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/*
* Copyright (c) 2013 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_GAIN_MAP_INTERNAL_H_
#define MODULES_AUDIO_PROCESSING_AGC2_GAIN_MAP_INTERNAL_H_
namespace webrtc {
static constexpr int kGainMapSize = 256;
// Maps input volumes, which are values in the [0, 255] range, to gains in dB.
// The values below are generated with numpy as follows:
// SI = 2 # Initial slope.
// SF = 0.25 # Final slope.
// D = 8/256 # Quantization factor.
// x = np.linspace(0, 255, 256) # Input volumes.
// y = (SF * x + (SI - SF) * (1 - np.exp(-D*x)) / D - 56).round()
static const int kGainMap[kGainMapSize] = {
-56, -54, -52, -50, -48, -47, -45, -43, -42, -40, -38, -37, -35, -34, -33,
-31, -30, -29, -27, -26, -25, -24, -23, -22, -20, -19, -18, -17, -16, -15,
-14, -14, -13, -12, -11, -10, -9, -8, -8, -7, -6, -5, -5, -4, -3,
-2, -2, -1, 0, 0, 1, 1, 2, 3, 3, 4, 4, 5, 5, 6,
6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13,
13, 14, 14, 15, 15, 15, 16, 16, 17, 17, 17, 18, 18, 18, 19,
19, 19, 20, 20, 21, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24,
24, 24, 25, 25, 25, 26, 26, 26, 27, 27, 27, 28, 28, 28, 28,
29, 29, 29, 30, 30, 30, 30, 31, 31, 31, 32, 32, 32, 32, 33,
33, 33, 33, 34, 34, 34, 35, 35, 35, 35, 36, 36, 36, 36, 37,
37, 37, 38, 38, 38, 38, 39, 39, 39, 39, 40, 40, 40, 40, 41,
41, 41, 41, 42, 42, 42, 42, 43, 43, 43, 44, 44, 44, 44, 45,
45, 45, 45, 46, 46, 46, 46, 47, 47, 47, 47, 48, 48, 48, 48,
49, 49, 49, 49, 50, 50, 50, 50, 51, 51, 51, 51, 52, 52, 52,
52, 53, 53, 53, 53, 54, 54, 54, 54, 55, 55, 55, 55, 56, 56,
56, 56, 57, 57, 57, 57, 58, 58, 58, 58, 59, 59, 59, 59, 60,
60, 60, 60, 61, 61, 61, 61, 62, 62, 62, 62, 63, 63, 63, 63,
64};
} // namespace webrtc
#endif // MODULES_AUDIO_PROCESSING_AGC2_GAIN_MAP_INTERNAL_H_
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