mirror of https://github.com/NekoX-Dev/NekoX.git
112 lines
4.9 KiB
C
112 lines
4.9 KiB
C
/***********************************************************************
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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 "celt_lpc.h"
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/*******************************************/
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/* LPC analysis filter */
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/* NB! State is kept internally and the */
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/* filter always starts with zero state */
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/* first d output samples are set to zero */
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/*******************************************/
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/* OPT: Using celt_fir() for this function should be faster, but it may cause
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integer overflows in intermediate values (not final results), which the
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current implementation silences by casting to unsigned. Enabling
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this should be safe in pretty much all cases, even though it is not technically
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C89-compliant. */
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#define USE_CELT_FIR 0
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void silk_LPC_analysis_filter(
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opus_int16 *out, /* O Output signal */
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const opus_int16 *in, /* I Input signal */
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const opus_int16 *B, /* I MA prediction coefficients, Q12 [order] */
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const opus_int32 len, /* I Signal length */
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const opus_int32 d, /* I Filter order */
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int arch /* I Run-time architecture */
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)
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{
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opus_int j;
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#if defined(FIXED_POINT) && USE_CELT_FIR
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opus_int16 num[SILK_MAX_ORDER_LPC];
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#else
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int ix;
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opus_int32 out32_Q12, out32;
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const opus_int16 *in_ptr;
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#endif
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celt_assert( d >= 6 );
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celt_assert( (d & 1) == 0 );
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celt_assert( d <= len );
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#if defined(FIXED_POINT) && USE_CELT_FIR
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celt_assert( d <= SILK_MAX_ORDER_LPC );
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for ( j = 0; j < d; j++ ) {
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num[ j ] = -B[ j ];
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}
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celt_fir( in + d, num, out + d, len - d, d, arch );
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for ( j = 0; j < d; j++ ) {
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out[ j ] = 0;
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}
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#else
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(void)arch;
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for( ix = d; ix < len; ix++ ) {
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in_ptr = &in[ ix - 1 ];
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out32_Q12 = silk_SMULBB( in_ptr[ 0 ], B[ 0 ] );
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/* Allowing wrap around so that two wraps can cancel each other. The rare
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cases where the result wraps around can only be triggered by invalid streams*/
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out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -1 ], B[ 1 ] );
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out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -2 ], B[ 2 ] );
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out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -3 ], B[ 3 ] );
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out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -4 ], B[ 4 ] );
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out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -5 ], B[ 5 ] );
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for( j = 6; j < d; j += 2 ) {
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out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -j ], B[ j ] );
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out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -j - 1 ], B[ j + 1 ] );
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}
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/* Subtract prediction */
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out32_Q12 = silk_SUB32_ovflw( silk_LSHIFT( (opus_int32)in_ptr[ 1 ], 12 ), out32_Q12 );
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/* Scale to Q0 */
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out32 = silk_RSHIFT_ROUND( out32_Q12, 12 );
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/* Saturate output */
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out[ ix ] = (opus_int16)silk_SAT16( out32 );
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}
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/* Set first d output samples to zero */
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silk_memset( out, 0, d * sizeof( opus_int16 ) );
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#endif
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}
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