| Index: opus/silk/LPC_analysis_filter.c
|
| ===================================================================
|
| --- opus/silk/LPC_analysis_filter.c (revision 0)
|
| +++ opus/silk/LPC_analysis_filter.c (revision 0)
|
| @@ -0,0 +1,85 @@
|
| +/***********************************************************************
|
| +Copyright (c) 2006-2011, Skype Limited. All rights reserved.
|
| +Redistribution and use in source and binary forms, with or without
|
| +modification, are permitted provided that the following conditions
|
| +are met:
|
| +- Redistributions of source code must retain the above copyright notice,
|
| +this list of conditions and the following disclaimer.
|
| +- Redistributions in binary form must reproduce the above copyright
|
| +notice, this list of conditions and the following disclaimer in the
|
| +documentation and/or other materials provided with the distribution.
|
| +- Neither the name of Internet Society, IETF or IETF Trust, nor the
|
| +names of specific contributors, may be used to endorse or promote
|
| +products derived from this software without specific prior written
|
| +permission.
|
| +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”
|
| +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
| +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
| +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
|
| +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
| +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
| +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
| +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
| +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
| +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
| +POSSIBILITY OF SUCH DAMAGE.
|
| +***********************************************************************/
|
| +
|
| +#ifdef HAVE_CONFIG_H
|
| +#include "config.h"
|
| +#endif
|
| +
|
| +#include "SigProc_FIX.h"
|
| +
|
| +/*******************************************/
|
| +/* LPC analysis filter */
|
| +/* NB! State is kept internally and the */
|
| +/* filter always starts with zero state */
|
| +/* first d output samples are set to zero */
|
| +/*******************************************/
|
| +
|
| +void silk_LPC_analysis_filter(
|
| + opus_int16 *out, /* O Output signal */
|
| + const opus_int16 *in, /* I Input signal */
|
| + const opus_int16 *B, /* I MA prediction coefficients, Q12 [order] */
|
| + const opus_int32 len, /* I Signal length */
|
| + const opus_int32 d /* I Filter order */
|
| +)
|
| +{
|
| + opus_int ix, j;
|
| + opus_int32 out32_Q12, out32;
|
| + const opus_int16 *in_ptr;
|
| +
|
| + silk_assert( d >= 6 );
|
| + silk_assert( (d & 1) == 0 );
|
| + silk_assert( d <= len );
|
| +
|
| + for( ix = d; ix < len; ix++ ) {
|
| + in_ptr = &in[ ix - 1 ];
|
| +
|
| + out32_Q12 = silk_SMULBB( in_ptr[ 0 ], B[ 0 ] );
|
| + /* Allowing wrap around so that two wraps can cancel each other. The rare
|
| + cases where the result wraps around can only be triggered by invalid streams*/
|
| + out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -1 ], B[ 1 ] );
|
| + out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -2 ], B[ 2 ] );
|
| + out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -3 ], B[ 3 ] );
|
| + out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -4 ], B[ 4 ] );
|
| + out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -5 ], B[ 5 ] );
|
| + for( j = 6; j < d; j += 2 ) {
|
| + out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -j ], B[ j ] );
|
| + out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -j - 1 ], B[ j + 1 ] );
|
| + }
|
| +
|
| + /* Subtract prediction */
|
| + out32_Q12 = silk_SUB32_ovflw( silk_LSHIFT( (opus_int32)in_ptr[ 1 ], 12 ), out32_Q12 );
|
| +
|
| + /* Scale to Q0 */
|
| + out32 = silk_RSHIFT_ROUND( out32_Q12, 12 );
|
| +
|
| + /* Saturate output */
|
| + out[ ix ] = (opus_int16)silk_SAT16( out32 );
|
| + }
|
| +
|
| + /* Set first d output samples to zero */
|
| + silk_memset( out, 0, d * sizeof( opus_int16 ) );
|
| +}
|
|
|
| Property changes on: opus/silk/LPC_analysis_filter.c
|
| ___________________________________________________________________
|
| Added: svn:eol-style
|
| + LF
|
|
|
|
|