xref: /aosp_15_r20/external/aac/libSYS/src/syslib_channelMapDescr.cpp (revision e54365361535b070c2db7374cec45c159c7d0e7a)

/* -----------------------------------------------------------------------------
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
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Commercially-licensed AAC software libraries, including floating-point versions
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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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[email protected]
----------------------------------------------------------------------------- */

/************************* System integration library **************************

   Author(s):   Thomas Dietzen

   Description:

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

/** \file   syslib_channelMapDescr.cpp
 *  \brief  Implementation of routines that handle the channel map descriptor.
 */

#include "syslib_channelMapDescr.h"

#define DFLT_CH_MAP_TAB_LEN \
  (15) /* Length of the default channel map info table. */

/**
 * \brief  The following arrays provide a channel map for each channel config (0
 * to 14).
 *
 * The i-th channel will be mapped to the postion a[i-1]+1
 * with i>0 and a[] is one of the following mapping arrays.
 */
static const UCHAR mapFallback[] = {0,  1,  2,  3,  4,  5,  6,  7,
                                    8,  9,  10, 11, 12, 13, 14, 15,
                                    16, 17, 18, 19, 20, 21, 22, 23};
static const UCHAR mapCfg1[] = {0, 1};
static const UCHAR mapCfg2[] = {0, 1};
static const UCHAR mapCfg3[] = {2, 0, 1};
static const UCHAR mapCfg4[] = {2, 0, 1, 3};
static const UCHAR mapCfg5[] = {2, 0, 1, 3, 4};
static const UCHAR mapCfg6[] = {2, 0, 1, 4, 5, 3};
static const UCHAR mapCfg7[] = {2, 6, 7, 0, 1, 4, 5, 3};
static const UCHAR mapCfg11[] = {2, 0, 1, 4, 5, 6, 3};
static const UCHAR mapCfg12[] = {2, 0, 1, 6, 7, 4, 5, 3};
static const UCHAR mapCfg13[] = {2,  6,  7,  0,  1,  10, 11, 4,
                                 5,  8,  3,  9,  14, 12, 13, 18,
                                 19, 15, 16, 17, 20, 21, 22, 23};
static const UCHAR mapCfg14[] = {2, 0, 1, 4, 5, 3, 6, 7};

/**
 * \brief  Default table comprising channel map information for each channel
 * config (0 to 14).
 */
static const CHANNEL_MAP_INFO mapInfoTabDflt[DFLT_CH_MAP_TAB_LEN] =
    {/* chCfg,  map,         numCh */
     /*  0 */ {mapFallback, 24},
     /*  1 */ {mapCfg1, 2},
     /*  2 */ {mapCfg2, 2},
     /*  3 */ {mapCfg3, 3},
     /*  4 */ {mapCfg4, 4},
     /*  5 */ {mapCfg5, 5},
     /*  6 */ {mapCfg6, 6},
     /*  7 */ {mapCfg7, 8},
     /*  8 */ {mapFallback, 24},
     /*  9 */ {mapFallback, 24},
     /* 10 */ {mapFallback, 24},
     /* 11 */ {mapCfg11, 7},
     /* 12 */ {mapCfg12, 8},
     /* 13 */ {mapCfg13, 24},
     /* 14 */ {mapCfg14, 8}};

/**
 * Get the mapping value for a specific channel and map index.
 */
UCHAR FDK_chMapDescr_getMapValue(const FDK_channelMapDescr* const pMapDescr,
                                 const UCHAR chIdx, const UINT mapIdx) {
  UCHAR mapValue = chIdx; /* Pass through by default. */

  FDK_ASSERT(pMapDescr != NULL);

  if ((pMapDescr->fPassThrough == 0) && (pMapDescr->pMapInfoTab != NULL) &&
      (pMapDescr->mapInfoTabLen > mapIdx)) { /* Nest sanity check to avoid
                                                possible memory access
                                                violation. */
    if (chIdx < pMapDescr->pMapInfoTab[mapIdx].numChannels) {
      mapValue = pMapDescr->pMapInfoTab[mapIdx].pChannelMap[chIdx];
    }
  }
  return mapValue;
}

/**
 * \brief  Evaluate whether single channel map is reasonable or not.
 *
 * \param  pMapInfo  Pointer to channel map.
 * \return           Value unequal to zero if map is valid, otherwise zero.
 */
static int fdk_chMapDescr_isValidMap(const CHANNEL_MAP_INFO* const pMapInfo) {
  int result = 1;
  UINT i;

  if (pMapInfo == NULL) {
    result = 0;
  } else {
    UINT numChannels = pMapInfo->numChannels;

    /* Check for all map values if they are inside the range 0 to numChannels-1
     * and unique. */
    if (numChannels < 32) { /* Optimized version for less than 32 channels.
                               Needs only one loop. */
      UINT mappedChMask = 0x0;
      for (i = 0; i < numChannels; i += 1) {
        mappedChMask |= 1 << pMapInfo->pChannelMap[i];
      }
      if (mappedChMask != (((UINT)1 << numChannels) - 1)) {
        result = 0;
      }
    } else { /* General case that can handle all number of channels but needs
                one more loop. */
      for (i = 0; (i < numChannels) && result; i += 1) {
        UINT j;
        UCHAR value0 = pMapInfo->pChannelMap[i];

        if (value0 > numChannels - 1) { /* out of range? */
          result = 0;
        }
        for (j = numChannels - 1; (j > i) && result; j -= 1) {
          if (value0 == pMapInfo->pChannelMap[j]) { /* not unique */
            result = 0;
          }
        }
      }
    }
  }

  return result;
}

/**
 * Evaluate whether channel map descriptor is reasonable or not.
 */
int FDK_chMapDescr_isValid(const FDK_channelMapDescr* const pMapDescr) {
  int result = 0;
  UINT i;

  if (pMapDescr != NULL) {
    result = 1;
    for (i = 0; (i < pMapDescr->mapInfoTabLen) && result; i += 1) {
      if (!fdk_chMapDescr_isValidMap(&pMapDescr->pMapInfoTab[i])) {
        result = 0;
      }
    }
  }
  return result;
}

/**
 * Initialize the complete channel map descriptor.
 */
void FDK_chMapDescr_init(FDK_channelMapDescr* const pMapDescr,
                         const CHANNEL_MAP_INFO* const pMapInfoTab,
                         const UINT mapInfoTabLen, const UINT fPassThrough) {
  if (pMapDescr != NULL) {
    int useDefaultTab = 1;

    pMapDescr->fPassThrough = (fPassThrough == 0) ? 0 : 1;

    if ((pMapInfoTab != NULL) && (mapInfoTabLen > 0)) {
      /* Set the valid custom mapping table. */
      pMapDescr->pMapInfoTab = pMapInfoTab;
      pMapDescr->mapInfoTabLen = mapInfoTabLen;
      /* Validate the complete descriptor. */
      useDefaultTab = (FDK_chMapDescr_isValid(pMapDescr) == 0) ? 1 : 0;
    }
    if (useDefaultTab != 0) {
      /* Set default table. */
      pMapDescr->pMapInfoTab = mapInfoTabDflt;
      pMapDescr->mapInfoTabLen = DFLT_CH_MAP_TAB_LEN;
    }
  }
}

/**
 * Set channel mapping bypass flag in a given channel map descriptor.
 */
int FDK_chMapDescr_setPassThrough(FDK_channelMapDescr* const pMapDescr,
                                  UINT fPassThrough) {
  int err = 1;

  if (pMapDescr != NULL) {
    if ((pMapDescr->pMapInfoTab != NULL) && (pMapDescr->mapInfoTabLen > 0)) {
      pMapDescr->fPassThrough = (fPassThrough == 0) ? 0 : 1;
      err = 0;
    }
  }

  return err;
}