cannam@154: /*********************************************************************** cannam@154: Copyright (c) 2006-2011, Skype Limited. All rights reserved. cannam@154: Redistribution and use in source and binary forms, with or without cannam@154: modification, are permitted provided that the following conditions cannam@154: are met: cannam@154: - Redistributions of source code must retain the above copyright notice, cannam@154: this list of conditions and the following disclaimer. cannam@154: - Redistributions in binary form must reproduce the above copyright cannam@154: notice, this list of conditions and the following disclaimer in the cannam@154: documentation and/or other materials provided with the distribution. cannam@154: - Neither the name of Internet Society, IETF or IETF Trust, nor the cannam@154: names of specific contributors, may be used to endorse or promote cannam@154: products derived from this software without specific prior written cannam@154: permission. cannam@154: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" cannam@154: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE cannam@154: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE cannam@154: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE cannam@154: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR cannam@154: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF cannam@154: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS cannam@154: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN cannam@154: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) cannam@154: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE cannam@154: POSSIBILITY OF SUCH DAMAGE. cannam@154: ***********************************************************************/ cannam@154: cannam@154: #ifdef HAVE_CONFIG_H cannam@154: #include "config.h" cannam@154: #endif cannam@154: cannam@154: #include "SigProc_FIX.h" cannam@154: #include "define.h" cannam@154: cannam@154: #define QA 24 cannam@154: #define A_LIMIT SILK_FIX_CONST( 0.99975, QA ) cannam@154: cannam@154: #define MUL32_FRAC_Q(a32, b32, Q) ((opus_int32)(silk_RSHIFT_ROUND64(silk_SMULL(a32, b32), Q))) cannam@154: cannam@154: /* Compute inverse of LPC prediction gain, and */ cannam@154: /* test if LPC coefficients are stable (all poles within unit circle) */ cannam@154: static opus_int32 LPC_inverse_pred_gain_QA_c( /* O Returns inverse prediction gain in energy domain, Q30 */ cannam@154: opus_int32 A_QA[ SILK_MAX_ORDER_LPC ], /* I Prediction coefficients */ cannam@154: const opus_int order /* I Prediction order */ cannam@154: ) cannam@154: { cannam@154: opus_int k, n, mult2Q; cannam@154: opus_int32 invGain_Q30, rc_Q31, rc_mult1_Q30, rc_mult2, tmp1, tmp2; cannam@154: cannam@154: invGain_Q30 = SILK_FIX_CONST( 1, 30 ); cannam@154: for( k = order - 1; k > 0; k-- ) { cannam@154: /* Check for stability */ cannam@154: if( ( A_QA[ k ] > A_LIMIT ) || ( A_QA[ k ] < -A_LIMIT ) ) { cannam@154: return 0; cannam@154: } cannam@154: cannam@154: /* Set RC equal to negated AR coef */ cannam@154: rc_Q31 = -silk_LSHIFT( A_QA[ k ], 31 - QA ); cannam@154: cannam@154: /* rc_mult1_Q30 range: [ 1 : 2^30 ] */ cannam@154: rc_mult1_Q30 = silk_SUB32( SILK_FIX_CONST( 1, 30 ), silk_SMMUL( rc_Q31, rc_Q31 ) ); cannam@154: silk_assert( rc_mult1_Q30 > ( 1 << 15 ) ); /* reduce A_LIMIT if fails */ cannam@154: silk_assert( rc_mult1_Q30 <= ( 1 << 30 ) ); cannam@154: cannam@154: /* Update inverse gain */ cannam@154: /* invGain_Q30 range: [ 0 : 2^30 ] */ cannam@154: invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 ); cannam@154: silk_assert( invGain_Q30 >= 0 ); cannam@154: silk_assert( invGain_Q30 <= ( 1 << 30 ) ); cannam@154: if( invGain_Q30 < SILK_FIX_CONST( 1.0f / MAX_PREDICTION_POWER_GAIN, 30 ) ) { cannam@154: return 0; cannam@154: } cannam@154: cannam@154: /* rc_mult2 range: [ 2^30 : silk_int32_MAX ] */ cannam@154: mult2Q = 32 - silk_CLZ32( silk_abs( rc_mult1_Q30 ) ); cannam@154: rc_mult2 = silk_INVERSE32_varQ( rc_mult1_Q30, mult2Q + 30 ); cannam@154: cannam@154: /* Update AR coefficient */ cannam@154: for( n = 0; n < (k + 1) >> 1; n++ ) { cannam@154: opus_int64 tmp64; cannam@154: tmp1 = A_QA[ n ]; cannam@154: tmp2 = A_QA[ k - n - 1 ]; cannam@154: tmp64 = silk_RSHIFT_ROUND64( silk_SMULL( silk_SUB_SAT32(tmp1, cannam@154: MUL32_FRAC_Q( tmp2, rc_Q31, 31 ) ), rc_mult2 ), mult2Q); cannam@154: if( tmp64 > silk_int32_MAX || tmp64 < silk_int32_MIN ) { cannam@154: return 0; cannam@154: } cannam@154: A_QA[ n ] = ( opus_int32 )tmp64; cannam@154: tmp64 = silk_RSHIFT_ROUND64( silk_SMULL( silk_SUB_SAT32(tmp2, cannam@154: MUL32_FRAC_Q( tmp1, rc_Q31, 31 ) ), rc_mult2), mult2Q); cannam@154: if( tmp64 > silk_int32_MAX || tmp64 < silk_int32_MIN ) { cannam@154: return 0; cannam@154: } cannam@154: A_QA[ k - n - 1 ] = ( opus_int32 )tmp64; cannam@154: } cannam@154: } cannam@154: cannam@154: /* Check for stability */ cannam@154: if( ( A_QA[ k ] > A_LIMIT ) || ( A_QA[ k ] < -A_LIMIT ) ) { cannam@154: return 0; cannam@154: } cannam@154: cannam@154: /* Set RC equal to negated AR coef */ cannam@154: rc_Q31 = -silk_LSHIFT( A_QA[ 0 ], 31 - QA ); cannam@154: cannam@154: /* Range: [ 1 : 2^30 ] */ cannam@154: rc_mult1_Q30 = silk_SUB32( SILK_FIX_CONST( 1, 30 ), silk_SMMUL( rc_Q31, rc_Q31 ) ); cannam@154: cannam@154: /* Update inverse gain */ cannam@154: /* Range: [ 0 : 2^30 ] */ cannam@154: invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 ); cannam@154: silk_assert( invGain_Q30 >= 0 ); cannam@154: silk_assert( invGain_Q30 <= ( 1 << 30 ) ); cannam@154: if( invGain_Q30 < SILK_FIX_CONST( 1.0f / MAX_PREDICTION_POWER_GAIN, 30 ) ) { cannam@154: return 0; cannam@154: } cannam@154: cannam@154: return invGain_Q30; cannam@154: } cannam@154: cannam@154: /* For input in Q12 domain */ cannam@154: opus_int32 silk_LPC_inverse_pred_gain_c( /* O Returns inverse prediction gain in energy domain, Q30 */ cannam@154: const opus_int16 *A_Q12, /* I Prediction coefficients, Q12 [order] */ cannam@154: const opus_int order /* I Prediction order */ cannam@154: ) cannam@154: { cannam@154: opus_int k; cannam@154: opus_int32 Atmp_QA[ SILK_MAX_ORDER_LPC ]; cannam@154: opus_int32 DC_resp = 0; cannam@154: cannam@154: /* Increase Q domain of the AR coefficients */ cannam@154: for( k = 0; k < order; k++ ) { cannam@154: DC_resp += (opus_int32)A_Q12[ k ]; cannam@154: Atmp_QA[ k ] = silk_LSHIFT32( (opus_int32)A_Q12[ k ], QA - 12 ); cannam@154: } cannam@154: /* If the DC is unstable, we don't even need to do the full calculations */ cannam@154: if( DC_resp >= 4096 ) { cannam@154: return 0; cannam@154: } cannam@154: return LPC_inverse_pred_gain_QA_c( Atmp_QA, order ); cannam@154: }