void SKP_Silk_resampler_private_ARMA4(
SKP_int32 S[], /* I/O: State vector [ 4 ] */
SKP_int16 out[], /* O: Output signal */
const SKP_int16 in[], /* I: Input signal */
const SKP_int16 Coef[], /* I: ARMA coefficients [ 7 ] */
SKP_int32 len /* I: Signal length */
)
{
SKP_int32 k;
SKP_int32 in_Q8, out1_Q8, out2_Q8, X;
for( k = 0; k < len; k++ ) {
in_Q8 = SKP_LSHIFT32( (SKP_int32)in[ k ], 8 );
/* Outputs of first and second biquad */
out1_Q8 = SKP_ADD_LSHIFT32( in_Q8, S[ 0 ], 2 );
out2_Q8 = SKP_ADD_LSHIFT32( out1_Q8, S[ 2 ], 2 );
/* Update states, which are stored in Q6. Coefficients are in Q14 here */
X = SKP_SMLAWB( S[ 1 ], in_Q8, Coef[ 0 ] );
S[ 0 ] = SKP_SMLAWB( X, out1_Q8, Coef[ 2 ] );
X = SKP_SMLAWB( S[ 3 ], out1_Q8, Coef[ 1 ] );
S[ 2 ] = SKP_SMLAWB( X, out2_Q8, Coef[ 4 ] );
S[ 1 ] = SKP_SMLAWB( SKP_RSHIFT32( in_Q8, 2 ), out1_Q8, Coef[ 3 ] );
S[ 3 ] = SKP_SMLAWB( SKP_RSHIFT32( out1_Q8, 2 ), out2_Q8, Coef[ 5 ] );
/* Apply gain and store to output. The coefficient is in Q16 */
out[ k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT32( SKP_SMLAWB( 128, out2_Q8, Coef[ 6 ] ), 8 ) );
}
}
/* Calculates correlation vector X'*t */
void SKP_Silk_corrVector_FIX(
const SKP_int16 *x, /* I x vector [L + order - 1] used to form data matrix X */
const SKP_int16 *t, /* I target vector [L] */
const SKP_int L, /* I Length of vectors */
const SKP_int order, /* I Max lag for correlation */
SKP_int32 *Xt, /* O Pointer to X'*t correlation vector [order] */
const SKP_int rshifts /* I Right shifts of correlations */
)
{
SKP_int lag, i;
const SKP_int16 *ptr1, *ptr2;
SKP_int32 inner_prod;
ptr1 = &x[ order - 1 ]; /* Points to first sample of column 0 of X: X[:,0] */
ptr2 = t;
/* Calculate X'*t */
if( rshifts > 0 ) {
/* Right shifting used */
for( lag = 0; lag < order; lag++ ) {
inner_prod = 0;
for( i = 0; i < L; i++ ) {
inner_prod += SKP_RSHIFT32( SKP_SMULBB( ptr1[ i ], ptr2[i] ), rshifts );
}
Xt[ lag ] = inner_prod; /* X[:,lag]'*t */
ptr1--; /* Go to next column of X */
}
} else {
SKP_assert( rshifts == 0 );
for( lag = 0; lag < order; lag++ ) {
Xt[ lag ] = SKP_Silk_inner_prod_aligned( ptr1, ptr2, L ); /* X[:,lag]'*t */
ptr1--; /* Go to next column of X */
}
}
}
/* Resample with a 2x downsampler (optional), a 2nd order AR filter followed by FIR interpolation */
void silk_resampler_private_down_FIR(
void *SS, /* I/O: Resampler state */
opus_int16 out[], /* O: Output signal */
const opus_int16 in[], /* I: Input signal */
opus_int32 inLen /* I: Number of input samples */
)
{
silk_resampler_state_struct *S = (silk_resampler_state_struct *)SS;
opus_int32 nSamplesIn;
opus_int32 max_index_Q16, index_increment_Q16;
opus_int16 buf1[ RESAMPLER_MAX_BATCH_SIZE_IN / 2 ];
opus_int32 buf2[ RESAMPLER_MAX_BATCH_SIZE_IN + RESAMPLER_DOWN_ORDER_FIR ];
const opus_int16 *FIR_Coefs;
/* Copy buffered samples to start of buffer */
SKP_memcpy( buf2, S->sFIR, RESAMPLER_DOWN_ORDER_FIR * sizeof( opus_int32 ) );
FIR_Coefs = &S->Coefs[ 2 ];
/* Iterate over blocks of frameSizeIn input samples */
index_increment_Q16 = S->invRatio_Q16;
while( 1 ) {
nSamplesIn = SKP_min( inLen, S->batchSize );
if( S->input2x == 1 ) {
/* Downsample 2x */
silk_resampler_down2( S->sDown2, buf1, in, nSamplesIn );
nSamplesIn = SKP_RSHIFT32( nSamplesIn, 1 );
/* Second-order AR filter (output in Q8) */
silk_resampler_private_AR2( S->sIIR, &buf2[ RESAMPLER_DOWN_ORDER_FIR ], buf1, S->Coefs, nSamplesIn );
} else {
/* Second-order AR filter (output in Q8) */
silk_resampler_private_AR2( S->sIIR, &buf2[ RESAMPLER_DOWN_ORDER_FIR ], in, S->Coefs, nSamplesIn );
}
max_index_Q16 = SKP_LSHIFT32( nSamplesIn, 16 );
/* Interpolate filtered signal */
if( S->FIR_Fracs == 1 ) {
out = silk_resampler_private_down_FIR_INTERPOL0(out, buf2, FIR_Coefs, max_index_Q16, index_increment_Q16);
} else {
out = silk_resampler_private_down_FIR_INTERPOL1(out, buf2, FIR_Coefs, max_index_Q16, index_increment_Q16, S->FIR_Fracs);
}
in += nSamplesIn << S->input2x;
inLen -= nSamplesIn << S->input2x;
if( inLen > S->input2x ) {
/* More iterations to do; copy last part of filtered signal to beginning of buffer */
SKP_memcpy( buf2, &buf2[ nSamplesIn ], RESAMPLER_DOWN_ORDER_FIR * sizeof( opus_int32 ) );
} else {
break;
}
}
/* Copy last part of filtered signal to the state for the next call */
SKP_memcpy( S->sFIR, &buf2[ nSamplesIn ], RESAMPLER_DOWN_ORDER_FIR * sizeof( opus_int32 ) );
}
/* Downsample by a factor 2, mediocre quality */
void SKP_Silk_resampler_down2(
SKP_int32 *S, /* I/O: State vector [ 2 ] */
SKP_int16 *out, /* O: Output signal [ len ] */
const SKP_int16 *in, /* I: Input signal [ floor(len/2) ] */
SKP_int32 inLen /* I: Number of input samples */
)
{
SKP_int32 k, len2 = SKP_RSHIFT32( inLen, 1 );
SKP_int32 in32, out32, Y, X;
SKP_assert( SKP_Silk_resampler_down2_0 > 0 );
SKP_assert( SKP_Silk_resampler_down2_1 < 0 );
/* Internal variables and state are in Q10 format */
for( k = 0; k < len2; k++ ) {
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ 2 * k ], 10 );
/* All-pass section for even input sample */
Y = SKP_SUB32( in32, S[ 0 ] );
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_down2_1 );
out32 = SKP_ADD32( S[ 0 ], X );
S[ 0 ] = SKP_ADD32( in32, X );
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ 2 * k + 1 ], 10 );
/* All-pass section for odd input sample, and add to output of previous section */
Y = SKP_SUB32( in32, S[ 1 ] );
X = SKP_SMULWB( Y, SKP_Silk_resampler_down2_0 );
out32 = SKP_ADD32( out32, S[ 1 ] );
out32 = SKP_ADD32( out32, X );
S[ 1 ] = SKP_ADD32( in32, X );
/* Add, convert back to int16 and store to output */
out[ k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( out32, 11 ) );
}
}
/* Calculates correlation matrix X'*X */
void SKP_Silk_corrMatrix_FIX(
const SKP_int16 *x, /* I x vector [L + order - 1] used to form data matrix X */
const SKP_int L, /* I Length of vectors */
const SKP_int order, /* I Max lag for correlation */
const SKP_int head_room, /* I Desired headroom */
SKP_int32 *XX, /* O Pointer to X'*X correlation matrix [ order x order ]*/
SKP_int *rshifts /* I/O Right shifts of correlations */
)
{
SKP_int i, j, lag, rshifts_local, head_room_rshifts;
SKP_int32 energy;
const SKP_int16 *ptr1, *ptr2;
/* Calculate energy to find shift used to fit in 32 bits */
SKP_Silk_sum_sqr_shift( &energy, &rshifts_local, x, L + order - 1 );
/* Add shifts to get the desired head room */
head_room_rshifts = SKP_max( head_room - SKP_Silk_CLZ32( energy ), 0 );
energy = SKP_RSHIFT32( energy, head_room_rshifts );
rshifts_local += head_room_rshifts;
/* Calculate energy of first column (0) of X: X[:,0]'*X[:,0] */
/* Remove contribution of first order - 1 samples */
for( i = 0; i < order - 1; i++ ) {
energy -= SKP_RSHIFT32( SKP_SMULBB( x[ i ], x[ i ] ), rshifts_local );
}
if( rshifts_local < *rshifts ) {
/* Adjust energy */
energy = SKP_RSHIFT32( energy, *rshifts - rshifts_local );
rshifts_local = *rshifts;
}
/* Calculate energy of remaining columns of X: X[:,j]'*X[:,j] */
/* Fill out the diagonal of the correlation matrix */
matrix_ptr( XX, 0, 0, order ) = energy;
ptr1 = &x[ order - 1 ]; /* First sample of column 0 of X */
for( j = 1; j < order; j++ ) {
energy = SKP_SUB32( energy, SKP_RSHIFT32( SKP_SMULBB( ptr1[ L - j ], ptr1[ L - j ] ), rshifts_local ) );
energy = SKP_ADD32( energy, SKP_RSHIFT32( SKP_SMULBB( ptr1[ -j ], ptr1[ -j ] ), rshifts_local ) );
matrix_ptr( XX, j, j, order ) = energy;
}
ptr2 = &x[ order - 2 ]; /* First sample of column 1 of X */
/* Calculate the remaining elements of the correlation matrix */
if( rshifts_local > 0 ) {
/* Right shifting used */
for( lag = 1; lag < order; lag++ ) {
/* Inner product of column 0 and column lag: X[:,0]'*X[:,lag] */
energy = 0;
for( i = 0; i < L; i++ ) {
energy += SKP_RSHIFT32( SKP_SMULBB( ptr1[ i ], ptr2[i] ), rshifts_local );
}
/* Calculate remaining off diagonal: X[:,j]'*X[:,j + lag] */
matrix_ptr( XX, lag, 0, order ) = energy;
matrix_ptr( XX, 0, lag, order ) = energy;
for( j = 1; j < ( order - lag ); j++ ) {
energy = SKP_SUB32( energy, SKP_RSHIFT32( SKP_SMULBB( ptr1[ L - j ], ptr2[ L - j ] ), rshifts_local ) );
energy = SKP_ADD32( energy, SKP_RSHIFT32( SKP_SMULBB( ptr1[ -j ], ptr2[ -j ] ), rshifts_local ) );
matrix_ptr( XX, lag + j, j, order ) = energy;
matrix_ptr( XX, j, lag + j, order ) = energy;
}
ptr2--; /* Update pointer to first sample of next column (lag) in X */
}
} else {
for( lag = 1; lag < order; lag++ ) {
/* Inner product of column 0 and column lag: X[:,0]'*X[:,lag] */
energy = SKP_Silk_inner_prod_aligned( ptr1, ptr2, L );
matrix_ptr( XX, lag, 0, order ) = energy;
matrix_ptr( XX, 0, lag, order ) = energy;
/* Calculate remaining off diagonal: X[:,j]'*X[:,j + lag] */
for( j = 1; j < ( order - lag ); j++ ) {
energy = SKP_SUB32( energy, SKP_SMULBB( ptr1[ L - j ], ptr2[ L - j ] ) );
energy = SKP_SMLABB( energy, ptr1[ -j ], ptr2[ -j ] );
matrix_ptr( XX, lag + j, j, order ) = energy;
matrix_ptr( XX, j, lag + j, order ) = energy;
}
ptr2--;/* Update pointer to first sample of next column (lag) in X */
}
}
*rshifts = rshifts_local;
}
void SKP_Silk_resampler_private_up2_HQ(
SKP_int32 *S, /* I/O: Resampler state [ 6 ] */
SKP_int16 *out, /* O: Output signal [ 2 * len ] */
const SKP_int16 *in, /* I: Input signal [ len ] */
SKP_int32 len /* I: Number of INPUT samples */
)
{
SKP_int32 k;
SKP_int32 in32, out32_1, out32_2, Y, X;
SKP_assert( SKP_Silk_resampler_up2_hq_0[ 0 ] > 0 );
SKP_assert( SKP_Silk_resampler_up2_hq_0[ 1 ] < 0 );
SKP_assert( SKP_Silk_resampler_up2_hq_1[ 0 ] > 0 );
SKP_assert( SKP_Silk_resampler_up2_hq_1[ 1 ] < 0 );
/* Internal variables and state are in Q10 format */
for( k = 0; k < len; k++ ) {
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ k ], 10 );
/* First all-pass section for even output sample */
Y = SKP_SUB32( in32, S[ 0 ] );
X = SKP_SMULWB( Y, SKP_Silk_resampler_up2_hq_0[ 0 ] );
out32_1 = SKP_ADD32( S[ 0 ], X );
S[ 0 ] = SKP_ADD32( in32, X );
/* Second all-pass section for even output sample */
Y = SKP_SUB32( out32_1, S[ 1 ] );
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_up2_hq_0[ 1 ] );
out32_2 = SKP_ADD32( S[ 1 ], X );
S[ 1 ] = SKP_ADD32( out32_1, X );
/* Biquad notch filter */
out32_2 = SKP_SMLAWB( out32_2, S[ 5 ], SKP_Silk_resampler_up2_hq_notch[ 2 ] );
out32_2 = SKP_SMLAWB( out32_2, S[ 4 ], SKP_Silk_resampler_up2_hq_notch[ 1 ] );
out32_1 = SKP_SMLAWB( out32_2, S[ 4 ], SKP_Silk_resampler_up2_hq_notch[ 0 ] );
S[ 5 ] = SKP_SUB32( out32_2, S[ 5 ] );
/* Apply gain in Q15, convert back to int16 and store to output */
out[ 2 * k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT32(
SKP_SMLAWB( 256, out32_1, SKP_Silk_resampler_up2_hq_notch[ 3 ] ), 9 ) );
/* First all-pass section for odd output sample */
Y = SKP_SUB32( in32, S[ 2 ] );
X = SKP_SMULWB( Y, SKP_Silk_resampler_up2_hq_1[ 0 ] );
out32_1 = SKP_ADD32( S[ 2 ], X );
S[ 2 ] = SKP_ADD32( in32, X );
/* Second all-pass section for odd output sample */
Y = SKP_SUB32( out32_1, S[ 3 ] );
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_up2_hq_1[ 1 ] );
out32_2 = SKP_ADD32( S[ 3 ], X );
S[ 3 ] = SKP_ADD32( out32_1, X );
/* Biquad notch filter */
out32_2 = SKP_SMLAWB( out32_2, S[ 4 ], SKP_Silk_resampler_up2_hq_notch[ 2 ] );
out32_2 = SKP_SMLAWB( out32_2, S[ 5 ], SKP_Silk_resampler_up2_hq_notch[ 1 ] );
out32_1 = SKP_SMLAWB( out32_2, S[ 5 ], SKP_Silk_resampler_up2_hq_notch[ 0 ] );
S[ 4 ] = SKP_SUB32( out32_2, S[ 4 ] );
/* Apply gain in Q15, convert back to int16 and store to output */
out[ 2 * k + 1 ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT32(
SKP_SMLAWB( 256, out32_1, SKP_Silk_resampler_up2_hq_notch[ 3 ] ), 9 ) );
}
}
/* Compute reflection coefficients from input signal */
void SKP_Silk_burg_modified(
SKP_int32 *res_nrg, /* O residual energy */
SKP_int *res_nrg_Q, /* O residual energy Q value */
SKP_int32 A_Q16[], /* O prediction coefficients (length order) */
const SKP_int16 x[], /* I input signal, length: nb_subfr * ( D + subfr_length ) */
const SKP_int subfr_length, /* I input signal subframe length (including D preceeding samples) */
const SKP_int nb_subfr, /* I number of subframes stacked in x */
const SKP_int32 WhiteNoiseFrac_Q32, /* I fraction added to zero-lag autocorrelation */
const SKP_int D /* I order */
)
{
SKP_int k, n, s, lz, rshifts, rshifts_extra;
SKP_int32 C0, num, nrg, rc_Q31, Atmp_QA, Atmp1, tmp1, tmp2, x1, x2;
const SKP_int16 *x_ptr;
SKP_int32 C_first_row[ SKP_Silk_MAX_ORDER_LPC ];
SKP_int32 C_last_row[ SKP_Silk_MAX_ORDER_LPC ];
SKP_int32 Af_QA[ SKP_Silk_MAX_ORDER_LPC ];
SKP_int32 CAf[ SKP_Silk_MAX_ORDER_LPC + 1 ];
SKP_int32 CAb[ SKP_Silk_MAX_ORDER_LPC + 1 ];
SKP_assert( subfr_length * nb_subfr <= MAX_FRAME_SIZE );
SKP_assert( nb_subfr <= MAX_NB_SUBFR );
/* Compute autocorrelations, added over subframes */
SKP_Silk_sum_sqr_shift( &C0, &rshifts, x, nb_subfr * subfr_length );
if( rshifts > MAX_RSHIFTS ) {
C0 = SKP_LSHIFT32( C0, rshifts - MAX_RSHIFTS );
SKP_assert( C0 > 0 );
rshifts = MAX_RSHIFTS;
} else {
lz = SKP_Silk_CLZ32( C0 ) - 1;
rshifts_extra = N_BITS_HEAD_ROOM - lz;
if( rshifts_extra > 0 ) {
rshifts_extra = SKP_min( rshifts_extra, MAX_RSHIFTS - rshifts );
C0 = SKP_RSHIFT32( C0, rshifts_extra );
} else {
rshifts_extra = SKP_max( rshifts_extra, MIN_RSHIFTS - rshifts );
C0 = SKP_LSHIFT32( C0, -rshifts_extra );
}
rshifts += rshifts_extra;
}
SKP_memset( C_first_row, 0, SKP_Silk_MAX_ORDER_LPC * sizeof( SKP_int32 ) );
if( rshifts > 0 ) {
for( s = 0; s < nb_subfr; s++ ) {
x_ptr = x + s * subfr_length;
for( n = 1; n < D + 1; n++ ) {
C_first_row[ n - 1 ] += (SKP_int32)SKP_RSHIFT64(
SKP_Silk_inner_prod16_aligned_64( x_ptr, x_ptr + n, subfr_length - n ), rshifts );
}
}
} else {
for( s = 0; s < nb_subfr; s++ ) {
x_ptr = x + s * subfr_length;
for( n = 1; n < D + 1; n++ ) {
C_first_row[ n - 1 ] += SKP_LSHIFT32(
SKP_Silk_inner_prod_aligned( x_ptr, x_ptr + n, subfr_length - n ), -rshifts );
}
}
}
SKP_memcpy( C_last_row, C_first_row, SKP_Silk_MAX_ORDER_LPC * sizeof( SKP_int32 ) );
/* Initialize */
CAb[ 0 ] = CAf[ 0 ] = C0 + SKP_SMMUL( WhiteNoiseFrac_Q32, C0 ) + 1; // Q(-rshifts)
for( n = 0; n < D; n++ ) {
/* Update first row of correlation matrix (without first element) */
/* Update last row of correlation matrix (without last element, stored in reversed order) */
/* Update C * Af */
/* Update C * flipud(Af) (stored in reversed order) */
if( rshifts > -2 ) {
for( s = 0; s < nb_subfr; s++ ) {
x_ptr = x + s * subfr_length;
x1 = -SKP_LSHIFT32( (SKP_int32)x_ptr[ n ], 16 - rshifts ); // Q(16-rshifts)
x2 = -SKP_LSHIFT32( (SKP_int32)x_ptr[ subfr_length - n - 1 ], 16 - rshifts ); // Q(16-rshifts)
tmp1 = SKP_LSHIFT32( (SKP_int32)x_ptr[ n ], QA - 16 ); // Q(QA-16)
tmp2 = SKP_LSHIFT32( (SKP_int32)x_ptr[ subfr_length - n - 1 ], QA - 16 ); // Q(QA-16)
for( k = 0; k < n; k++ ) {
C_first_row[ k ] = SKP_SMLAWB( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); // Q( -rshifts )
C_last_row[ k ] = SKP_SMLAWB( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); // Q( -rshifts )
Atmp_QA = Af_QA[ k ];
tmp1 = SKP_SMLAWB( tmp1, Atmp_QA, x_ptr[ n - k - 1 ] ); // Q(QA-16)
tmp2 = SKP_SMLAWB( tmp2, Atmp_QA, x_ptr[ subfr_length - n + k ] ); // Q(QA-16)
}
tmp1 = SKP_LSHIFT32( -tmp1, 32 - QA - rshifts ); // Q(16-rshifts)
tmp2 = SKP_LSHIFT32( -tmp2, 32 - QA - rshifts ); // Q(16-rshifts)
for( k = 0; k <= n; k++ ) {
CAf[ k ] = SKP_SMLAWB( CAf[ k ], tmp1, x_ptr[ n - k ] ); // Q( -rshift )
CAb[ k ] = SKP_SMLAWB( CAb[ k ], tmp2, x_ptr[ subfr_length - n + k - 1 ] ); // Q( -rshift )
}
}
} else {
for( s = 0; s < nb_subfr; s++ ) {
x_ptr = x + s * subfr_length;
x1 = -SKP_LSHIFT32( (SKP_int32)x_ptr[ n ], -rshifts ); // Q( -rshifts )
x2 = -SKP_LSHIFT32( (SKP_int32)x_ptr[ subfr_length - n - 1 ], -rshifts ); // Q( -rshifts )
tmp1 = SKP_LSHIFT32( (SKP_int32)x_ptr[ n ], 17 ); // Q17
tmp2 = SKP_LSHIFT32( (SKP_int32)x_ptr[ subfr_length - n - 1 ], 17 ); // Q17
for( k = 0; k < n; k++ ) {
C_first_row[ k ] = SKP_MLA( C_first_row[ k ], x1, x_ptr[ n - k - 1 ] ); // Q( -rshifts )
C_last_row[ k ] = SKP_MLA( C_last_row[ k ], x2, x_ptr[ subfr_length - n + k ] ); // Q( -rshifts )
Atmp1 = SKP_RSHIFT_ROUND( Af_QA[ k ], QA - 17 ); // Q17
tmp1 = SKP_MLA( tmp1, x_ptr[ n - k - 1 ], Atmp1 ); // Q17
tmp2 = SKP_MLA( tmp2, x_ptr[ subfr_length - n + k ], Atmp1 ); // Q17
}
tmp1 = -tmp1; // Q17
tmp2 = -tmp2; // Q17
for( k = 0; k <= n; k++ ) {
CAf[ k ] = SKP_SMLAWW( CAf[ k ], tmp1,
SKP_LSHIFT32( (SKP_int32)x_ptr[ n - k ], -rshifts - 1 ) ); // Q( -rshift )
CAb[ k ] = SKP_SMLAWW( CAb[ k ], tmp2,
SKP_LSHIFT32( (SKP_int32)x_ptr[ subfr_length - n + k - 1 ], -rshifts - 1 ) );// Q( -rshift )
}
}
}
/* Calculate nominator and denominator for the next order reflection (parcor) coefficient */
tmp1 = C_first_row[ n ]; // Q( -rshifts )
tmp2 = C_last_row[ n ]; // Q( -rshifts )
num = 0; // Q( -rshifts )
nrg = SKP_ADD32( CAb[ 0 ], CAf[ 0 ] ); // Q( 1-rshifts )
for( k = 0; k < n; k++ ) {
Atmp_QA = Af_QA[ k ];
lz = SKP_Silk_CLZ32( SKP_abs( Atmp_QA ) ) - 1;
lz = SKP_min( 32 - QA, lz );
Atmp1 = SKP_LSHIFT32( Atmp_QA, lz ); // Q( QA + lz )
tmp1 = SKP_ADD_LSHIFT32( tmp1, SKP_SMMUL( C_last_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); // Q( -rshifts )
tmp2 = SKP_ADD_LSHIFT32( tmp2, SKP_SMMUL( C_first_row[ n - k - 1 ], Atmp1 ), 32 - QA - lz ); // Q( -rshifts )
num = SKP_ADD_LSHIFT32( num, SKP_SMMUL( CAb[ n - k ], Atmp1 ), 32 - QA - lz ); // Q( -rshifts )
nrg = SKP_ADD_LSHIFT32( nrg, SKP_SMMUL( SKP_ADD32( CAb[ k + 1 ], CAf[ k + 1 ] ),
Atmp1 ), 32 - QA - lz ); // Q( 1-rshifts )
}
CAf[ n + 1 ] = tmp1; // Q( -rshifts )
CAb[ n + 1 ] = tmp2; // Q( -rshifts )
num = SKP_ADD32( num, tmp2 ); // Q( -rshifts )
num = SKP_LSHIFT32( -num, 1 ); // Q( 1-rshifts )
/* Calculate the next order reflection (parcor) coefficient */
if( SKP_abs( num ) < nrg ) {
rc_Q31 = SKP_DIV32_varQ( num, nrg, 31 );
} else {
/* Negative energy or ratio too high; set remaining coefficients to zero and exit loop */
SKP_memset( &Af_QA[ n ], 0, ( D - n ) * sizeof( SKP_int32 ) );
SKP_assert( 0 );
break;
}
/* Update the AR coefficients */
for( k = 0; k < (n + 1) >> 1; k++ ) {
tmp1 = Af_QA[ k ]; // QA
tmp2 = Af_QA[ n - k - 1 ]; // QA
Af_QA[ k ] = SKP_ADD_LSHIFT32( tmp1, SKP_SMMUL( tmp2, rc_Q31 ), 1 ); // QA
Af_QA[ n - k - 1 ] = SKP_ADD_LSHIFT32( tmp2, SKP_SMMUL( tmp1, rc_Q31 ), 1 ); // QA
}
Af_QA[ n ] = SKP_RSHIFT32( rc_Q31, 31 - QA ); // QA
/* Update C * Af and C * Ab */
for( k = 0; k <= n + 1; k++ ) {
tmp1 = CAf[ k ]; // Q( -rshifts )
tmp2 = CAb[ n - k + 1 ]; // Q( -rshifts )
CAf[ k ] = SKP_ADD_LSHIFT32( tmp1, SKP_SMMUL( tmp2, rc_Q31 ), 1 ); // Q( -rshifts )
CAb[ n - k + 1 ] = SKP_ADD_LSHIFT32( tmp2, SKP_SMMUL( tmp1, rc_Q31 ), 1 ); // Q( -rshifts )
}
}
/* Return residual energy */
nrg = CAf[ 0 ]; // Q( -rshifts )
tmp1 = 1 << 16; // Q16
for( k = 0; k < D; k++ ) {
Atmp1 = SKP_RSHIFT_ROUND( Af_QA[ k ], QA - 16 ); // Q16
nrg = SKP_SMLAWW( nrg, CAf[ k + 1 ], Atmp1 ); // Q( -rshifts )
tmp1 = SKP_SMLAWW( tmp1, Atmp1, Atmp1 ); // Q16
A_Q16[ k ] = -Atmp1;
}
*res_nrg = SKP_SMLAWW( nrg, SKP_SMMUL( WhiteNoiseFrac_Q32, C0 ), -tmp1 ); // Q( -rshifts )
*res_nrg_Q = -rshifts;
}
/* Resample with a 2x downsampler (optional), a 2nd order AR filter followed by FIR interpolation */
void SKP_Silk_resampler_private_down_FIR(
void *SS, /* I/O: Resampler state */
SKP_int16 out[], /* O: Output signal */
const SKP_int16 in[], /* I: Input signal */
SKP_int32 inLen /* I: Number of input samples */
)
{
SKP_Silk_resampler_state_struct *S = (SKP_Silk_resampler_state_struct *)SS;
SKP_int32 nSamplesIn, interpol_ind;
SKP_int32 max_index_Q16, index_Q16, index_increment_Q16, res_Q6;
SKP_int16 buf1[ RESAMPLER_MAX_BATCH_SIZE_IN / 2 ];
SKP_int32 buf2[ RESAMPLER_MAX_BATCH_SIZE_IN + RESAMPLER_DOWN_ORDER_FIR ];
SKP_int32 *buf_ptr;
const SKP_int16 *interpol_ptr, *FIR_Coefs;
/* Copy buffered samples to start of buffer */
SKP_memcpy( buf2, S->sFIR, RESAMPLER_DOWN_ORDER_FIR * sizeof( SKP_int32 ) );
FIR_Coefs = &S->Coefs[ 2 ];
/* Iterate over blocks of frameSizeIn input samples */
index_increment_Q16 = S->invRatio_Q16;
while( 1 ) {
nSamplesIn = SKP_min( inLen, S->batchSize );
if( S->input2x == 1 ) {
/* Downsample 2x */
SKP_Silk_resampler_down2( S->sDown2, buf1, in, nSamplesIn );
nSamplesIn = SKP_RSHIFT32( nSamplesIn, 1 );
/* Second-order AR filter (output in Q8) */
SKP_Silk_resampler_private_AR2( S->sIIR, &buf2[ RESAMPLER_DOWN_ORDER_FIR ], buf1, S->Coefs, nSamplesIn );
} else {
/* Second-order AR filter (output in Q8) */
SKP_Silk_resampler_private_AR2( S->sIIR, &buf2[ RESAMPLER_DOWN_ORDER_FIR ], in, S->Coefs, nSamplesIn );
}
max_index_Q16 = SKP_LSHIFT32( nSamplesIn, 16 );
/* Interpolate filtered signal */
if( S->FIR_Fracs == 1 ) {
for( index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16 ) {
/* Integer part gives pointer to buffered input */
buf_ptr = buf2 + SKP_RSHIFT( index_Q16, 16 );
/* Inner product */
res_Q6 = SKP_SMULWB( SKP_ADD32( buf_ptr[ 0 ], buf_ptr[ 11 ] ), FIR_Coefs[ 0 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 1 ], buf_ptr[ 10 ] ), FIR_Coefs[ 1 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 2 ], buf_ptr[ 9 ] ), FIR_Coefs[ 2 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 3 ], buf_ptr[ 8 ] ), FIR_Coefs[ 3 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 4 ], buf_ptr[ 7 ] ), FIR_Coefs[ 4 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 5 ], buf_ptr[ 6 ] ), FIR_Coefs[ 5 ] );
/* Scale down, saturate and store in output array */
*out++ = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( res_Q6, 6 ) );
}
} else {
for( index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16 ) {
/* Integer part gives pointer to buffered input */
buf_ptr = buf2 + SKP_RSHIFT( index_Q16, 16 );
/* Fractional part gives interpolation coefficients */
interpol_ind = SKP_SMULWB( index_Q16 & 0xFFFF, S->FIR_Fracs );
/* Inner product */
interpol_ptr = &FIR_Coefs[ RESAMPLER_DOWN_ORDER_FIR / 2 * interpol_ind ];
res_Q6 = SKP_SMULWB( buf_ptr[ 0 ], interpol_ptr[ 0 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 1 ], interpol_ptr[ 1 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 2 ], interpol_ptr[ 2 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 3 ], interpol_ptr[ 3 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 4 ], interpol_ptr[ 4 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 5 ], interpol_ptr[ 5 ] );
interpol_ptr = &FIR_Coefs[ RESAMPLER_DOWN_ORDER_FIR / 2 * ( S->FIR_Fracs - 1 - interpol_ind ) ];
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 11 ], interpol_ptr[ 0 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 10 ], interpol_ptr[ 1 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 9 ], interpol_ptr[ 2 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 8 ], interpol_ptr[ 3 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 7 ], interpol_ptr[ 4 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 6 ], interpol_ptr[ 5 ] );
/* Scale down, saturate and store in output array */
*out++ = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( res_Q6, 6 ) );
}
}
in += nSamplesIn << S->input2x;
inLen -= nSamplesIn << S->input2x;
if( inLen > S->input2x ) {
/* More iterations to do; copy last part of filtered signal to beginning of buffer */
SKP_memcpy( buf2, &buf2[ nSamplesIn ], RESAMPLER_DOWN_ORDER_FIR * sizeof( SKP_int32 ) );
} else {
break;
}
}
/* Copy last part of filtered signal to the state for the next call */
SKP_memcpy( S->sFIR, &buf2[ nSamplesIn ], RESAMPLER_DOWN_ORDER_FIR * sizeof( SKP_int32 ) );
}
