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