93 lines
3.9 KiB
C
93 lines
3.9 KiB
C
|
/***********************************************************************
|
||
|
|
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"
|
||
|
|
|
||
|
|
/* Slower than schur(), but more accurate. */
|
||
|
|
/* Uses SMULL(), available on armv4 */
|
||
|
|
opus_int32 silk_schur64( /* O returns residual energy */
|
||
|
|
opus_int32 rc_Q16[], /* O Reflection coefficients [order] Q16 */
|
||
|
|
const opus_int32 c[], /* I Correlations [order+1] */
|
||
|
|
opus_int32 order /* I Prediction order */
|
||
|
|
)
|
||
|
|
{
|
||
|
|
opus_int k, n;
|
||
|
|
opus_int32 C[ SILK_MAX_ORDER_LPC + 1 ][ 2 ];
|
||
|
|
opus_int32 Ctmp1_Q30, Ctmp2_Q30, rc_tmp_Q31;
|
||
|
|
|
||
|
|
silk_assert( order==6||order==8||order==10||order==12||order==14||order==16 );
|
||
|
|
|
||
|
|
/* Check for invalid input */
|
||
|
|
if( c[ 0 ] <= 0 ) {
|
||
|
|
silk_memset( rc_Q16, 0, order * sizeof( opus_int32 ) );
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
for( k = 0; k < order + 1; k++ ) {
|
||
|
|
C[ k ][ 0 ] = C[ k ][ 1 ] = c[ k ];
|
||
|
|
}
|
||
|
|
|
||
|
|
for( k = 0; k < order; k++ ) {
|
||
|
|
/* Check that we won't be getting an unstable rc, otherwise stop here. */
|
||
|
|
if (silk_abs_int32(C[ k + 1 ][ 0 ]) >= C[ 0 ][ 1 ]) {
|
||
|
|
if ( C[ k + 1 ][ 0 ] > 0 ) {
|
||
|
|
rc_Q16[ k ] = -SILK_FIX_CONST( .99f, 16 );
|
||
|
|
} else {
|
||
|
|
rc_Q16[ k ] = SILK_FIX_CONST( .99f, 16 );
|
||
|
|
}
|
||
|
|
k++;
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Get reflection coefficient: divide two Q30 values and get result in Q31 */
|
||
|
|
rc_tmp_Q31 = silk_DIV32_varQ( -C[ k + 1 ][ 0 ], C[ 0 ][ 1 ], 31 );
|
||
|
|
|
||
|
|
/* Save the output */
|
||
|
|
rc_Q16[ k ] = silk_RSHIFT_ROUND( rc_tmp_Q31, 15 );
|
||
|
|
|
||
|
|
/* Update correlations */
|
||
|
|
for( n = 0; n < order - k; n++ ) {
|
||
|
|
Ctmp1_Q30 = C[ n + k + 1 ][ 0 ];
|
||
|
|
Ctmp2_Q30 = C[ n ][ 1 ];
|
||
|
|
|
||
|
|
/* Multiply and add the highest int32 */
|
||
|
|
C[ n + k + 1 ][ 0 ] = Ctmp1_Q30 + silk_SMMUL( silk_LSHIFT( Ctmp2_Q30, 1 ), rc_tmp_Q31 );
|
||
|
|
C[ n ][ 1 ] = Ctmp2_Q30 + silk_SMMUL( silk_LSHIFT( Ctmp1_Q30, 1 ), rc_tmp_Q31 );
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
for(; k < order; k++ ) {
|
||
|
|
rc_Q16[ k ] = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
return silk_max_32( 1, C[ 0 ][ 1 ] );
|
||
|
|
}
|