libAACenc/src/chaosmeasure.cpp

   1
   2 /* -----------------------------------------------------------------------------------------------------------
   3 Software License for The Fraunhofer FDK AAC Codec Library for Android
   4
   5 © Copyright  1995 - 2013 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
   6   All rights reserved.
   7
   8  1.    INTRODUCTION
   9 The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
  10 the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
  11 This FDK AAC Codec software is intended to be used on a wide variety of Android devices.
  12
  13 AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
  14 audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
  15 independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
  16 of the MPEG specifications.
  17
  18 Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
  19 may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
  20 individually for the purpose of encoding or decoding bit streams in products that are compliant with
  21 the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
  22 these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
  23 software may already be covered under those patent licenses when it is used for those licensed purposes only.
  24
  25 Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
  26 are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
  27 applications information and documentation.
  28
  29 2.    COPYRIGHT LICENSE
  30
  31 Redistribution and use in source and binary forms, with or without modification, are permitted without
  32 payment of copyright license fees provided that you satisfy the following conditions:
  33
  34 You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
  35 your modifications thereto in source code form.
  36
  37 You must retain the complete text of this software license in the documentation and/or other materials
  38 provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
  39 You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
  40 modifications thereto to recipients of copies in binary form.
  41
  42 The name of Fraunhofer may not be used to endorse or promote products derived from this library without
  43 prior written permission.
  44
  45 You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
  46 software or your modifications thereto.
  47
  48 Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
  49 and the date of any change. For modified versions of the FDK AAC Codec, the term
  50 "Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
  51 "Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android."
  52
  53 3.    NO PATENT LICENSE
  54
  55 NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
  56 ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
  57 respect to this software.
  58
  59 You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
  60 by appropriate patent licenses.
  61
  62 4.    DISCLAIMER
  63
  64 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
  65 "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
  66 of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  67 CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
  68 including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
  69 or business interruption, however caused and on any theory of liability, whether in contract, strict
  70 liability, or tort (including negligence), arising in any way out of the use of this software, even if
  71 advised of the possibility of such damage.
  72
  73 5.    CONTACT INFORMATION
  74
  75 Fraunhofer Institute for Integrated Circuits IIS
  76 Attention: Audio and Multimedia Departments - FDK AAC LL
  77 Am Wolfsmantel 33
  78 91058 Erlangen, Germany
  79
  80 www.iis.fraunhofer.de/amm
  81 amm-info@iis.fraunhofer.de
  82 ----------------------------------------------------------------------------------------------------------- */
  83
  84 /******************************** MPEG Audio Encoder **************************
  85
  86    Initial author:       M. Werner
  87    contents/description: Chaos measure calculation
  88
  89 ******************************************************************************/
  90
  91 #include "chaosmeasure.h"
  92
  93 /*****************************************************************************
  94     functionname: FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast
  95     description:  Eberlein method of chaos measure calculation by high-pass
  96                   filtering amplitude spectrum
  97                   A special case of FDKaacEnc_CalculateChaosMeasureTonalGeneric --
  98                   highly optimized
  99 *****************************************************************************/
 100 static void
 101 FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast( FIXP_DBL  *RESTRICT paMDCTDataNM0,
 102                                INT        numberOfLines,
 103                                FIXP_DBL  *RESTRICT chaosMeasure )
 104 {
 105   INT i, j;
 106
 107   /* calculate chaos measure by "peak filter" */
 108   for (i=0; i<2; i++) {
 109     /* make even and odd pass through data */
 110     FIXP_DBL left,center; /* left, center tap of filter */
 111
 112     left   = (FIXP_DBL)((LONG)paMDCTDataNM0[i]^((LONG)paMDCTDataNM0[i]>>(DFRACT_BITS-1)));
 113     center = (FIXP_DBL)((LONG)paMDCTDataNM0[i+2]^((LONG)paMDCTDataNM0[i+2]>>(DFRACT_BITS-1)));
 114
 115     for (j = i+2; j < numberOfLines - 2; j+=2) {
 116       FIXP_DBL right = (FIXP_DBL)((LONG)paMDCTDataNM0[j+2]^((LONG)paMDCTDataNM0[j+2]>>(DFRACT_BITS-1)));
 117       FIXP_DBL tmp = (left>>1)+(right>>1);
 118
 119       if (tmp < center ) {
 120          INT leadingBits = CntLeadingZeros(center)-1;
 121          tmp = schur_div(tmp<<leadingBits, center<<leadingBits, 8);
 122          chaosMeasure[j] = fMult(tmp,tmp);
 123       }
 124       else {
 125          chaosMeasure[j] = (FIXP_DBL)MAXVAL_DBL;
 126       }
 127
 128       left   = center;
 129       center = right;
 130     }
 131   }
 132
 133   /* provide chaos measure for first few lines */
 134   chaosMeasure[0] = chaosMeasure[2];
 135   chaosMeasure[1] = chaosMeasure[2];
 136
 137   /* provide chaos measure for last few lines */
 138   for (i = (numberOfLines-3); i < numberOfLines; i++)
 139     chaosMeasure[i] = FL2FXCONST_DBL(0.5);
 140 }
 141
 142
 143 /*****************************************************************************
 144     functionname: FDKaacEnc_CalculateChaosMeasure
 145     description:  calculates a chaosmeasure for every line, different methods
 146                   are available. 0 means tonal, 1 means noiselike
 147     returns:
 148     input:        MDCT data, number of lines
 149     output:       chaosMeasure
 150 *****************************************************************************/
 151 void
 152 FDKaacEnc_CalculateChaosMeasure( FIXP_DBL    *paMDCTDataNM0,
 153                        INT          numberOfLines,
 154                        FIXP_DBL    *chaosMeasure )
 155
 156 {
 157     FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast( paMDCTDataNM0,
 158                                    numberOfLines,
 159                                    chaosMeasure );
 160 }
 161