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a05ee82c4c
This CL adds the GainCurveApplier (GCA). It owns a FixedDigitalLevelEstimator (LE) and an InterpolatedGainCurve (IGC). The GCA uses the LE to compute the input signal level, looks up a gain from IGC and applies it on the signal. The other IGC and LE submodules were added in previous CLs [1] and [2]. This CL also turns on AGC2 in the APM fuzzer. [1] https://webrtc-review.googlesource.com/c/src/+/51920 [2] https://webrtc-review.googlesource.com/c/src/+/52381 Bug: webrtc:7949 Change-Id: Idb10cc3ca9d6d2e4ac5824cc3391ed8aa680f6cd Reviewed-on: https://webrtc-review.googlesource.com/54361 Commit-Queue: Alex Loiko <aleloi@webrtc.org> Reviewed-by: Sam Zackrisson <saza@webrtc.org> Cr-Commit-Position: refs/heads/master@{#22103}
74 lines
2.8 KiB
C++
74 lines
2.8 KiB
C++
/*
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* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef MODULES_AUDIO_PROCESSING_AGC2_LIMITER_H_
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#define MODULES_AUDIO_PROCESSING_AGC2_LIMITER_H_
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#include <array>
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#include "modules/audio_processing/agc2/agc2_testing_common.h"
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namespace webrtc {
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// A class for computing gain curve parameters. The gain curve is
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// defined by constants kLimiterMaxInputLevelDbFs, kLimiterKneeSmoothnessDb,
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// kLimiterCompressionRatio. The curve consints of one linear part,
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// one quadratic polynomial part and another linear part. The
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// constants define the parameters of the parts.
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class Limiter {
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public:
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Limiter();
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double max_input_level_db() const { return max_input_level_db_; }
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double max_input_level_linear() const { return max_input_level_linear_; }
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double knee_start_linear() const { return knee_start_linear_; }
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double limiter_start_linear() const { return limiter_start_linear_; }
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// These methods can be marked 'constexpr' in C++ 14.
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double GetOutputLevelDbfs(double input_level_dbfs) const;
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double GetGainLinear(double input_level_linear) const;
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double GetGainFirstDerivativeLinear(double x) const;
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double GetGainIntegralLinear(double x0, double x1) const;
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private:
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double GetKneeRegionOutputLevelDbfs(double input_level_dbfs) const;
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double GetCompressorRegionOutputLevelDbfs(double input_level_dbfs) const;
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static constexpr double max_input_level_db_ = test::kLimiterMaxInputLevelDbFs;
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static constexpr double knee_smoothness_db_ = test::kLimiterKneeSmoothnessDb;
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static constexpr double compression_ratio_ = test::kLimiterCompressionRatio;
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const double max_input_level_linear_;
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// Do not modify signal with level <= knee_start_dbfs_.
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const double knee_start_dbfs_;
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const double knee_start_linear_;
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// The upper end of the knee region, which is between knee_start_dbfs_ and
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// limiter_start_dbfs_.
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const double limiter_start_dbfs_;
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const double limiter_start_linear_;
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// Coefficients {a, b, c} of the knee region polynomial
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// ax^2 + bx + c in the DB scale.
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const std::array<double, 3> knee_region_polynomial_;
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// Parameters for the computation of the first derivative of GetGainLinear().
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const double gain_curve_limiter_d1_;
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const double gain_curve_limiter_d2_;
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// Parameters for the computation of the integral of GetGainLinear().
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const double gain_curve_limiter_i1_;
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const double gain_curve_limiter_i2_;
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};
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} // namespace webrtc
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#endif // MODULES_AUDIO_PROCESSING_AGC2_LIMITER_H_
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