| /*********************************************************************** |
| Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
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| modification, are permitted provided that the following conditions |
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| - Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
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| products derived from this software without specific prior written |
| permission. |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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| ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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| ***********************************************************************/ |
| |
| #ifdef HAVE_CONFIG_H |
| #include "config.h" |
| #endif |
| |
| #include "main_FIX.h" |
| |
| void silk_LTP_analysis_filter_FIX( |
| opus_int16 *LTP_res, /* O LTP residual signal of length MAX_NB_SUBFR * ( pre_length + subfr_length ) */ |
| const opus_int16 *x, /* I Pointer to input signal with at least max( pitchL ) preceding samples */ |
| const opus_int16 LTPCoef_Q14[ LTP_ORDER * MAX_NB_SUBFR ],/* I LTP_ORDER LTP coefficients for each MAX_NB_SUBFR subframe */ |
| const opus_int pitchL[ MAX_NB_SUBFR ], /* I Pitch lag, one for each subframe */ |
| const opus_int32 invGains_Q16[ MAX_NB_SUBFR ], /* I Inverse quantization gains, one for each subframe */ |
| const opus_int subfr_length, /* I Length of each subframe */ |
| const opus_int nb_subfr, /* I Number of subframes */ |
| const opus_int pre_length /* I Length of the preceding samples starting at &x[0] for each subframe */ |
| ) |
| { |
| const opus_int16 *x_ptr, *x_lag_ptr; |
| opus_int16 Btmp_Q14[ LTP_ORDER ]; |
| opus_int16 *LTP_res_ptr; |
| opus_int k, i; |
| opus_int32 LTP_est; |
| |
| x_ptr = x; |
| LTP_res_ptr = LTP_res; |
| for( k = 0; k < nb_subfr; k++ ) { |
| |
| x_lag_ptr = x_ptr - pitchL[ k ]; |
| |
| Btmp_Q14[ 0 ] = LTPCoef_Q14[ k * LTP_ORDER ]; |
| Btmp_Q14[ 1 ] = LTPCoef_Q14[ k * LTP_ORDER + 1 ]; |
| Btmp_Q14[ 2 ] = LTPCoef_Q14[ k * LTP_ORDER + 2 ]; |
| Btmp_Q14[ 3 ] = LTPCoef_Q14[ k * LTP_ORDER + 3 ]; |
| Btmp_Q14[ 4 ] = LTPCoef_Q14[ k * LTP_ORDER + 4 ]; |
| |
| /* LTP analysis FIR filter */ |
| for( i = 0; i < subfr_length + pre_length; i++ ) { |
| LTP_res_ptr[ i ] = x_ptr[ i ]; |
| |
| /* Long-term prediction */ |
| LTP_est = silk_SMULBB( x_lag_ptr[ LTP_ORDER / 2 ], Btmp_Q14[ 0 ] ); |
| LTP_est = silk_SMLABB_ovflw( LTP_est, x_lag_ptr[ 1 ], Btmp_Q14[ 1 ] ); |
| LTP_est = silk_SMLABB_ovflw( LTP_est, x_lag_ptr[ 0 ], Btmp_Q14[ 2 ] ); |
| LTP_est = silk_SMLABB_ovflw( LTP_est, x_lag_ptr[ -1 ], Btmp_Q14[ 3 ] ); |
| LTP_est = silk_SMLABB_ovflw( LTP_est, x_lag_ptr[ -2 ], Btmp_Q14[ 4 ] ); |
| |
| LTP_est = silk_RSHIFT_ROUND( LTP_est, 14 ); /* round and -> Q0*/ |
| |
| /* Subtract long-term prediction */ |
| LTP_res_ptr[ i ] = (opus_int16)silk_SAT16( (opus_int32)x_ptr[ i ] - LTP_est ); |
| |
| /* Scale residual */ |
| LTP_res_ptr[ i ] = silk_SMULWB( invGains_Q16[ k ], LTP_res_ptr[ i ] ); |
| |
| x_lag_ptr++; |
| } |
| |
| /* Update pointers */ |
| LTP_res_ptr += subfr_length + pre_length; |
| x_ptr += subfr_length; |
| } |
| } |
| |