1
2 /* -----------------------------------------------------------------------------------------------------------
3 Software 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
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: Pre echo control
88
89 ******************************************************************************/
90
91 #include "pre_echo_control.h"
92 #include "psy_configuration.h"
93
FDKaacEnc_InitPreEchoControl(FIXP_DBL * RESTRICT pbThresholdNm1,INT * calcPreEcho,INT numPb,FIXP_DBL * RESTRICT sfbPcmQuantThreshold,INT * mdctScalenm1)94 void FDKaacEnc_InitPreEchoControl(FIXP_DBL *RESTRICT pbThresholdNm1,
95 INT *calcPreEcho,
96 INT numPb,
97 FIXP_DBL *RESTRICT sfbPcmQuantThreshold,
98 INT *mdctScalenm1)
99 {
100 *mdctScalenm1 = PCM_QUANT_THR_SCALE>>1;
101
102 FDKmemcpy(pbThresholdNm1, sfbPcmQuantThreshold, numPb*sizeof(FIXP_DBL));
103
104 *calcPreEcho = 1;
105 }
106
107
FDKaacEnc_PreEchoControl(FIXP_DBL * RESTRICT pbThresholdNm1,INT calcPreEcho,INT numPb,INT maxAllowedIncreaseFactor,FIXP_SGL minRemainingThresholdFactor,FIXP_DBL * RESTRICT pbThreshold,INT mdctScale,INT * mdctScalenm1)108 void FDKaacEnc_PreEchoControl(FIXP_DBL *RESTRICT pbThresholdNm1,
109 INT calcPreEcho,
110 INT numPb,
111 INT maxAllowedIncreaseFactor,
112 FIXP_SGL minRemainingThresholdFactor,
113 FIXP_DBL *RESTRICT pbThreshold,
114 INT mdctScale,
115 INT *mdctScalenm1)
116 {
117 int i;
118 FIXP_DBL tmpThreshold1, tmpThreshold2;
119 int scaling;
120
121 /* If lastWindowSequence in previous frame was start- or stop-window,
122 skip preechocontrol calculation */
123 if (calcPreEcho==0) {
124 /* copy thresholds to internal memory */
125 FDKmemcpy(pbThresholdNm1, pbThreshold, numPb*sizeof(FIXP_DBL));
126 *mdctScalenm1 = mdctScale;
127 return;
128 }
129
130 if ( mdctScale > *mdctScalenm1 ) {
131 /* if current thresholds are downscaled more than the ones from the last block */
132 scaling = 2*(mdctScale-*mdctScalenm1);
133 for(i = 0; i < numPb; i++) {
134
135 /* multiplication with return data type fract ist equivalent to int multiplication */
136 FDK_ASSERT(scaling>=0);
137 tmpThreshold1 = maxAllowedIncreaseFactor * (pbThresholdNm1[i]>>scaling);
138 tmpThreshold2 = fMult(minRemainingThresholdFactor, pbThreshold[i]);
139
140 FIXP_DBL tmp = pbThreshold[i];
141
142 /* copy thresholds to internal memory */
143 pbThresholdNm1[i] = tmp;
144
145 tmp = fixMin(tmp, tmpThreshold1);
146 pbThreshold[i] = fixMax(tmp, tmpThreshold2);
147 }
148 }
149 else {
150 /* if thresholds of last block are more downscaled than the current ones */
151 scaling = 2*(*mdctScalenm1-mdctScale);
152 for(i = 0; i < numPb; i++) {
153
154 /* multiplication with return data type fract ist equivalent to int multiplication */
155 tmpThreshold1 = (maxAllowedIncreaseFactor>>1) * pbThresholdNm1[i];
156 tmpThreshold2 = fMult(minRemainingThresholdFactor, pbThreshold[i]);
157
158 /* copy thresholds to internal memory */
159 pbThresholdNm1[i] = pbThreshold[i];
160
161 FDK_ASSERT(scaling>=0);
162 if((pbThreshold[i]>>(scaling+1)) > tmpThreshold1) {
163 pbThreshold[i] = tmpThreshold1<<(scaling+1);
164 }
165 pbThreshold[i] = fixMax(pbThreshold[i], tmpThreshold2);
166 }
167 }
168
169 *mdctScalenm1 = mdctScale;
170 }
171