143 lines
6.2 KiB
C
143 lines
6.2 KiB
C
/***********************************************************************
|
|
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.
|
|
***********************************************************************/
|
|
|
|
#ifdef OPUS_ENABLED
|
|
#include "opus/opus_config.h"
|
|
#endif
|
|
|
|
/* NLSF stabilizer: */
|
|
/* */
|
|
/* - Moves NLSFs further apart if they are too close */
|
|
/* - Moves NLSFs away from borders if they are too close */
|
|
/* - High effort to achieve a modification with minimum */
|
|
/* Euclidean distance to input vector */
|
|
/* - Output are sorted NLSF coefficients */
|
|
/* */
|
|
|
|
#include "opus/silk/SigProc_FIX.h"
|
|
|
|
/* Constant Definitions */
|
|
#define MAX_LOOPS 20
|
|
|
|
/* NLSF stabilizer, for a single input data vector */
|
|
void silk_NLSF_stabilize(
|
|
opus_int16 *NLSF_Q15, /* I/O Unstable/stabilized normalized LSF vector in Q15 [L] */
|
|
const opus_int16 *NDeltaMin_Q15, /* I Min distance vector, NDeltaMin_Q15[L] must be >= 1 [L+1] */
|
|
const opus_int L /* I Number of NLSF parameters in the input vector */
|
|
)
|
|
{
|
|
opus_int i, I=0, k, loops;
|
|
opus_int16 center_freq_Q15;
|
|
opus_int32 diff_Q15, min_diff_Q15, min_center_Q15, max_center_Q15;
|
|
|
|
/* This is necessary to ensure an output within range of a opus_int16 */
|
|
silk_assert( NDeltaMin_Q15[L] >= 1 );
|
|
|
|
for( loops = 0; loops < MAX_LOOPS; loops++ ) {
|
|
/**************************/
|
|
/* Find smallest distance */
|
|
/**************************/
|
|
/* First element */
|
|
min_diff_Q15 = NLSF_Q15[0] - NDeltaMin_Q15[0];
|
|
I = 0;
|
|
/* Middle elements */
|
|
for( i = 1; i <= L-1; i++ ) {
|
|
diff_Q15 = NLSF_Q15[i] - ( NLSF_Q15[i-1] + NDeltaMin_Q15[i] );
|
|
if( diff_Q15 < min_diff_Q15 ) {
|
|
min_diff_Q15 = diff_Q15;
|
|
I = i;
|
|
}
|
|
}
|
|
/* Last element */
|
|
diff_Q15 = ( 1 << 15 ) - ( NLSF_Q15[L-1] + NDeltaMin_Q15[L] );
|
|
if( diff_Q15 < min_diff_Q15 ) {
|
|
min_diff_Q15 = diff_Q15;
|
|
I = L;
|
|
}
|
|
|
|
/***************************************************/
|
|
/* Now check if the smallest distance non-negative */
|
|
/***************************************************/
|
|
if( min_diff_Q15 >= 0 ) {
|
|
return;
|
|
}
|
|
|
|
if( I == 0 ) {
|
|
/* Move away from lower limit */
|
|
NLSF_Q15[0] = NDeltaMin_Q15[0];
|
|
|
|
} else if( I == L) {
|
|
/* Move away from higher limit */
|
|
NLSF_Q15[L-1] = ( 1 << 15 ) - NDeltaMin_Q15[L];
|
|
|
|
} else {
|
|
/* Find the lower extreme for the location of the current center frequency */
|
|
min_center_Q15 = 0;
|
|
for( k = 0; k < I; k++ ) {
|
|
min_center_Q15 += NDeltaMin_Q15[k];
|
|
}
|
|
min_center_Q15 += silk_RSHIFT( NDeltaMin_Q15[I], 1 );
|
|
|
|
/* Find the upper extreme for the location of the current center frequency */
|
|
max_center_Q15 = 1 << 15;
|
|
for( k = L; k > I; k-- ) {
|
|
max_center_Q15 -= NDeltaMin_Q15[k];
|
|
}
|
|
max_center_Q15 -= silk_RSHIFT( NDeltaMin_Q15[I], 1 );
|
|
|
|
/* Move apart, sorted by value, keeping the same center frequency */
|
|
center_freq_Q15 = (opus_int16)silk_LIMIT_32( silk_RSHIFT_ROUND( (opus_int32)NLSF_Q15[I-1] + (opus_int32)NLSF_Q15[I], 1 ),
|
|
min_center_Q15, max_center_Q15 );
|
|
NLSF_Q15[I-1] = center_freq_Q15 - silk_RSHIFT( NDeltaMin_Q15[I], 1 );
|
|
NLSF_Q15[I] = NLSF_Q15[I-1] + NDeltaMin_Q15[I];
|
|
}
|
|
}
|
|
|
|
/* Safe and simple fall back method, which is less ideal than the above */
|
|
if( loops == MAX_LOOPS )
|
|
{
|
|
/* Insertion sort (fast for already almost sorted arrays): */
|
|
/* Best case: O(n) for an already sorted array */
|
|
/* Worst case: O(n^2) for an inversely sorted array */
|
|
silk_insertion_sort_increasing_all_values_int16( &NLSF_Q15[0], L );
|
|
|
|
/* First NLSF should be no less than NDeltaMin[0] */
|
|
NLSF_Q15[0] = silk_max_int( NLSF_Q15[0], NDeltaMin_Q15[0] );
|
|
|
|
/* Keep delta_min distance between the NLSFs */
|
|
for( i = 1; i < L; i++ )
|
|
NLSF_Q15[i] = silk_max_int( NLSF_Q15[i], NLSF_Q15[i-1] + NDeltaMin_Q15[i] );
|
|
|
|
/* Last NLSF should be no higher than 1 - NDeltaMin[L] */
|
|
NLSF_Q15[L-1] = silk_min_int( NLSF_Q15[L-1], (1<<15) - NDeltaMin_Q15[L] );
|
|
|
|
/* Keep NDeltaMin distance between the NLSFs */
|
|
for( i = L-2; i >= 0; i-- )
|
|
NLSF_Q15[i] = silk_min_int( NLSF_Q15[i], NLSF_Q15[i+1] - NDeltaMin_Q15[i+1] );
|
|
}
|
|
}
|