tpenc_adts.cpp - Android社区 - https://www.androidos.net.cn/

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

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
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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.

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You must make available free of charge copies of the complete source code of the FDK AAC Codec and your
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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
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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 Audio Encoder **************************

Initial author:       Alex Groeschel
   contents/description: ADTS Transport Headers support

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

#include "tpenc_adts.h"

#include "tpenc_lib.h"
#include "tpenc_asc.h"

int adtsWrite_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->protection_absent) {
    return 0;
  }
  return ( FDKcrcStartReg(&pAdts->crcInfo, hBs, mBits) );
}

void adtsWrite_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->protection_absent == 0)
  {
    FDKcrcEndReg(&pAdts->crcInfo, hBs, reg);
  }
}

int adtsWrite_GetHeaderBits( HANDLE_ADTS hAdts )
{
  int bits = 0;

if (hAdts->currentBlock == 0) {
    /* Static and variable header bits */
    bits = 56;
    if (!hAdts->protection_absent) {
      /* Add header/ single raw data block CRC bits */
      bits += 16;
      if (hAdts->num_raw_blocks>0) {
        /* Add bits of raw data block position markers */
        bits += (hAdts->num_raw_blocks)*16;
      }
    }
  }
  if (!hAdts->protection_absent && hAdts->num_raw_blocks>0) {
    /* Add raw data block CRC bits. Not really part of the header, put they cause bit overhead to be accounted. */
    bits += 16;
  }

hAdts->headerBits = bits;

return bits;
}

INT adtsWrite_Init(HANDLE_ADTS hAdts, CODER_CONFIG *config)
{
  /* Sanity checks */
  if ( config->nSubFrames < 1
    || config->nSubFrames > 4
    || (int)config->aot > 4
    || (int)config->aot < 1 ) {
    return -1;
  }

/* fixed header */
  if (config->flags & CC_MPEG_ID) {
    hAdts->mpeg_id = 0; /* MPEG 4 */
  } else {
    hAdts->mpeg_id = 1; /* MPEG 2 */
  }
  hAdts->layer=0;
  hAdts->protection_absent = ! (config->flags & CC_PROTECTION);
  hAdts->profile = ((int)config->aot) - 1;
  hAdts->sample_freq_index = getSamplingRateIndex(config->samplingRate);
  hAdts->sample_freq = config->samplingRate;
  hAdts->private_bit=0;
  hAdts->channel_mode = config->channelMode;
  hAdts->original=0;
  hAdts->home=0;
  /* variable header */
  hAdts->copyright_id=0;
  hAdts->copyright_start=0;

hAdts->num_raw_blocks=config->nSubFrames-1; /* 0 means 1 raw data block */

FDKcrcInit(&hAdts->crcInfo, 0x8005, 0xFFFF, 16);

hAdts->currentBlock = 0;

return 0;
}

int adtsWrite_EncodeHeader(HANDLE_ADTS hAdts,
                                 HANDLE_FDK_BITSTREAM hBitStream,
                                 int buffer_fullness,
                                 int frame_length)
{
  INT crcIndex = 0;

hAdts->headerBits = adtsWrite_GetHeaderBits(hAdts);

FDK_ASSERT(((frame_length+hAdts->headerBits)/8)<0x2000);      /*13 bit*/
  FDK_ASSERT(buffer_fullness<0x800);    /* 11 bit   */

if (!hAdts->protection_absent) {
    FDKcrcReset(&hAdts->crcInfo);
  }

if (hAdts->currentBlock == 0) {
    FDKresetBitbuffer(hBitStream, BS_WRITER);
  }

hAdts->subFrameStartBit = FDKgetValidBits(hBitStream);

/* Skip new header if this is raw data block 1..n */
  if (hAdts->currentBlock == 0)
  {
    FDKresetBitbuffer(hBitStream, BS_WRITER);

if (hAdts->num_raw_blocks == 0) {
      crcIndex = adtsWrite_CrcStartReg(hAdts, hBitStream, 0);
    }

/* fixed header */
    FDKwriteBits(hBitStream, 0xFFF, 12);
    FDKwriteBits(hBitStream, hAdts->mpeg_id, 1);
    FDKwriteBits(hBitStream, hAdts->layer, 2);
    FDKwriteBits(hBitStream, hAdts->protection_absent, 1);
    FDKwriteBits(hBitStream, hAdts->profile, 2);
    FDKwriteBits(hBitStream, hAdts->sample_freq_index, 4);
    FDKwriteBits(hBitStream, hAdts->private_bit, 1);
    FDKwriteBits(hBitStream, getChannelConfig(hAdts->channel_mode), 3);
    FDKwriteBits(hBitStream, hAdts->original, 1);
    FDKwriteBits(hBitStream, hAdts->home, 1);
    /* variable header */
    FDKwriteBits(hBitStream, hAdts->copyright_id, 1);
    FDKwriteBits(hBitStream, hAdts->copyright_start, 1);
    FDKwriteBits(hBitStream, (frame_length + hAdts->headerBits)>>3, 13);
    FDKwriteBits(hBitStream, buffer_fullness, 11);
    FDKwriteBits(hBitStream, hAdts->num_raw_blocks, 2);

if (!hAdts->protection_absent) {
      int i;

/* End header CRC portion for single raw data block and write dummy zero values for unknown fields. */
      if (hAdts->num_raw_blocks == 0) {
        adtsWrite_CrcEndReg(hAdts, hBitStream, crcIndex);
      } else {
        for (i=0; i<hAdts->num_raw_blocks; i++) {
          FDKwriteBits(hBitStream, 0, 16);
        }
      }
      FDKwriteBits(hBitStream, 0, 16);
    }
  } /* End of ADTS header */

return 0;
}

void adtsWrite_EndRawDataBlock(HANDLE_ADTS hAdts,
                          HANDLE_FDK_BITSTREAM hBs,
                          int *pBits)
{
  if (!hAdts->protection_absent) {
    FDK_BITSTREAM bsWriter;

FDKinitBitStream(&bsWriter, hBs->hBitBuf.Buffer, hBs->hBitBuf.bufSize, 0, BS_WRITER);
    FDKpushFor(&bsWriter, 56);

if (hAdts->num_raw_blocks == 0) {
      FDKwriteBits(&bsWriter, FDKcrcGetCRC(&hAdts->crcInfo), 16);
    } else {
      int distance;

/* Write CRC of current raw data block */
      FDKwriteBits(hBs, FDKcrcGetCRC(&hAdts->crcInfo), 16);

/* Write distance to current data block */
      if (hAdts->currentBlock < hAdts->num_raw_blocks) {
        FDKpushFor(&bsWriter, hAdts->currentBlock*16);
        distance = FDKgetValidBits(hBs) - (56 + (hAdts->num_raw_blocks)*16 + 16);
        FDKwriteBits(&bsWriter, distance>>3, 16);
      }
    }
    FDKsyncCache(&bsWriter);
  }

/* Write total frame lenth for multiple raw data blocks and header CRC */
  if (hAdts->num_raw_blocks > 0 && hAdts->currentBlock == hAdts->num_raw_blocks) {
    FDK_BITSTREAM bsWriter;
    int crcIndex = 0;

FDKinitBitStream(&bsWriter, hBs->hBitBuf.Buffer, hBs->hBitBuf.bufSize, 0, BS_WRITER);

if (!hAdts->protection_absent) {
      FDKcrcReset(&hAdts->crcInfo);
      crcIndex = FDKcrcStartReg(&hAdts->crcInfo, &bsWriter, 0);
    }
    /* Write total frame length */
    FDKpushFor(&bsWriter, 56-28+2);
    FDKwriteBits(&bsWriter, FDKgetValidBits(hBs)>>3, 13);

/* Write header CRC */
    if (!hAdts->protection_absent) {
      FDKpushFor(&bsWriter, 11+2 + (hAdts->num_raw_blocks)*16);
      FDKcrcEndReg(&hAdts->crcInfo, &bsWriter, crcIndex);
      FDKwriteBits(&bsWriter, FDKcrcGetCRC(&hAdts->crcInfo), 16);
    }
    FDKsyncCache(&bsWriter);
  }

/* Correct *pBits to reflect the amount of bits of the current subframe */
  *pBits -= hAdts->subFrameStartBit;
  if (!hAdts->protection_absent && hAdts->num_raw_blocks > 0) {
    /* Fixup CRC bits, since they come after each raw data block */
    *pBits += 16;
  }
  hAdts->currentBlock++;
}

C++程序 | 316行 | 11.58 KB

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