| Index: webrtc/modules/audio_coding/codecs/opus/opus/src/silk/NLSF_stabilize.c
|
| diff --git a/webrtc/modules/audio_coding/codecs/opus/opus/src/silk/NLSF_stabilize.c b/webrtc/modules/audio_coding/codecs/opus/opus/src/silk/NLSF_stabilize.c
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| new file mode 100644
|
| index 0000000000000000000000000000000000000000..1fa1ea379bdd8a4979e6f19dd74ab9af69942cec
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| --- /dev/null
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| +++ b/webrtc/modules/audio_coding/codecs/opus/opus/src/silk/NLSF_stabilize.c
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| @@ -0,0 +1,142 @@
|
| +/***********************************************************************
|
| +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 HAVE_CONFIG_H
|
| +#include "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 "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] );
|
| + }
|
| +}
|
|
|
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