1885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org/*********************************************************************** 2885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgCopyright (c) 2006-2011, Skype Limited. All rights reserved. 3885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgRedistribution and use in source and binary forms, with or without 4885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgmodification, are permitted provided that the following conditions 5885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgare met: 6885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org- Redistributions of source code must retain the above copyright notice, 7885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgthis list of conditions and the following disclaimer. 8885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org- Redistributions in binary form must reproduce the above copyright 9885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgnotice, this list of conditions and the following disclaimer in the 10885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgdocumentation and/or other materials provided with the distribution. 11e3ea049fcaee2247e45f0ce793d4313babb4ef69tlegrand@chromium.org- Neither the name of Internet Society, IETF or IETF Trust, nor the 12885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgnames of specific contributors, may be used to endorse or promote 13885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgproducts derived from this software without specific prior written 14885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgpermission. 15e3ea049fcaee2247e45f0ce793d4313babb4ef69tlegrand@chromium.orgTHIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 16885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgAND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgIMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 19885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgLIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgCONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgSUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgINTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgCONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgPOSSIBILITY OF SUCH DAMAGE. 26885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org***********************************************************************/ 27885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 28885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#ifdef HAVE_CONFIG_H 29885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#include "config.h" 30885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#endif 31885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 32885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#include "SigProc_FIX.h" 33885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#include "SigProc_FLP.h" 34885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 35885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org#define RC_THRESHOLD 0.9999f 36885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 37885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org/* compute inverse of LPC prediction gain, and */ 38885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org/* test if LPC coefficients are stable (all poles within unit circle) */ 39885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org/* this code is based on silk_a2k_FLP() */ 40885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.orgsilk_float silk_LPC_inverse_pred_gain_FLP( /* O return inverse prediction gain, energy domain */ 41885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org const silk_float *A, /* I prediction coefficients [order] */ 42885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org opus_int32 order /* I prediction order */ 43885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org) 44885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org{ 45885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org opus_int k, n; 46885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org double invGain, rc, rc_mult1, rc_mult2; 47885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org silk_float Atmp[ 2 ][ SILK_MAX_ORDER_LPC ]; 48885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org silk_float *Aold, *Anew; 49885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 50885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org Anew = Atmp[ order & 1 ]; 51885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org silk_memcpy( Anew, A, order * sizeof(silk_float) ); 52885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org 53885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org invGain = 1.0; 54885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org for( k = order - 1; k > 0; k-- ) { 55885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org rc = -Anew[ k ]; 56885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org if( rc > RC_THRESHOLD || rc < -RC_THRESHOLD ) { 57885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org return 0.0f; 58885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org } 59885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org rc_mult1 = 1.0f - rc * rc; 60885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org rc_mult2 = 1.0f / rc_mult1; 61885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org invGain *= rc_mult1; 62885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org /* swap pointers */ 63885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org Aold = Anew; 64885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org Anew = Atmp[ k & 1 ]; 65885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org for( n = 0; n < k; n++ ) { 66885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org Anew[ n ] = (silk_float)( ( Aold[ n ] - Aold[ k - n - 1 ] * rc ) * rc_mult2 ); 67885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org } 68885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org } 69885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org rc = -Anew[ 0 ]; 70885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org if( rc > RC_THRESHOLD || rc < -RC_THRESHOLD ) { 71885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org return 0.0f; 72885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org } 73885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org rc_mult1 = 1.0f - rc * rc; 74885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org invGain *= rc_mult1; 75885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org return (silk_float)invGain; 76885f2ff5a7a7d6a73432d26a6c0ae9147e6b452sergeyu@chromium.org} 77