media/libopus/silk/tuning_parameters.h

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  27
  28 #ifndef SILK_TUNING_PARAMETERS_H
  29 #define SILK_TUNING_PARAMETERS_H
  30
  31 #ifdef __cplusplus
  32 extern "C"
  33 {
  34 #endif
  35
  36 /* Decay time for bitreservoir */
  37 #define BITRESERVOIR_DECAY_TIME_MS                      500
  38
  39 /*******************/
  40 /* Pitch estimator */
  41 /*******************/
  42
  43 /* Level of noise floor for whitening filter LPC analysis in pitch analysis */
  44 #define FIND_PITCH_WHITE_NOISE_FRACTION                 1e-3f
  45
  46 /* Bandwidth expansion for whitening filter in pitch analysis */
  47 #define FIND_PITCH_BANDWIDTH_EXPANSION                  0.99f
  48
  49 /*********************/
  50 /* Linear prediction */
  51 /*********************/
  52
  53 /* LPC analysis regularization */
  54 #define FIND_LPC_COND_FAC                               1e-5f
  55
  56 /* Max cumulative LTP gain */
  57 #define MAX_SUM_LOG_GAIN_DB                             250.0f
  58
  59 /* LTP analysis defines */
  60 #define LTP_CORR_INV_MAX                                0.03f
  61
  62 /***********************/
  63 /* High pass filtering */
  64 /***********************/
  65
  66 /* Smoothing parameters for low end of pitch frequency range estimation */
  67 #define VARIABLE_HP_SMTH_COEF1                          0.1f
  68 #define VARIABLE_HP_SMTH_COEF2                          0.015f
  69 #define VARIABLE_HP_MAX_DELTA_FREQ                      0.4f
  70
  71 /* Min and max cut-off frequency values (-3 dB points) */
  72 #define VARIABLE_HP_MIN_CUTOFF_HZ                       60
  73 #define VARIABLE_HP_MAX_CUTOFF_HZ                       100
  74
  75 /***********/
  76 /* Various */
  77 /***********/
  78
  79 /* VAD threshold */
  80 #define SPEECH_ACTIVITY_DTX_THRES                       0.05f
  81
  82 /* Speech Activity LBRR enable threshold */
  83 #define LBRR_SPEECH_ACTIVITY_THRES                      0.3f
  84
  85 /*************************/
  86 /* Perceptual parameters */
  87 /*************************/
  88
  89 /* reduction in coding SNR during low speech activity */
  90 #define BG_SNR_DECR_dB                                  2.0f
  91
  92 /* factor for reducing quantization noise during voiced speech */
  93 #define HARM_SNR_INCR_dB                                2.0f
  94
  95 /* factor for reducing quantization noise for unvoiced sparse signals */
  96 #define SPARSE_SNR_INCR_dB                              2.0f
  97
  98 /* threshold for sparseness measure above which to use lower quantization offset during unvoiced */
  99 #define ENERGY_VARIATION_THRESHOLD_QNT_OFFSET           0.6f
 100
 101 /* warping control */
 102 #define WARPING_MULTIPLIER                              0.015f
 103
 104 /* fraction added to first autocorrelation value */
 105 #define SHAPE_WHITE_NOISE_FRACTION                      3e-5f
 106
 107 /* noise shaping filter chirp factor */
 108 #define BANDWIDTH_EXPANSION                             0.94f
 109
 110 /* harmonic noise shaping */
 111 #define HARMONIC_SHAPING                                0.3f
 112
 113 /* extra harmonic noise shaping for high bitrates or noisy input */
 114 #define HIGH_RATE_OR_LOW_QUALITY_HARMONIC_SHAPING       0.2f
 115
 116 /* parameter for shaping noise towards higher frequencies */
 117 #define HP_NOISE_COEF                                   0.25f
 118
 119 /* parameter for shaping noise even more towards higher frequencies during voiced speech */
 120 #define HARM_HP_NOISE_COEF                              0.35f
 121
 122 /* parameter for applying a high-pass tilt to the input signal */
 123 #define INPUT_TILT                                      0.05f
 124
 125 /* parameter for extra high-pass tilt to the input signal at high rates */
 126 #define HIGH_RATE_INPUT_TILT                            0.1f
 127
 128 /* parameter for reducing noise at the very low frequencies */
 129 #define LOW_FREQ_SHAPING                                4.0f
 130
 131 /* less reduction of noise at the very low frequencies for signals with low SNR at low frequencies */
 132 #define LOW_QUALITY_LOW_FREQ_SHAPING_DECR               0.5f
 133
 134 /* subframe smoothing coefficient for HarmBoost, HarmShapeGain, Tilt (lower -> more smoothing) */
 135 #define SUBFR_SMTH_COEF                                 0.4f
 136
 137 /* parameters defining the R/D tradeoff in the residual quantizer */
 138 #define LAMBDA_OFFSET                                   1.2f
 139 #define LAMBDA_SPEECH_ACT                               -0.2f
 140 #define LAMBDA_DELAYED_DECISIONS                        -0.05f
 141 #define LAMBDA_INPUT_QUALITY                            -0.1f
 142 #define LAMBDA_CODING_QUALITY                           -0.2f
 143 #define LAMBDA_QUANT_OFFSET                             0.8f
 144
 145 /* Compensation in bitrate calculations for 10 ms modes */
 146 #define REDUCE_BITRATE_10_MS_BPS                        2200
 147
 148 /* Maximum time before allowing a bandwidth transition */
 149 #define MAX_BANDWIDTH_SWITCH_DELAY_MS                   5000
 150
 151 #ifdef __cplusplus
 152 }
 153 #endif
 154
 155 #endif /* SILK_TUNING_PARAMETERS_H */