libAACenc/src/block_switch.h

   1
   2 /* -----------------------------------------------------------------------------------------------------------
   3 Software License for The Fraunhofer FDK AAC Codec Library for Android
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   5 © Copyright  1995 - 2013 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
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   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.
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  18 Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
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  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.
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  56 ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
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  64 This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
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  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-4 AAC Encoder  **************************
  85
  86    Author(s):   M. Werner
  87    Description: Block switching
  88
  89 ******************************************************************************/
  90
  91 #ifndef _BLOCK_SWITCH_H
  92 #define _BLOCK_SWITCH_H
  93
  94 #include "common_fix.h"
  95
  96 #include "psy_const.h"
  97
  98 /****************** Defines ******************************/
  99   #define BLOCK_SWITCH_WINDOWS    8                   /* number of windows for energy calculation */
 100
 101 #define BLOCK_SWITCHING_IIR_LEN    2                  /* Length of HighPass-IIR-Filter for Attack-Detection */
 102 #define BLOCK_SWITCH_ENERGY_SHIFT  7                  /* should be logDualis(BLOCK_SWITCH_WINDOW_LEN) to avoid overflow in windowNrgs. */
 103
 104 #define LAST_WINDOW 0
 105 #define THIS_WINDOW 1
 106
 107
 108 /****************** Structures ***************************/
 109 typedef struct{
 110   INT   lastWindowSequence;
 111   INT   windowShape;
 112   INT   lastWindowShape;
 113   UINT  nBlockSwitchWindows;                       /* number of windows for energy calculation */
 114   INT   attack;
 115   INT   lastattack;
 116   INT   attackIndex;
 117   INT   lastAttackIndex;
 118   INT   allowShortFrames;                          /* for Low Delay, don't allow short frames */
 119   INT   allowLookAhead;                            /* for Low Delay, don't do look-ahead */
 120   INT   noOfGroups;
 121   INT   groupLen[MAX_NO_OF_GROUPS];
 122   FIXP_DBL maxWindowNrg;                           /* max energy in subwindows */
 123
 124   FIXP_DBL windowNrg[2][BLOCK_SWITCH_WINDOWS];     /* time signal energy in Subwindows (last and current) */
 125   FIXP_DBL windowNrgF[2][BLOCK_SWITCH_WINDOWS];    /* filtered time signal energy in segments (last and current) */
 126   FIXP_DBL accWindowNrg;                           /* recursively accumulated windowNrgF */
 127
 128   FIXP_DBL iirStates[BLOCK_SWITCHING_IIR_LEN];     /* filter delay-line */
 129
 130 } BLOCK_SWITCHING_CONTROL;
 131
 132
 133
 134
 135
 136 void FDKaacEnc_InitBlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, INT isLowDelay);
 137
 138 int FDKaacEnc_BlockSwitching(BLOCK_SWITCHING_CONTROL *blockSwitchingControl, const INT granuleLength, const int isLFE, const INT_PCM *pTimeSignal);
 139
 140 int FDKaacEnc_SyncBlockSwitching(
 141       BLOCK_SWITCHING_CONTROL *blockSwitchingControlLeft,
 142       BLOCK_SWITCHING_CONTROL *blockSwitchingControlRight,
 143       const INT noOfChannels,
 144       const INT commonWindow);
 145
 146 #endif  /* #ifndef _BLOCK_SWITCH_H */