
/* -----------------------------------------------------------------------------------------------------------
Software License for The Fraunhofer FDK AAC Codec Library for Android

© Copyright  1995 - 2012 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
  All rights reserved.

 1.    INTRODUCTION
The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software that implements
the MPEG Advanced Audio Coding ("AAC") encoding and decoding scheme for digital audio.
This FDK AAC Codec software is intended to be used on a wide variety of Android devices.

AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient general perceptual
audio codecs. AAC-ELD is considered the best-performing full-bandwidth communications codec by
independent studies and is widely deployed. AAC has been standardized by ISO and IEC as part
of the MPEG specifications.

Patent licenses for necessary patent claims for the FDK AAC Codec (including those of Fraunhofer)
may be obtained through Via Licensing (www.vialicensing.com) or through the respective patent owners
individually for the purpose of encoding or decoding bit streams in products that are compliant with
the ISO/IEC MPEG audio standards. Please note that most manufacturers of Android devices already license
these patent claims through Via Licensing or directly from the patent owners, and therefore FDK AAC Codec
software may already be covered under those patent licenses when it is used for those licensed purposes only.

Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
are also available from Fraunhofer. Users are encouraged to check the Fraunhofer website for additional
applications information and documentation.

2.    COPYRIGHT LICENSE

Redistribution and use in source and binary forms, with or without modification, are permitted without
payment of copyright license fees provided that you satisfy the following conditions:

You must retain the complete text of this software license in redistributions of the FDK AAC Codec or
your modifications thereto in source code form.

You must retain the complete text of this software license in the documentation and/or other materials
provided with redistributions of the FDK AAC Codec or your modifications thereto in binary form.
You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
modifications thereto to recipients of copies in binary form.

The name of Fraunhofer may not be used to endorse or promote products derived from this library without
prior written permission.

You may not charge copyright license fees for anyone to use, copy or distribute the FDK AAC Codec
software or your modifications thereto.

Your modified versions of the FDK AAC Codec must carry prominent notices stating that you changed the software
and the date of any change. For modified versions of the FDK AAC Codec, the term
"Fraunhofer FDK AAC Codec Library for Android" must be replaced by the term
"Third-Party Modified Version of the Fraunhofer FDK AAC Codec Library for Android."

3.    NO PATENT LICENSE

NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer,
ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with
respect to this software.

You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized
by appropriate patent licenses.

4.    DISCLAIMER

This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright holders and contributors
"AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, including but not limited to the implied warranties
of merchantability and fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary, or consequential damages,
including but not limited to procurement of substitute goods or services; loss of use, data, or profits,
or business interruption, however caused and on any theory of liability, whether in contract, strict
liability, or tort (including negligence), arising in any way out of the use of this software, even if
advised of the possibility of such damage.

5.    CONTACT INFORMATION

Fraunhofer Institute for Integrated Circuits IIS
Attention: Audio and Multimedia Departments - FDK AAC LL
Am Wolfsmantel 33
91058 Erlangen, Germany

www.iis.fraunhofer.de/amm
amm-info@iis.fraunhofer.de
----------------------------------------------------------------------------------------------------------- */

/*****************************  MPEG-4 AAC Decoder  **************************

   Author(s):   Josef Hoepfl
   Description: ADTS interface

******************************************************************************/

#include "tpdec_adts.h"


#include "FDK_bitstream.h"



void adtsRead_CrcInit(HANDLE_ADTS pAdts) /*!< pointer to adts crc info stucture */
{
  FDKcrcInit(&pAdts->crcInfo, 0x8005, 0xFFFF, 16);
}

int adtsRead_CrcStartReg(
                     HANDLE_ADTS pAdts,          /*!< pointer to adts stucture */
                     HANDLE_FDK_BITSTREAM hBs,   /*!< handle to current bit buffer structure */
                     int mBits                   /*!< number of bits in crc region */
                   )
{
  if (pAdts->bs.protection_absent) {
    return 0;
  }

  return ( FDKcrcStartReg(&pAdts->crcInfo, hBs, mBits) );

}

void adtsRead_CrcEndReg(
                    HANDLE_ADTS pAdts, /*!< pointer to adts crc info stucture */
                    HANDLE_FDK_BITSTREAM hBs,   /*!< handle to current bit buffer structure */
                    int reg                    /*!< crc region */
                  )
{
  if (pAdts->bs.protection_absent == 0)
  {
    FDKcrcEndReg(&pAdts->crcInfo, hBs, reg);
  }
}

TRANSPORTDEC_ERROR adtsRead_CrcCheck( HANDLE_ADTS pAdts )
{
  TRANSPORTDEC_ERROR ErrorStatus = TRANSPORTDEC_OK;
  USHORT crc;

  if (pAdts->bs.protection_absent)
    return TRANSPORTDEC_OK;

  crc = FDKcrcGetCRC(&pAdts->crcInfo);
  if (crc != pAdts->crcReadValue)
  {
    return (TRANSPORTDEC_CRC_ERROR);
  }

  return (ErrorStatus);
}



#define Adts_Length_SyncWord                     12
#define Adts_Length_Id                            1
#define Adts_Length_Layer                         2
#define Adts_Length_ProtectionAbsent              1
#define Adts_Length_Profile                       2
#define Adts_Length_SamplingFrequencyIndex        4
#define Adts_Length_PrivateBit                    1
#define Adts_Length_ChannelConfiguration          3
#define Adts_Length_OriginalCopy                  1
#define Adts_Length_Home                          1
#define Adts_Length_CopyrightIdentificationBit    1
#define Adts_Length_CopyrightIdentificationStart  1
#define Adts_Length_FrameLength                  13
#define Adts_Length_BufferFullness               11
#define Adts_Length_NumberOfRawDataBlocksInFrame  2
#define Adts_Length_CrcCheck                     16

TRANSPORTDEC_ERROR adtsRead_DecodeHeader(
        HANDLE_ADTS           pAdts,
        CSAudioSpecificConfig *pAsc,
        HANDLE_FDK_BITSTREAM  hBs,
        const INT             ignoreBufferFullness
        )
{
  INT crcReg;

  INT valBits;
  INT cmp_buffer_fullness;
  int i, adtsHeaderLength;

  STRUCT_ADTS_BS bs;

#ifdef TP_PCE_ENABLE
  CProgramConfig oldPce;
  /* Store the old PCE temporarily. Maybe we'll need it later if we
     have channelConfig=0 and no PCE in this frame. */
  FDKmemcpy(&oldPce, &pAsc->m_progrConfigElement, sizeof(CProgramConfig));
#endif

  valBits = FDKgetValidBits(hBs);

  /* adts_fixed_header */
  bs.mpeg_id           = FDKreadBits(hBs, Adts_Length_Id);
  bs.layer             = FDKreadBits(hBs, Adts_Length_Layer);
  bs.protection_absent = FDKreadBits(hBs, Adts_Length_ProtectionAbsent);
  bs.profile           = FDKreadBits(hBs, Adts_Length_Profile);
  bs.sample_freq_index = FDKreadBits(hBs, Adts_Length_SamplingFrequencyIndex);
  bs.private_bit       = FDKreadBits(hBs, Adts_Length_PrivateBit);
  bs.channel_config    = FDKreadBits(hBs, Adts_Length_ChannelConfiguration);
  bs.original          = FDKreadBits(hBs, Adts_Length_OriginalCopy);
  bs.home              = FDKreadBits(hBs, Adts_Length_Home);

  /* adts_variable_header */
  bs.copyright_id    = FDKreadBits(hBs, Adts_Length_CopyrightIdentificationBit);
  bs.copyright_start = FDKreadBits(hBs, Adts_Length_CopyrightIdentificationStart);
  bs.frame_length    = FDKreadBits(hBs, Adts_Length_FrameLength);
  bs.adts_fullness   = FDKreadBits(hBs, Adts_Length_BufferFullness);
  bs.num_raw_blocks  = FDKreadBits(hBs, Adts_Length_NumberOfRawDataBlocksInFrame);
  bs.num_pce_bits    = 0;

  adtsHeaderLength = ADTS_HEADERLENGTH;

  if (!bs.protection_absent) {
    FDKcrcReset(&pAdts->crcInfo);
    FDKpushBack(hBs, 56);   /* complete fixed and variable header! */
    crcReg = FDKcrcStartReg(&pAdts->crcInfo, hBs, 0);
    FDKpushFor(hBs, 56);
  }

  if (! bs.protection_absent && bs.num_raw_blocks>0) {
    for (i=0; i<bs.num_raw_blocks; i++) {
      pAdts->rawDataBlockDist[i] = (USHORT)FDKreadBits(hBs, 16);
      adtsHeaderLength += 16;
    }
    /* Change raw data blocks to delta values */
    pAdts->rawDataBlockDist[bs.num_raw_blocks] = bs.frame_length - 7 - bs.num_raw_blocks*2 - 2 ;
    for (i=bs.num_raw_blocks; i>0; i--) {
      pAdts->rawDataBlockDist[i] -= pAdts->rawDataBlockDist[i-1];
    }
  }

  /* adts_error_check */
  if (!bs.protection_absent)
  {
    USHORT crc_check;

    FDKcrcEndReg(&pAdts->crcInfo, hBs, crcReg);
    crc_check = FDKreadBits(hBs, Adts_Length_CrcCheck);
    adtsHeaderLength += Adts_Length_CrcCheck;

    pAdts->crcReadValue = crc_check;
    /* Check header CRC in case of multiple raw data blocks */
    if (bs.num_raw_blocks > 0) {
      if (pAdts->crcReadValue != FDKcrcGetCRC(&pAdts->crcInfo)) {
        return TRANSPORTDEC_CRC_ERROR;
      }
      /* Reset CRC for the upcoming raw_data_block() */
      FDKcrcReset(&pAdts->crcInfo);
    }
  }


  /* check if valid header */
  if (
      (bs.layer != 0) ||                          // we only support MPEG ADTS
      (bs.sample_freq_index >= 13)                // we only support 96kHz - 7350kHz
      ) {
    FDKpushFor(hBs, bs.frame_length * 8);   // try again one frame later
    return TRANSPORTDEC_UNSUPPORTED_FORMAT;
  }

  /* special treatment of id-bit */
  if ( (bs.mpeg_id == 0) && (pAdts->decoderCanDoMpeg4 == 0) )
  {
    /* MPEG-2 decoder cannot play MPEG-4 bitstreams */


    FDKpushFor(hBs, bs.frame_length * 8);  // try again one frame later
    return TRANSPORTDEC_UNSUPPORTED_FORMAT;
  }

  if (!ignoreBufferFullness)
  {
    cmp_buffer_fullness = bs.frame_length*8 + bs.adts_fullness*32*getNumberOfEffectiveChannels(bs.channel_config);


    /* Evaluate buffer fullness */
    if (bs.adts_fullness != 0x7FF)
    {
      if (pAdts->BufferFullnesStartFlag)
      {
        if ( valBits < cmp_buffer_fullness )
        {
          /* Condition for start of decoding is not fulfilled */

          /* The current frame will not be decoded */
          FDKpushBack(hBs, adtsHeaderLength);

          if ( (cmp_buffer_fullness+adtsHeaderLength) > ((TRANSPORTDEC_INBUF_SIZE<<3)-7) ) {
            return TRANSPORTDEC_SYNC_ERROR;
          } else {
            return TRANSPORTDEC_NOT_ENOUGH_BITS;
          }
        }
        else
        {
          pAdts->BufferFullnesStartFlag = 0;
        }
      }
    }
  }


  /* Get info from ADTS header */
  AudioSpecificConfig_Init(pAsc);
  pAsc->m_aot                    = (AUDIO_OBJECT_TYPE)(bs.profile + 1);
  pAsc->m_samplingFrequencyIndex = bs.sample_freq_index;
  pAsc->m_samplingFrequency      = SamplingRateTable[bs.sample_freq_index];
  pAsc->m_channelConfiguration   = bs.channel_config;
  pAsc->m_samplesPerFrame        = 1024;

#ifdef TP_PCE_ENABLE
  if (bs.channel_config == 0)
  {
    int pceBits = 0;
    UINT alignAnchor = FDKgetValidBits(hBs);
    
    if (FDKreadBits(hBs,3) == ID_PCE) {
      /* Got luck! Parse the PCE */
      int crcReg;
      crcReg = adtsRead_CrcStartReg(pAdts, hBs, 0);

      CProgramConfig_Read(&pAsc->m_progrConfigElement, hBs, alignAnchor);

      adtsRead_CrcEndReg(pAdts, hBs, crcReg);
      pceBits = alignAnchor - FDKgetValidBits(hBs);
      /* store the number of PCE bits */
      bs.num_pce_bits = pceBits;
    }
    else {
      /* No PCE in this frame! Push back the ID tag bits. */
      FDKpushBack(hBs,3);

      /* Encoders do not have to write a PCE in each frame.
         So if we already have a valid PCE we have to use it. */
      if (  oldPce.isValid
        && (bs.sample_freq_index == pAdts->bs.sample_freq_index)  /* we could compare the complete fixed header (bytes) here! */
        && (bs.channel_config    == pAdts->bs.channel_config) /* == 0 */
        && (bs.mpeg_id           == pAdts->bs.mpeg_id) )
      { /* Restore previous PCE which is still valid */
        FDKmemcpy(&pAsc->m_progrConfigElement, &oldPce, sizeof(CProgramConfig));
      }
      else if (bs.mpeg_id == 0) {
        /* If not it seems that we have a implicit channel configuration.
           This mode is not allowed in the context of ISO/IEC 14496-3.
           Skip this frame and try the next one. */
        FDKpushFor(hBs, (bs.frame_length<<3) - adtsHeaderLength - 3);
        return TRANSPORTDEC_UNSUPPORTED_FORMAT;
      }
      /* else {
         ISO/IEC 13818-7 implicit channel mapping is allowed.
         So just open the box of chocolates to see what we got.
      } */
    }
  }
#endif /* TP_PCE_ENABLE */

  /* Copy bit stream data struct to persistent memory now, once we passed all sanity checks above. */
  FDKmemcpy(&pAdts->bs, &bs, sizeof(STRUCT_ADTS_BS));

  return TRANSPORTDEC_OK;
}

int adtsRead_GetRawDataBlockLength(
        HANDLE_ADTS pAdts,
        INT         blockNum
        )
{
  int length;

  if (pAdts->bs.num_raw_blocks == 0) {
    length = (pAdts->bs.frame_length - 7) << 3;    /* aac_frame_length subtracted by the header size (7 bytes). */
    if (pAdts->bs.protection_absent == 0)
      length -= 16;                                                                   /* substract 16 bit CRC */
  } else {
    if (pAdts->bs.protection_absent) {
      length = -1; /* raw data block length is unknown */
    } else {
      if (blockNum < 0 || blockNum > 3) {
        return TRANSPORTDEC_INVALID_PARAMETER;
      }
      length = (pAdts->rawDataBlockDist[blockNum] << 3) - 16;
    }
  }
  if (blockNum == 0) {
    length -= pAdts->bs.num_pce_bits;
  }
  return length;
}


