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      1 /*
      2  ** Copyright 2003-2010, VisualOn, Inc.
      3  **
      4  ** Licensed under the Apache License, Version 2.0 (the "License");
      5  ** you may not use this file except in compliance with the License.
      6  ** You may obtain a copy of the License at
      7  **
      8  **     http://www.apache.org/licenses/LICENSE-2.0
      9  **
     10  ** Unless required by applicable law or agreed to in writing, software
     11  ** distributed under the License is distributed on an "AS IS" BASIS,
     12  ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  ** See the License for the specific language governing permissions and
     14  ** limitations under the License.
     15  */
     16 /*******************************************************************************
     17 	File:		pre_echo_control.c
     18 
     19 	Content:	Pre echo control functions
     20 
     21 *******************************************************************************/
     22 
     23 #include "basic_op.h"
     24 #include "oper_32b.h"
     25 
     26 #include "oper_32b.h"
     27 #include "pre_echo_control.h"
     28 
     29 
     30 /*****************************************************************************
     31 *
     32 * function name:InitPreEchoControl
     33 * description: init pre echo control parameter
     34 *
     35 *****************************************************************************/
     36 void InitPreEchoControl(Word32 *pbThresholdNm1,
     37                         Word16  numPb,
     38                         Word32 *pbThresholdQuiet)
     39 {
     40   Word16 pb;
     41 
     42   for(pb=0; pb<numPb; pb++) {
     43     pbThresholdNm1[pb] = pbThresholdQuiet[pb];
     44   }
     45 }
     46 
     47 /*****************************************************************************
     48 *
     49 * function name:PreEchoControl
     50 * description: update shreshold to avoid pre echo
     51 *			   thr(n) = max(rpmin*thrq(n), min(thrq(n), rpelev*thrq1(n)))
     52 *
     53 *
     54 *****************************************************************************/
     55 void PreEchoControl(Word32 *pbThresholdNm1,
     56                     Word16  numPb,
     57                     Word32  maxAllowedIncreaseFactor,
     58                     Word16  minRemainingThresholdFactor,
     59                     Word32 *pbThreshold,
     60                     Word16  mdctScale,
     61                     Word16  mdctScalenm1)
     62 {
     63   Word32 i;
     64   Word32 tmpThreshold1, tmpThreshold2;
     65   Word32 scaling;
     66 
     67   /* maxAllowedIncreaseFactor is hard coded to 2 */
     68   (void)maxAllowedIncreaseFactor;
     69 
     70   scaling = ((mdctScale - mdctScalenm1) << 1);
     71 
     72   if ( scaling > 0 ) {
     73     for(i = 0; i < numPb; i++) {
     74       tmpThreshold1 = pbThresholdNm1[i] >> (scaling-1);
     75       tmpThreshold2 = L_mpy_ls(pbThreshold[i], minRemainingThresholdFactor);
     76 
     77       /* copy thresholds to internal memory */
     78       pbThresholdNm1[i] = pbThreshold[i];
     79 
     80 
     81       if(pbThreshold[i] > tmpThreshold1) {
     82         pbThreshold[i] = tmpThreshold1;
     83       }
     84 
     85       if(tmpThreshold2 > pbThreshold[i]) {
     86         pbThreshold[i] = tmpThreshold2;
     87       }
     88 
     89     }
     90   }
     91   else {
     92     scaling = -scaling;
     93     for(i = 0; i < numPb; i++) {
     94 
     95       tmpThreshold1 = pbThresholdNm1[i] << 1;
     96       tmpThreshold2 = L_mpy_ls(pbThreshold[i], minRemainingThresholdFactor);
     97 
     98       /* copy thresholds to internal memory */
     99       pbThresholdNm1[i] = pbThreshold[i];
    100 
    101 
    102       if(((pbThreshold[i] >> scaling) > tmpThreshold1)) {
    103         pbThreshold[i] = tmpThreshold1 << scaling;
    104       }
    105 
    106       if(tmpThreshold2 > pbThreshold[i]) {
    107         pbThreshold[i] = tmpThreshold2;
    108       }
    109 
    110     }
    111   }
    112 }
    113 
    114