libFDK/include/FDK_crc.h

   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:
  87    contents/description: CRC calculation
  88
  89 ******************************************************************************/
  90
  91 #ifndef FDK_CRC_H
  92 #define FDK_CRC_H
  93
  94
  95
  96 #include "FDK_bitstream.h"
  97
  98
  99 #define MAX_CRC_REGS 3    /*!< Maximal number of overlapping crc region in ADTS channel pair element is two.
 100                                Select three independent regions preventively. */
 101
 102 /**
 103  *  This structure describes single crc region used for crc calculation.
 104  */
 105 typedef struct
 106 {
 107   UCHAR isActive;
 108   INT   maxBits;
 109   UINT  bitBufCntBits;
 110   UINT  validBits;
 111
 112 } CCrcRegData;
 113
 114 /**
 115  *  CRC info structure.
 116  */
 117 typedef struct
 118 {
 119     CCrcRegData  crcRegData[MAX_CRC_REGS];   /*!< Multiple crc region description. */
 120     const USHORT       *pCrcLookup;          /*!< Pointer to lookup table filled in FDK_crcInit(). */
 121
 122     USHORT              crcPoly;             /*!< CRC generator polynom. */
 123     USHORT              crcMask;             /*!< CRC mask. */
 124     USHORT              startValue;          /*!< CRC start value. */
 125     UCHAR               crcLen;              /*!< CRC length. */
 126
 127     UINT                regStart;            /*!< Start region marker for synchronization. */
 128     UINT                regStop;             /*!< Stop region marker for synchronization. */
 129
 130     USHORT              crcValue;            /*!< Crc value to be calculated. */
 131
 132 } FDK_CRCINFO;
 133
 134 /**
 135  *  CRC info handle.
 136  */
 137 typedef FDK_CRCINFO* HANDLE_FDK_CRCINFO;
 138
 139
 140 /**
 141  * \brief  Initialize CRC structure.
 142  *
 143  * The function initializes existing crc info structure with denoted configuration.
 144  *
 145  * \param hCrcInfo              Pointer to an outlying allocated crc info structure.
 146  * \param crcPoly               Configure crc polynom.
 147  * \param crcStartValue         Configure crc start value.
 148  * \param crcLen                Configure crc length.
 149  *
 150  * \return  none
 151  */
 152 void FDKcrcInit(
 153         HANDLE_FDK_CRCINFO              hCrcInfo,
 154         const UINT                      crcPoly,
 155         const UINT                      crcStartValue,
 156         const UINT                      crcLen
 157         );
 158
 159 /**
 160  * \brief  Reset CRC info structure.
 161  *
 162  * This function clears all intern states of the crc structure.
 163  *
 164  * \param hCrcInfo              Pointer to crc info stucture.
 165  *
 166  * \return  none
 167  */
 168 void FDKcrcReset(
 169         HANDLE_FDK_CRCINFO              hCrcInfo
 170         );
 171
 172
 173 /**
 174  * \brief  Start CRC region with maximum number of bits.
 175  *
 176  * This function marks position in bitstream to be used as start point for crc calculation.
 177  * Bitstream range for crc calculation can be limited or kept dynamic depending on mBits parameter.
 178  * The crc region has to be terminated with FDKcrcEndReg() in each case.
 179  *
 180  * \param hCrcInfo              Pointer to crc info stucture.
 181  * \param hBs                   Pointer to current bit buffer structure.
 182  * \param mBits                 Number of bits in crc region to be calculated.
 183  *                              - mBits > 0: Zero padding will be used for CRC calculation, if there
 184  *                                           are less than mBits bits available.
 185  *                              - mBits < 0: No zero padding is done.
 186  *                              - mBits = 0: The number of bits used in crc calculation is dynamically,
 187  *                                           depending on bitstream position between FDKcrcStartReg() and
 188  *                                           FDKcrcEndReg() call.
 189  *
 190  * \return  ID for the created region, -1 in case of an error
 191  */
 192 INT FDKcrcStartReg(
 193         HANDLE_FDK_CRCINFO              hCrcInfo,
 194         const HANDLE_FDK_BITSTREAM      hBs,
 195         const INT                       mBits
 196         );
 197
 198
 199 /**
 200  * \brief  Ends CRC region.
 201  *
 202  * This function terminates crc region specified with FDKcrcStartReg(). The number of bits in crc region depends
 203  * on mBits parameter of FDKcrcStartReg().
 204  * This function calculates and updates crc in info structure.
 205  *
 206  * \param hCrcInfo              Pointer to crc info stucture.
 207  * \param hBs                   Pointer to current bit buffer structure.
 208  * \param reg                   Crc region ID created in FDKcrcStartReg().
 209  *
 210  * \return  0 on success
 211  */
 212 INT FDKcrcEndReg(
 213         HANDLE_FDK_CRCINFO              hCrcInfo,
 214         const HANDLE_FDK_BITSTREAM      hBs,
 215         const INT                       reg
 216         );
 217
 218
 219 /**
 220  * \brief  This function returns crc value from info struct.
 221  *
 222  * \param hCrcInfo              Pointer to crc info stucture.
 223  *
 224  * \return  CRC value masked with crc length.
 225  */
 226 USHORT FDKcrcGetCRC(
 227         const HANDLE_FDK_CRCINFO        hCrcInfo
 228         );
 229
 230
 231 #endif /* FDK_CRC_H */