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 /*!
85 \file
86 \brief CRC check coutines
87 */
88
89 #include "sbr_crc.h"
90
91 #include "FDK_bitstream.h"
92 #include "transcendent.h"
93
94 #define MAXCRCSTEP 16
95 #define MAXCRCSTEP_LD 4
96
97 /*!
98 \brief crc calculation
99 */
100 static ULONG
calcCRC(HANDLE_CRC hCrcBuf,ULONG bValue,int nBits)101 calcCRC (HANDLE_CRC hCrcBuf, ULONG bValue, int nBits)
102 {
103 int i;
104 ULONG bMask = (1UL << (nBits - 1));
105
106 for (i = 0; i < nBits; i++, bMask >>= 1) {
107 USHORT flag = (hCrcBuf->crcState & hCrcBuf->crcMask) ? 1 : 0;
108 USHORT flag1 = (bMask & bValue) ? 1 : 0;
109
110 flag ^= flag1;
111 hCrcBuf->crcState <<= 1;
112 if (flag)
113 hCrcBuf->crcState ^= hCrcBuf->crcPoly;
114 }
115
116 return (hCrcBuf->crcState);
117 }
118
119
120 /*!
121 \brief crc
122 */
123 static int
getCrc(HANDLE_FDK_BITSTREAM hBs,ULONG NrBits)124 getCrc (HANDLE_FDK_BITSTREAM hBs, ULONG NrBits)
125 {
126 int i;
127 CRC_BUFFER CrcBuf;
128
129 CrcBuf.crcState = SBR_CRC_START;
130 CrcBuf.crcPoly = SBR_CRC_POLY;
131 CrcBuf.crcMask = SBR_CRC_MASK;
132
133 int CrcStep = NrBits>>MAXCRCSTEP_LD;
134
135 int CrcNrBitsRest = (NrBits - CrcStep * MAXCRCSTEP);
136 ULONG bValue;
137
138 for (i = 0; i < CrcStep; i++) {
139 bValue = FDKreadBits (hBs, MAXCRCSTEP);
140 calcCRC (&CrcBuf, bValue, MAXCRCSTEP);
141 }
142
143 bValue = FDKreadBits (hBs, CrcNrBitsRest);
144 calcCRC (&CrcBuf, bValue, CrcNrBitsRest);
145
146 return (CrcBuf.crcState & SBR_CRC_RANGE);
147
148 }
149
150
151 /*!
152 \brief crc interface
153 \return 1: CRC OK, 0: CRC check failure
154 */
155 int
SbrCrcCheck(HANDLE_FDK_BITSTREAM hBs,LONG NrBits)156 SbrCrcCheck (HANDLE_FDK_BITSTREAM hBs, /*!< handle to bit-buffer */
157 LONG NrBits) /*!< max. CRC length */
158 {
159 int crcResult = 1;
160 ULONG NrCrcBits;
161 ULONG crcCheckResult;
162 LONG NrBitsAvailable;
163 ULONG crcCheckSum;
164
165 crcCheckSum = FDKreadBits (hBs, 10);
166
167 NrBitsAvailable = FDKgetValidBits(hBs);
168 if (NrBitsAvailable <= 0){
169 return 0;
170 }
171
172 NrCrcBits = fixMin ((INT)NrBits, (INT)NrBitsAvailable);
173
174 crcCheckResult = getCrc (hBs, NrCrcBits);
175 FDKpushBack(hBs, (NrBitsAvailable - FDKgetValidBits(hBs)) );
176
177
178 if (crcCheckResult != crcCheckSum) {
179 crcResult = 0;
180 }
181
182 return (crcResult);
183 }
184