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      1 /*
      2  *  Copyright (c) 2011 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 WEBRTC_MODULES_AUDIO_PROCESSING_AGC_MAIN_SOURCE_ANALOG_AGC_H_
     12 #define WEBRTC_MODULES_AUDIO_PROCESSING_AGC_MAIN_SOURCE_ANALOG_AGC_H_
     13 
     14 #include "webrtc/modules/audio_processing/agc/digital_agc.h"
     15 #include "webrtc/modules/audio_processing/agc/include/gain_control.h"
     16 #include "webrtc/typedefs.h"
     17 
     18 //#define MIC_LEVEL_FEEDBACK
     19 #ifdef WEBRTC_AGC_DEBUG_DUMP
     20 #include <stdio.h>
     21 #endif
     22 
     23 /* Analog Automatic Gain Control variables:
     24  * Constant declarations (inner limits inside which no changes are done)
     25  * In the beginning the range is narrower to widen as soon as the measure
     26  * 'Rxx160_LP' is inside it. Currently the starting limits are -22.2+/-1dBm0
     27  * and the final limits -22.2+/-2.5dBm0. These levels makes the speech signal
     28  * go towards -25.4dBm0 (-31.4dBov). Tuned with wbfile-31.4dBov.pcm
     29  * The limits are created by running the AGC with a file having the desired
     30  * signal level and thereafter plotting Rxx160_LP in the dBm0-domain defined
     31  * by out=10*log10(in/260537279.7); Set the target level to the average level
     32  * of our measure Rxx160_LP. Remember that the levels are in blocks of 16 in
     33  * Q(-7). (Example matlab code: round(db2pow(-21.2)*16/2^7) )
     34  */
     35 #define RXX_BUFFER_LEN  10
     36 
     37 static const int16_t kMsecSpeechInner = 520;
     38 static const int16_t kMsecSpeechOuter = 340;
     39 
     40 static const int16_t kNormalVadThreshold = 400;
     41 
     42 static const int16_t kAlphaShortTerm = 6; // 1 >> 6 = 0.0156
     43 static const int16_t kAlphaLongTerm = 10; // 1 >> 10 = 0.000977
     44 
     45 typedef struct
     46 {
     47     // Configurable parameters/variables
     48     uint32_t            fs;                 // Sampling frequency
     49     int16_t             compressionGaindB;  // Fixed gain level in dB
     50     int16_t             targetLevelDbfs;    // Target level in -dBfs of envelope (default -3)
     51     int16_t             agcMode;            // Hard coded mode (adaptAna/adaptDig/fixedDig)
     52     uint8_t             limiterEnable;      // Enabling limiter (on/off (default off))
     53     WebRtcAgc_config_t  defaultConfig;
     54     WebRtcAgc_config_t  usedConfig;
     55 
     56     // General variables
     57     int16_t             initFlag;
     58     int16_t             lastError;
     59 
     60     // Target level parameters
     61     // Based on the above: analogTargetLevel = round((32767*10^(-22/20))^2*16/2^7)
     62     int32_t             analogTargetLevel;  // = RXX_BUFFER_LEN * 846805;       -22 dBfs
     63     int32_t             startUpperLimit;    // = RXX_BUFFER_LEN * 1066064;      -21 dBfs
     64     int32_t             startLowerLimit;    // = RXX_BUFFER_LEN * 672641;       -23 dBfs
     65     int32_t             upperPrimaryLimit;  // = RXX_BUFFER_LEN * 1342095;      -20 dBfs
     66     int32_t             lowerPrimaryLimit;  // = RXX_BUFFER_LEN * 534298;       -24 dBfs
     67     int32_t             upperSecondaryLimit;// = RXX_BUFFER_LEN * 2677832;      -17 dBfs
     68     int32_t             lowerSecondaryLimit;// = RXX_BUFFER_LEN * 267783;       -27 dBfs
     69     uint16_t            targetIdx;          // Table index for corresponding target level
     70 #ifdef MIC_LEVEL_FEEDBACK
     71     uint16_t            targetIdxOffset;    // Table index offset for level compensation
     72 #endif
     73     int16_t             analogTarget;       // Digital reference level in ENV scale
     74 
     75     // Analog AGC specific variables
     76     int32_t             filterState[8];     // For downsampling wb to nb
     77     int32_t             upperLimit;         // Upper limit for mic energy
     78     int32_t             lowerLimit;         // Lower limit for mic energy
     79     int32_t             Rxx160w32;          // Average energy for one frame
     80     int32_t             Rxx16_LPw32;        // Low pass filtered subframe energies
     81     int32_t             Rxx160_LPw32;       // Low pass filtered frame energies
     82     int32_t             Rxx16_LPw32Max;     // Keeps track of largest energy subframe
     83     int32_t             Rxx16_vectorw32[RXX_BUFFER_LEN];// Array with subframe energies
     84     int32_t             Rxx16w32_array[2][5];// Energy values of microphone signal
     85     int32_t             env[2][10];         // Envelope values of subframes
     86 
     87     int16_t             Rxx16pos;           // Current position in the Rxx16_vectorw32
     88     int16_t             envSum;             // Filtered scaled envelope in subframes
     89     int16_t             vadThreshold;       // Threshold for VAD decision
     90     int16_t             inActive;           // Inactive time in milliseconds
     91     int16_t             msTooLow;           // Milliseconds of speech at a too low level
     92     int16_t             msTooHigh;          // Milliseconds of speech at a too high level
     93     int16_t             changeToSlowMode;   // Change to slow mode after some time at target
     94     int16_t             firstCall;          // First call to the process-function
     95     int16_t             msZero;             // Milliseconds of zero input
     96     int16_t             msecSpeechOuterChange;// Min ms of speech between volume changes
     97     int16_t             msecSpeechInnerChange;// Min ms of speech between volume changes
     98     int16_t             activeSpeech;       // Milliseconds of active speech
     99     int16_t             muteGuardMs;        // Counter to prevent mute action
    100     int16_t             inQueue;            // 10 ms batch indicator
    101 
    102     // Microphone level variables
    103     int32_t             micRef;             // Remember ref. mic level for virtual mic
    104     uint16_t            gainTableIdx;       // Current position in virtual gain table
    105     int32_t             micGainIdx;         // Gain index of mic level to increase slowly
    106     int32_t             micVol;             // Remember volume between frames
    107     int32_t             maxLevel;           // Max possible vol level, incl dig gain
    108     int32_t             maxAnalog;          // Maximum possible analog volume level
    109     int32_t             maxInit;            // Initial value of "max"
    110     int32_t             minLevel;           // Minimum possible volume level
    111     int32_t             minOutput;          // Minimum output volume level
    112     int32_t             zeroCtrlMax;        // Remember max gain => don't amp low input
    113     int32_t             lastInMicLevel;
    114 
    115     int16_t             scale;              // Scale factor for internal volume levels
    116 #ifdef MIC_LEVEL_FEEDBACK
    117     int16_t             numBlocksMicLvlSat;
    118     uint8_t             micLvlSat;
    119 #endif
    120     // Structs for VAD and digital_agc
    121     AgcVad_t            vadMic;
    122     DigitalAgc_t        digitalAgc;
    123 
    124 #ifdef WEBRTC_AGC_DEBUG_DUMP
    125     FILE* fpt;
    126     FILE* agcLog;
    127     int32_t fcount;
    128 #endif
    129 
    130     int16_t             lowLevelSignal;
    131 } Agc_t;
    132 
    133 #endif // WEBRTC_MODULES_AUDIO_PROCESSING_AGC_MAIN_SOURCE_ANALOG_AGC_H_
    134