1
2/* -----------------------------------------------------------------------------------------------------------
3Software License for The Fraunhofer FDK AAC Codec Library for Android
4
5� Copyright  1995 - 2013 Fraunhofer-Gesellschaft zur F�rderung der angewandten Forschung e.V.
6  All rights reserved.
7
8 1.    INTRODUCTION
9The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
10the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
11This FDK AAC Codec software is intended to be used on a wide variety of Android devices.
12
13AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
14audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
15independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
16of the MPEG specifications.
17
18Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
19may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
20individually for the purpose of encoding or decoding bit streams in products that are compliant with
21the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
22these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
23software may already be covered under those patent licenses when it is used for those licensed purposes only.
24
25Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
26are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
27applications information and documentation.
28
292.    COPYRIGHT LICENSE
30
31Redistribution and use in source and binary forms, with or without modification, are permitted without
32payment of copyright license fees provided that you satisfy the following conditions:
33
34You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
35your modifications thereto in source code form.
36
37You must retain the complete text of this software license in the documentation and/or other materials
38provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
39You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
40modifications thereto to recipients of copies in binary form.
41
42The name of Fraunhofer may not be used to endorse or promote products derived from this library without
43prior written permission.
44
45You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
46software or your modifications thereto.
47
48Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
49and 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
533.    NO PATENT LICENSE
54
55NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
56ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
57respect to this software.
58
59You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
60by appropriate patent licenses.
61
624.    DISCLAIMER
63
64This 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
66of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
67CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
68including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
69or business interruption, however caused and on any theory of liability, whether in contract, strict
70liability, or tort (including negligence), arising in any way out of the use of this software, even if
71advised of the possibility of such damage.
72
735.    CONTACT INFORMATION
74
75Fraunhofer Institute for Integrated Circuits IIS
76Attention: Audio and Multimedia Departments - FDK AAC LL
77Am Wolfsmantel 33
7891058 Erlangen, Germany
79
80www.iis.fraunhofer.de/amm
81amm-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*****************************************************************************/
100static void
101FDKaacEnc_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*****************************************************************************/
151void
152FDKaacEnc_CalculateChaosMeasure( FIXP_DBL    *paMDCTDataNM0,
153                       INT          numberOfLines,
154                       FIXP_DBL    *chaosMeasure )
155
156{
157    FDKaacEnc_FDKaacEnc_CalculateChaosMeasurePeakFast( paMDCTDataNM0,
158                                   numberOfLines,
159                                   chaosMeasure );
160}
161
162