/*
 *  Copyright (C) 2010-2018 Team Kodi
 *  This file is part of Kodi - https://kodi.tv
 *
 *  SPDX-License-Identifier: GPL-2.0-or-later
 *  See LICENSES/README.md for more information.
 */

#include "AEStreamInfo.h"
#include "utils/log.h"
#include <algorithm>
#include <string.h>

#define DTS_PREAMBLE_14BE  0x1FFFE800
#define DTS_PREAMBLE_14LE  0xFF1F00E8
#define DTS_PREAMBLE_16BE  0x7FFE8001
#define DTS_PREAMBLE_16LE  0xFE7F0180
#define DTS_PREAMBLE_HD    0x64582025
#define DTS_PREAMBLE_XCH   0x5a5a5a5a
#define DTS_PREAMBLE_XXCH  0x47004a03
#define DTS_PREAMBLE_X96K  0x1d95f262
#define DTS_PREAMBLE_XBR   0x655e315e
#define DTS_PREAMBLE_LBR   0x0a801921
#define DTS_PREAMBLE_XLL   0x41a29547
#define DTS_SFREQ_COUNT    16
#define MAX_EAC3_BLOCKS    6
#define UNKNOWN_DTS_EXTENSION 255

static const uint16_t AC3Bitrates   [] = {32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 448, 512, 576, 640};
static const uint16_t AC3FSCod      [] = {48000, 44100, 32000, 0};
static const uint8_t  AC3BlkCod     [] = {1, 2, 3, 6};
static const uint8_t  AC3Channels   [] = {2, 1, 2, 3, 3, 4, 4, 5};
static const uint8_t  DTSChannels   [] = {1, 2, 2, 2, 2, 3, 3, 4, 4, 5, 6, 6, 6, 7, 8, 8};
static const uint8_t  THDChanMap    [] = {2, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1};

static const uint32_t DTSSampleRates[DTS_SFREQ_COUNT] =
{
  0     ,
  8000  ,
  16000 ,
  32000 ,
  64000 ,
  128000,
  11025 ,
  22050 ,
  44100 ,
  88200 ,
  176400,
  12000 ,
  24000 ,
  48000 ,
  96000 ,
  192000
};

CAEStreamParser::CAEStreamParser() :
  m_syncFunc      (&CAEStreamParser::DetectType)
{
  av_crc_init(m_crcTrueHD, 0, 16, 0x2D, sizeof(m_crcTrueHD));
}

double CAEStreamInfo::GetDuration() const
{
  double duration = 0;
  switch (m_type)
  {
    case STREAM_TYPE_AC3:
      duration = 0.032;
      break;
    case STREAM_TYPE_EAC3:
      duration = 6144.0 / m_sampleRate / 4;
      break;
    case STREAM_TYPE_TRUEHD:
      int rate;
      if (m_sampleRate == 48000 ||
          m_sampleRate == 96000 ||
          m_sampleRate == 192000)
        rate = 192000;
      else
        rate = 176400;
      duration = 3840.0 / rate;
      break;
    case STREAM_TYPE_DTS_512:
    case STREAM_TYPE_DTSHD_CORE:
    case STREAM_TYPE_DTSHD:
    case STREAM_TYPE_DTSHD_MA:
      duration = 512.0 / m_sampleRate;
      break;
    case STREAM_TYPE_DTS_1024:
      duration = 1024.0 / m_sampleRate;
      break;
    case STREAM_TYPE_DTS_2048:
      duration = 2048.0 / m_sampleRate;
      break;
    default:
      CLog::Log(LOGERROR, "CAEStreamInfo::GetDuration - invalid stream type");
      break;
  }
  return duration * 1000;
}

bool CAEStreamInfo::operator==(const CAEStreamInfo& info) const
{
  if (m_type != info.m_type)
    return false;
  if (m_dataIsLE != info.m_dataIsLE)
    return false;
  if (m_repeat != info.m_repeat)
    return false;
  return true;
}

CAEStreamParser::~CAEStreamParser() = default;

void CAEStreamParser::Reset()
{
  m_skipBytes = 0;
  m_bufferSize = 0;
  m_needBytes = 0;
  m_hasSync = false;
}

int CAEStreamParser::AddData(uint8_t *data, unsigned int size, uint8_t **buffer/* = NULL */, unsigned int *bufferSize/* = 0 */)
{
  if (size == 0)
  {
    if (bufferSize)
      *bufferSize = 0;
    return 0;
  }

  if (m_skipBytes)
  {
    unsigned int canSkip = std::min(size, m_skipBytes);
    unsigned int room = sizeof(m_buffer) - m_bufferSize;
    unsigned int copy = std::min(room, canSkip);

    memcpy(m_buffer + m_bufferSize, data, copy);
    m_bufferSize += copy;
    m_skipBytes -= copy;

    if (m_skipBytes)
    {
      if (bufferSize)
        *bufferSize = 0;
      return copy;
    }

    GetPacket(buffer, bufferSize);
    return copy;
  }
  else
  {
    unsigned int consumed = 0;
    unsigned int offset = 0;
    unsigned int room = sizeof(m_buffer) - m_bufferSize;
    while(1)
    {
      if (!size)
      {
        if (bufferSize)
          *bufferSize = 0;
        return consumed;
      }

      unsigned int copy = std::min(room, size);
      memcpy(m_buffer + m_bufferSize, data, copy);
      m_bufferSize += copy;
      consumed += copy;
      data += copy;
      size -= copy;
      room -= copy;

      if (m_needBytes > m_bufferSize)
        continue;

      m_needBytes = 0;
      offset = (this->*m_syncFunc)(m_buffer, m_bufferSize);

      if (m_hasSync || m_needBytes)
        break;
      else
      {
        /* lost sync */
        m_syncFunc = &CAEStreamParser::DetectType;
        m_info.m_type = CAEStreamInfo::STREAM_TYPE_NULL;
        m_info.m_repeat = 1;

        /* if the buffer is full, or the offset < the buffer size */
        if (m_bufferSize == sizeof(m_buffer) || offset < m_bufferSize)
        {
          m_bufferSize -= offset;
          room += offset;
          memmove(m_buffer, m_buffer + offset, m_bufferSize);
        }
      }
    }

    /* if we got here, we acquired sync on the buffer */

    /* align the buffer */
    if (offset)
    {
      m_bufferSize -= offset;
      memmove(m_buffer, m_buffer + offset, m_bufferSize);
    }

    /* bytes to skip until the next packet */
    m_skipBytes = std::max(0, (int)m_fsize - (int)m_bufferSize);
    if (m_skipBytes)
    {
      if (bufferSize)
        *bufferSize = 0;
      return consumed;
    }

    if (!m_needBytes)
      GetPacket(buffer, bufferSize);
    else if (bufferSize)
      *bufferSize = 0;

    return consumed;
  }
}

void CAEStreamParser::GetPacket(uint8_t **buffer, unsigned int *bufferSize)
{
  /* if the caller wants the packet */
  if (buffer)
  {
    /* if it is dtsHD and we only want the core, just fetch that */
    unsigned int size = m_fsize;
    if (m_info.m_type == CAEStreamInfo::STREAM_TYPE_DTSHD_CORE)
      size = m_coreSize;

    /* make sure the buffer is allocated and big enough */
    if (!*buffer || !bufferSize || *bufferSize < size)
    {
      delete[] *buffer;
      *buffer = new uint8_t[size];
    }

    /* copy the data into the buffer and update the size */
    memcpy(*buffer, m_buffer, size);
    if (bufferSize)
      *bufferSize = size;
  }

  /* remove the parsed data from the buffer */
  m_bufferSize -= m_fsize;
  memmove(m_buffer, m_buffer + m_fsize, m_bufferSize);
  m_fsize = 0;
  m_coreSize = 0;
}

/* SYNC FUNCTIONS */

/*
  This function looks for sync words across the types in parallel, and only does an exhaustive
  test if it finds a syncword. Once sync has been established, the relevent sync function sets
  m_syncFunc to itself. This function will only be called again if total sync is lost, which
  allows is to switch stream types on the fly much like a real receiver does.
*/
unsigned int CAEStreamParser::DetectType(uint8_t *data, unsigned int size)
{
  unsigned int skipped  = 0;
  unsigned int possible = 0;

  while (size > 8)
  {
    /* if it could be DTS */
    unsigned int header = data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3];
    if (header == DTS_PREAMBLE_14LE ||
        header == DTS_PREAMBLE_14BE ||
        header == DTS_PREAMBLE_16LE ||
        header == DTS_PREAMBLE_16BE)
    {
      unsigned int skip = SyncDTS(data, size);
      if (m_hasSync || m_needBytes)
        return skipped + skip;
      else
        possible = skipped;
    }

    /* if it could be AC3 */
    if (data[0] == 0x0b && data[1] == 0x77)
    {
      unsigned int skip = SyncAC3(data, size);
      if (m_hasSync || m_needBytes)
        return skipped + skip;
      else
        possible = skipped;
    }

    /* if it could be TrueHD */
    if (data[4] == 0xf8 && data[5] == 0x72 && data[6] == 0x6f && data[7] == 0xba)
    {
      unsigned int skip = SyncTrueHD(data, size);
      if (m_hasSync)
        return skipped + skip;
      else
        possible = skipped;
    }

    /* move along one byte */
    --size;
    ++skipped;
    ++data;
  }

  return possible ? possible : skipped;
}

bool CAEStreamParser::TrySyncAC3(uint8_t *data, unsigned int size, bool resyncing, bool wantEAC3dependent)
{
  if (size < 8)
    return false;

  /* look for an ac3 sync word */
  if (data[0] != 0x0b || data[1] != 0x77)
    return false;

  uint8_t bsid  = data[5] >> 3;
  uint8_t acmod = data[6] >> 5;
  uint8_t lfeon;

  int8_t pos = 4;
  if ((acmod & 0x1) && (acmod != 0x1))
    pos -= 2;
  if (acmod & 0x4 )
    pos -= 2;
  if (acmod == 0x2)
    pos -= 2;
  if (pos < 0)
    lfeon = (data[7] & 0x64) ? 1 : 0;
  else
    lfeon = ((data[6] >> pos) & 0x1) ? 1 : 0;

  if (bsid > 0x11 || acmod > 7)
    return false;

  if (bsid <= 10)
  {
    /* Normal AC-3 */

    if (wantEAC3dependent)
      return false;

    uint8_t fscod = data[4] >> 6;
    uint8_t frmsizecod = data[4] & 0x3F;
    if (fscod == 3 || frmsizecod > 37)
      return false;

    /* get the details we need to check crc1 and framesize */
    unsigned int bitRate = AC3Bitrates[frmsizecod >> 1];
    unsigned int framesize = 0;
    switch (fscod)
    {
      case 0: framesize = bitRate * 2; break;
      case 1: framesize = (320 * bitRate / 147 + (frmsizecod & 1 ? 1 : 0)); break;
      case 2: framesize = bitRate * 4; break;
    }

    m_fsize = framesize << 1;
    m_info.m_sampleRate = AC3FSCod[fscod];

    /* dont do extensive testing if we have not lost sync */
    if (m_info.m_type == CAEStreamInfo::STREAM_TYPE_AC3 && !resyncing)
      return true;

    /* this may be the main stream of EAC3 */
    unsigned int fsizeMain = m_fsize;
    unsigned int reqBytes = fsizeMain + 8;
    if (size < reqBytes) {
      /* not enough data to check for E-AC3 dependent frame, request more */
      m_needBytes = reqBytes;
      m_fsize = 0;
      /* no need to resync => return true */
      return true;
    }
    if (TrySyncAC3(data + fsizeMain, size - fsizeMain, resyncing, /*wantEAC3dependent*/ true)) {
      /* concatenate the main and dependent frames */
      m_fsize += fsizeMain;
      return true;
    }

    unsigned int crc_size;
    /* if we have enough data, validate the entire packet, else try to validate crc2 (5/8 of the packet) */
    if (framesize <= size)
      crc_size = framesize - 1;
    else
      crc_size = (framesize >> 1) + (framesize >> 3) - 1;

    if (crc_size <= size)
      if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &data[2], crc_size * 2))
        return false;

    /* if we get here, we can sync */
    m_hasSync = true;
    m_info.m_channels = AC3Channels[acmod] + lfeon;
    m_syncFunc = &CAEStreamParser::SyncAC3;
    m_info.m_type = CAEStreamInfo::STREAM_TYPE_AC3;
    m_info.m_ac3FrameSize = m_fsize;
    m_info.m_repeat = 1;

    CLog::Log(LOGINFO, "CAEStreamParser::TrySyncAC3 - AC3 stream detected (%d channels, %dHz)", m_info.m_channels, m_info.m_sampleRate);
    return true;
  }
  else
  {
    // Enhanced AC-3
    uint8_t strmtyp = data[2] >> 6;
    if (strmtyp == 3)
      return false;

    if (strmtyp != 1 && wantEAC3dependent)
    {
      CLog::Log(LOGDEBUG, "CAEStreamParser::TrySyncAC3 - Unexpected stream type: %d (wantEAC3dependent: %d)",
                strmtyp, wantEAC3dependent);
      return false;
    }

    unsigned int framesize = (((data[2] & 0x7) << 8) | data[3]) + 1;
    uint8_t fscod = (data[4] >> 6) & 0x3;
    uint8_t cod = (data[4] >> 4) & 0x3;
    uint8_t acmod = (data[4] >> 1) & 0x7;
    uint8_t lfeon = data[4] & 0x1;
    uint8_t blocks;

    if (fscod == 0x3)
    {
      if (cod == 0x3)
        return false;

      blocks = 6;
      m_info.m_sampleRate = AC3FSCod[cod] >> 1;
    }
    else
    {
      blocks = AC3BlkCod[cod];
      m_info.m_sampleRate = AC3FSCod[fscod];
    }

    m_fsize = framesize << 1;
    m_info.m_repeat = MAX_EAC3_BLOCKS / blocks;

    if (m_info.m_type == CAEStreamInfo::STREAM_TYPE_EAC3 && m_hasSync && !resyncing)
      return true;

    // if we get here, we can sync
    m_hasSync = true;
    m_info.m_channels = AC3Channels[acmod] + lfeon;
    m_syncFunc = &CAEStreamParser::SyncAC3;
    m_info.m_type = CAEStreamInfo::STREAM_TYPE_EAC3;
    m_info.m_ac3FrameSize = m_fsize;

    CLog::Log(LOGINFO, "CAEStreamParser::TrySyncAC3 - E-AC3 stream detected (%d channels, %dHz)", m_info.m_channels, m_info.m_sampleRate);
    return true;
  }
}

unsigned int CAEStreamParser::SyncAC3(uint8_t *data, unsigned int size)
{
  unsigned int skip = 0;

  for (; size - skip > 7; ++skip, ++data)
  {
    bool resyncing = (skip != 0);
    if (TrySyncAC3(data, size - skip, resyncing, /*wantEAC3dependent*/ false))
      return skip;
  }

  // if we get here, the entire packet is invalid and we have lost sync
  CLog::Log(LOGINFO, "CAEStreamParser::SyncAC3 - AC3 sync lost");
  m_hasSync = false;
  return skip;
}

unsigned int CAEStreamParser::SyncDTS(uint8_t *data, unsigned int size)
{
  if (size < 13)
  {
    if (m_needBytes < 13)
      m_needBytes = 14;
    return 0;
  }

  unsigned int skip = 0;
  for (; size - skip > 13; ++skip, ++data)
  {
    unsigned int header = data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3];
    unsigned int hd_sync = 0;
    unsigned int dtsBlocks;
    unsigned int amode;
    unsigned int sfreq;
    unsigned int target_rate;
    unsigned int extension = 0;
    unsigned int ext_type = UNKNOWN_DTS_EXTENSION;
    unsigned int lfe;
    int bits;

    switch (header)
    {
      /* 14bit BE */
      case DTS_PREAMBLE_14BE:
        if (data[4] != 0x07 || (data[5] & 0xf0) != 0xf0)
          continue;
        dtsBlocks = (((data[5] & 0x7) << 4) | ((data[6] & 0x3C) >> 2)) + 1;
        m_fsize = (((((data[6] & 0x3) << 8) | data[7]) << 4) | ((data[8] & 0x3C) >> 2)) + 1;
        amode = ((data[8] & 0x3) << 4) | ((data[9] & 0xF0) >> 4);
        target_rate = ((data[10] & 0x3e) >> 1);
        extension = ((data[11] & 0x1));
        ext_type = ((data[11] & 0xe) >> 1);
        sfreq = data[9] & 0xF;
        lfe = (data[12] & 0x18) >> 3;
        m_info.m_dataIsLE  = false;
        bits = 14;
        break;

      /* 14bit LE */
      case DTS_PREAMBLE_14LE:
        if (data[5] != 0x07 || (data[4] & 0xf0) != 0xf0)
          continue;
        dtsBlocks = (((data[4] & 0x7) << 4) | ((data[7] & 0x3C) >> 2)) + 1;
        m_fsize = (((((data[7] & 0x3) << 8) | data[6]) << 4) | ((data[9] & 0x3C) >> 2)) + 1;
        amode = ((data[9] & 0x3) << 4) | ((data[8] & 0xF0) >> 4);
        target_rate = ((data[11] & 0x3e) >> 1);
        extension = ((data[10] & 0x1));
        ext_type = ((data[10] & 0xe) >> 1);
        sfreq = data[8] & 0xF;
        lfe = (data[13] & 0x18) >> 3;
        m_info.m_dataIsLE = true;
        bits = 14;
        break;

      /* 16bit BE */
      case DTS_PREAMBLE_16BE:
        dtsBlocks = (((data[4] & 0x1) << 7) | ((data[5] & 0xFC) >> 2)) + 1;
        m_fsize = (((((data[5] & 0x3) << 8) | data[6]) << 4) | ((data[7] & 0xF0) >> 4)) + 1;
        amode = ((data[7] & 0x0F) << 2) | ((data[8] & 0xC0) >> 6);
        sfreq = (data[8] & 0x3C) >> 2;
        target_rate = ((data[8] & 0x03) << 3) | ((data[9] & 0xe0) >> 5);
        extension = (data[10] & 0x10) >> 4;
        ext_type = (data[10] & 0xe0) >> 5;
        lfe = (data[10] >> 1) & 0x3;
        m_info.m_dataIsLE = false;
        bits = 16;
        break;

      /* 16bit LE */
      case DTS_PREAMBLE_16LE:
        dtsBlocks = (((data[5] & 0x1) << 7) | ((data[4] & 0xFC) >> 2)) + 1;
        m_fsize = (((((data[4] & 0x3) << 8) | data[7]) << 4) | ((data[6] & 0xF0) >> 4)) + 1;
        amode = ((data[6] & 0x0F) << 2) | ((data[9] & 0xC0) >> 6);
        sfreq = (data[9] & 0x3C) >> 2;
        target_rate = ((data[9] & 0x03) << 3) | ((data[8] & 0xe0) >> 5);
        extension = (data[11] & 0x10) >> 4;
        ext_type = (data[11] & 0xe0) >> 5;
        lfe = (data[11] >> 1) & 0x3;
        m_info.m_dataIsLE = true;
        bits = 16;
        break;

      default:
        continue;
    }

    if (sfreq == 0 || sfreq >= DTS_SFREQ_COUNT)
      continue;

    /* make sure the framesize is sane */
    if (m_fsize < 96 || m_fsize > 16384)
      continue;

    bool invalid = false;
    CAEStreamInfo::DataType dataType;
    switch (dtsBlocks << 5)
    {
      case 512 : dataType = CAEStreamInfo::STREAM_TYPE_DTS_512 ; break;
      case 1024: dataType = CAEStreamInfo::STREAM_TYPE_DTS_1024; break;
      case 2048: dataType = CAEStreamInfo::STREAM_TYPE_DTS_2048; break;
      default:
        invalid = true;
        break;
    }

    if (invalid)
      continue;

    /* adjust the fsize for 14 bit streams */
    if (bits == 14)
      m_fsize = m_fsize / 14 * 16;

    /* we need enough data to check for DTS-HD */
    if (size - skip < m_fsize + 10)
    {
      /* we can assume DTS sync at this point */
      m_syncFunc  = &CAEStreamParser::SyncDTS;
      m_needBytes = m_fsize + 10;
      m_fsize     = 0;

      return skip;
    }

    /* look for DTS-HD */
    hd_sync = (data[m_fsize] << 24) | (data[m_fsize + 1] << 16) | (data[m_fsize + 2] << 8) | data[m_fsize + 3];
    if (hd_sync == DTS_PREAMBLE_HD)
    {
      int hd_size;
      bool blownup = (data[m_fsize + 5] & 0x20) != 0;
      if (blownup)
        hd_size = (((data[m_fsize + 6] & 0x01) << 19) | (data[m_fsize + 7] << 11) | (data[m_fsize + 8] << 3) | ((data[m_fsize + 9] & 0xe0) >> 5)) + 1;
      else
        hd_size = (((data[m_fsize + 6] & 0x1f) << 11) | (data[m_fsize + 7] << 3) | ((data[m_fsize + 8] & 0xe0) >> 5)) + 1;

      int header_size;
      if (blownup)
        header_size = (((data[m_fsize + 5] & 0x1f) << 7) | ((data[m_fsize + 6] & 0xfe) >> 1)) + 1;
      else
        header_size = (((data[m_fsize + 5] & 0x1f) << 3) | ((data[m_fsize + 6] & 0xe0) >> 5)) + 1;

      hd_sync = data[m_fsize + header_size] << 24 | data[m_fsize + header_size + 1] << 16 | data[m_fsize + header_size + 2] << 8 | data[m_fsize + header_size + 3];

      /* set the type according to core or not */
      if (m_coreOnly)
        dataType = CAEStreamInfo::STREAM_TYPE_DTSHD_CORE;
      else if (hd_sync == DTS_PREAMBLE_XLL)
        dataType = CAEStreamInfo::STREAM_TYPE_DTSHD_MA;
      else if (hd_sync == DTS_PREAMBLE_XCH ||
               hd_sync == DTS_PREAMBLE_XXCH ||
               hd_sync == DTS_PREAMBLE_X96K ||
               hd_sync == DTS_PREAMBLE_XBR ||
               hd_sync == DTS_PREAMBLE_LBR)
        dataType = CAEStreamInfo::STREAM_TYPE_DTSHD;
      else
        dataType = m_info.m_type;

      m_coreSize = m_fsize;
      m_fsize += hd_size;
    }

    unsigned int sampleRate = DTSSampleRates[sfreq];
    if (!m_hasSync || skip || dataType != m_info.m_type || sampleRate != m_info.m_sampleRate || dtsBlocks != m_dtsBlocks)
    {
      m_hasSync = true;
      m_info.m_type = dataType;
      m_info.m_sampleRate = sampleRate;
      m_dtsBlocks = dtsBlocks;
      m_info.m_channels = DTSChannels[amode] + (lfe ? 1 : 0);
      m_syncFunc = &CAEStreamParser::SyncDTS;
      m_info.m_repeat = 1;

      if (dataType == CAEStreamInfo::STREAM_TYPE_DTSHD_MA)
      {
        m_info.m_channels += 2; /* FIXME: this needs to be read out, not sure how to do that yet */
        m_info.m_dtsPeriod = (192000 * (8 >> 1)) * (m_dtsBlocks << 5) / m_info.m_sampleRate;
      }
      else if (dataType == CAEStreamInfo::STREAM_TYPE_DTSHD)
      {
        m_info.m_dtsPeriod = (192000 * (2 >> 1)) * (m_dtsBlocks << 5) / m_info.m_sampleRate;
      }
      else
      {
        m_info.m_dtsPeriod = (m_info.m_sampleRate * (2 >> 1)) * (m_dtsBlocks << 5) / m_info.m_sampleRate;
      }

      std::string type;
      switch (dataType)
      {
        case CAEStreamInfo::STREAM_TYPE_DTSHD:
          type = "dtsHD";
          break;
        case CAEStreamInfo::STREAM_TYPE_DTSHD_MA:
          type = "dtsHD MA";
          break;
        case CAEStreamInfo::STREAM_TYPE_DTSHD_CORE:
          type = "dtsHD (core)";
          break;
        default:
          type = "dts";
          break;
      }

      if (extension)
      {
        switch (ext_type)
        {
          case 0:
            type += " XCH";
            break;
          case 2:
            type += " X96";
            break;
          case 6:
            type += " XXCH";
            break;
          default:
            type += " ext unknown";
            break;
        }
      }

      CLog::Log(LOGINFO, "CAEStreamParser::SyncDTS - %s stream detected (%d channels, %dHz, %dbit %s, period: %u, syncword: 0x%x, target rate: 0x%x, framesize %u))",
                type.c_str(), m_info.m_channels, m_info.m_sampleRate,
                bits, m_info.m_dataIsLE ? "LE" : "BE",
                m_info.m_dtsPeriod, hd_sync, target_rate, m_fsize);
    }

    return skip;
  }

  /* lost sync */
  CLog::Log(LOGINFO, "CAEStreamParser::SyncDTS - DTS sync lost");
  m_hasSync = false;
  return skip;
}

inline unsigned int CAEStreamParser::GetTrueHDChannels(const uint16_t chanmap)
{
  int channels = 0;
  for (int i = 0; i < 13; ++i)
    channels += THDChanMap[i] * ((chanmap >> i) & 1);
  return channels;
}

unsigned int CAEStreamParser::SyncTrueHD(uint8_t *data, unsigned int size)
{
  unsigned int left = size;
  unsigned int skip = 0;

  /* if MLP */
  for (; left; ++skip, ++data, --left)
  {
    /* if we dont have sync and there is less the 8 bytes, then break out */
    if (!m_hasSync && left < 8)
      return size;

    /* if its a major audio unit */
    uint16_t length   = ((data[0] & 0x0F) << 8 | data[1]) << 1;
    uint32_t syncword = ((((data[4] << 8 | data[5]) << 8) | data[6]) << 8) | data[7];
    if (syncword == 0xf8726fba)
    {
      /* we need 32 bytes to sync on a master audio unit */
      if (left < 32)
        return skip;

      /* get the rate and ensure its valid */
      int rate = (data[8] & 0xf0) >> 4;
      if (rate == 0xF)
        continue;

      unsigned int major_sync_size = 28;
      if (data[29] & 1)
      {
        /* extension(s) present, look up count */
        int extension_count = data[30] >> 4;
        major_sync_size += 2 + extension_count * 2;
      }

      if (left < 4 + major_sync_size)
        return skip;

      /* verify the crc of the audio unit */
      uint16_t crc = av_crc(m_crcTrueHD, 0, data + 4, major_sync_size - 4);
      crc ^= (data[4 + major_sync_size - 3] << 8) | data[4 + major_sync_size - 4];
      if (((data[4 + major_sync_size - 1] << 8) | data[4 + major_sync_size - 2]) != crc)
        continue;

      /* get the sample rate and substreams, we have a valid master audio unit */
      m_info.m_sampleRate = (rate & 0x8 ? 44100 : 48000) << (rate & 0x7);
      m_substreams = (data[20] & 0xF0) >> 4;

      /* get the number of encoded channels */
      uint16_t channel_map = ((data[10] & 0x1F) << 8) | data[11];
      if (!channel_map)
        channel_map = (data[9] << 1) | (data[10] >> 7);
      m_info.m_channels = CAEStreamParser::GetTrueHDChannels(channel_map);

      if (!m_hasSync)
        CLog::Log(LOGINFO, "CAEStreamParser::SyncTrueHD - TrueHD stream detected (%d channels, %dHz)", m_info.m_channels, m_info.m_sampleRate);

      m_hasSync = true;
      m_fsize = length;
      m_info.m_type = CAEStreamInfo::STREAM_TYPE_TRUEHD;
      m_syncFunc = &CAEStreamParser::SyncTrueHD;
      m_info.m_repeat = 1;
      return skip;
    }
    else
    {
      /* we cant sink to a subframe until we have the information from a master audio unit */
      if (!m_hasSync)
        continue;

      /* if there is not enough data left to verify the packet, just return the skip amount */
      if (left < (unsigned int)m_substreams * 4)
        return skip;

      /* verify the parity */
      int     p     = 0;
      uint8_t check = 0;
      for (int i = -1; i < m_substreams; ++i)
      {
        check ^= data[p++];
        check ^= data[p++];
        if (i == -1 || data[p - 2] & 0x80)
        {
          check ^= data[p++];
          check ^= data[p++];
        }
      }

      /* if the parity nibble does not match */
      if ((((check >> 4) ^ check) & 0xF) != 0xF)
      {
        /* lost sync */
        m_hasSync  = false;
        CLog::Log(LOGINFO, "CAEStreamParser::SyncTrueHD - Sync Lost");
        continue;
      }
      else
      {
        m_fsize = length;
        return skip;
      }
    }
  }

  /* lost sync */
  m_hasSync  = false;
  return skip;
}

