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-rw-r--r--media/libopus/silk/A2NLSF.c267
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diff --git a/media/libopus/silk/A2NLSF.c b/media/libopus/silk/A2NLSF.c
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+/***********************************************************************
+Copyright (c) 2006-2011, Skype Limited. All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+- Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+- Neither the name of Internet Society, IETF or IETF Trust, nor the
+names of specific contributors, may be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+***********************************************************************/
+
+/* Conversion between prediction filter coefficients and NLSFs */
+/* Requires the order to be an even number */
+/* A piecewise linear approximation maps LSF <-> cos(LSF) */
+/* Therefore the result is not accurate NLSFs, but the two */
+/* functions are accurate inverses of each other */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "SigProc_FIX.h"
+#include "tables.h"
+
+/* Number of binary divisions, when not in low complexity mode */
+#define BIN_DIV_STEPS_A2NLSF_FIX 3 /* must be no higher than 16 - log2( LSF_COS_TAB_SZ_FIX ) */
+#define MAX_ITERATIONS_A2NLSF_FIX 16
+
+/* Helper function for A2NLSF(..) */
+/* Transforms polynomials from cos(n*f) to cos(f)^n */
+static OPUS_INLINE void silk_A2NLSF_trans_poly(
+ opus_int32 *p, /* I/O Polynomial */
+ const opus_int dd /* I Polynomial order (= filter order / 2 ) */
+)
+{
+ opus_int k, n;
+
+ for( k = 2; k <= dd; k++ ) {
+ for( n = dd; n > k; n-- ) {
+ p[ n - 2 ] -= p[ n ];
+ }
+ p[ k - 2 ] -= silk_LSHIFT( p[ k ], 1 );
+ }
+}
+/* Helper function for A2NLSF(..) */
+/* Polynomial evaluation */
+static OPUS_INLINE opus_int32 silk_A2NLSF_eval_poly( /* return the polynomial evaluation, in Q16 */
+ opus_int32 *p, /* I Polynomial, Q16 */
+ const opus_int32 x, /* I Evaluation point, Q12 */
+ const opus_int dd /* I Order */
+)
+{
+ opus_int n;
+ opus_int32 x_Q16, y32;
+
+ y32 = p[ dd ]; /* Q16 */
+ x_Q16 = silk_LSHIFT( x, 4 );
+
+ if ( opus_likely( 8 == dd ) )
+ {
+ y32 = silk_SMLAWW( p[ 7 ], y32, x_Q16 );
+ y32 = silk_SMLAWW( p[ 6 ], y32, x_Q16 );
+ y32 = silk_SMLAWW( p[ 5 ], y32, x_Q16 );
+ y32 = silk_SMLAWW( p[ 4 ], y32, x_Q16 );
+ y32 = silk_SMLAWW( p[ 3 ], y32, x_Q16 );
+ y32 = silk_SMLAWW( p[ 2 ], y32, x_Q16 );
+ y32 = silk_SMLAWW( p[ 1 ], y32, x_Q16 );
+ y32 = silk_SMLAWW( p[ 0 ], y32, x_Q16 );
+ }
+ else
+ {
+ for( n = dd - 1; n >= 0; n-- ) {
+ y32 = silk_SMLAWW( p[ n ], y32, x_Q16 ); /* Q16 */
+ }
+ }
+ return y32;
+}
+
+static OPUS_INLINE void silk_A2NLSF_init(
+ const opus_int32 *a_Q16,
+ opus_int32 *P,
+ opus_int32 *Q,
+ const opus_int dd
+)
+{
+ opus_int k;
+
+ /* Convert filter coefs to even and odd polynomials */
+ P[dd] = silk_LSHIFT( 1, 16 );
+ Q[dd] = silk_LSHIFT( 1, 16 );
+ for( k = 0; k < dd; k++ ) {
+ P[ k ] = -a_Q16[ dd - k - 1 ] - a_Q16[ dd + k ]; /* Q16 */
+ Q[ k ] = -a_Q16[ dd - k - 1 ] + a_Q16[ dd + k ]; /* Q16 */
+ }
+
+ /* Divide out zeros as we have that for even filter orders, */
+ /* z = 1 is always a root in Q, and */
+ /* z = -1 is always a root in P */
+ for( k = dd; k > 0; k-- ) {
+ P[ k - 1 ] -= P[ k ];
+ Q[ k - 1 ] += Q[ k ];
+ }
+
+ /* Transform polynomials from cos(n*f) to cos(f)^n */
+ silk_A2NLSF_trans_poly( P, dd );
+ silk_A2NLSF_trans_poly( Q, dd );
+}
+
+/* Compute Normalized Line Spectral Frequencies (NLSFs) from whitening filter coefficients */
+/* If not all roots are found, the a_Q16 coefficients are bandwidth expanded until convergence. */
+void silk_A2NLSF(
+ opus_int16 *NLSF, /* O Normalized Line Spectral Frequencies in Q15 (0..2^15-1) [d] */
+ opus_int32 *a_Q16, /* I/O Monic whitening filter coefficients in Q16 [d] */
+ const opus_int d /* I Filter order (must be even) */
+)
+{
+ opus_int i, k, m, dd, root_ix, ffrac;
+ opus_int32 xlo, xhi, xmid;
+ opus_int32 ylo, yhi, ymid, thr;
+ opus_int32 nom, den;
+ opus_int32 P[ SILK_MAX_ORDER_LPC / 2 + 1 ];
+ opus_int32 Q[ SILK_MAX_ORDER_LPC / 2 + 1 ];
+ opus_int32 *PQ[ 2 ];
+ opus_int32 *p;
+
+ /* Store pointers to array */
+ PQ[ 0 ] = P;
+ PQ[ 1 ] = Q;
+
+ dd = silk_RSHIFT( d, 1 );
+
+ silk_A2NLSF_init( a_Q16, P, Q, dd );
+
+ /* Find roots, alternating between P and Q */
+ p = P; /* Pointer to polynomial */
+
+ xlo = silk_LSFCosTab_FIX_Q12[ 0 ]; /* Q12*/
+ ylo = silk_A2NLSF_eval_poly( p, xlo, dd );
+
+ if( ylo < 0 ) {
+ /* Set the first NLSF to zero and move on to the next */
+ NLSF[ 0 ] = 0;
+ p = Q; /* Pointer to polynomial */
+ ylo = silk_A2NLSF_eval_poly( p, xlo, dd );
+ root_ix = 1; /* Index of current root */
+ } else {
+ root_ix = 0; /* Index of current root */
+ }
+ k = 1; /* Loop counter */
+ i = 0; /* Counter for bandwidth expansions applied */
+ thr = 0;
+ while( 1 ) {
+ /* Evaluate polynomial */
+ xhi = silk_LSFCosTab_FIX_Q12[ k ]; /* Q12 */
+ yhi = silk_A2NLSF_eval_poly( p, xhi, dd );
+
+ /* Detect zero crossing */
+ if( ( ylo <= 0 && yhi >= thr ) || ( ylo >= 0 && yhi <= -thr ) ) {
+ if( yhi == 0 ) {
+ /* If the root lies exactly at the end of the current */
+ /* interval, look for the next root in the next interval */
+ thr = 1;
+ } else {
+ thr = 0;
+ }
+ /* Binary division */
+ ffrac = -256;
+ for( m = 0; m < BIN_DIV_STEPS_A2NLSF_FIX; m++ ) {
+ /* Evaluate polynomial */
+ xmid = silk_RSHIFT_ROUND( xlo + xhi, 1 );
+ ymid = silk_A2NLSF_eval_poly( p, xmid, dd );
+
+ /* Detect zero crossing */
+ if( ( ylo <= 0 && ymid >= 0 ) || ( ylo >= 0 && ymid <= 0 ) ) {
+ /* Reduce frequency */
+ xhi = xmid;
+ yhi = ymid;
+ } else {
+ /* Increase frequency */
+ xlo = xmid;
+ ylo = ymid;
+ ffrac = silk_ADD_RSHIFT( ffrac, 128, m );
+ }
+ }
+
+ /* Interpolate */
+ if( silk_abs( ylo ) < 65536 ) {
+ /* Avoid dividing by zero */
+ den = ylo - yhi;
+ nom = silk_LSHIFT( ylo, 8 - BIN_DIV_STEPS_A2NLSF_FIX ) + silk_RSHIFT( den, 1 );
+ if( den != 0 ) {
+ ffrac += silk_DIV32( nom, den );
+ }
+ } else {
+ /* No risk of dividing by zero because abs(ylo - yhi) >= abs(ylo) >= 65536 */
+ ffrac += silk_DIV32( ylo, silk_RSHIFT( ylo - yhi, 8 - BIN_DIV_STEPS_A2NLSF_FIX ) );
+ }
+ NLSF[ root_ix ] = (opus_int16)silk_min_32( silk_LSHIFT( (opus_int32)k, 8 ) + ffrac, silk_int16_MAX );
+
+ silk_assert( NLSF[ root_ix ] >= 0 );
+
+ root_ix++; /* Next root */
+ if( root_ix >= d ) {
+ /* Found all roots */
+ break;
+ }
+ /* Alternate pointer to polynomial */
+ p = PQ[ root_ix & 1 ];
+
+ /* Evaluate polynomial */
+ xlo = silk_LSFCosTab_FIX_Q12[ k - 1 ]; /* Q12*/
+ ylo = silk_LSHIFT( 1 - ( root_ix & 2 ), 12 );
+ } else {
+ /* Increment loop counter */
+ k++;
+ xlo = xhi;
+ ylo = yhi;
+ thr = 0;
+
+ if( k > LSF_COS_TAB_SZ_FIX ) {
+ i++;
+ if( i > MAX_ITERATIONS_A2NLSF_FIX ) {
+ /* Set NLSFs to white spectrum and exit */
+ NLSF[ 0 ] = (opus_int16)silk_DIV32_16( 1 << 15, d + 1 );
+ for( k = 1; k < d; k++ ) {
+ NLSF[ k ] = (opus_int16)silk_ADD16( NLSF[ k-1 ], NLSF[ 0 ] );
+ }
+ return;
+ }
+
+ /* Error: Apply progressively more bandwidth expansion and run again */
+ silk_bwexpander_32( a_Q16, d, 65536 - silk_LSHIFT( 1, i ) );
+
+ silk_A2NLSF_init( a_Q16, P, Q, dd );
+ p = P; /* Pointer to polynomial */
+ xlo = silk_LSFCosTab_FIX_Q12[ 0 ]; /* Q12*/
+ ylo = silk_A2NLSF_eval_poly( p, xlo, dd );
+ if( ylo < 0 ) {
+ /* Set the first NLSF to zero and move on to the next */
+ NLSF[ 0 ] = 0;
+ p = Q; /* Pointer to polynomial */
+ ylo = silk_A2NLSF_eval_poly( p, xlo, dd );
+ root_ix = 1; /* Index of current root */
+ } else {
+ root_ix = 0; /* Index of current root */
+ }
+ k = 1; /* Reset loop counter */
+ }
+ }
+ }
+}
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