compute_interpolated_gain_curve.h (1820B)
1 /* 2 * Copyright (c) 2018 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef MODULES_AUDIO_PROCESSING_AGC2_COMPUTE_INTERPOLATED_GAIN_CURVE_H_ 12 #define MODULES_AUDIO_PROCESSING_AGC2_COMPUTE_INTERPOLATED_GAIN_CURVE_H_ 13 14 #include <array> 15 16 #include "modules/audio_processing/agc2/agc2_common.h" 17 18 namespace webrtc { 19 20 namespace test { 21 22 // Parameters for interpolated gain curve using under-approximation to 23 // avoid saturation. 24 // 25 // The saturation gain is defined in order to let hard-clipping occur for 26 // those samples having a level that falls in the saturation region. It is an 27 // upper bound of the actual gain to apply - i.e., that returned by the 28 // limiter. 29 30 // Knee and beyond-knee regions approximation parameters. 31 // The gain curve is approximated as a piece-wise linear function. 32 // `approx_params_x_` are the boundaries between adjacent linear pieces, 33 // `approx_params_m_` and `approx_params_q_` are the slope and the y-intercept 34 // values of each piece. 35 struct InterpolatedParameters { 36 std::array<float, kInterpolatedGainCurveTotalPoints> 37 computed_approximation_params_x; 38 std::array<float, kInterpolatedGainCurveTotalPoints> 39 computed_approximation_params_m; 40 std::array<float, kInterpolatedGainCurveTotalPoints> 41 computed_approximation_params_q; 42 }; 43 44 InterpolatedParameters ComputeInterpolatedGainCurveApproximationParams(); 45 } // namespace test 46 } // namespace webrtc 47 48 #endif // MODULES_AUDIO_PROCESSING_AGC2_COMPUTE_INTERPOLATED_GAIN_CURVE_H_