include "absl/strings/string_view.h" +#include "modules/audio_processing/agc2/agc2_common.h" +#include "rtc_base/gtest_prod_util.h" +#include "system_wrappers/include/metrics.h" + +namespace webrtc { + +class ApmDataDumper; + +constexpr float kInputLevelScalingFactor = 32768.0f; + +// Defined as DbfsToLinear(kLimiterMaxInputLevelDbFs) +constexpr float kMaxInputLevelLinear = static_cast<float>(36766.300710566735); + +// Interpolated gain curve using under-approximation to avoid saturation. +// +// The goal of this class is allowing fast look ups to get an accurate +// estimates of the gain to apply given an estimated input level. +class InterpolatedGainCurve { + public: + enum class GainCurveRegion { + kIdentity = 0, + kKnee = 1, + kLimiter = 2, + kSaturation = 3 + }; + + struct Stats { + // Region in which the output level equals the input one. + size_t look_ups_identity_region = 0; + // Smoothing between the identity and the limiter regions. + size_t look_ups_knee_region = 0; + // Limiter region in which the output and input levels are linearly related. + size_t look_ups_limiter_region = 0; + // Region in which saturation may occur since the input level is beyond the + // maximum expected by the limiter. + size_t look_ups_saturation_region = 0; + // True if stats have been populated. + bool available = false; + + // The current region, and for how many frames the level has been + // in that region. + GainCurveRegion region = GainCurveRegion::kIdentity; + int64_t region_duration_frames = 0; + }; + + InterpolatedGainCurve(ApmDataDumper* apm_data_dumper, + absl::string_view histogram_name_prefix); + ~InterpolatedGainCurve(); + + InterpolatedGainCurve(const InterpolatedGainCurve&) = delete; + InterpolatedGainCurve& operator=(const InterpolatedGainCurve&) = delete; + + Stats get_stats() const { return stats_; } + + // Given a non-negative input level (linear scale), a scalar factor to apply + // to a sub-frame is returned. + // Levels above kLimiterMaxInputLevelDbFs will be reduced to 0 dBFS + // after applying this gain + float LookUpGainToApply(float input_level) const; + + private: + // For comparing 'approximation_params_*_' with ones computed by + // ComputeInterpolatedGainCurve. + FRIEND_TEST_ALL_PREFIXES(GainController2InterpolatedGainCurve, + CheckApproximationParams); + + struct RegionLogger { + metrics::Histogram* identity_histogram; + metrics::Histogram* knee_histogram; + metrics::Histogram* limiter_histogram; + metrics::Histogram* saturation_histogram; + + RegionLogger(absl::string_view identity_histogram_name, + absl::string_view knee_histogram_name, + absl::string_view limiter_histogram_name, + absl::string_view saturation_histogram_name); + + ~RegionLogger(); + + void LogRegionStats(const InterpolatedGainCurve::Stats& stats) const; + } region_logger_; + + void UpdateStats(float input_level) const; + + ApmDataDumper* const apm_data_dumper_; + + static constexpr std::array<float, kInterpolatedGainCurveTotalPoints> + approximation_params_x_ = { + {30057.296875, 30148.986328125, 30240.67578125, 30424.052734375, + 30607.4296875, 30790.806640625, 30974.18359375, 31157.560546875, + 31340.939453125, 31524.31640625, 31707.693359375, 31891.0703125, + 32074.447265625, 32257.82421875, 32441.201171875, 32624.580078125, + 32807.95703125, 32991.33203125, 33174.7109375, 33358.08984375, + 33541.46484375, 33724.84375, 33819.53515625, 34009.5390625, + 34200.05859375, 34389.81640625, 34674.48828125, 35054.375, + 35434.86328125, 35814.81640625, 36195.16796875, 36575.03125}}; + static constexpr std::array<float, kInterpolatedGainCurveTotalPoints> + approximation_params_m_ = { + {-3.515235675877192989e-07, -1.050251626111275982e-06, + -2.085213736791047268e-06, -3.443004743530764244e-06, + -4.773849468620028347e-06, -6.077375928725814447e-06, + -7.353257842623861507e-06, -8.601219633419532329e-06, + -9.821013009059242904e-06, -1.101243378798244521e-05, + -1.217532644659513608e-05, -1.330956911260727793e-05, + -1.441507538402220234e-05, -1.549179251014720649e-05, + -1.653970684856176376e-05, -1.755882840370759368e-05, + -1.854918446042574942e-05, -1.951086778717581183e-05, + -2.044398024736437947e-05, -2.1348627342376858e-05, + -2.222496914328075945e-05, -2.265374678245279938e-05, + -2.242570917587727308e-05, -2.220122041762806475e-05, + -2.19802095671184361e-05, -2.176260204578284174e-05, + -2.133731686626560986e-05, -2.092481918225530535e-05, + -2.052459603874012828e-05, -2.013615448959171772e-05, + -1.975903069251216948e-05, -1.939277899509761482e-05}}; + + static constexpr std::array<float, kInterpolatedGainCurveTotalPoints> + approximation_params_q_ = { + {1.010565876960754395, 1.031631827354431152, 1.062929749488830566, + 1.104239225387573242, 1.144973039627075195, 1.185109615325927734, + 1.224629044532775879, 1.263512492179870605, 1.301741957664489746, + 1.339300632476806641, 1.376173257827758789, 1.412345528602600098, + 1.447803974151611328, 1.482536554336547852, 1.516532182693481445, + 1.549780607223510742, 1.582272171974182129, 1.613999366760253906, + 1.644955039024353027, 1.675132393836975098, 1.704526185989379883, + 1.718986630439758301, 1.711274504661560059, 1.703639745712280273, + 1.696081161499023438, 1.688597679138183594, 1.673851132392883301, + 1.659391283988952637, 1.645209431648254395, 1.631297469139099121, + 1.617647409439086914, 1.604251742362976074}}; + + // Stats. + mutable Stats stats_; +}; + +} // namespace webrtc + +#endif // MODULES_AUDIO_PROCESSING_AGC2_INTERPOLATED_GAIN_CURVE_H_ |