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/*!

 ***********************************************************************

 * \file errorconcealment.c

 *

 * \brief

 *    Implements error concealment scheme for H.264 decoder

 *

 * \date

 *    6.10.2000

 *

 * \version

 *    1.0

 *

 * \note

 *    This simple error concealment implemented in this decoder uses

 *    the existing dependencies of syntax elements.

 *    In case that an element is detected as false this elements and all

 *    dependend elements are marked as elements to conceal in the ec_flag[]

 *    array. If the decoder requests a new element by the function

 *    readSyntaxElement_xxxx() this array is checked first if an error concealment has

 *    to be applied on this element.

 *    In case that an error occured a concealed element is given to the

 *    decoding function in macroblock().

 *

 * \author

 *    Main contributors (see contributors.h for copyright, address and affiliation details)

 *    - Sebastian Purreiter   <sebastian.purreiter@mch.siemens.de>

 ***********************************************************************

 */

#include "contributors.h"

#include "global.h"

#include "elements.h"

static int ec_flag[SE_MAX_ELEMENTS];        //!< array to set errorconcealment

/*

static char SEtypes[][25] =

{

    "SE_HEADER",

    "SE_PTYPE",

    "SE_MBTYPE",

    "SE_REFFRAME",

    "SE_INTRAPREDMODE",

    "SE_MVD",

    "SE_CBP_INTRA",

    "SE_LUM_DC_INTRA",

    "SE_CHR_DC_INTRA",

    "SE_LUM_AC_INTRA",

    "SE_CHR_AC_INTRA",

    "SE_CBP_INTER",

    "SE_LUM_DC_INTER",

    "SE_CHR_DC_INTER",

    "SE_LUM_AC_INTER",

    "SE_CHR_AC_INTER",

    "SE_DELTA_QUANT_INTER",

    "SE_DELTA_QUANT_INTRA",

    "SE_BFRAME",

    "SE_EOS"

};

*/

/*!

 ***********************************************************************

 * \brief

 *    set concealment for all elements in same partition

 *    and dependend syntax elements

 * \return

 *    EC_REQ, elements of same type or depending type need error concealment. \n

 *    EX_SYNC   sync on next header

 ***********************************************************************

 */

int set_ec_flag(

  int se)   //!< type of syntax element to conceal

{

  /*

  if (ec_flag[se] == NO_EC)

    printf("Error concealment on element %s\n",SEtypes[se]);

  */

  switch (se)

  {

  case SE_HEADER :

    ec_flag[SE_HEADER] = EC_REQ;

  case SE_PTYPE :

    ec_flag[SE_PTYPE] = EC_REQ;

  case SE_MBTYPE :

    ec_flag[SE_MBTYPE] = EC_REQ;

  case SE_REFFRAME :

    ec_flag[SE_REFFRAME] = EC_REQ;

    ec_flag[SE_MVD] = EC_REQ; // set all motion vectors to zero length

    se = SE_CBP_INTER;      // conceal also Inter texture elements

    break;

  case SE_INTRAPREDMODE :

    ec_flag[SE_INTRAPREDMODE] = EC_REQ;

    se = SE_CBP_INTRA;      // conceal also Intra texture elements

    break;

  case SE_MVD :

    ec_flag[SE_MVD] = EC_REQ;

    se = SE_CBP_INTER;      // conceal also Inter texture elements

    break;

  default:

    break;

  }

  switch (se)

  {

  case SE_CBP_INTRA :

    ec_flag[SE_CBP_INTRA] = EC_REQ;

  case SE_LUM_DC_INTRA :

    ec_flag[SE_LUM_DC_INTRA] = EC_REQ;

  case SE_CHR_DC_INTRA :

    ec_flag[SE_CHR_DC_INTRA] = EC_REQ;

  case SE_LUM_AC_INTRA :

    ec_flag[SE_LUM_AC_INTRA] = EC_REQ;

  case SE_CHR_AC_INTRA :

    ec_flag[SE_CHR_AC_INTRA] = EC_REQ;

    break;

  case SE_CBP_INTER :

    ec_flag[SE_CBP_INTER] = EC_REQ;

  case SE_LUM_DC_INTER :

    ec_flag[SE_LUM_DC_INTER] = EC_REQ;

  case SE_CHR_DC_INTER :

    ec_flag[SE_CHR_DC_INTER] = EC_REQ;

  case SE_LUM_AC_INTER :

    ec_flag[SE_LUM_AC_INTER] = EC_REQ;

  case SE_CHR_AC_INTER :

    ec_flag[SE_CHR_AC_INTER] = EC_REQ;

    break;

  case SE_DELTA_QUANT_INTER :

    ec_flag[SE_DELTA_QUANT_INTER] = EC_REQ;

    break;

  case SE_DELTA_QUANT_INTRA :

    ec_flag[SE_DELTA_QUANT_INTRA] = EC_REQ;

    break;

  default:

    break;

  }

  return EC_REQ;

}

/*!

 ***********************************************************************

 * \brief

 *    resets EC_Flags called at the start of each slice

 *

 ***********************************************************************

 */

void reset_ec_flags()

{

  int i;

  for (i=0; i<SE_MAX_ELEMENTS; i++)

    ec_flag[i] = NO_EC;

}

/*!

 ***********************************************************************

 * \brief

 *    get error concealed element in dependence of syntax

 *    element se.                                                          \n

 *    This function implements the error concealment.

 * \return

 *    NO_EC if no error concealment required                               \n

 *    EC_REQ if element requires error concealment

 ***********************************************************************

 */

int get_concealed_element(SyntaxElement *sym)

{

  if (ec_flag[sym->type] == NO_EC)

    return NO_EC;

/*

#if TRACE

  printf("TRACE: get concealed element for %s!!!\n", SEtypes[sym->type]);

#endif

*/

  switch (sym->type)

  {

  case SE_HEADER :

    sym->len = 31;

    sym->inf = 0; // Picture Header

    break;

  case SE_PTYPE : // inter_img_1

  case SE_MBTYPE : // set COPY_MB

  case SE_REFFRAME :

    sym->len = 1;

    sym->inf = 0;

    break;

  case SE_INTRAPREDMODE :

  case SE_MVD :

    sym->len = 1;

    sym->inf = 0;  // set vector to zero length

    break;

  case SE_CBP_INTRA :

    sym->len = 5;

    sym->inf = 0; // codenumber 3 <=> no CBP information for INTRA images

    break;

  case SE_LUM_DC_INTRA :

  case SE_CHR_DC_INTRA :

  case SE_LUM_AC_INTRA :

  case SE_CHR_AC_INTRA :

    sym->len = 1;

    sym->inf = 0;  // return EOB

    break;

  case SE_CBP_INTER :

    sym->len = 1;

    sym->inf = 0; // codenumber 1 <=> no CBP information for INTER images

    break;

  case SE_LUM_DC_INTER :

  case SE_CHR_DC_INTER :

  case SE_LUM_AC_INTER :

  case SE_CHR_AC_INTER :

    sym->len = 1;

    sym->inf = 0;  // return EOB

    break;

  case SE_DELTA_QUANT_INTER:

    sym->len = 1;

    sym->inf = 0;

    break;

  case SE_DELTA_QUANT_INTRA:

    sym->len = 1;

    sym->inf = 0;

    break;

  default:

    break;

  }

  return EC_REQ;

}