77 lines
3.6 KiB
C
77 lines
3.6 KiB
C
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/***********************************************************************
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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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/* Compute autocorrelation */
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void silk_autocorr(
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opus_int32 *results, /* O Result (length correlationCount) */
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opus_int *scale, /* O Scaling of the correlation vector */
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const opus_int16 *inputData, /* I Input data to correlate */
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const opus_int inputDataSize, /* I Length of input */
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const opus_int correlationCount /* I Number of correlation taps to compute */
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)
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{
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opus_int i, lz, nRightShifts, corrCount;
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opus_int64 corr64;
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corrCount = silk_min_int( inputDataSize, correlationCount );
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/* compute energy (zero-lag correlation) */
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corr64 = silk_inner_prod16_aligned_64( inputData, inputData, inputDataSize );
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/* deal with all-zero input data */
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corr64 += 1;
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/* number of leading zeros */
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lz = silk_CLZ64( corr64 );
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/* scaling: number of right shifts applied to correlations */
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nRightShifts = 35 - lz;
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*scale = nRightShifts;
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if( nRightShifts <= 0 ) {
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results[ 0 ] = silk_LSHIFT( (opus_int32)silk_CHECK_FIT32( corr64 ), -nRightShifts );
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/* compute remaining correlations based on int32 inner product */
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for( i = 1; i < corrCount; i++ ) {
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results[ i ] = silk_LSHIFT( silk_inner_prod_aligned( inputData, inputData + i, inputDataSize - i ), -nRightShifts );
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}
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} else {
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results[ 0 ] = (opus_int32)silk_CHECK_FIT32( silk_RSHIFT64( corr64, nRightShifts ) );
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/* compute remaining correlations based on int64 inner product */
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for( i = 1; i < corrCount; i++ ) {
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results[ i ] = (opus_int32)silk_CHECK_FIT32( silk_RSHIFT64( silk_inner_prod16_aligned_64( inputData, inputData + i, inputDataSize - i ), nRightShifts ) );
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}
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}
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}
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