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1 /*********************************************************************** |
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2 Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
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3 Redistribution and use in source and binary forms, with or without |
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4 modification, are permitted provided that the following conditions |
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5 are met: |
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6 - Redistributions of source code must retain the above copyright notice, |
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7 this list of conditions and the following disclaimer. |
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8 - Redistributions in binary form must reproduce the above copyright |
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9 notice, this list of conditions and the following disclaimer in the |
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10 documentation and/or other materials provided with the distribution. |
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11 - Neither the name of Internet Society, IETF or IETF Trust, nor the |
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12 names of specific contributors, may be used to endorse or promote |
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13 products derived from this software without specific prior written |
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14 permission. |
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15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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25 POSSIBILITY OF SUCH DAMAGE. |
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26 ***********************************************************************/ |
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27 |
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28 #ifdef HAVE_CONFIG_H |
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29 #include "config.h" |
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30 #endif |
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31 |
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32 #include "SigProc_FIX.h" |
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33 |
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34 /* Step up function, converts reflection coefficients to prediction coefficients */ |
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35 void silk_k2a( |
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36 opus_int32 *A_Q24, /* O Prediction coefficients [order] Q24 */ |
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37 const opus_int16 *rc_Q15, /* I Reflection coefficients [order] Q15 */ |
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38 const opus_int32 order /* I Prediction order */ |
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39 ) |
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40 { |
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41 opus_int k, n; |
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42 opus_int32 Atmp[ SILK_MAX_ORDER_LPC ]; |
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43 |
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44 for( k = 0; k < order; k++ ) { |
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45 for( n = 0; n < k; n++ ) { |
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46 Atmp[ n ] = A_Q24[ n ]; |
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47 } |
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48 for( n = 0; n < k; n++ ) { |
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49 A_Q24[ n ] = silk_SMLAWB( A_Q24[ n ], silk_LSHIFT( Atmp[ k - n - 1 ], 1 ), rc_Q15[ k ] ); |
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50 } |
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51 A_Q24[ k ] = -silk_LSHIFT( (opus_int32)rc_Q15[ k ], 9 ); |
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52 } |
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53 } |