/* High-pass filter with cutoff frequency adaptation based on pitch lag statistics */
void SKP_Silk_HP_variable_cutoff_FIX(
SKP_Silk_encoder_state_FIX *psEnc, /* I/O Encoder state FIX */
SKP_Silk_encoder_control_FIX *psEncCtrl, /* I/O Encoder control FIX */
SKP_int16 *out, /* O high-pass filtered output signal */
const SKP_int16 *in /* I input signal */
)
{
SKP_int quality_Q15;
SKP_int32 B_Q28[ 3 ], A_Q28[ 2 ];
SKP_int32 Fc_Q19, r_Q28, r_Q22;
SKP_int32 pitch_freq_Hz_Q16, pitch_freq_log_Q7, delta_freq_Q7;
/*********************************************/
/* Estimate Low End of Pitch Frequency Range */
/*********************************************/
if( psEnc->sCmn.prev_sigtype == SIG_TYPE_VOICED ) {
/* difference, in log domain */
pitch_freq_Hz_Q16 = SKP_DIV32_16( SKP_LSHIFT( SKP_MUL( psEnc->sCmn.fs_kHz, 1000 ), 16 ), psEnc->sCmn.prevLag );
pitch_freq_log_Q7 = SKP_Silk_lin2log( pitch_freq_Hz_Q16 ) - ( 16 << 7 ); //0x70
/* adjustment based on quality */
quality_Q15 = psEncCtrl->input_quality_bands_Q15[ 0 ];
pitch_freq_log_Q7 = SKP_SUB32( pitch_freq_log_Q7, SKP_SMULWB( SKP_SMULWB( SKP_LSHIFT( quality_Q15, 2 ), quality_Q15 ),
pitch_freq_log_Q7 - SKP_LOG2_VARIABLE_HP_MIN_FREQ_Q7 ) );
pitch_freq_log_Q7 = SKP_ADD32( pitch_freq_log_Q7, SKP_RSHIFT( SKP_FIX_CONST( 0.6, 15 ) - quality_Q15, 9 ) );
//delta_freq = pitch_freq_log - psEnc->variable_HP_smth1;
delta_freq_Q7 = pitch_freq_log_Q7 - SKP_RSHIFT( psEnc->variable_HP_smth1_Q15, 8 );
if( delta_freq_Q7 < 0 ) {
/* less smoothing for decreasing pitch frequency, to track something close to the minimum */
delta_freq_Q7 = SKP_MUL( delta_freq_Q7, 3 );
}
/* limit delta, to reduce impact of outliers */
delta_freq_Q7 = SKP_LIMIT_32( delta_freq_Q7, -SKP_FIX_CONST( VARIABLE_HP_MAX_DELTA_FREQ, 7 ), SKP_FIX_CONST( VARIABLE_HP_MAX_DELTA_FREQ, 7 ) );
/* update smoother */
psEnc->variable_HP_smth1_Q15 = SKP_SMLAWB( psEnc->variable_HP_smth1_Q15,
SKP_MUL( SKP_LSHIFT( psEnc->speech_activity_Q8, 1 ), delta_freq_Q7 ), SKP_FIX_CONST( VARIABLE_HP_SMTH_COEF1, 16 ) );
}
/* second smoother */
psEnc->variable_HP_smth2_Q15 = SKP_SMLAWB( psEnc->variable_HP_smth2_Q15,
psEnc->variable_HP_smth1_Q15 - psEnc->variable_HP_smth2_Q15, SKP_FIX_CONST( VARIABLE_HP_SMTH_COEF2, 16 ) );
/* convert from log scale to Hertz */
psEncCtrl->pitch_freq_low_Hz = SKP_Silk_log2lin( SKP_RSHIFT( psEnc->variable_HP_smth2_Q15, 8 ) );
/* limit frequency range */
psEncCtrl->pitch_freq_low_Hz = SKP_LIMIT_32( psEncCtrl->pitch_freq_low_Hz,
SKP_FIX_CONST( VARIABLE_HP_MIN_FREQ, 0 ), SKP_FIX_CONST( VARIABLE_HP_MAX_FREQ, 0 ) );
/********************************/
/* Compute Filter Coefficients */
/********************************/
/* compute cut-off frequency, in radians */
//Fc_num = (SKP_float)( 0.45f * 2.0f * 3.14159265359 * psEncCtrl->pitch_freq_low_Hz );
//Fc_denom = (SKP_float)( 1e3f * psEnc->sCmn.fs_kHz );
SKP_assert( psEncCtrl->pitch_freq_low_Hz <= SKP_int32_MAX / SKP_RADIANS_CONSTANT_Q19 );
Fc_Q19 = SKP_DIV32_16( SKP_SMULBB( SKP_RADIANS_CONSTANT_Q19, psEncCtrl->pitch_freq_low_Hz ), psEnc->sCmn.fs_kHz ); // range: 3704 - 27787, 11-15 bits
SKP_assert( Fc_Q19 >= 3704 );
SKP_assert( Fc_Q19 <= 27787 );
r_Q28 = SKP_FIX_CONST( 1.0, 28 ) - SKP_MUL( SKP_FIX_CONST( 0.92, 9 ), Fc_Q19 );
SKP_assert( r_Q28 >= 255347779 );
SKP_assert( r_Q28 <= 266690872 );
/* b = r * [ 1; -2; 1 ]; */
/* a = [ 1; -2 * r * ( 1 - 0.5 * Fc^2 ); r^2 ]; */
B_Q28[ 0 ] = r_Q28;
B_Q28[ 1 ] = SKP_LSHIFT( -r_Q28, 1 );
B_Q28[ 2 ] = r_Q28;
// -r * ( 2 - Fc * Fc );
r_Q22 = SKP_RSHIFT( r_Q28, 6 );
A_Q28[ 0 ] = SKP_SMULWW( r_Q22, SKP_SMULWW( Fc_Q19, Fc_Q19 ) - SKP_FIX_CONST( 2.0, 22 ) );
A_Q28[ 1 ] = SKP_SMULWW( r_Q22, r_Q22 );
/********************************/
/* High-Pass Filter */
/********************************/
SKP_Silk_biquad_alt( in, B_Q28, A_Q28, psEnc->sCmn.In_HP_State, out, psEnc->sCmn.frame_length );
}
SKP_int SKP_Silk_decode_frame(
SKP_Silk_decoder_state *psDec, /* I/O Pointer to Silk decoder state */
ec_dec *psRangeDec, /* I/O Compressor data structure */
SKP_int16 pOut[], /* O Pointer to output speech frame */
SKP_int32 *pN, /* O Pointer to size of output frame */
const SKP_int nBytes, /* I Payload length */
SKP_int lostFlag /* I 0: no loss, 1 loss, 2 decode fec */
)
{
SKP_Silk_decoder_control sDecCtrl;
SKP_int i, L, mv_len, ret = 0;
SKP_int8 flags;
SKP_int32 LBRR_symbol;
SKP_int pulses[ MAX_FRAME_LENGTH ];
TIC(DECODE_FRAME)
L = psDec->frame_length;
sDecCtrl.LTP_scale_Q14 = 0;
/* Safety checks */
SKP_assert( L > 0 && L <= MAX_FRAME_LENGTH );
/********************************************/
/* Decode Frame if packet is not lost */
/********************************************/
if( lostFlag != PACKET_LOST && psDec->nFramesDecoded == 0 ) {
/* First decoder call for this payload */
/* Decode VAD flags and LBRR flag */
flags = SKP_RSHIFT( psRangeDec->buf[ 0 ], 7 - psDec->nFramesPerPacket ) &
( SKP_LSHIFT( 1, psDec->nFramesPerPacket + 1 ) - 1 );
psDec->LBRR_flag = flags & 1;
for( i = psDec->nFramesPerPacket - 1; i >= 0 ; i-- ) {
flags = SKP_RSHIFT( flags, 1 );
psDec->VAD_flags[ i ] = flags & 1;
}
for( i = 0; i < psDec->nFramesPerPacket + 1; i++ ) {
ec_dec_icdf( psRangeDec, SKP_Silk_uniform2_iCDF, 8 );
}
/* Decode LBRR flags */
SKP_memset( psDec->LBRR_flags, 0, sizeof( psDec->LBRR_flags ) );
if( psDec->LBRR_flag ) {
if( psDec->nFramesPerPacket == 1 ) {
psDec->LBRR_flags[ 0 ] = 1;
} else {
LBRR_symbol = ec_dec_icdf( psRangeDec, SKP_Silk_LBRR_flags_iCDF_ptr[ psDec->nFramesPerPacket - 2 ], 8 ) + 1;
for( i = 0; i < psDec->nFramesPerPacket; i++ ) {
psDec->LBRR_flags[ i ] = SKP_RSHIFT( LBRR_symbol, i ) & 1;
}
}
}
if( lostFlag == DECODE_NORMAL ) {
/* Regular decoding: skip all LBRR data */
for( i = 0; i < psDec->nFramesPerPacket; i++ ) {
if( psDec->LBRR_flags[ i ] ) {
SKP_Silk_decode_indices( psDec, psRangeDec, i, 1 );
SKP_Silk_decode_pulses( psRangeDec, pulses, psDec->indices.signalType,
psDec->indices.quantOffsetType, psDec->frame_length );
}
}
}
}
if( lostFlag == DECODE_LBRR && psDec->LBRR_flags[ psDec->nFramesDecoded ] == 0 ) {
/* Treat absent LBRR data as lost frame */
lostFlag = PACKET_LOST;
psDec->nFramesDecoded++;
}
if( lostFlag != PACKET_LOST ) {
/*********************************************/
/* Decode quantization indices of side info */
/*********************************************/
TIC(decode_indices)
SKP_Silk_decode_indices( psDec, psRangeDec, psDec->nFramesDecoded, lostFlag );
TOC(decode_indices)
/*********************************************/
/* Decode quantization indices of excitation */
/*********************************************/
TIC(decode_pulses)
SKP_Silk_decode_pulses( psRangeDec, pulses, psDec->indices.signalType,
psDec->indices.quantOffsetType, psDec->frame_length );
TOC(decode_pulses)
/********************************************/
/* Decode parameters and pulse signal */
/********************************************/
TIC(decode_params)
SKP_Silk_decode_parameters( psDec, &sDecCtrl );
TOC(decode_params)
/* Update length. Sampling frequency may have changed */
L = psDec->frame_length;
/********************************************************/
/* Run inverse NSQ */
/********************************************************/
TIC(decode_core)
SKP_Silk_decode_core( psDec, &sDecCtrl, pOut, pulses );
TOC(decode_core)
/********************************************************/
/* Update PLC state */
/********************************************************/
SKP_Silk_PLC( psDec, &sDecCtrl, pOut, L, 0 );
psDec->lossCnt = 0;
psDec->prevSignalType = psDec->indices.signalType;
SKP_assert( psDec->prevSignalType >= 0 && psDec->prevSignalType <= 2 );
/* A frame has been decoded without errors */
psDec->first_frame_after_reset = 0;
psDec->nFramesDecoded++;
} else {
/* Handle packet loss by extrapolation */
SKP_Silk_PLC( psDec, &sDecCtrl, pOut, L, 1 );
}
/*************************/
/* Update output buffer. */
/*************************/
SKP_assert( psDec->ltp_mem_length >= psDec->frame_length );
mv_len = psDec->ltp_mem_length - psDec->frame_length;
SKP_memmove( psDec->outBuf, &psDec->outBuf[ psDec->frame_length ], mv_len * sizeof(SKP_int16) );
SKP_memcpy( &psDec->outBuf[ mv_len ], pOut, psDec->frame_length * sizeof( SKP_int16 ) );
/****************************************************************/
/* Ensure smooth connection of extrapolated and good frames */
/****************************************************************/
SKP_Silk_PLC_glue_frames( psDec, &sDecCtrl, pOut, L );
/************************************************/
/* Comfort noise generation / estimation */
/************************************************/
SKP_Silk_CNG( psDec, &sDecCtrl, pOut, L );
/********************************************/
/* HP filter output */
/********************************************/
TIC(HP_out)
SKP_Silk_biquad_alt( pOut, psDec->HP_B, psDec->HP_A, psDec->HPState, pOut, L );
TOC(HP_out)
/* Update some decoder state variables */
psDec->lagPrev = sDecCtrl.pitchL[ psDec->nb_subfr - 1 ];
/********************************************/
/* set output frame length */
/********************************************/
*pN = ( SKP_int16 )L;
TOC(DECODE_FRAME)
return ret;
}
/* High-pass filter with cutoff frequency adaptation based on pitch lag statistics */
void SKP_Silk_HP_variable_cutoff_FLP(
SKP_Silk_encoder_state_FLP *psEnc, /* I/O Encoder state FLP */
SKP_Silk_encoder_control_FLP *psEncCtrl, /* I/O Encoder control FLP */
SKP_int16 *out, /* O High-pass filtered output signal */
const SKP_int16 *in /* I Input signal */
)
{
SKP_float pitch_freq_Hz, pitch_freq_log, quality, delta_freq, smth_coef, Fc, r;
SKP_int32 B_Q28[ 3 ], A_Q28[ 2 ];
/*********************************************/
/* Estimate low end of pitch frequency range */
/*********************************************/
if( psEnc->sCmn.prev_sigtype == SIG_TYPE_VOICED ) {
/* Difference, in log domain */
pitch_freq_Hz = 1e3f * psEnc->sCmn.fs_kHz / psEnc->sCmn.prevLag;
pitch_freq_log = SKP_Silk_log2( pitch_freq_Hz );
/* Adjustment based on quality */
quality = psEncCtrl->input_quality_bands[ 0 ];
pitch_freq_log -= quality * quality * ( pitch_freq_log - SKP_Silk_log2( VARIABLE_HP_MIN_FREQ ) );
pitch_freq_log += 0.5f * ( 0.6f - quality );
delta_freq = pitch_freq_log - psEnc->variable_HP_smth1;
if( delta_freq < 0.0 ) {
/* Less smoothing for decreasing pitch frequency, to track something close to the minimum */
delta_freq *= 3.0f;
}
/* Limit delta, to reduce impact of outliers */
delta_freq = SKP_LIMIT_float( delta_freq, -VARIABLE_HP_MAX_DELTA_FREQ, VARIABLE_HP_MAX_DELTA_FREQ );
/* Update smoother */
smth_coef = VARIABLE_HP_SMTH_COEF1 * psEnc->speech_activity;
psEnc->variable_HP_smth1 += smth_coef * delta_freq;
}
/* Second smoother */
psEnc->variable_HP_smth2 += VARIABLE_HP_SMTH_COEF2 * ( psEnc->variable_HP_smth1 - psEnc->variable_HP_smth2 );
/* Convert from log scale to Hertz */
psEncCtrl->pitch_freq_low_Hz = ( SKP_float )pow( 2.0f, psEnc->variable_HP_smth2 );
/* Limit frequency range */
psEncCtrl->pitch_freq_low_Hz = SKP_LIMIT_float( psEncCtrl->pitch_freq_low_Hz, VARIABLE_HP_MIN_FREQ, VARIABLE_HP_MAX_FREQ );
/*******************************/
/* Compute filter coefficients */
/*******************************/
/* Compute cut-off frequency, in radians */
Fc = ( SKP_float )( 0.45f * 2.0f * 3.14159265359 * psEncCtrl->pitch_freq_low_Hz / ( 1e3f * psEnc->sCmn.fs_kHz ) );
/* 2nd order ARMA coefficients */
r = 1.0f - 0.92f * Fc;
/* b = r * [1; -2; 1]; */
/* a = [1; -2 * r * (1 - 0.5 * Fc^2); r^2]; */
B_Q28[ 0 ] = SKP_float2int( ( 1 << 28 ) * r );
B_Q28[ 1 ] = SKP_float2int( ( 1 << 28 ) * -2.0f * r );
B_Q28[ 2 ] = B_Q28[ 0 ];
A_Q28[ 0 ] = SKP_float2int( ( 1 << 28 ) * -2.0f * r * ( 1.0f - 0.5f * Fc * Fc ) );
A_Q28[ 1 ] = SKP_float2int( ( 1 << 28 ) * r * r );
/********************/
/* High-pass filter */
/********************/
SKP_Silk_biquad_alt( in, B_Q28, A_Q28, psEnc->sCmn.In_HP_State, out, psEnc->sCmn.frame_length );
}
/* Deactivate by setting psEncC->transition_frame_no = 0; */
void SKP_Silk_LP_variable_cutoff(
SKP_Silk_LP_state *psLP, /* I/O LP filter state */
SKP_int16 *out, /* O Low-pass filtered output signal */
const SKP_int16 *in, /* I Input signal */
const SKP_int frame_length /* I Frame length */
)
{
SKP_int32 B_Q28[ TRANSITION_NB ], A_Q28[ TRANSITION_NA ], fac_Q16 = 0;
SKP_int ind = 0;
SKP_assert( psLP->transition_frame_no >= 0 );
SKP_assert( ( ( ( psLP->transition_frame_no <= TRANSITION_FRAMES_DOWN ) && ( psLP->mode == 0 ) ) ||
( ( psLP->transition_frame_no <= TRANSITION_FRAMES_UP ) && ( psLP->mode == 1 ) ) ) );
/* Interpolate filter coefficients if needed */
if( psLP->transition_frame_no > 0 ) {
if( psLP->mode == 0 ) {
if( psLP->transition_frame_no < TRANSITION_FRAMES_DOWN ) {
/* Calculate index and interpolation factor for interpolation */
#if( TRANSITION_INT_STEPS_DOWN == 32 )
fac_Q16 = SKP_LSHIFT( psLP->transition_frame_no, 16 - 5 );
#else
fac_Q16 = SKP_DIV32_16( SKP_LSHIFT( psLP->transition_frame_no, 16 ), TRANSITION_INT_STEPS_DOWN );
#endif
ind = SKP_RSHIFT( fac_Q16, 16 );
fac_Q16 -= SKP_LSHIFT( ind, 16 );
SKP_assert( ind >= 0 );
SKP_assert( ind < TRANSITION_INT_NUM );
/* Interpolate filter coefficients */
SKP_Silk_LP_interpolate_filter_taps( B_Q28, A_Q28, ind, fac_Q16 );
/* Increment transition frame number for next frame */
psLP->transition_frame_no++;
} else if( psLP->transition_frame_no == TRANSITION_FRAMES_DOWN ) {
/* End of transition phase */
SKP_Silk_LP_interpolate_filter_taps( B_Q28, A_Q28, TRANSITION_INT_NUM - 1, 0 );
}
} else if( psLP->mode == 1 ) {
if( psLP->transition_frame_no < TRANSITION_FRAMES_UP ) {
/* Calculate index and interpolation factor for interpolation */
#if( TRANSITION_INT_STEPS_UP == 64 )
fac_Q16 = SKP_LSHIFT( TRANSITION_FRAMES_UP - psLP->transition_frame_no, 16 - 6 );
#else
fac_Q16 = SKP_DIV32_16( SKP_LSHIFT( TRANSITION_FRAMES_UP - psLP->transition_frame_no, 16 ), TRANSITION_INT_STEPS_UP );
#endif
ind = SKP_RSHIFT( fac_Q16, 16 );
fac_Q16 -= SKP_LSHIFT( ind, 16 );
SKP_assert( ind >= 0 );
SKP_assert( ind < TRANSITION_INT_NUM );
/* Interpolate filter coefficients */
SKP_Silk_LP_interpolate_filter_taps( B_Q28, A_Q28, ind, fac_Q16 );
/* Increment transition frame number for next frame */
psLP->transition_frame_no++;
} else if( psLP->transition_frame_no == TRANSITION_FRAMES_UP ) {
/* End of transition phase */
SKP_Silk_LP_interpolate_filter_taps( B_Q28, A_Q28, 0, 0 );
}
}
}
if( psLP->transition_frame_no > 0 ) {
/* ARMA low-pass filtering */
SKP_assert( TRANSITION_NB == 3 && TRANSITION_NA == 2 );
SKP_Silk_biquad_alt( in, B_Q28, A_Q28, psLP->In_LP_State, out, frame_length );
} else {
/* Instead of using the filter, copy input directly to output */
SKP_memcpy( out, in, frame_length * sizeof( SKP_int16 ) );
}
}