freeswitch/libs/silk/src/SKP_Silk_process_gains_FIX.c

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#include "SKP_Silk_main_FIX.h"
#include "SKP_Silk_tuning_parameters.h"

/* Processing of gains */
void SKP_Silk_process_gains_FIX(
    SKP_Silk_encoder_state_FIX      *psEnc,         /* I/O  Encoder state_FIX                           */
    SKP_Silk_encoder_control_FIX    *psEncCtrl      /* I/O  Encoder control_FIX                         */
)
{
    SKP_Silk_shape_state_FIX    *psShapeSt = &psEnc->sShape;
    SKP_int     k;
    SKP_int32   s_Q16, InvMaxSqrVal_Q16, gain, gain_squared, ResNrg, ResNrgPart, quant_offset_Q10;

    /* Gain reduction when LTP coding gain is high */
    if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
        /*s = -0.5f * SKP_sigmoid( 0.25f * ( psEncCtrl->LTPredCodGain - 12.0f ) ); */
        s_Q16 = -SKP_Silk_sigm_Q15( SKP_RSHIFT_ROUND( psEncCtrl->LTPredCodGain_Q7 - SKP_FIX_CONST( 12.0, 7 ), 4 ) );
        for( k = 0; k < NB_SUBFR; k++ ) {
            psEncCtrl->Gains_Q16[ k ] = SKP_SMLAWB( psEncCtrl->Gains_Q16[ k ], psEncCtrl->Gains_Q16[ k ], s_Q16 );
        }
    }

    /* Limit the quantized signal */
    InvMaxSqrVal_Q16 = SKP_DIV32_16( SKP_Silk_log2lin( 
        SKP_SMULWB( SKP_FIX_CONST( 70.0, 7 ) - psEncCtrl->current_SNR_dB_Q7, SKP_FIX_CONST( 0.33, 16 ) ) ), psEnc->sCmn.subfr_length );

    for( k = 0; k < NB_SUBFR; k++ ) {
        /* Soft limit on ratio residual energy and squared gains */
        ResNrg     = psEncCtrl->ResNrg[ k ];
        ResNrgPart = SKP_SMULWW( ResNrg, InvMaxSqrVal_Q16 );
        if( psEncCtrl->ResNrgQ[ k ] > 0 ) {
            if( psEncCtrl->ResNrgQ[ k ] < 32 ) {
                ResNrgPart = SKP_RSHIFT_ROUND( ResNrgPart, psEncCtrl->ResNrgQ[ k ] );
            } else {
                ResNrgPart = 0;
            }
        } else if( psEncCtrl->ResNrgQ[k] != 0 ) {
            if( ResNrgPart > SKP_RSHIFT( SKP_int32_MAX, -psEncCtrl->ResNrgQ[ k ] ) ) {
                ResNrgPart = SKP_int32_MAX;
            } else {
                ResNrgPart = SKP_LSHIFT( ResNrgPart, -psEncCtrl->ResNrgQ[ k ] );
            }
        }
        gain = psEncCtrl->Gains_Q16[ k ];
        gain_squared = SKP_ADD_SAT32( ResNrgPart, SKP_SMMUL( gain, gain ) );
        if( gain_squared < SKP_int16_MAX ) {
            /* recalculate with higher precision */
            gain_squared = SKP_SMLAWW( SKP_LSHIFT( ResNrgPart, 16 ), gain, gain );
            SKP_assert( gain_squared > 0 );
            gain = SKP_Silk_SQRT_APPROX( gain_squared );                  /* Q8   */
            psEncCtrl->Gains_Q16[ k ] = SKP_LSHIFT_SAT32( gain, 8 );        /* Q16  */
        } else {
            gain = SKP_Silk_SQRT_APPROX( gain_squared );                  /* Q0   */
            psEncCtrl->Gains_Q16[ k ] = SKP_LSHIFT_SAT32( gain, 16 );       /* Q16  */
        }
    }

    /* Noise shaping quantization */
    SKP_Silk_gains_quant( psEncCtrl->sCmn.GainsIndices, psEncCtrl->Gains_Q16, 
        &psShapeSt->LastGainIndex, psEnc->sCmn.nFramesInPayloadBuf );
    /* Set quantizer offset for voiced signals. Larger offset when LTP coding gain is low or tilt is high (ie low-pass) */
    if( psEncCtrl->sCmn.sigtype == SIG_TYPE_VOICED ) {
        if( psEncCtrl->LTPredCodGain_Q7 + SKP_RSHIFT( psEncCtrl->input_tilt_Q15, 8 ) > SKP_FIX_CONST( 1.0, 7 ) ) {
            psEncCtrl->sCmn.QuantOffsetType = 0;
        } else {
            psEncCtrl->sCmn.QuantOffsetType = 1;
        }
    }

    /* Quantizer boundary adjustment */
    quant_offset_Q10 = SKP_Silk_Quantization_Offsets_Q10[ psEncCtrl->sCmn.sigtype ][ psEncCtrl->sCmn.QuantOffsetType ];
    psEncCtrl->Lambda_Q10 = SKP_FIX_CONST( LAMBDA_OFFSET, 10 )
                          + SKP_SMULBB( SKP_FIX_CONST( LAMBDA_DELAYED_DECISIONS, 10 ), psEnc->sCmn.nStatesDelayedDecision )
                          + SKP_SMULWB( SKP_FIX_CONST( LAMBDA_SPEECH_ACT,        18 ), psEnc->speech_activity_Q8          )
                          + SKP_SMULWB( SKP_FIX_CONST( LAMBDA_INPUT_QUALITY,     12 ), psEncCtrl->input_quality_Q14       )
                          + SKP_SMULWB( SKP_FIX_CONST( LAMBDA_CODING_QUALITY,    12 ), psEncCtrl->coding_quality_Q14      )
                          + SKP_SMULWB( SKP_FIX_CONST( LAMBDA_QUANT_OFFSET,      16 ), quant_offset_Q10                   );

    SKP_assert( psEncCtrl->Lambda_Q10 > 0 );
    SKP_assert( psEncCtrl->Lambda_Q10 < SKP_FIX_CONST( 2, 10 ) );
}