path: root/libPCMutils/src/pcmdmx_lib.cpp

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

© Copyright  1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
Forschung e.V. All rights reserved.

 1.    INTRODUCTION
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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
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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
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You may use this FDK AAC Codec software or modifications thereto only for
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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
----------------------------------------------------------------------------- */

/**************************** PCM utility library ******************************

   Author(s):   Christian Griebel

   Description: Defines functions that perform downmixing or a simple channel
                expansion in the PCM time domain.

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

#include "pcmdmx_lib.h"

#include "genericStds.h"
#include "fixpoint_math.h"
#include "FDK_core.h"

/* library version */
#include "version.h"
/* library title */
#define PCMDMX_LIB_TITLE "PCM Downmix Lib"

#define FALSE 0
#define TRUE 1
#define IN 0
#define OUT 1

/* Type definitions: */
#define FIXP_DMX FIXP_SGL
#define FX_DMX2FX_DBL(x) FX_SGL2FX_DBL((FIXP_SGL)(x))
#define FX_DBL2FX_DMX(x) FX_DBL2FX_SGL(x)
#define FL2FXCONST_DMX(x) FL2FXCONST_SGL(x)
#define MAXVAL_DMX MAXVAL_SGL
#define FX_DMX2SHRT(x) ((SHORT)(x))
#define FX_DMX2FL(x) FX_DBL2FL(FX_DMX2FX_DBL(x))

/* Fixed and unique channel group indices.
 * The last group index has to be smaller than ( 4 ). */
#define CH_GROUP_FRONT (0)
#define CH_GROUP_SIDE (1)
#define CH_GROUP_REAR (2)
#define CH_GROUP_LFE (3)

/* Fixed and unique channel plain indices. */
#define CH_PLAIN_NORMAL (0)
#define CH_PLAIN_TOP (1)
#define CH_PLAIN_BOTTOM (2)

/* The ordering of the following fixed channel labels has to be in MPEG-4 style.
 * From the center to the back with left and right channel interleaved (starting
 * with left). The last channel label index has to be smaller than ( 8 ). */
#define CENTER_FRONT_CHANNEL (0) /* C  */
#define LEFT_FRONT_CHANNEL (1)   /* L  */
#define RIGHT_FRONT_CHANNEL (2)  /* R  */
#define LEFT_REAR_CHANNEL \
  (3) /* Lr (aka left back channel) or center back channel */
#define RIGHT_REAR_CHANNEL (4)      /* Rr (aka right back channel) */
#define LOW_FREQUENCY_CHANNEL (5)   /* Lf */
#define LEFT_MULTIPRPS_CHANNEL (6)  /* Left multipurpose channel */
#define RIGHT_MULTIPRPS_CHANNEL (7) /* Right multipurpose channel */

/* 22.2 channel specific fixed channel lables: */
#define LEFT_SIDE_CHANNEL (8)            /* Lss  */
#define RIGHT_SIDE_CHANNEL (9)           /* Rss  */
#define CENTER_REAR_CHANNEL (10)         /* Cs   */
#define CENTER_FRONT_CHANNEL_TOP (11)    /* Cv   */
#define LEFT_FRONT_CHANNEL_TOP (12)      /* Lv   */
#define RIGHT_FRONT_CHANNEL_TOP (13)     /* Rv   */
#define LEFT_SIDE_CHANNEL_TOP (14)       /* Lvss */
#define RIGHT_SIDE_CHANNEL_TOP (15)      /* Rvss */
#define CENTER_SIDE_CHANNEL_TOP (16)     /* Ts   */
#define LEFT_REAR_CHANNEL_TOP (17)       /* Lvr  */
#define RIGHT_REAR_CHANNEL_TOP (18)      /* Rvr  */
#define CENTER_REAR_CHANNEL_TOP (19)     /* Cvr  */
#define CENTER_FRONT_CHANNEL_BOTTOM (20) /* Cb   */
#define LEFT_FRONT_CHANNEL_BOTTOM (21)   /* Lb   */
#define RIGHT_FRONT_CHANNEL_BOTTOM (22)  /* Rb   */
#define LOW_FREQUENCY_CHANNEL_2 (23)     /* LFE2 */

/* More constants */
#define ONE_CHANNEL (1)
#define TWO_CHANNEL (2)
#define SIX_CHANNEL (6)
#define EIGHT_CHANNEL (8)
#define TWENTY_FOUR_CHANNEL (24)

#define PCMDMX_THRESHOLD_MAP_HEAT_1 (0) /* Store only exact matches */
#define PCMDMX_THRESHOLD_MAP_HEAT_2 (20)
#define PCMDMX_THRESHOLD_MAP_HEAT_3 \
  (256) /* Do not assign normal channels to LFE */

#define SP_Z_NRM (0)
#define SP_Z_TOP (2)
#define SP_Z_BOT (-2)
#define SP_Z_LFE (-18)
#define SP_Z_MUL (8) /* Should be smaller than SP_Z_LFE */

typedef struct {
  SCHAR x; /* horizontal position:  center (0), left (-), right (+) */
  SCHAR y; /* deepth position:      front, side, back, position */
  SCHAR z; /* heigth positions:     normal, top, bottom, lfe */
} PCM_DMX_SPEAKER_POSITION;

/* CAUTION: The maximum x-value should be less or equal to
 * PCMDMX_SPKR_POS_X_MAX_WIDTH. */
static const PCM_DMX_SPEAKER_POSITION spkrSlotPos[] = {
    /*  x,  y,  z  */
    {0, 0, SP_Z_NRM},  /* 0  CENTER_FRONT_CHANNEL        */
    {-2, 0, SP_Z_NRM}, /* 1  LEFT_FRONT_CHANNEL          */
    {2, 0, SP_Z_NRM},  /* 2  RIGHT_FRONT_CHANNEL         */
    {-3, 4, SP_Z_NRM}, /* 3  LEFT_REAR_CHANNEL           */
    {3, 4, SP_Z_NRM},  /* 4  RIGHT_REAR_CHANNEL          */
    {0, 0, SP_Z_LFE},  /* 5  LOW_FREQUENCY_CHANNEL       */
    {-2, 2, SP_Z_MUL}, /* 6  LEFT_MULTIPRPS_CHANNEL      */
    {2, 2, SP_Z_MUL}   /* 7  RIGHT_MULTIPRPS_CHANNEL     */
};

/* List of packed channel modes */
typedef enum { /* CH_MODE_<numFrontCh>_<numSideCh>_<numBackCh>_<numLfCh> */
               CH_MODE_UNDEFINED = 0x0000,
               /* 1 channel */
               CH_MODE_1_0_0_0 = 0x0001, /* chCfg 1 */
               /* 2 channels */
               CH_MODE_2_0_0_0 = 0x0002 /* chCfg 2 */
                                        /* 3 channels */
               ,
               CH_MODE_3_0_0_0 = 0x0003, /* chCfg 3 */
               CH_MODE_2_0_1_0 = 0x0102,
               CH_MODE_2_0_0_1 = 0x1002,
               /* 4 channels */
               CH_MODE_3_0_1_0 = 0x0103, /* chCfg 4 */
               CH_MODE_2_0_2_0 = 0x0202,
               CH_MODE_2_0_1_1 = 0x1102,
               CH_MODE_4_0_0_0 = 0x0004,
               /* 5 channels */
               CH_MODE_3_0_2_0 = 0x0203, /* chCfg 5 */
               CH_MODE_2_0_2_1 = 0x1202,
               CH_MODE_3_0_1_1 = 0x1103,
               CH_MODE_3_2_0_0 = 0x0023,
               CH_MODE_5_0_0_0 = 0x0005,
               /* 6 channels */
               CH_MODE_3_0_2_1 = 0x1203, /* chCfg 6 */
               CH_MODE_3_2_0_1 = 0x1023,
               CH_MODE_3_2_1_0 = 0x0123,
               CH_MODE_5_0_1_0 = 0x0105,
               CH_MODE_6_0_0_0 = 0x0006,
               /* 7 channels */
               CH_MODE_2_2_2_1 = 0x1222,
               CH_MODE_3_0_3_1 = 0x1303, /* chCfg 11 */
               CH_MODE_3_2_1_1 = 0x1123,
               CH_MODE_3_2_2_0 = 0x0223,
               CH_MODE_3_0_2_2 = 0x2203,
               CH_MODE_5_0_2_0 = 0x0205,
               CH_MODE_5_0_1_1 = 0x1105,
               CH_MODE_7_0_0_0 = 0x0007,
               /* 8 channels */
               CH_MODE_3_2_2_1 = 0x1223,
               CH_MODE_3_0_4_1 = 0x1403, /* chCfg 12 */
               CH_MODE_5_0_2_1 = 0x1205, /* chCfg 7 + 14 */
               CH_MODE_5_2_1_0 = 0x0125,
               CH_MODE_3_2_1_2 = 0x2123,
               CH_MODE_2_2_2_2 = 0x2222,
               CH_MODE_3_0_3_2 = 0x2303,
               CH_MODE_8_0_0_0 = 0x0008

} PCM_DMX_CHANNEL_MODE;

/* These are the channel configurations linked to
   the number of output channels give by the user: */
static const PCM_DMX_CHANNEL_MODE outChModeTable[(8) + 1] = {
    CH_MODE_UNDEFINED,
    CH_MODE_1_0_0_0, /* 1 channel  */
    CH_MODE_2_0_0_0  /* 2 channels */
    ,
    CH_MODE_3_0_0_0, /* 3 channels */
    CH_MODE_3_0_1_0, /* 4 channels */
    CH_MODE_3_0_2_0, /* 5 channels */
    CH_MODE_3_0_2_1  /* 6 channels */
    ,
    CH_MODE_3_0_3_1, /* 7 channels */
    CH_MODE_3_0_4_1  /* 8 channels */
};

static const FIXP_DMX abMixLvlValueTab[8] = {
    FL2FXCONST_DMX(0.500f), /* scaled by 1 */
    FL2FXCONST_DMX(0.841f), FL2FXCONST_DMX(0.707f), FL2FXCONST_DMX(0.596f),
    FL2FXCONST_DMX(0.500f), FL2FXCONST_DMX(0.422f), FL2FXCONST_DMX(0.355f),
    FL2FXCONST_DMX(0.0f)};

static const FIXP_DMX lfeMixLvlValueTab[16] = {
    /*             value,        scale */
    FL2FXCONST_DMX(0.7905f), /*     2 */
    FL2FXCONST_DMX(0.5000f), /*     2 */
    FL2FXCONST_DMX(0.8395f), /*     1 */
    FL2FXCONST_DMX(0.7065f), /*     1 */
    FL2FXCONST_DMX(0.5945f), /*     1 */
    FL2FXCONST_DMX(0.500f),  /*     1 */
    FL2FXCONST_DMX(0.841f),  /*     0 */
    FL2FXCONST_DMX(0.707f),  /*     0 */
    FL2FXCONST_DMX(0.596f),  /*     0 */
    FL2FXCONST_DMX(0.500f),  /*     0 */
    FL2FXCONST_DMX(0.316f),  /*     0 */
    FL2FXCONST_DMX(0.178f),  /*     0 */
    FL2FXCONST_DMX(0.100f),  /*     0 */
    FL2FXCONST_DMX(0.032f),  /*     0 */
    FL2FXCONST_DMX(0.010f),  /*     0 */
    FL2FXCONST_DMX(0.000f)   /*     0 */
};

/* MPEG matrix mixdown:
    Set 1:  L' = (1 + 2^-0.5 + A )^-1 * [L + C * 2^-0.5 + A * Ls];
            R' = (1 + 2^-0.5 + A )^-1 * [R + C * 2^-0.5 + A * Rs];

    Set 2:  L' = (1 + 2^-0.5 + 2A )^-1 * [L + C * 2^-0.5 - A * (Ls + Rs)];
            R' = (1 + 2^-0.5 + 2A )^-1 * [R + C * 2^-0.5 + A * (Ls + Rs)];

    M = (3 + 2A)^-1 * [L + C + R + A*(Ls + Rs)];
*/
static const FIXP_DMX mpegMixDownIdx2Coef[4] = {
    FL2FXCONST_DMX(0.70710678f), FL2FXCONST_DMX(0.5f),
    FL2FXCONST_DMX(0.35355339f), FL2FXCONST_DMX(0.0f)};

static const FIXP_DMX mpegMixDownIdx2PreFact[3][4] = {
    {/* Set 1: */
     FL2FXCONST_DMX(0.4142135623730950f), FL2FXCONST_DMX(0.4530818393219728f),
     FL2FXCONST_DMX(0.4852813742385703f), FL2FXCONST_DMX(0.5857864376269050f)},
    {/* Set 2: */
     FL2FXCONST_DMX(0.3203772410170407f), FL2FXCONST_DMX(0.3693980625181293f),
     FL2FXCONST_DMX(0.4142135623730950f), FL2FXCONST_DMX(0.5857864376269050f)},
    {/* Mono DMX set: */
     FL2FXCONST_DMX(0.2265409196609864f), FL2FXCONST_DMX(0.25f),
     FL2FXCONST_DMX(0.2697521433898179f), FL2FXCONST_DMX(0.3333333333333333f)}};

#define TYPE_NONE (0x00)
#define TYPE_PCE_DATA (0x01)
#define TYPE_DSE_CLEV_DATA (0x02)
#define TYPE_DSE_SLEV_DATA (0x04)
#define TYPE_DSE_DMIX_AB_DATA (0x08)
#define TYPE_DSE_DMIX_LFE_DATA (0x10)
#define TYPE_DSE_DMX_GAIN_DATA (0x20)
#define TYPE_DSE_DMX_CGL_DATA (0x40)
#define TYPE_DSE_DATA (0x7E)

typedef struct {
  UINT typeFlags;
  /* From DSE */
  UCHAR cLevIdx;
  UCHAR sLevIdx;
  UCHAR dmixIdxA;
  UCHAR dmixIdxB;
  UCHAR dmixIdxLfe;
  UCHAR dmxGainIdx2;
  UCHAR dmxGainIdx5;
  /* From PCE */
  UCHAR matrixMixdownIdx;
  /* Attributes: */
  SCHAR pseudoSurround; /*!< If set to 1 the signal is pseudo surround
                           compatible. The value 0 tells that it is not. If the
                           value is -1 the information is not available.  */
  UINT expiryCount; /*!< Counter to monitor the life time of a meta data set. */

} DMX_BS_META_DATA;

/* Default metadata */
static const DMX_BS_META_DATA dfltMetaData = {0, 2, 2, 2,  2, 15,
                                              0, 0, 0, -1, 0};

/* Dynamic (user) params:
     See the definition of PCMDMX_PARAM for details on the specific fields. */
typedef struct {
  DMX_PROFILE_TYPE dmxProfile; /*!< Linked to DMX_PRFL_STANDARD              */
  UINT expiryFrame;            /*!< Linked to DMX_BS_DATA_EXPIRY_FRAME       */
  DUAL_CHANNEL_MODE dualChannelMode; /*!< Linked to DMX_DUAL_CHANNEL_MODE */
  PSEUDO_SURROUND_MODE
  pseudoSurrMode;          /*!< Linked to DMX_PSEUDO_SURROUND_MODE       */
  SHORT numOutChannelsMin; /*!< Linked to MIN_NUMBER_OF_OUTPUT_CHANNELS  */
  SHORT numOutChannelsMax; /*!< Linked to MAX_NUMBER_OF_OUTPUT_CHANNELS  */
  UCHAR frameDelay;        /*!< Linked to DMX_BS_DATA_DELAY              */

} PCM_DMX_USER_PARAMS;

/* Modules main data structure: */
struct PCM_DMX_INSTANCE {
  /* Metadata */
  DMX_BS_META_DATA bsMetaData[(1) + 1];
  PCM_DMX_USER_PARAMS userParams;

  UCHAR applyProcessing; /*!< Flag to en-/disable modules processing.
                              The max channel limiting is done independently. */
};

/* Memory allocation macro */
C_ALLOC_MEM(PcmDmxInstance, struct PCM_DMX_INSTANCE, 1)

static UINT getSpeakerDistance(PCM_DMX_SPEAKER_POSITION posA,
                               PCM_DMX_SPEAKER_POSITION posB) {
  PCM_DMX_SPEAKER_POSITION diff;

  diff.x = posA.x - posB.x;
  diff.y = posA.y - posB.y;
  diff.z = posA.z - posB.z;

  return ((diff.x * diff.x) + (diff.y * diff.y) + (diff.z * diff.z));
}

static PCM_DMX_SPEAKER_POSITION getSpeakerPos(AUDIO_CHANNEL_TYPE chType,
                                              UCHAR chIndex, UCHAR numChInGrp) {
#define PCMDMX_SPKR_POS_X_MAX_WIDTH (3)
#define PCMDMX_SPKR_POS_Y_SPREAD (2)
#define PCMDMX_SPKR_POS_Z_SPREAD (2)

  PCM_DMX_SPEAKER_POSITION spkrPos = {0, 0, 0};
  AUDIO_CHANNEL_TYPE chGrp = (AUDIO_CHANNEL_TYPE)(chType & 0x0F);
  unsigned fHasCenter = numChInGrp & 0x1;
  unsigned chGrpWidth = numChInGrp >> 1;
  unsigned fIsCenter = 0;
  unsigned fIsLfe = (chType == ACT_LFE) ? 1 : 0;
  int offset = 0;

  FDK_ASSERT(chIndex < numChInGrp);

  if ((chGrp == ACT_FRONT) && fHasCenter) {
    if (chIndex == 0) fIsCenter = 1;
    chIndex = (UCHAR)fMax(0, chIndex - 1);
  } else if (fHasCenter && (chIndex == numChInGrp - 1)) {
    fIsCenter = 1;
  }
  /* now all even indices are left (-) */
  if (!fIsCenter) {
    offset = chIndex >> 1;
    if ((chGrp > ACT_FRONT) && (chType != ACT_SIDE) && !fIsLfe) {
      /* the higher the index the lower the distance to the center position */
      offset = chGrpWidth - fHasCenter - offset;
    }
    if ((chIndex & 0x1) == 0) { /* even */
      offset = -(offset + 1);
    } else {
      offset += 1;
    }
  }
  /* apply the offset */
  if (chType == ACT_SIDE) {
    spkrPos.x = (offset < 0) ? -PCMDMX_SPKR_POS_X_MAX_WIDTH
                             : PCMDMX_SPKR_POS_X_MAX_WIDTH;
    spkrPos.y = /* 1x */ PCMDMX_SPKR_POS_Y_SPREAD + (SCHAR)fAbs(offset) - 1;
    spkrPos.z = 0;
  } else {
    unsigned spread =
        ((chGrpWidth == 1) && (!fIsLfe)) ? PCMDMX_SPKR_POS_X_MAX_WIDTH - 1 : 1;
    spkrPos.x = (SCHAR)offset * (SCHAR)spread;
    if (fIsLfe) {
      spkrPos.y = 0;
      spkrPos.z = SP_Z_LFE;
    } else {
      spkrPos.y = (SCHAR)fMax((SCHAR)chGrp - 1, 0) * PCMDMX_SPKR_POS_Y_SPREAD;
      spkrPos.z = (SCHAR)chType >> 4;
      if (spkrPos.z == 2) { /* ACT_BOTTOM */
        spkrPos.z = -1;
      }
      spkrPos.z *= PCMDMX_SPKR_POS_Z_SPREAD;
    }
  }
  return spkrPos;
}

/** Return the channel mode of a given horizontal channel plain (normal, top,
 *bottom) for a given channel configuration. NOTE: This function shall get
 *obsolete once the channel mode has been changed to be nonambiguous.
 * @param [in] Index of the requested channel plain.
 * @param [in] The packed channel mode for the complete channel configuration
 *(all plains).
 * @param [in] The MPEG-4 channel configuration index which is necessary in
 *cases where the (packed) channel mode is ambiguous.
 * @returns Returns the packed channel mode of the requested channel plain.
 **/
static PCM_DMX_CHANNEL_MODE getChMode4Plain(
    const int plainIndex, const PCM_DMX_CHANNEL_MODE totChMode,
    const int chCfg) {
  PCM_DMX_CHANNEL_MODE plainChMode = totChMode;

  switch (totChMode) {
    case CH_MODE_5_0_2_1:
      if (chCfg == 14) {
        switch (plainIndex) {
          case CH_PLAIN_BOTTOM:
            plainChMode = (PCM_DMX_CHANNEL_MODE)0x0000;
            break;
          case CH_PLAIN_TOP:
            plainChMode = CH_MODE_2_0_0_0;
            break;
          case CH_PLAIN_NORMAL:
          default:
            plainChMode = CH_MODE_3_0_2_1;
            break;
        }
      }
      break;
    default:
      break;
  }

  return plainChMode;
}

static inline UINT getIdxSum(UCHAR numCh) {
  UINT result = 0;
  int i;
  for (i = 1; i < numCh; i += 1) {
    result += i;
  }
  return result;
}

/** Evaluate a given channel configuration and extract a packed channel mode. In
 *addition the function generates a channel offset table for the mapping to the
 *internal representation. This function is the inverse to the
 *getChannelDescription() routine.
 * @param [in] The total number of channels of the given configuration.
 * @param [in] Array holding the corresponding channel types for each channel.
 * @param [in] Array holding the corresponding channel type indices for each
 *channel.
 * @param [out] Array where the buffer offsets for each channel are stored into.
 * @param [out] The generated packed channel mode that represents the given
 *input configuration.
 * @returns Returns an error code.
 **/
static PCMDMX_ERROR getChannelMode(
    const UINT numChannels,                 /* in */
    const AUDIO_CHANNEL_TYPE channelType[], /* in */
    UCHAR channelIndices[],                 /* in */
    UCHAR offsetTable[(8)],                 /* out */
    PCM_DMX_CHANNEL_MODE *chMode            /* out */
) {
  UINT idxSum[(3)][(4)];
  UCHAR numCh[(3)][(4)];
  UCHAR mapped[(8)];
  PCM_DMX_SPEAKER_POSITION spkrPos[(8)];
  PCMDMX_ERROR err = PCMDMX_OK;
  unsigned ch, numMappedInChs = 0;
  unsigned startSlot;
  unsigned stopSlot = LOW_FREQUENCY_CHANNEL;

  FDK_ASSERT(channelType != NULL);
  FDK_ASSERT(channelIndices != NULL);
  FDK_ASSERT(offsetTable != NULL);
  FDK_ASSERT(chMode != NULL);

  /* For details see ISO/IEC 13818-7:2005(E), 8.5.3 Channel configuration */
  FDKmemclear(idxSum, (3) * (4) * sizeof(UINT));
  FDKmemclear(numCh, (3) * (4) * sizeof(UCHAR));
  FDKmemclear(mapped, (8) * sizeof(UCHAR));
  FDKmemclear(spkrPos, (8) * sizeof(PCM_DMX_SPEAKER_POSITION));
  /* Init output */
  FDKmemset(offsetTable, 255, (8) * sizeof(UCHAR));
  *chMode = CH_MODE_UNDEFINED;

  /* Determine how many channels are assigned to each channels each group: */
  for (ch = 0; ch < numChannels; ch += 1) {
    unsigned chGrp = fMax(
        (channelType[ch] & 0x0F) - 1,
        0); /* Assign all undefined channels (ACT_NONE) to front channels. */
    numCh[channelType[ch] >> 4][chGrp] += 1;
    idxSum[channelType[ch] >> 4][chGrp] += channelIndices[ch];
  }
  if (numChannels > TWO_CHANNEL) {
    int chGrp;
    /* Sanity check on the indices */
    for (chGrp = 0; chGrp < (4); chGrp += 1) {
      int plane;
      for (plane = 0; plane < (3); plane += 1) {
        if (idxSum[plane][chGrp] != getIdxSum(numCh[plane][chGrp])) {
          unsigned idxCnt = 0;
          for (ch = 0; ch < numChannels; ch += 1) {
            if (channelType[ch] ==
                (AUDIO_CHANNEL_TYPE)((plane << 4) | ((chGrp + 1) & 0xF))) {
              channelIndices[ch] = idxCnt++;
            }
          }
          err = PCMDMX_INVALID_CH_CONFIG;
        }
      }
    }
  }
  /* Mapping HEAT 1:
   *   Determine the speaker position of each input channel and map it to a
   * internal slot if it matches exactly (with zero distance). */
  for (ch = 0; ch < numChannels; ch += 1) {
    UINT mapDist = (unsigned)-1;
    unsigned mapCh, mapPos = (unsigned)-1;
    unsigned chGrp = fMax(
        (channelType[ch] & 0x0F) - 1,
        0); /* Assign all undefined channels (ACT_NONE) to front channels. */

    if (channelIndices[ch] >= numCh[channelType[ch] >> 4][chGrp])
      return PCMDMX_INVALID_CH_CONFIG;
    spkrPos[ch] = getSpeakerPos(channelType[ch], channelIndices[ch],
                                numCh[channelType[ch] >> 4][chGrp]);

    for (mapCh = 0; mapCh <= stopSlot; mapCh += 1) {
      if (offsetTable[mapCh] == 255) {
        UINT dist = getSpeakerDistance(spkrPos[ch], spkrSlotPos[mapCh]);
        if (dist < mapDist) {
          mapPos = mapCh;
          mapDist = dist;
        }
      }
    }
    if (mapDist <= PCMDMX_THRESHOLD_MAP_HEAT_1) {
      offsetTable[mapPos] = (UCHAR)ch;
      mapped[ch] = 1;
      numMappedInChs += 1;
    }
  }

  /* Mapping HEAT 2:
   *   Go through the unmapped input channels and assign them to the internal
   * slots that matches best (least distance). But assign center channels to
   * center slots only. */
  startSlot =
      ((numCh[CH_PLAIN_NORMAL][CH_GROUP_FRONT] & 0x1) || (numChannels >= (8)))
          ? 0
          : 1;
  for (ch = 0; ch < (unsigned)numChannels; ch += 1) {
    if (!mapped[ch]) {
      UINT mapDist = (unsigned)-1;
      unsigned mapCh, mapPos = (unsigned)-1;

      for (mapCh = startSlot; mapCh <= stopSlot; mapCh += 1) {
        if (offsetTable[mapCh] == 255) {
          UINT dist = getSpeakerDistance(spkrPos[ch], spkrSlotPos[mapCh]);
          if (dist < mapDist) {
            mapPos = mapCh;
            mapDist = dist;
          }
        }
      }
      if ((mapPos <= stopSlot) && (mapDist < PCMDMX_THRESHOLD_MAP_HEAT_2) &&
          (((spkrPos[ch].x != 0) && (spkrSlotPos[mapPos].x != 0)) /* XOR */
           || ((spkrPos[ch].x == 0) &&
               (spkrSlotPos[mapPos].x ==
                0)))) { /* Assign center channels to center slots only. */
        offsetTable[mapPos] = (UCHAR)ch;
        mapped[ch] = 1;
        numMappedInChs += 1;
      }
    }
  }

  /* Mapping HEAT 3:
   *   Assign the rest by searching for the nearest input channel for each
   * internal slot. */
  for (ch = startSlot; (ch < (8)) && (numMappedInChs < numChannels); ch += 1) {
    if (offsetTable[ch] == 255) {
      UINT mapDist = (unsigned)-1;
      unsigned mapCh, mapPos = (unsigned)-1;

      for (mapCh = 0; mapCh < (unsigned)numChannels; mapCh += 1) {
        if (!mapped[mapCh]) {
          UINT dist = getSpeakerDistance(spkrPos[mapCh], spkrSlotPos[ch]);
          if (dist < mapDist) {
            mapPos = mapCh;
            mapDist = dist;
          }
        }
      }
      if (mapDist < PCMDMX_THRESHOLD_MAP_HEAT_3) {
        offsetTable[ch] = (UCHAR)mapPos;
        mapped[mapPos] = 1;
        numMappedInChs += 1;
        if ((spkrPos[mapPos].x == 0) && (spkrSlotPos[ch].x != 0) &&
            (numChannels <
             (8))) { /* Skip the paired slot if we assigned a center channel. */
          ch += 1;
        }
      }
    }
  }

  /* Finaly compose the channel mode */
  for (ch = 0; ch < (4); ch += 1) {
    int plane, numChInGrp = 0;
    for (plane = 0; plane < (3); plane += 1) {
      numChInGrp += numCh[plane][ch];
    }
    *chMode = (PCM_DMX_CHANNEL_MODE)(*chMode | (numChInGrp << (ch * 4)));
  }

  return err;
}

/** Generate a channel offset table and complete channel description for a given
 *(packed) channel mode. This function is the inverse to the getChannelMode()
 *routine but does not support weird channel configurations.
 * @param [in] The packed channel mode of the configuration to be processed.
 * @param [in] Array containing the channel mapping to be used (From MPEG PCE
 *ordering to whatever is required).
 * @param [out] Array where corresponding channel types for each channels are
 *stored into.
 * @param [out] Array where corresponding channel type indices for each output
 *channel are stored into.
 * @param [out] Array where the buffer offsets for each channel are stored into.
 * @returns None.
 **/
static void getChannelDescription(
    const PCM_DMX_CHANNEL_MODE chMode,         /* in */
    const FDK_channelMapDescr *const mapDescr, /* in */
    AUDIO_CHANNEL_TYPE channelType[],          /* out */
    UCHAR channelIndices[],                    /* out */
    UCHAR offsetTable[(8)]                     /* out */
) {
  int grpIdx, plainIdx, numPlains = 1, numTotalChannels = 0;
  int chCfg, ch = 0;

  FDK_ASSERT(channelType != NULL);
  FDK_ASSERT(channelIndices != NULL);
  FDK_ASSERT(mapDescr != NULL);
  FDK_ASSERT(offsetTable != NULL);

  /* Init output arrays */
  FDKmemclear(channelType, (8) * sizeof(AUDIO_CHANNEL_TYPE));
  FDKmemclear(channelIndices, (8) * sizeof(UCHAR));
  FDKmemset(offsetTable, 255, (8) * sizeof(UCHAR));

  /* Summerize to get the total number of channels */
  for (grpIdx = 0; grpIdx < (4); grpIdx += 1) {
    numTotalChannels += (chMode >> (grpIdx * 4)) & 0xF;
  }

  /* Get the appropriate channel map */
  switch (chMode) {
    case CH_MODE_1_0_0_0:
    case CH_MODE_2_0_0_0:
    case CH_MODE_3_0_0_0:
    case CH_MODE_3_0_1_0:
    case CH_MODE_3_0_2_0:
    case CH_MODE_3_0_2_1:
      chCfg = numTotalChannels;
      break;
    case CH_MODE_3_0_3_1:
      chCfg = 11;
      break;
    case CH_MODE_3_0_4_1:
      chCfg = 12;
      break;
    case CH_MODE_5_0_2_1:
      chCfg = 7;
      break;
    default:
      /* fallback */
      chCfg = 0;
      break;
  }

  /* Compose channel offset table */

  for (plainIdx = 0; plainIdx < numPlains; plainIdx += 1) {
    PCM_DMX_CHANNEL_MODE plainChMode;
    UCHAR numChInGrp[(4)];

    plainChMode = getChMode4Plain(plainIdx, chMode, chCfg);

    /* Extract the number of channels per group */
    numChInGrp[CH_GROUP_FRONT] = plainChMode & 0xF;
    numChInGrp[CH_GROUP_SIDE] = (plainChMode >> 4) & 0xF;
    numChInGrp[CH_GROUP_REAR] = (plainChMode >> 8) & 0xF;
    numChInGrp[CH_GROUP_LFE] = (plainChMode >> 12) & 0xF;

    /* Non-symmetric channels */
    if ((numChInGrp[CH_GROUP_FRONT] & 0x1) && (plainIdx == CH_PLAIN_NORMAL)) {
      /* Odd number of front channels -> we have a center channel.
         In MPEG-4 the center has the index 0. */
      int mappedIdx = FDK_chMapDescr_getMapValue(mapDescr, (UCHAR)ch, chCfg);
      offsetTable[CENTER_FRONT_CHANNEL] = (UCHAR)mappedIdx;
      channelType[mappedIdx] = ACT_FRONT;
      channelIndices[mappedIdx] = 0;
      ch += 1;
    }

    for (grpIdx = 0; grpIdx < (4); grpIdx += 1) {
      AUDIO_CHANNEL_TYPE type = ACT_NONE;
      int chMapPos = 0, maxChannels = 0;
      int chIdx = 0; /* Index of channel within the specific group */

      switch (grpIdx) {
        case CH_GROUP_FRONT:
          type = (AUDIO_CHANNEL_TYPE)((plainIdx << 4) | ACT_FRONT);
          switch (plainIdx) {
            default:
              chMapPos = LEFT_FRONT_CHANNEL;
              chIdx = numChInGrp[grpIdx] & 0x1;
              break;
          }
          maxChannels = 3;
          break;
        case CH_GROUP_SIDE:
          /* Always map side channels to the multipurpose group. */
          type = (AUDIO_CHANNEL_TYPE)((plainIdx << 4) | ACT_SIDE);
          if (plainIdx == CH_PLAIN_TOP) {
            chMapPos = LEFT_SIDE_CHANNEL_TOP;
            maxChannels = 3;
          } else {
            chMapPos = LEFT_MULTIPRPS_CHANNEL;
            maxChannels = 2;
          }
          break;
        case CH_GROUP_REAR:
          type = (AUDIO_CHANNEL_TYPE)((plainIdx << 4) | ACT_BACK);
          if (plainIdx == CH_PLAIN_TOP) {
            chMapPos = LEFT_REAR_CHANNEL_TOP;
            maxChannels = 3;
          } else {
            chMapPos = LEFT_REAR_CHANNEL;
            maxChannels = 2;
          }
          break;
        case CH_GROUP_LFE:
          if (plainIdx == CH_PLAIN_NORMAL) {
            type = ACT_LFE;
            chMapPos = LOW_FREQUENCY_CHANNEL;
            maxChannels = 1;
          }
          break;
        default:
          break;
      }

      /* Map all channels in this group */
      for (; chIdx < numChInGrp[grpIdx]; chIdx += 1) {
        int mappedIdx = FDK_chMapDescr_getMapValue(mapDescr, (UCHAR)ch, chCfg);
        if ((chIdx == maxChannels) || (offsetTable[chMapPos] < 255)) {
          /* No space left in this channel group! */
          if (offsetTable[LEFT_MULTIPRPS_CHANNEL] ==
              255) { /* Use the multipurpose group: */
            chMapPos = LEFT_MULTIPRPS_CHANNEL;
          } else {
            FDK_ASSERT(0);
          }
        }
        offsetTable[chMapPos] = (UCHAR)mappedIdx;
        channelType[mappedIdx] = type;
        channelIndices[mappedIdx] = (UCHAR)chIdx;
        chMapPos += 1;
        ch += 1;
      }
    }
  }
}

/** Private helper function for downmix matrix manipulation that initializes
 *  one row in a given downmix matrix (corresponding to one output channel).
 * @param [inout] Pointer to fixed-point parts of the downmix matrix.
 * @param [inout] Pointer to scale factor matrix associated to the downmix
 *factors.
 * @param [in]    Index of channel (row) to be initialized.
 * @returns       Nothing to return.
 **/
static void dmxInitChannel(FIXP_DMX mixFactors[(8)][(8)],
                           INT mixScales[(8)][(8)], const unsigned int outCh) {
  unsigned int inCh;
  for (inCh = 0; inCh < (8); inCh += 1) {
    if (inCh == outCh) {
      mixFactors[outCh][inCh] = FL2FXCONST_DMX(0.5f);
      mixScales[outCh][inCh] = 1;
    } else {
      mixFactors[outCh][inCh] = FL2FXCONST_DMX(0.0f);
      mixScales[outCh][inCh] = 0;
    }
  }
}

/** Private helper function for downmix matrix manipulation that does a reset
 *  of one row in a given downmix matrix (corresponding to one output channel).
 * @param [inout] Pointer to fixed-point parts of the downmix matrix.
 * @param [inout] Pointer to scale factor matrix associated to the downmix
 *factors.
 * @param [in]    Index of channel (row) to be cleared/reset.
 * @returns       Nothing to return.
 **/
static void dmxClearChannel(FIXP_DMX mixFactors[(8)][(8)],
                            INT mixScales[(8)][(8)], const unsigned int outCh) {
  FDK_ASSERT((outCh >= 0) && (outCh < (8)));
  FDKmemclear(&mixFactors[outCh], (8) * sizeof(FIXP_DMX));
  FDKmemclear(&mixScales[outCh], (8) * sizeof(INT));
}

/** Private helper function for downmix matrix manipulation that applies a
 *source channel (row) scaled by a given mix factor to a destination channel
 *(row) in a given downmix matrix. Existing mix factors of the destination
 *channel (row) will get overwritten.
 * @param [inout] Pointer to fixed-point parts of the downmix matrix.
 * @param [inout] Pointer to scale factor matrix associated to the downmix
 *factors.
 * @param [in]    Index of source channel (row).
 * @param [in]    Index of destination channel (row).
 * @param [in]    Fixed-point part of mix factor to be applied.
 * @param [in]    Scale factor of mix factor to be applied.
 * @returns       Nothing to return.
 **/
static void dmxSetChannel(FIXP_DMX mixFactors[(8)][(8)],
                          INT mixScales[(8)][(8)], const unsigned int dstCh,
                          const unsigned int srcCh, const FIXP_DMX factor,
                          const INT scale) {
  int ch;
  for (ch = 0; ch < (8); ch += 1) {
    if (mixFactors[srcCh][ch] != (FIXP_DMX)0) {
      mixFactors[dstCh][ch] =
          FX_DBL2FX_DMX(fMult(mixFactors[srcCh][ch], factor));
      mixScales[dstCh][ch] = mixScales[srcCh][ch] + scale;
    }
  }
}

/** Private helper function for downmix matrix manipulation that adds a source
 *channel (row) scaled by a given mix factor to a destination channel (row) in a
 *given downmix matrix.
 * @param [inout] Pointer to fixed-point parts of the downmix matrix.
 * @param [inout] Pointer to scale factor matrix associated to the downmix
 *factors.
 * @param [in]    Index of source channel (row).
 * @param [in]    Index of destination channel (row).
 * @param [in]    Fixed-point part of mix factor to be applied.
 * @param [in]    Scale factor of mix factor to be applied.
 * @returns       Nothing to return.
 **/
static void dmxAddChannel(FIXP_DMX mixFactors[(8)][(8)],
                          INT mixScales[(8)][(8)], const unsigned int dstCh,
                          const unsigned int srcCh, const FIXP_DMX factor,
                          const INT scale) {
  int ch;
  for (ch = 0; ch < (8); ch += 1) {
    FIXP_DBL addFact = fMult(mixFactors[srcCh][ch], factor);
    if (addFact != (FIXP_DMX)0) {
      INT newScale = mixScales[srcCh][ch] + scale;
      if (mixFactors[dstCh][ch] != (FIXP_DMX)0) {
        if (newScale > mixScales[dstCh][ch]) {
          mixFactors[dstCh][ch] >>= newScale - mixScales[dstCh][ch];
        } else {
          addFact >>= mixScales[dstCh][ch] - newScale;
          newScale = mixScales[dstCh][ch];
        }
      }
      mixFactors[dstCh][ch] += FX_DBL2FX_DMX(addFact);
      mixScales[dstCh][ch] = newScale;
    }
  }
}

/** Private function that creates a downmix factor matrix depending on the input
 and output
 *  configuration, the user parameters as well as the given metadata. This
 function is the modules
 *  brain and hold all downmix algorithms.
 * @param [in]  Flag that indicates if inChMode holds a real (packed) channel
 mode or has been converted to a MPEG-4 channel configuration index.
 * @param [in]  Dependent on the inModeIsCfg flag this field hands in a (packed)
 channel mode or the corresponding MPEG-4 channel configuration index.of the
 input configuration.
 * @param [in]  The (packed) channel mode of the output configuration.
 * @param [in]  Pointer to structure holding all current user parameter.
 * @param [in]  Pointer to field holding all current meta data.
 * @param [out] Pointer to fixed-point parts of the downmix matrix. Normalized
 to one scale factor.
 * @param [out] The common scale factor of the downmix matrix.
 * @returns     An error code.
 **/
static PCMDMX_ERROR getMixFactors(const UCHAR inModeIsCfg,
                                  PCM_DMX_CHANNEL_MODE inChMode,
                                  const PCM_DMX_CHANNEL_MODE outChMode,
                                  const PCM_DMX_USER_PARAMS *pParams,
                                  const DMX_BS_META_DATA *pMetaData,
                                  FIXP_DMX mixFactors[(8)][(8)],
                                  INT *pOutScale) {
  PCMDMX_ERROR err = PCMDMX_OK;
  INT mixScales[(8)][(8)];
  INT maxScale = 0;
  int numInChannel;
  int numOutChannel;
  int dmxMethod;
  unsigned int outCh, inChCfg = 0;
  unsigned int valid[(8)] = {0};

  FDK_ASSERT(pMetaData != NULL);
  FDK_ASSERT(mixFactors != NULL);
  /* Check on a supported output configuration.
     Add new one only after extensive testing! */
  if (!((outChMode == CH_MODE_1_0_0_0) || (outChMode == CH_MODE_2_0_0_0) ||
        (outChMode == CH_MODE_3_0_2_1) || (outChMode == CH_MODE_3_0_4_1) ||
        (outChMode == CH_MODE_5_0_2_1))) {
    FDK_ASSERT(0);
  }

  if (inModeIsCfg) {
    /* Convert channel config to channel mode: */
    inChCfg = (unsigned int)inChMode;
    switch (inChCfg) {
      case 1:
      case 2:
      case 3:
      case 4:
      case 5:
      case 6:
        inChMode = outChModeTable[inChCfg];
        break;
      case 11:
        inChMode = CH_MODE_3_0_3_1;
        break;
      case 12:
        inChMode = CH_MODE_3_0_4_1;
        break;
      case 7:
      case 14:
        inChMode = CH_MODE_5_0_2_1;
        break;
      default:
        FDK_ASSERT(0);
    }
  }

  /* Extract the total number of input channels */
  numInChannel = (inChMode & 0xF) + ((inChMode >> 4) & 0xF) +
                 ((inChMode >> 8) & 0xF) + ((inChMode >> 12) & 0xF);
  /* Extract the total number of output channels */
  numOutChannel = (outChMode & 0xF) + ((outChMode >> 4) & 0xF) +
                  ((outChMode >> 8) & 0xF) + ((outChMode >> 12) & 0xF);

  /* MPEG ammendment 4 aka ETSI metadata and fallback mode: */

  /* Create identity DMX matrix: */
  for (outCh = 0; outCh < (8); outCh += 1) {
    dmxInitChannel(mixFactors, mixScales, outCh);
  }
  if (((inChMode >> 12) & 0xF) == 0) {
    /* Clear empty or wrongly mapped input channel */
    dmxClearChannel(mixFactors, mixScales, LOW_FREQUENCY_CHANNEL);
  }

  /* FIRST STAGE: */
  if (numInChannel > SIX_CHANNEL) { /* Always use MPEG equations either with
                                       meta data or with default values. */
    FIXP_DMX dMixFactA, dMixFactB;
    INT dMixScaleA, dMixScaleB;
    int isValidCfg = TRUE;

    /* Get factors from meta data */
    dMixFactA = abMixLvlValueTab[pMetaData->dmixIdxA];
    dMixScaleA = (pMetaData->dmixIdxA == 0) ? 1 : 0;
    dMixFactB = abMixLvlValueTab[pMetaData->dmixIdxB];
    dMixScaleB = (pMetaData->dmixIdxB == 0) ? 1 : 0;

    /* Check if input is in the list of supported configurations */
    switch (inChMode) {
      case CH_MODE_3_2_1_1: /* chCfg 11 but with side channels */
      case CH_MODE_3_2_1_0:
        isValidCfg = FALSE;
        err = PCMDMX_INVALID_MODE;
        FDK_FALLTHROUGH;
      case CH_MODE_3_0_3_1: /* chCfg 11 */
        /* 6.1ch:  C' = C;  L' = L;  R' = R;  LFE' = LFE;
                   Ls' = Ls*dmix_a_idx + Cs*dmix_b_idx;
                   Rs' = Rs*dmix_a_idx + Cs*dmix_b_idx; */
        dmxClearChannel(
            mixFactors, mixScales,
            RIGHT_MULTIPRPS_CHANNEL); /* clear empty input channel */
        dmxSetChannel(mixFactors, mixScales, LEFT_REAR_CHANNEL,
                      LEFT_REAR_CHANNEL, dMixFactA, dMixScaleA);
        dmxSetChannel(mixFactors, mixScales, LEFT_REAR_CHANNEL,
                      LEFT_MULTIPRPS_CHANNEL, dMixFactB, dMixScaleB);
        dmxSetChannel(mixFactors, mixScales, RIGHT_REAR_CHANNEL,
                      RIGHT_REAR_CHANNEL, dMixFactA, dMixScaleA);
        dmxSetChannel(mixFactors, mixScales, RIGHT_REAR_CHANNEL,
                      LEFT_MULTIPRPS_CHANNEL, dMixFactB, dMixScaleB);
        break;
      case CH_MODE_3_0_4_1: /* chCfg 12 */
        /* 7.1ch Surround Back:  C' = C;  L' = L;  R' = R;  LFE' = LFE;
                                 Ls' = Ls*dmix_a_idx + Lsr*dmix_b_idx;
                                 Rs' = Rs*dmix_a_idx + Rsr*dmix_b_idx; */
        dmxSetChannel(mixFactors, mixScales, LEFT_REAR_CHANNEL,
                      LEFT_REAR_CHANNEL, dMixFactA, dMixScaleA);
        dmxSetChannel(mixFactors, mixScales, LEFT_REAR_CHANNEL,
                      LEFT_MULTIPRPS_CHANNEL, dMixFactB, dMixScaleB);
        dmxSetChannel(mixFactors, mixScales, RIGHT_REAR_CHANNEL,
                      RIGHT_REAR_CHANNEL, dMixFactA, dMixScaleA);
        dmxSetChannel(mixFactors, mixScales, RIGHT_REAR_CHANNEL,
                      RIGHT_MULTIPRPS_CHANNEL, dMixFactB, dMixScaleB);
        break;
      case CH_MODE_5_0_1_0:
      case CH_MODE_5_0_1_1:
        dmxClearChannel(mixFactors, mixScales,
                        RIGHT_REAR_CHANNEL); /* clear empty input channel */
        dmxSetChannel(mixFactors, mixScales, RIGHT_REAR_CHANNEL,
                      LEFT_REAR_CHANNEL, FL2FXCONST_DMX(0.5f), 1);
        dmxSetChannel(mixFactors, mixScales, LEFT_REAR_CHANNEL,
                      LEFT_REAR_CHANNEL, FL2FXCONST_DMX(0.5f), 1);
        FDK_FALLTHROUGH;
      case CH_MODE_5_2_1_0:
        isValidCfg = FALSE;
        err = PCMDMX_INVALID_MODE;
        FDK_FALLTHROUGH;
      case CH_MODE_5_0_2_1: /* chCfg 7 || 14 */
        if (inChCfg == 14) {
          /* 7.1ch Front Height:  C' = C;  Ls' = Ls;  Rs' = Rs;  LFE' = LFE;
                                  L' = L*dmix_a_idx + Lv*dmix_b_idx;
                                  R' = R*dmix_a_idx + Rv*dmix_b_idx; */
          dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                        LEFT_FRONT_CHANNEL, dMixFactA, dMixScaleA);
          dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                        LEFT_MULTIPRPS_CHANNEL, dMixFactB, dMixScaleB);
          dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                        RIGHT_FRONT_CHANNEL, dMixFactA, dMixScaleA);
          dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                        RIGHT_MULTIPRPS_CHANNEL, dMixFactB, dMixScaleB);
        } else {
          /* 7.1ch Front:  Ls' = Ls;  Rs' = Rs;  LFE' = LFE;
                           C' = C + (Lc+Rc)*dmix_a_idx;
                           L' = L + Lc*dmix_b_idx;
                           R' = R + Rc*dmix_b_idx; */
          dmxSetChannel(mixFactors, mixScales, CENTER_FRONT_CHANNEL,
                        LEFT_MULTIPRPS_CHANNEL, dMixFactA, dMixScaleA);
          dmxSetChannel(mixFactors, mixScales, CENTER_FRONT_CHANNEL,
                        RIGHT_MULTIPRPS_CHANNEL, dMixFactA, dMixScaleA);
          dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                        LEFT_MULTIPRPS_CHANNEL, dMixFactB, dMixScaleB);
          dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                        LEFT_FRONT_CHANNEL, FL2FXCONST_DMX(0.5f), 1);
          dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                        RIGHT_MULTIPRPS_CHANNEL, dMixFactB, dMixScaleB);
          dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                        RIGHT_FRONT_CHANNEL, FL2FXCONST_DMX(0.5f), 1);
        }
        break;
      default:
        /* Nothing to do. Just use the identity matrix. */
        isValidCfg = FALSE;
        err = PCMDMX_INVALID_MODE;
        break;
    }

    /* Add additional DMX gain */
    if ((isValidCfg == TRUE) &&
        (pMetaData->dmxGainIdx5 != 0)) { /* Apply DMX gain 5 */
      FIXP_DMX dmxGain;
      INT dmxScale;
      INT sign = (pMetaData->dmxGainIdx5 & 0x40) ? -1 : 1;
      INT val = pMetaData->dmxGainIdx5 & 0x3F;

      /* 10^(dmx_gain_5/80) */
      dmxGain = FX_DBL2FX_DMX(
          fLdPow(FL2FXCONST_DBL(0.830482023721841f), 2, /* log2(10) */
                 (FIXP_DBL)(sign * val * (LONG)FL2FXCONST_DBL(0.0125f)), 0,
                 &dmxScale));
      /* Currently only positive scale factors supported! */
      if (dmxScale < 0) {
        dmxGain >>= -dmxScale;
        dmxScale = 0;
      }

      dmxSetChannel(mixFactors, mixScales, CENTER_FRONT_CHANNEL,
                    CENTER_FRONT_CHANNEL, dmxGain, dmxScale);
      dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                    LEFT_FRONT_CHANNEL, dmxGain, dmxScale);
      dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                    RIGHT_FRONT_CHANNEL, dmxGain, dmxScale);
      dmxSetChannel(mixFactors, mixScales, LEFT_REAR_CHANNEL, LEFT_REAR_CHANNEL,
                    dmxGain, dmxScale);
      dmxSetChannel(mixFactors, mixScales, RIGHT_REAR_CHANNEL,
                    RIGHT_REAR_CHANNEL, dmxGain, dmxScale);
      dmxSetChannel(mixFactors, mixScales, LOW_FREQUENCY_CHANNEL,
                    LOW_FREQUENCY_CHANNEL, dmxGain, dmxScale);
    }

    /* Mark the output channels */
    valid[CENTER_FRONT_CHANNEL] = 1;
    valid[LEFT_FRONT_CHANNEL] = 1;
    valid[RIGHT_FRONT_CHANNEL] = 1;
    valid[LEFT_REAR_CHANNEL] = 1;
    valid[RIGHT_REAR_CHANNEL] = 1;
    valid[LOW_FREQUENCY_CHANNEL] = 1;

    /* Update channel mode for the next stage */
    inChMode = CH_MODE_3_0_2_1;
  }

    /* For the X (> 6) to 6 channel downmix we had no choice.
       To mix from 6 to 2 (or 1) channel(s) we have several possibilities (MPEG
       DSE | MPEG PCE | ITU | ARIB | DLB). Use profile and the metadata
       available flags to determine which equation to use: */

#define DMX_METHOD_MPEG_AMD4 1
#define DMX_METHOD_MPEG_LEGACY 2
#define DMX_METHOD_ARIB_JAPAN 4
#define DMX_METHOD_ITU_RECOM 8
#define DMX_METHOD_CUSTOM 16

  dmxMethod = DMX_METHOD_MPEG_AMD4; /* default */

  if ((pParams->dmxProfile == DMX_PRFL_FORCE_MATRIX_MIX) &&
      (pMetaData->typeFlags & TYPE_PCE_DATA)) {
    dmxMethod = DMX_METHOD_MPEG_LEGACY;
  } else if (!(pMetaData->typeFlags &
               (TYPE_DSE_CLEV_DATA | TYPE_DSE_SLEV_DATA))) {
    switch (pParams->dmxProfile) {
      default:
      case DMX_PRFL_STANDARD:
        /* dmxMethod = DMX_METHOD_MPEG_AMD4; */
        break;
      case DMX_PRFL_MATRIX_MIX:
      case DMX_PRFL_FORCE_MATRIX_MIX:
        if (pMetaData->typeFlags & TYPE_PCE_DATA) {
          dmxMethod = DMX_METHOD_MPEG_LEGACY;
        }
        break;
      case DMX_PRFL_ARIB_JAPAN:
        dmxMethod = DMX_METHOD_ARIB_JAPAN;
        break;
    }
  }

  /* SECOND STAGE: */
  if (numOutChannel <= TWO_CHANNEL) {
    /* Create DMX matrix according to input configuration */
    switch (inChMode) {
      case CH_MODE_2_0_0_0: /* chCfg 2 */
        /* Apply the dual channel mode. */
        switch (pParams->dualChannelMode) {
          case CH1_MODE: /* L' = 0.707 * Ch1;
                            R' = 0.707 * Ch1; */
            dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                          LEFT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
            dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                          LEFT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
            break;
          case CH2_MODE: /* L' = 0.707 * Ch2;
                            R' = 0.707 * Ch2; */
            dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                          RIGHT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
            dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                          RIGHT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
            break;
          case MIXED_MODE: /* L' = 0.5*Ch1 + 0.5*Ch2;
                              R' = 0.5*Ch1 + 0.5*Ch2; */
            dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                          LEFT_FRONT_CHANNEL, FL2FXCONST_DMX(0.5f), 0);
            dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                          RIGHT_FRONT_CHANNEL, FL2FXCONST_DMX(0.5f), 0);
            dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                          LEFT_FRONT_CHANNEL, FL2FXCONST_DMX(0.5f), 0);
            dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                          RIGHT_FRONT_CHANNEL, FL2FXCONST_DMX(0.5f), 0);
            break;
          default:
          case STEREO_MODE:
            /* Nothing to do */
            break;
        }
        break;
      /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
       * - - - - - - - - - - - - - - - - - - - */
      case CH_MODE_2_0_1_0: {
        FIXP_DMX sMixLvl;
        if (dmxMethod == DMX_METHOD_ARIB_JAPAN) {
          /* L' = 0.707*L + 0.5*S;  R' = 0.707*R + 0.5*S; */
          dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                        LEFT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
          dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                        RIGHT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
          sMixLvl = FL2FXCONST_DMX(0.5f);
        } else { /* L' = L + 0.707*S;  R' = R + 0.707*S; */
          sMixLvl = FL2FXCONST_DMX(0.707f);
        }
        dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                      LEFT_REAR_CHANNEL, sMixLvl, 0);
        dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                      LEFT_REAR_CHANNEL, sMixLvl, 0);
      } break;
      /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
       * - - - - - - - - - - - - - - - - - - - */
      case CH_MODE_3_0_0_0: /* chCfg 3 */
      {
        FIXP_DMX cMixLvl;
        if (dmxMethod == DMX_METHOD_ARIB_JAPAN) {
          /* L' = 0.707*L + 0.5*C;  R' = 0.707*R + 0.5*C; */
          dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                        LEFT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
          dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                        RIGHT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
          cMixLvl = FL2FXCONST_DMX(0.5f);
        } else { /* L' = L + 0.707*C;  R' = R + 0.707*C; */
          cMixLvl = FL2FXCONST_DMX(0.707f);
        }
        dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                      CENTER_FRONT_CHANNEL, cMixLvl, 0);
        dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                      CENTER_FRONT_CHANNEL, cMixLvl, 0);
      } break;
      /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
       * - - - - - - - - - - - - - - - - - - - */
      case CH_MODE_3_0_1_0: /* chCfg 4 */
      {
        FIXP_DMX csMixLvl;
        if (dmxMethod == DMX_METHOD_ARIB_JAPAN) {
          /* L' = 0.707*L + 0.5*C + 0.5*S;  R' = 0.707*R + 0.5*C + 0.5*S; */
          dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                        LEFT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
          dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                        RIGHT_FRONT_CHANNEL, FL2FXCONST_DMX(0.707f), 0);
          csMixLvl = FL2FXCONST_DMX(0.5f);
        } else { /* L' = L + 0.707*C + 0.707*S;
                    R' = R + 0.707*C + 0.707*S; */
          csMixLvl = FL2FXCONST_DMX(0.707f);
        }
        dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                      CENTER_FRONT_CHANNEL, csMixLvl, 0);
        dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                      LEFT_REAR_CHANNEL, csMixLvl, 0);
        dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                      CENTER_FRONT_CHANNEL, csMixLvl, 0);
        dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                      LEFT_REAR_CHANNEL, csMixLvl, 0);
      } break;
      /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
       * - - - - - - - - - - - - - - - - - - - */
      case CH_MODE_3_0_2_0: /* chCfg 5 */
      case CH_MODE_3_0_2_1: /* chCfg 6 */
      {
        switch (dmxMethod) {
          default:
          case DMX_METHOD_MPEG_AMD4: {
            FIXP_DMX cMixLvl, sMixLvl, lMixLvl;
            INT cMixScale, sMixScale, lMixScale;

            /* Get factors from meta data */
            cMixLvl = abMixLvlValueTab[pMetaData->cLevIdx];
            cMixScale = (pMetaData->cLevIdx == 0) ? 1 : 0;
            sMixLvl = abMixLvlValueTab[pMetaData->sLevIdx];
            sMixScale = (pMetaData->sLevIdx == 0) ? 1 : 0;
            lMixLvl = lfeMixLvlValueTab[pMetaData->dmixIdxLfe];
            if (pMetaData->dmixIdxLfe <= 1) {
              lMixScale = 2;
            } else if (pMetaData->dmixIdxLfe <= 5) {
              lMixScale = 1;
            } else {
              lMixScale = 0;
            }
            /* Setup the DMX matrix */
            if ((pParams->pseudoSurrMode == FORCE_PS_DMX) ||
                ((pParams->pseudoSurrMode == AUTO_PS_DMX) &&
                 (pMetaData->pseudoSurround ==
                  1))) { /* L' = L + C*clev - (Ls+Rs)*slev + LFE*lflev;
                            R' = R + C*clev + (Ls+Rs)*slev + LFE*lflev; */
              dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                            CENTER_FRONT_CHANNEL, cMixLvl, cMixScale);
              dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                            LEFT_REAR_CHANNEL, -sMixLvl, sMixScale);
              dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                            RIGHT_REAR_CHANNEL, -sMixLvl, sMixScale);
              dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                            LOW_FREQUENCY_CHANNEL, lMixLvl, lMixScale);
              dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                            CENTER_FRONT_CHANNEL, cMixLvl, cMixScale);
              dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                            LEFT_REAR_CHANNEL, sMixLvl, sMixScale);
              dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                            RIGHT_REAR_CHANNEL, sMixLvl, sMixScale);
              dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                            LOW_FREQUENCY_CHANNEL, lMixLvl, lMixScale);
            } else { /* L' = L + C*clev + Ls*slev + LFE*llev;
                        R' = R + C*clev + Rs*slev + LFE*llev; */
              dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                            CENTER_FRONT_CHANNEL, cMixLvl, cMixScale);
              dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                            LEFT_REAR_CHANNEL, sMixLvl, sMixScale);
              dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                            LOW_FREQUENCY_CHANNEL, lMixLvl, lMixScale);
              dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                            CENTER_FRONT_CHANNEL, cMixLvl, cMixScale);
              dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                            RIGHT_REAR_CHANNEL, sMixLvl, sMixScale);
              dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                            LOW_FREQUENCY_CHANNEL, lMixLvl, lMixScale);
            }

            /* Add additional DMX gain */
            if (pMetaData->dmxGainIdx2 != 0) { /* Apply DMX gain 2 */
              FIXP_DMX dmxGain;
              INT dmxScale;
              INT sign = (pMetaData->dmxGainIdx2 & 0x40) ? -1 : 1;
              INT val = pMetaData->dmxGainIdx2 & 0x3F;

              /* 10^(dmx_gain_2/80) */
              dmxGain = FX_DBL2FX_DMX(
                  fLdPow(FL2FXCONST_DBL(0.830482023721841f), 2, /* log2(10) */
                         (FIXP_DBL)(sign * val * (LONG)FL2FXCONST_DBL(0.0125f)),
                         0, &dmxScale));
              /* Currently only positive scale factors supported! */
              if (dmxScale < 0) {
                dmxGain >>= -dmxScale;
                dmxScale = 0;
              }

              dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                            LEFT_FRONT_CHANNEL, dmxGain, dmxScale);
              dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                            RIGHT_FRONT_CHANNEL, dmxGain, dmxScale);
            }
          } break;
          case DMX_METHOD_ARIB_JAPAN:
          case DMX_METHOD_MPEG_LEGACY: {
            FIXP_DMX flev, clev, slevLL, slevLR, slevRL, slevRR;
            FIXP_DMX mtrxMixDwnCoef =
                mpegMixDownIdx2Coef[pMetaData->matrixMixdownIdx];

            if ((pParams->pseudoSurrMode == FORCE_PS_DMX) ||
                ((pParams->pseudoSurrMode == AUTO_PS_DMX) &&
                 (pMetaData->pseudoSurround == 1))) {
              if (dmxMethod == DMX_METHOD_ARIB_JAPAN) {
                /* 3/2 input: L' = 0.707 * [L+0.707*C-k*Ls-k*Rs];
                              R' = 0.707 * [R+0.707*C+k*Ls+k*Rs]; */
                flev = mpegMixDownIdx2Coef[0]; /* a = 0.707 */
              } else { /* 3/2 input: L' = (1.707+2*A)^-1 *
                          [L+0.707*C-A*Ls-A*Rs]; R' = (1.707+2*A)^-1 *
                          [R+0.707*C+A*Ls+A*Rs]; */
                flev = mpegMixDownIdx2PreFact[1][pMetaData->matrixMixdownIdx];
              }
              slevRR = slevRL = FX_DBL2FX_DMX(fMult(flev, mtrxMixDwnCoef));
              slevLL = slevLR = -slevRL;
            } else {
              if (dmxMethod == DMX_METHOD_ARIB_JAPAN) {
                /* 3/2 input: L' = 0.707 * [L+0.707*C+k*Ls];
                              R' = 0.707 * [R+0.707*C+k*Rs]; */
                flev = mpegMixDownIdx2Coef[0]; /* a = 0.707 */
              } else { /* 3/2 input: L' = (1.707+A)^-1 * [L+0.707*C+A*Ls];
                                     R' = (1.707+A)^-1 * [R+0.707*C+A*Rs]; */
                flev = mpegMixDownIdx2PreFact[0][pMetaData->matrixMixdownIdx];
              }
              slevRR = slevLL = FX_DBL2FX_DMX(fMult(flev, mtrxMixDwnCoef));
              slevLR = slevRL = (FIXP_DMX)0;
            }
            /* common factor */
            clev =
                FX_DBL2FX_DMX(fMult(flev, mpegMixDownIdx2Coef[0] /* 0.707 */));

            dmxSetChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                          LEFT_FRONT_CHANNEL, flev, 0);
            dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                          CENTER_FRONT_CHANNEL, clev, 0);
            dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                          LEFT_REAR_CHANNEL, slevLL, 0);
            dmxAddChannel(mixFactors, mixScales, LEFT_FRONT_CHANNEL,
                          RIGHT_REAR_CHANNEL, slevLR, 0);

            dmxSetChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                          RIGHT_FRONT_CHANNEL, flev, 0);
            dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                          CENTER_FRONT_CHANNEL, clev, 0);
            dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                          LEFT_REAR_CHANNEL, slevRL, 0);
            dmxAddChannel(mixFactors, mixScales, RIGHT_FRONT_CHANNEL,
                          RIGHT_REAR_CHANNEL, slevRR, 0);
          } break;
        } /* switch (dmxMethod) */
      } break;
      default:
        /* This configuration does not fit to any known downmix equation! */
        err = PCMDMX_INVALID_MODE;
        break;
    } /* switch (inChMode) */

    /* Mark the output channels */
    FDKmemclear(valid, (8) * sizeof(unsigned int));
    valid[LEFT_FRONT_CHANNEL] = 1;
    valid[RIGHT_FRONT_CHANNEL] = 1;
  }

  if (numOutChannel == ONE_CHANNEL) {
    FIXP_DMX monoMixLevel;
    INT monoMixScale = 0;

    dmxClearChannel(mixFactors, mixScales,
                    CENTER_FRONT_CHANNEL); /* C is not in the mix */

    if (dmxMethod ==
        DMX_METHOD_MPEG_LEGACY) { /* C' = (3+2*A)^-1 * [C+L+R+A*Ls+A+Rs]; */
      monoMixLevel = mpegMixDownIdx2PreFact[2][pMetaData->matrixMixdownIdx];

      mixFactors[CENTER_FRONT_CHANNEL][CENTER_FRONT_CHANNEL] = monoMixLevel;
      mixFactors[CENTER_FRONT_CHANNEL][LEFT_FRONT_CHANNEL] = monoMixLevel;
      mixFactors[CENTER_FRONT_CHANNEL][RIGHT_FRONT_CHANNEL] = monoMixLevel;
      monoMixLevel = FX_DBL2FX_DMX(fMult(
          monoMixLevel, mpegMixDownIdx2Coef[pMetaData->matrixMixdownIdx]));
      mixFactors[CENTER_FRONT_CHANNEL][LEFT_REAR_CHANNEL] = monoMixLevel;
      mixFactors[CENTER_FRONT_CHANNEL][RIGHT_REAR_CHANNEL] = monoMixLevel;
    } else {
      switch (dmxMethod) {
        case DMX_METHOD_MPEG_AMD4:
          /* C' = L + R; */
          monoMixLevel = FL2FXCONST_DMX(0.5f);
          monoMixScale = 1;
          break;
        default:
          /* C' = 0.5*L + 0.5*R; */
          monoMixLevel = FL2FXCONST_DMX(0.5f);
          monoMixScale = 0;
          break;
      }
      dmxSetChannel(mixFactors, mixScales, CENTER_FRONT_CHANNEL,
                    LEFT_FRONT_CHANNEL, monoMixLevel, monoMixScale);
      dmxAddChannel(mixFactors, mixScales, CENTER_FRONT_CHANNEL,
                    RIGHT_FRONT_CHANNEL, monoMixLevel, monoMixScale);
    }

    /* Mark the output channel */
    FDKmemclear(valid, (8) * sizeof(unsigned int));
    valid[CENTER_FRONT_CHANNEL] = 1;
  }

#define MAX_SEARCH_START_VAL (-7)

  {
    LONG chSum[(8)];
    INT chSumMax = MAX_SEARCH_START_VAL;

    /* Determine the current maximum scale factor */
    for (outCh = 0; outCh < (8); outCh += 1) {
      if (valid[outCh] != 0) {
        unsigned int inCh;
        for (inCh = 0; inCh < (8); inCh += 1) {
          if (mixScales[outCh][inCh] > maxScale) { /* Store the new maximum */
            maxScale = mixScales[outCh][inCh];
          }
        }
      }
    }

    /* Individualy analyse output chanal levels */
    for (outCh = 0; outCh < (8); outCh += 1) {
      chSum[outCh] = MAX_SEARCH_START_VAL;
      if (valid[outCh] != 0) {
        int ovrflwProtScale = 0;
        unsigned int inCh;

        /* Accumulate all factors for each output channel */
        chSum[outCh] = 0;
        for (inCh = 0; inCh < (8); inCh += 1) {
          SHORT addFact = FX_DMX2SHRT(mixFactors[outCh][inCh]);
          if (mixScales[outCh][inCh] <= maxScale) {
            addFact >>= maxScale - mixScales[outCh][inCh];
          } else {
            addFact <<= mixScales[outCh][inCh] - maxScale;
          }
          chSum[outCh] += addFact;
        }
        if (chSum[outCh] > (LONG)MAXVAL_SGL) {
          while (chSum[outCh] > (LONG)MAXVAL_SGL) {
            ovrflwProtScale += 1;
            chSum[outCh] >>= 1;
          }
        } else if (chSum[outCh] > 0) {
          while ((chSum[outCh] << 1) <= (LONG)MAXVAL_SGL) {
            ovrflwProtScale -= 1;
            chSum[outCh] <<= 1;
          }
        }
        /* Store the differential scaling in the same array */
        chSum[outCh] = ovrflwProtScale;
      }
    }

    for (outCh = 0; outCh < (8); outCh += 1) {
      if ((valid[outCh] != 0) &&
          (chSum[outCh] > chSumMax)) { /* Store the new maximum */
        chSumMax = chSum[outCh];
      }
    }
    maxScale = fMax(maxScale + chSumMax, 0);

    /* Normalize all factors */
    for (outCh = 0; outCh < (8); outCh += 1) {
      if (valid[outCh] != 0) {
        unsigned int inCh;
        for (inCh = 0; inCh < (8); inCh += 1) {
          if (mixFactors[outCh][inCh] != (FIXP_DMX)0) {
            if (mixScales[outCh][inCh] <= maxScale) {
              mixFactors[outCh][inCh] >>= maxScale - mixScales[outCh][inCh];
            } else {
              mixFactors[outCh][inCh] <<= mixScales[outCh][inCh] - maxScale;
            }
            mixScales[outCh][inCh] = maxScale;
          }
        }
      }
    }
  }

  /* return the scale factor */
  *pOutScale = maxScale;

  return (err);
}

/** Open and initialize an instance of the PCM downmix module
 * @param [out] Pointer to a buffer receiving the handle of the new instance.
 * @returns Returns an error code.
 **/
PCMDMX_ERROR pcmDmx_Open(HANDLE_PCM_DOWNMIX *pSelf) {
  HANDLE_PCM_DOWNMIX self;

  if (pSelf == NULL) {
    return (PCMDMX_INVALID_HANDLE);
  }

  *pSelf = NULL;

  self = (HANDLE_PCM_DOWNMIX)GetPcmDmxInstance(0);
  if (self == NULL) {
    return (PCMDMX_OUT_OF_MEMORY);
  }

  /* Reset the full instance */
  pcmDmx_Reset(self, PCMDMX_RESET_FULL);

  *pSelf = self;

  return (PCMDMX_OK);
}

/** Reset all static values like e.g. mixdown coefficients.
 * @param [in] Handle of PCM downmix module instance.
 * @param [in] Flags telling which parts of the module shall be reset.
 * @returns Returns an error code.
 **/
PCMDMX_ERROR pcmDmx_Reset(HANDLE_PCM_DOWNMIX self, UINT flags) {
  if (self == NULL) {
    return (PCMDMX_INVALID_HANDLE);
  }

  if (flags & PCMDMX_RESET_PARAMS) {
    PCM_DMX_USER_PARAMS *pParams = &self->userParams;

    pParams->dualChannelMode = STEREO_MODE;
    pParams->pseudoSurrMode = NEVER_DO_PS_DMX;
    pParams->numOutChannelsMax = (6);
    pParams->numOutChannelsMin = (0);
    pParams->frameDelay = 0;
    pParams->expiryFrame = (0);

    self->applyProcessing = 0;
  }

  if (flags & PCMDMX_RESET_BS_DATA) {
    int slot;
    /* Init all slots with a default set */
    for (slot = 0; slot <= (1); slot += 1) {
      FDKmemcpy(&self->bsMetaData[slot], &dfltMetaData,
                sizeof(DMX_BS_META_DATA));
    }
  }

  return (PCMDMX_OK);
}

/** Set one parameter for one instance of the PCM downmix module.
 * @param [in] Handle of PCM downmix module instance.
 * @param [in] Parameter to be set.
 * @param [in] Parameter value.
 * @returns Returns an error code.
 **/
PCMDMX_ERROR pcmDmx_SetParam(HANDLE_PCM_DOWNMIX self, const PCMDMX_PARAM param,
                             const INT value) {
  switch (param) {
    case DMX_PROFILE_SETTING:
      switch ((DMX_PROFILE_TYPE)value) {
        case DMX_PRFL_STANDARD:
        case DMX_PRFL_MATRIX_MIX:
        case DMX_PRFL_FORCE_MATRIX_MIX:
        case DMX_PRFL_ARIB_JAPAN:
          break;
        default:
          return (PCMDMX_UNABLE_TO_SET_PARAM);
      }
      if (self == NULL) return (PCMDMX_INVALID_HANDLE);
      self->userParams.dmxProfile = (DMX_PROFILE_TYPE)value;
      break;

    case DMX_BS_DATA_EXPIRY_FRAME:
      if (self == NULL) return (PCMDMX_INVALID_HANDLE);
      self->userParams.expiryFrame = (value > 0) ? (UINT)value : 0;
      break;

    case DMX_BS_DATA_DELAY:
      if ((value > (1)) || (value < 0)) {
        return (PCMDMX_UNABLE_TO_SET_PARAM);
      }
      if (self == NULL) {
        return (PCMDMX_INVALID_HANDLE);
      }
      self->userParams.frameDelay = (UCHAR)value;
      break;

    case MIN_NUMBER_OF_OUTPUT_CHANNELS:
      switch (value) { /* supported output channels */
        case -1:
        case 0:
        case ONE_CHANNEL:
        case TWO_CHANNEL:
        case SIX_CHANNEL:
        case EIGHT_CHANNEL:
          break;
        default:
          return (PCMDMX_UNABLE_TO_SET_PARAM);
      }
      if (self == NULL) return (PCMDMX_INVALID_HANDLE);
      /* Store the new value */
      self->userParams.numOutChannelsMin = (value > 0) ? (SHORT)value : -1;
      if ((value > 0) && (self->userParams.numOutChannelsMax > 0) &&
          (value > self->userParams
                       .numOutChannelsMax)) { /* MIN > MAX would be an invalid
                                                 state. Thus set MAX = MIN in
                                                 this case. */
        self->userParams.numOutChannelsMax = self->userParams.numOutChannelsMin;
      }
      break;

    case MAX_NUMBER_OF_OUTPUT_CHANNELS:
      switch (value) { /* supported output channels */
        case -1:
        case 0:
        case ONE_CHANNEL:
        case TWO_CHANNEL:
        case SIX_CHANNEL:
        case EIGHT_CHANNEL:
          break;
        default:
          return (PCMDMX_UNABLE_TO_SET_PARAM);
      }
      if (self == NULL) return (PCMDMX_INVALID_HANDLE);
      /* Store the new value */
      self->userParams.numOutChannelsMax = (value > 0) ? (SHORT)value : -1;
      if ((value > 0) &&
          (value < self->userParams
                       .numOutChannelsMin)) { /* MAX < MIN would be an invalid
                                                 state. Thus set MIN = MAX in
                                                 this case. */
        self->userParams.numOutChannelsMin = self->userParams.numOutChannelsMax;
      }
      break;

    case DMX_DUAL_CHANNEL_MODE:
      switch ((DUAL_CHANNEL_MODE)value) {
        case STEREO_MODE:
        case CH1_MODE:
        case CH2_MODE:
        case MIXED_MODE:
          break;
        default:
          return (PCMDMX_UNABLE_TO_SET_PARAM);
      }
      if (self == NULL) return (PCMDMX_INVALID_HANDLE);
      self->userParams.dualChannelMode = (DUAL_CHANNEL_MODE)value;
      self->applyProcessing = ((DUAL_CHANNEL_MODE)value != STEREO_MODE)
                                  ? 1
                                  : 0; /* Force processing if necessary. */
      break;

    case DMX_PSEUDO_SURROUND_MODE:
      switch ((PSEUDO_SURROUND_MODE)value) {
        case NEVER_DO_PS_DMX:
        case AUTO_PS_DMX:
        case FORCE_PS_DMX:
          break;
        default:
          return (PCMDMX_UNABLE_TO_SET_PARAM);
      }
      if (self == NULL) return (PCMDMX_INVALID_HANDLE);
      self->userParams.pseudoSurrMode = (PSEUDO_SURROUND_MODE)value;
      break;

    default:
      return (PCMDMX_UNKNOWN_PARAM);
  }

  return (PCMDMX_OK);
}

/** Get one parameter value of one PCM downmix module instance.
 * @param [in] Handle of PCM downmix module instance.
 * @param [in] Parameter to be set.
 * @param [out] Pointer to buffer receiving the parameter value.
 * @returns Returns an error code.
 **/
PCMDMX_ERROR pcmDmx_GetParam(HANDLE_PCM_DOWNMIX self, const PCMDMX_PARAM param,
                             INT *const pValue) {
  PCM_DMX_USER_PARAMS *pUsrParams;

  if ((self == NULL) || (pValue == NULL)) {
    return (PCMDMX_INVALID_HANDLE);
  }
  pUsrParams = &self->userParams;

  switch (param) {
    case DMX_PROFILE_SETTING:
      *pValue = (INT)pUsrParams->dmxProfile;
      break;
    case DMX_BS_DATA_EXPIRY_FRAME:
      *pValue = (INT)pUsrParams->expiryFrame;
      break;
    case DMX_BS_DATA_DELAY:
      *pValue = (INT)pUsrParams->frameDelay;
      break;
    case MIN_NUMBER_OF_OUTPUT_CHANNELS:
      *pValue = (INT)pUsrParams->numOutChannelsMin;
      break;
    case MAX_NUMBER_OF_OUTPUT_CHANNELS:
      *pValue = (INT)pUsrParams->numOutChannelsMax;
      break;
    case DMX_DUAL_CHANNEL_MODE:
      *pValue = (INT)pUsrParams->dualChannelMode;
      break;
    case DMX_PSEUDO_SURROUND_MODE:
      *pValue = (INT)pUsrParams->pseudoSurrMode;
      break;
    default:
      return (PCMDMX_UNKNOWN_PARAM);
  }

  return (PCMDMX_OK);
}

/*
 * Read DMX meta-data from a data stream element.
 */
PCMDMX_ERROR pcmDmx_Parse(HANDLE_PCM_DOWNMIX self, HANDLE_FDK_BITSTREAM hBs,
                          UINT ancDataBits, int isMpeg2) {
  PCMDMX_ERROR errorStatus = PCMDMX_OK;

#define MAX_DSE_ANC_BYTES (16)    /* 15 bytes */
#define ANC_DATA_SYNC_BYTE (0xBC) /* ancillary data sync byte. */

  DMX_BS_META_DATA *pBsMetaData;

  int skip4Dmx = 0, skip4Ext = 0;
  int dmxLvlAvail = 0, extDataAvail = 0;
  UINT foundNewData = 0;
  UINT minAncBits = ((isMpeg2) ? 5 : 3) * 8;

  if ((self == NULL) || (hBs == NULL)) {
    return (PCMDMX_INVALID_HANDLE);
  }

  /* sanity checks */
  if ((ancDataBits < minAncBits) || (ancDataBits > FDKgetValidBits(hBs))) {
    return (PCMDMX_CORRUPT_ANC_DATA);
  }

  pBsMetaData = &self->bsMetaData[0];

  if (isMpeg2) {
    /* skip DVD ancillary data */
    FDKpushFor(hBs, 16);
  }

  /* check sync word */
  if (FDKreadBits(hBs, 8) != ANC_DATA_SYNC_BYTE) {
    return (PCMDMX_CORRUPT_ANC_DATA);
  }

  /* skip MPEG audio type and Dolby surround mode */
  FDKpushFor(hBs, 4);

  if (isMpeg2) {
    /* int numAncBytes = */ FDKreadBits(hBs, 4);
    /* advanced dynamic range control */
    if (FDKreadBit(hBs)) skip4Dmx += 24;
    /* dialog normalization */
    if (FDKreadBit(hBs)) skip4Dmx += 8;
    /* reproduction_level */
    if (FDKreadBit(hBs)) skip4Dmx += 8;
  } else {
    FDKpushFor(hBs, 2); /* drc presentation mode */
    pBsMetaData->pseudoSurround = (SCHAR)FDKreadBit(hBs);
    FDKpushFor(hBs, 4); /* reserved bits */
  }

  /* downmixing levels MPEGx status */
  dmxLvlAvail = FDKreadBit(hBs);

  if (isMpeg2) {
    /* scale factor CRC status */
    if (FDKreadBit(hBs)) skip4Ext += 16;
  } else {
    /* ancillary data extension status */
    extDataAvail = FDKreadBit(hBs);
  }

  /* audio coding and compression status */
  if (FDKreadBit(hBs)) skip4Ext += 16;
  /* coarse grain timecode status */
  if (FDKreadBit(hBs)) skip4Ext += 16;
  /* fine grain timecode status */
  if (FDKreadBit(hBs)) skip4Ext += 16;

  /* skip the useless data to get to the DMX levels */
  FDKpushFor(hBs, skip4Dmx);

  /* downmix_levels_MPEGX */
  if (dmxLvlAvail) {
    if (FDKreadBit(hBs)) { /* center_mix_level_on */
      pBsMetaData->cLevIdx = (UCHAR)FDKreadBits(hBs, 3);
      foundNewData |= TYPE_DSE_CLEV_DATA;
    } else {
      FDKreadBits(hBs, 3);
    }
    if (FDKreadBit(hBs)) { /* surround_mix_level_on */
      pBsMetaData->sLevIdx = (UCHAR)FDKreadBits(hBs, 3);
      foundNewData |= TYPE_DSE_SLEV_DATA;
    } else {
      FDKreadBits(hBs, 3);
    }
  }

  /* skip the useless data to get to the ancillary data extension */
  FDKpushFor(hBs, skip4Ext);

  /* anc data extension (MPEG-4 only) */
  if (extDataAvail) {
    int extDmxLvlSt, extDmxGainSt, extDmxLfeSt;

    FDKreadBit(hBs); /* reserved bit */
    extDmxLvlSt = FDKreadBit(hBs);
    extDmxGainSt = FDKreadBit(hBs);
    extDmxLfeSt = FDKreadBit(hBs);
    FDKreadBits(hBs, 4); /* reserved bits */

    if (extDmxLvlSt) {
      pBsMetaData->dmixIdxA = (UCHAR)FDKreadBits(hBs, 3);
      pBsMetaData->dmixIdxB = (UCHAR)FDKreadBits(hBs, 3);
      FDKreadBits(hBs, 2); /* reserved bits */
      foundNewData |= TYPE_DSE_DMIX_AB_DATA;
    }
    if (extDmxGainSt) {
      pBsMetaData->dmxGainIdx5 = (UCHAR)FDKreadBits(hBs, 7);
      FDKreadBit(hBs); /* reserved bit */
      pBsMetaData->dmxGainIdx2 = (UCHAR)FDKreadBits(hBs, 7);
      FDKreadBit(hBs); /* reserved bit */
      foundNewData |= TYPE_DSE_DMX_GAIN_DATA;
    }
    if (extDmxLfeSt) {
      pBsMetaData->dmixIdxLfe = (UCHAR)FDKreadBits(hBs, 4);
      FDKreadBits(hBs, 4); /* reserved bits */
      foundNewData |= TYPE_DSE_DMIX_LFE_DATA;
    }
  }

  /* final sanity check on the amount of read data */
  if ((INT)FDKgetValidBits(hBs) < 0) {
    errorStatus = PCMDMX_CORRUPT_ANC_DATA;
  }

  if ((errorStatus == PCMDMX_OK) && (foundNewData != 0)) {
    /* announce new data */
    pBsMetaData->typeFlags |= foundNewData;
    /* reset expiry counter */
    pBsMetaData->expiryCount = 0;
  }

  return (errorStatus);
}

/*
 * Read DMX meta-data from a data stream element.
 */
PCMDMX_ERROR pcmDmx_ReadDvbAncData(HANDLE_PCM_DOWNMIX self, UCHAR *pAncDataBuf,
                                   UINT ancDataBytes, int isMpeg2) {
  PCMDMX_ERROR errorStatus = PCMDMX_OK;
  FDK_BITSTREAM bs;
  HANDLE_FDK_BITSTREAM hBs = &bs;

  if (self == NULL) {
    return (PCMDMX_INVALID_HANDLE);
  }

  /* sanity checks */
  if ((pAncDataBuf == NULL) || (ancDataBytes == 0)) {
    return (PCMDMX_CORRUPT_ANC_DATA);
  }

  FDKinitBitStream(hBs, pAncDataBuf, MAX_DSE_ANC_BYTES, ancDataBytes * 8,
                   BS_READER);

  errorStatus = pcmDmx_Parse(self, hBs, ancDataBytes * 8, isMpeg2);

  return (errorStatus);
}

/** Set the matrix mixdown information extracted from the PCE of an AAC
 *bitstream. Note: Call only if matrix_mixdown_idx_present is true.
 * @param [in] Handle of PCM downmix module instance.
 * @param [in] The 2 bit matrix mixdown index extracted from PCE.
 * @param [in] The pseudo surround enable flag extracted from PCE.
 * @returns Returns an error code.
 **/
PCMDMX_ERROR pcmDmx_SetMatrixMixdownFromPce(HANDLE_PCM_DOWNMIX self,
                                            int matrixMixdownPresent,
                                            int matrixMixdownIdx,
                                            int pseudoSurroundEnable) {
  if (self == NULL) {
    return (PCMDMX_INVALID_HANDLE);
  }

  {
    DMX_BS_META_DATA *pBsMetaData = &self->bsMetaData[0];

    if (matrixMixdownPresent) {
      pBsMetaData->pseudoSurround = (pseudoSurroundEnable) ? 1 : 0;
      pBsMetaData->matrixMixdownIdx = matrixMixdownIdx & 0x03;
      pBsMetaData->typeFlags |= TYPE_PCE_DATA;
      /* Reset expiry counter */
      pBsMetaData->expiryCount = 0;
    }
  }

  return (PCMDMX_OK);
}

/** Apply down or up mixing.
 * @param [in]    Handle of PCM downmix module instance.
 * @param [inout] Pointer to buffer that hold the time domain signal.
 * @param [in]    Pointer where the amount of output samples is returned into.
 * @param [in]    Size of pPcmBuf.
 * @param [inout] Pointer where the amount of output channels is returned into.
 * @param [in]    Input and output samples are processed interleaved.
 * @param [inout] Array where the corresponding channel type for each output
 *audio channel is stored into.
 * @param [inout] Array where the corresponding channel type index for each
 *output audio channel is stored into.
 * @param [in]    Array containing the out channel mapping to be used (From MPEG
 *PCE ordering to whatever is required).
 * @param [out]   Pointer on a field receiving the scale factor that has to be
 *applied on all samples afterwards. If the handed pointer is NULL scaling is
 *done internally.
 * @returns Returns an error code.
 **/
PCMDMX_ERROR pcmDmx_ApplyFrame(HANDLE_PCM_DOWNMIX self, DMX_PCM *pPcmBuf,
                               const int pcmBufSize, UINT frameSize,
                               INT *nChannels, INT fInterleaved,
                               AUDIO_CHANNEL_TYPE channelType[],
                               UCHAR channelIndices[],
                               const FDK_channelMapDescr *const mapDescr,
                               INT *pDmxOutScale) {
  PCM_DMX_USER_PARAMS *pParam = NULL;
  PCMDMX_ERROR errorStatus = PCMDMX_OK;
  DUAL_CHANNEL_MODE dualChannelMode;
  PCM_DMX_CHANNEL_MODE inChMode;
  PCM_DMX_CHANNEL_MODE outChMode;
  INT devNull; /* Just a dummy to avoid a lot of branches in the code */
  int numOutChannels, numInChannels;
  int inStride, outStride, offset;
  int dmxMaxScale, dmxScale;
  int slot;
  UCHAR inOffsetTable[(8)];

  DMX_BS_META_DATA bsMetaData;

  if ((self == NULL) || (nChannels == NULL) || (channelType == NULL) ||
      (channelIndices == NULL) || (!FDK_chMapDescr_isValid(mapDescr))) {
    return (PCMDMX_INVALID_HANDLE);
  }

  /* Init the output scaling */
  dmxScale = 0;
  if (pDmxOutScale != NULL) {
    /* Avoid final scaling internally and hand it to the outside world. */
    *pDmxOutScale = 0;
    dmxMaxScale = (3);
  } else {
    /* Apply the scaling internally. */
    pDmxOutScale = &devNull; /* redirect to temporal stack memory */
    dmxMaxScale = 0;
  }

  pParam = &self->userParams;
  numInChannels = *nChannels;

  /* Perform some input sanity checks */
  if (pPcmBuf == NULL) {
    return (PCMDMX_INVALID_ARGUMENT);
  }
  if (frameSize == 0) {
    return (PCMDMX_INVALID_ARGUMENT);
  }
  if (numInChannels == 0) {
    return (PCMDMX_INVALID_ARGUMENT);
  }
  if (numInChannels > (8)) {
    return (PCMDMX_INVALID_CH_CONFIG);
  }

  /* Check on misconfiguration */
  FDK_ASSERT((pParam->numOutChannelsMax <= 0) ||
             (pParam->numOutChannelsMax >= pParam->numOutChannelsMin));

  /* Determine if the module has to do processing */
  if ((self->applyProcessing == 0) &&
      ((pParam->numOutChannelsMax <= 0) ||
       (pParam->numOutChannelsMax >= numInChannels)) &&
      (pParam->numOutChannelsMin <= numInChannels)) {
    /* Nothing to do */
    return (errorStatus);
  }

  /* Determine the number of output channels */
  if ((pParam->numOutChannelsMax > 0) &&
      (numInChannels > pParam->numOutChannelsMax)) {
    numOutChannels = pParam->numOutChannelsMax;
  } else if (numInChannels < pParam->numOutChannelsMin) {
    numOutChannels = pParam->numOutChannelsMin;
  } else {
    numOutChannels = numInChannels;
  }

  /* Check I/O buffer size */
  if ((UINT)pcmBufSize < (UINT)numOutChannels * frameSize) {
    return (PCMDMX_OUTPUT_BUFFER_TOO_SMALL);
  }

  dualChannelMode = pParam->dualChannelMode;

  /* Analyse input channel configuration and get channel offset
   * table that can be accessed with the fixed channel labels. */
  errorStatus = getChannelMode(numInChannels, channelType, channelIndices,
                               inOffsetTable, &inChMode);
  if (PCMDMX_IS_FATAL_ERROR(errorStatus) || (inChMode == CH_MODE_UNDEFINED)) {
    /* We don't need to restore because the channel
       configuration has not been changed. Just exit. */
    return (PCMDMX_INVALID_CH_CONFIG);
  }

  /* Set input stride and offset */
  if (fInterleaved) {
    inStride = numInChannels;
    offset = 1; /* Channel specific offset factor */
  } else {
    inStride = 1;
    offset = frameSize; /* Channel specific offset factor */
  }

  /* Reset downmix meta data if necessary */
  if ((pParam->expiryFrame > 0) &&
      (++self->bsMetaData[0].expiryCount >
       pParam
           ->expiryFrame)) { /* The metadata read from bitstream is too old. */
#ifdef FDK_ASSERT_ENABLE
    PCMDMX_ERROR err = pcmDmx_Reset(self, PCMDMX_RESET_BS_DATA);
    FDK_ASSERT(err == PCMDMX_OK);
#else
    pcmDmx_Reset(self, PCMDMX_RESET_BS_DATA);
#endif
  }
  FDKmemcpy(&bsMetaData, &self->bsMetaData[pParam->frameDelay],
            sizeof(DMX_BS_META_DATA));
  /* Maintain delay line */
  for (slot = pParam->frameDelay; slot > 0; slot -= 1) {
    FDKmemcpy(&self->bsMetaData[slot], &self->bsMetaData[slot - 1],
              sizeof(DMX_BS_META_DATA));
  }

  /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   * - - - - - - - - - - - - - - - - - - */
  if (numInChannels > numOutChannels) { /* Apply downmix */
    DMX_PCM *pInPcm[(8)] = {NULL};
    DMX_PCM *pOutPcm[(8)] = {NULL};
    FIXP_DMX mixFactors[(8)][(8)];
    UCHAR outOffsetTable[(8)];
    UINT sample;
    int chCfg = 0;
    int bypScale = 0;

    if (numInChannels > SIX_CHANNEL) {
      AUDIO_CHANNEL_TYPE multiPurposeChType[2];

      /* Get the type of the multipurpose channels */
      multiPurposeChType[0] =
          channelType[inOffsetTable[LEFT_MULTIPRPS_CHANNEL]];
      multiPurposeChType[1] =
          channelType[inOffsetTable[RIGHT_MULTIPRPS_CHANNEL]];

      /* Check if the input configuration is one defined in the standard. */
      switch (inChMode) {
        case CH_MODE_5_0_2_1: /* chCfg 7 || 14 */
          /* Further analyse the input config to distinguish the two
           * CH_MODE_5_0_2_1 configs. */
          if ((multiPurposeChType[0] == ACT_FRONT_TOP) &&
              (multiPurposeChType[1] == ACT_FRONT_TOP)) {
            chCfg = 14;
          } else {
            chCfg = 7;
          }
          break;
        case CH_MODE_3_0_3_1: /* chCfg 11 */
          chCfg = 11;
          break;
        case CH_MODE_3_0_4_1: /* chCfg 12 */
          chCfg = 12;
          break;
        default:
          chCfg = 0; /* Not a known config */
          break;
      }
    }

    /* Set this stages output stride and channel mode: */
    outStride = (fInterleaved) ? numOutChannels : 1;
    outChMode = outChModeTable[numOutChannels];
    FDK_ASSERT(outChMode != CH_MODE_UNDEFINED);

    /* Get channel description and channel mapping for the desired output
     * configuration. */
    getChannelDescription(outChMode, mapDescr, channelType, channelIndices,
                          outOffsetTable);
    /* Now there is no way back because we modified the channel configuration!
     */

    /* Create the DMX matrix */
    errorStatus =
        getMixFactors((chCfg > 0) ? 1 : 0,
                      (chCfg > 0) ? (PCM_DMX_CHANNEL_MODE)chCfg : inChMode,
                      outChMode, pParam, &bsMetaData, mixFactors, &dmxScale);
    /* No fatal errors can occur here. The function is designed to always return
       a valid matrix. The error code is used to signal configurations and
       matrices that are not conform to any standard. */

    /* Determine the final scaling */
    bypScale = fMin(dmxMaxScale, dmxScale);
    *pDmxOutScale += bypScale;
    dmxScale -= bypScale;

    { /* Set channel pointer for input. Remove empty cols. */
      int inCh, outCh, map[(8)];
      int ch = 0;
      for (inCh = 0; inCh < (8); inCh += 1) {
        if (inOffsetTable[inCh] < (UCHAR)numInChannels) {
          pInPcm[ch] = &pPcmBuf[inOffsetTable[inCh] * offset];
          map[ch++] = inCh;
        }
      }
      for (; ch < (8); ch += 1) {
        map[ch] = ch;
      }

      /* Remove unused cols from factor matrix */
      for (inCh = 0; inCh < numInChannels; inCh += 1) {
        if (inCh != map[inCh]) {
          for (outCh = 0; outCh < (8); outCh += 1) {
            mixFactors[outCh][inCh] = mixFactors[outCh][map[inCh]];
          }
        }
      }

      /* Set channel pointer for output. Remove empty cols. */
      ch = 0;
      for (outCh = 0; outCh < (8); outCh += 1) {
        if (outOffsetTable[outCh] < (UCHAR)numOutChannels) {
          pOutPcm[ch] = &pPcmBuf[outOffsetTable[outCh] * offset];
          map[ch++] = outCh;
        }
      }
      for (; ch < (8); ch += 1) {
        map[ch] = ch;
      }

      /* Remove unused rows from factor matrix */
      for (outCh = 0; outCh < numOutChannels; outCh += 1) {
        if (outCh != map[outCh]) {
          FDKmemcpy(&mixFactors[outCh], &mixFactors[map[outCh]],
                    (8) * sizeof(FIXP_DMX));
        }
      }
    }

    /* Sample processing loop */
    for (sample = 0; sample < frameSize; sample++) {
      DMX_PCM tIn[(8)] = {0};
      FIXP_DBL tOut[(8)] = {(FIXP_DBL)0};
      int inCh, outCh;

      /* Preload all input samples */
      for (inCh = 0; inCh < numInChannels; inCh += 1) {
        if (pInPcm[inCh] != NULL) {
          tIn[inCh] = *pInPcm[inCh];
          pInPcm[inCh] += inStride;
        } else {
          tIn[inCh] = (DMX_PCM)0;
        }
      }
      /* Apply downmix coefficients to input samples and accumulate for output
       */
      for (outCh = 0; outCh < numOutChannels; outCh += 1) {
        for (inCh = 0; inCh < numInChannels; inCh += 1) {
          tOut[outCh] += fMult((DMX_PCMF)tIn[inCh], mixFactors[outCh][inCh]);
        }
        FDK_ASSERT(pOutPcm[outCh] >= pPcmBuf);
        FDK_ASSERT(pOutPcm[outCh] < &pPcmBuf[pcmBufSize]);
        /* Write sample */
        *pOutPcm[outCh] = (DMX_PCM)SATURATE_SHIFT(
            tOut[outCh], DFRACT_BITS - DMX_PCM_BITS - dmxScale, DMX_PCM_BITS);
        pOutPcm[outCh] += outStride;
      }
    }

    /* Update the number of output channels */
    *nChannels = numOutChannels;

  } /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
       - - - - - - - - - - - - - - - - - - */
  else if (numInChannels < numOutChannels) { /* Apply rudimentary upmix */
    /* Set up channel pointer */
    UCHAR outOffsetTable[(8)];

    /* FIRST STAGE
         Create a stereo/dual channel signal */
    if (numInChannels == ONE_CHANNEL) {
      DMX_PCM *pInPcm[(8)];
      DMX_PCM *pOutLF, *pOutRF;
      UINT sample;

      /* Set this stages output stride and channel mode: */
      outStride = (fInterleaved) ? TWO_CHANNEL : 1;
      outChMode = outChModeTable[TWO_CHANNEL];

      /* Get channel description and channel mapping for this
       * stages number of output channels (always STEREO). */
      getChannelDescription(outChMode, mapDescr, channelType, channelIndices,
                            outOffsetTable);
      /* Now there is no way back because we modified the channel configuration!
       */

      /* Set input channel pointer. The first channel is always at index 0. */
      pInPcm[CENTER_FRONT_CHANNEL] =
          &pPcmBuf[(frameSize - 1) *
                   inStride]; /* Considering input mapping could lead to a
                                 invalid pointer here if the channel is not
                                 declared to be a front channel. */

      /* Set output channel pointer (for this stage). */
      pOutLF = &pPcmBuf[outOffsetTable[LEFT_FRONT_CHANNEL] * offset +
                        (frameSize - 1) * outStride];
      pOutRF = &pPcmBuf[outOffsetTable[RIGHT_FRONT_CHANNEL] * offset +
                        (frameSize - 1) * outStride];

      /* 1/0 input: */
      for (sample = 0; sample < frameSize; sample++) {
        /* L' = C;  R' = C; */
        *pOutLF = *pOutRF = *pInPcm[CENTER_FRONT_CHANNEL];

        pInPcm[CENTER_FRONT_CHANNEL] -= inStride;
        pOutLF -= outStride;
        pOutRF -= outStride;
      }

      /* Prepare for next stage: */
      inStride = outStride;
      inChMode = outChMode;
      FDKmemcpy(inOffsetTable, outOffsetTable, (8) * sizeof(UCHAR));
    }

    /* SECOND STAGE
         Extend with zero channels to achieved the desired number of output
       channels. */
    if (numOutChannels > TWO_CHANNEL) {
      DMX_PCM *pIn[(8)] = {NULL};
      DMX_PCM *pOut[(8)] = {NULL};
      UINT sample;
      AUDIO_CHANNEL_TYPE inChTypes[(8)];
      UCHAR inChIndices[(8)];
      UCHAR numChPerGrp[2][(4)];
      int nContentCh = 0; /* Number of channels with content */
      int nEmptyCh = 0;   /* Number of channels with content */
      int ch, chGrp, isCompatible = 1;

      /* Do not change the signalling which is the channel types and indices.
         Just reorder and add channels. So first save the input signalling. */
      FDKmemcpy(inChTypes, channelType,
                numInChannels * sizeof(AUDIO_CHANNEL_TYPE));
      FDKmemclear(inChTypes + numInChannels,
                  ((8) - numInChannels) * sizeof(AUDIO_CHANNEL_TYPE));
      FDKmemcpy(inChIndices, channelIndices, numInChannels * sizeof(UCHAR));
      FDKmemclear(inChIndices + numInChannels,
                  ((8) - numInChannels) * sizeof(UCHAR));

      /* Set this stages output stride and channel mode: */
      outStride = (fInterleaved) ? numOutChannels : 1;
      outChMode = outChModeTable[numOutChannels];
      FDK_ASSERT(outChMode != CH_MODE_UNDEFINED);

      /* Check if input channel config can be easily mapped to the desired
       * output config. */
      for (chGrp = 0; chGrp < (4); chGrp += 1) {
        numChPerGrp[IN][chGrp] = (inChMode >> (chGrp * 4)) & 0xF;
        numChPerGrp[OUT][chGrp] = (outChMode >> (chGrp * 4)) & 0xF;

        if (numChPerGrp[IN][chGrp] > numChPerGrp[OUT][chGrp]) {
          isCompatible = 0;
          break;
        }
      }

      if (isCompatible) {
        /* Get new channel description and channel
         * mapping for the desired output channel mode. */
        getChannelDescription(outChMode, mapDescr, channelType, channelIndices,
                              outOffsetTable);
        /* If the input config has a back center channel but the output
           config has not, copy it to left and right (if available). */
        if ((numChPerGrp[IN][CH_GROUP_REAR] % 2) &&
            !(numChPerGrp[OUT][CH_GROUP_REAR] % 2)) {
          if (numChPerGrp[IN][CH_GROUP_REAR] == 1) {
            inOffsetTable[RIGHT_REAR_CHANNEL] =
                inOffsetTable[LEFT_REAR_CHANNEL];
          } else if (numChPerGrp[IN][CH_GROUP_REAR] == 3) {
            inOffsetTable[RIGHT_MULTIPRPS_CHANNEL] =
                inOffsetTable[LEFT_MULTIPRPS_CHANNEL];
          }
        }
      } else {
        /* Just copy and extend the original config */
        FDKmemcpy(outOffsetTable, inOffsetTable, (8) * sizeof(UCHAR));
      }

      /* Set I/O channel pointer.
         Note: The following assignment algorithm clears the channel offset
         tables. Thus they can not be used afterwards. */
      for (ch = 0; ch < (8); ch += 1) {
        if ((outOffsetTable[ch] < 255) &&
            (inOffsetTable[ch] < 255)) { /* Set I/O pointer: */
          pIn[nContentCh] =
              &pPcmBuf[inOffsetTable[ch] * offset + (frameSize - 1) * inStride];
          pOut[nContentCh] = &pPcmBuf[outOffsetTable[ch] * offset +
                                      (frameSize - 1) * outStride];
          /* Update signalling */
          channelType[outOffsetTable[ch]] = inChTypes[inOffsetTable[ch]];
          channelIndices[outOffsetTable[ch]] = inChIndices[inOffsetTable[ch]];
          inOffsetTable[ch] = 255;
          outOffsetTable[ch] = 255;
          nContentCh += 1;
        }
      }
      if (isCompatible) {
        /* Assign the remaining input channels.
           This is just a safety appliance. We should never need it. */
        for (ch = 0; ch < (8); ch += 1) {
          if (inOffsetTable[ch] < 255) {
            int outCh;
            for (outCh = 0; outCh < (8); outCh += 1) {
              if (outOffsetTable[outCh] < 255) {
                break;
              }
            }
            if (outCh >= (8)) {
              FDK_ASSERT(0);
              break;
            }
            /* Set I/O pointer: */
            pIn[nContentCh] = &pPcmBuf[inOffsetTable[ch] * offset +
                                       (frameSize - 1) * inStride];
            pOut[nContentCh] = &pPcmBuf[outOffsetTable[outCh] * offset +
                                        (frameSize - 1) * outStride];
            /* Update signalling */
            FDK_ASSERT(inOffsetTable[outCh] < numInChannels);
            FDK_ASSERT(outOffsetTable[outCh] < numOutChannels);
            channelType[outOffsetTable[outCh]] = inChTypes[inOffsetTable[ch]];
            channelIndices[outOffsetTable[outCh]] =
                inChIndices[inOffsetTable[ch]];
            inOffsetTable[ch] = 255;
            outOffsetTable[outCh] = 255;
            nContentCh += 1;
          }
        }
        /* Set the remaining output channel pointer */
        for (ch = 0; ch < (8); ch += 1) {
          if (outOffsetTable[ch] < 255) {
            pOut[nContentCh + nEmptyCh] = &pPcmBuf[outOffsetTable[ch] * offset +
                                                   (frameSize - 1) * outStride];
            /* Expand output signalling */
            channelType[outOffsetTable[ch]] = ACT_NONE;
            channelIndices[outOffsetTable[ch]] = (UCHAR)nEmptyCh;
            outOffsetTable[ch] = 255;
            nEmptyCh += 1;
          }
        }
      } else {
        /* Set the remaining output channel pointer */
        for (ch = nContentCh; ch < numOutChannels; ch += 1) {
          pOut[ch] = &pPcmBuf[ch * offset + (frameSize - 1) * outStride];
          /* Expand output signalling */
          channelType[ch] = ACT_NONE;
          channelIndices[ch] = (UCHAR)nEmptyCh;
          nEmptyCh += 1;
        }
      }

      /* First copy the channels that have signal */
      for (sample = 0; sample < frameSize; sample += 1) {
        DMX_PCM tIn[(8)];
        /* Read all channel samples */
        for (ch = 0; ch < nContentCh; ch += 1) {
          tIn[ch] = *pIn[ch];
          pIn[ch] -= inStride;
        }
        /* Write all channel samples */
        for (ch = 0; ch < nContentCh; ch += 1) {
          *pOut[ch] = tIn[ch];
          pOut[ch] -= outStride;
        }
      }

      /* Clear all the other channels */
      for (sample = 0; sample < frameSize; sample++) {
        for (ch = nContentCh; ch < numOutChannels; ch += 1) {
          *pOut[ch] = (DMX_PCM)0;
          pOut[ch] -= outStride;
        }
      }
    }

    /* update the number of output channels */
    *nChannels = numOutChannels;
  } /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
       - - - - - - - - - - - - - - - - - - */
  else if (numInChannels == numOutChannels) {
    /* Don't need to change the channel description here */

    switch (numInChannels) {
      case 2: { /* Set up channel pointer */
        DMX_PCM *pInPcm[(8)];
        DMX_PCM *pOutL, *pOutR;
        FIXP_DMX flev;

        UINT sample;

        if (fInterleaved) {
          inStride = numInChannels;
          outStride =
              2; /* fixed !!! (below stereo is donwmixed to mono if required */
          offset = 1; /* Channel specific offset factor */
        } else {
          inStride = 1;
          outStride = 1;
          offset = frameSize; /* Channel specific offset factor */
        }

        /* Set input channel pointer */
        pInPcm[LEFT_FRONT_CHANNEL] =
            &pPcmBuf[inOffsetTable[LEFT_FRONT_CHANNEL] * offset];
        pInPcm[RIGHT_FRONT_CHANNEL] =
            &pPcmBuf[inOffsetTable[RIGHT_FRONT_CHANNEL] * offset];

        /* Set output channel pointer (same as input) */
        pOutL = pInPcm[LEFT_FRONT_CHANNEL];
        pOutR = pInPcm[RIGHT_FRONT_CHANNEL];

        /* Set downmix levels: */
        flev = FL2FXCONST_DMX(0.70710678f);
        /* 2/0 input: */
        switch (dualChannelMode) {
          case CH1_MODE: /* L' = 0.707 * Ch1;  R' = 0.707 * Ch1 */
            for (sample = 0; sample < frameSize; sample++) {
              *pOutL = *pOutR = (DMX_PCM)SATURATE_RIGHT_SHIFT(
                  fMult((DMX_PCMF)*pInPcm[LEFT_FRONT_CHANNEL], flev),
                  DFRACT_BITS - DMX_PCM_BITS, DMX_PCM_BITS);

              pInPcm[LEFT_FRONT_CHANNEL] += inStride;
              pOutL += outStride;
              pOutR += outStride;
            }
            break;
          case CH2_MODE: /* L' = 0.707 * Ch2;  R' = 0.707 * Ch2 */
            for (sample = 0; sample < frameSize; sample++) {
              *pOutL = *pOutR = (DMX_PCM)SATURATE_RIGHT_SHIFT(
                  fMult((DMX_PCMF)*pInPcm[RIGHT_FRONT_CHANNEL], flev),
                  DFRACT_BITS - DMX_PCM_BITS, DMX_PCM_BITS);

              pInPcm[RIGHT_FRONT_CHANNEL] += inStride;
              pOutL += outStride;
              pOutR += outStride;
            }
            break;
          case MIXED_MODE: /* L' = 0.5*Ch1 + 0.5*Ch2;  R' = 0.5*Ch1 + 0.5*Ch2 */
            for (sample = 0; sample < frameSize; sample++) {
              *pOutL = *pOutR = (*pInPcm[LEFT_FRONT_CHANNEL] >> 1) +
                                (*pInPcm[RIGHT_FRONT_CHANNEL] >> 1);

              pInPcm[LEFT_FRONT_CHANNEL] += inStride;
              pInPcm[RIGHT_FRONT_CHANNEL] += inStride;
              pOutL += outStride;
              pOutR += outStride;
            }
            break;
          default:
          case STEREO_MODE:
            /* nothing to do */
            break;
        }
      } break;

      default:
        /* nothing to do */
        break;
    }
  }

  return (errorStatus);
}

/** Close an instance of the PCM downmix module.
 * @param [inout] Pointer to a buffer containing the handle of the instance.
 * @returns Returns an error code.
 **/
PCMDMX_ERROR pcmDmx_Close(HANDLE_PCM_DOWNMIX *pSelf) {
  if (pSelf == NULL) {
    return (PCMDMX_INVALID_HANDLE);
  }

  FreePcmDmxInstance(pSelf);
  *pSelf = NULL;

  return (PCMDMX_OK);
}

/** Get library info for this module.
 * @param [out] Pointer to an allocated LIB_INFO structure.
 * @returns Returns an error code.
 */
PCMDMX_ERROR pcmDmx_GetLibInfo(LIB_INFO *info) {
  int i;

  if (info == NULL) {
    return PCMDMX_INVALID_ARGUMENT;
  }

  /* Search for next free tab */
  for (i = 0; i < FDK_MODULE_LAST; i++) {
    if (info[i].module_id == FDK_NONE) break;
  }
  if (i == FDK_MODULE_LAST) {
    return PCMDMX_INVALID_ARGUMENT;
  }

  /* Add the library info */
  info[i].module_id = FDK_PCMDMX;
  info[i].version =
      LIB_VERSION(PCMUTIL_LIB_VL0, PCMUTIL_LIB_VL1, PCMUTIL_LIB_VL2);
  LIB_VERSION_STRING(info + i);
  info[i].build_date = PCMUTIL_LIB_BUILD_DATE;
  info[i].build_time = PCMUTIL_LIB_BUILD_TIME;
  info[i].title = PCMDMX_LIB_TITLE;

  /* Set flags */
  info[i].flags = 0 | CAPF_DMX_BLIND /* At least blind downmixing is possible */
                  | CAPF_DMX_PCE     /* Guided downmix with data from MPEG-2/4
                                        Program Config Elements (PCE). */
                  | CAPF_DMX_ARIB /* PCE guided downmix with slightly different
                                     equations and levels. */
                  | CAPF_DMX_DVB  /* Guided downmix with data from DVB ancillary
                                     data fields. */
                  | CAPF_DMX_CH_EXP /* Simple upmixing by dublicating channels
                                       or adding zero channels. */
                  | CAPF_DMX_6_CH | CAPF_DMX_8_CH;

  /* Add lib info for FDK tools (if not yet done). */
  FDK_toolsGetLibInfo(info);

  return PCMDMX_OK;
}