jedioutcast/utils/roq2/mpeg/getblk.c

/* getblk.c, DCT block decoding                                             */



/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */



/*

 * Disclaimer of Warranty

 *

 * These software programs are available to the user without any license fee or

 * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims

 * any and all warranties, whether express, implied, or statuary, including any

 * implied warranties or merchantability or of fitness for a particular

 * purpose.  In no event shall the copyright-holder be liable for any

 * incidental, punitive, or consequential damages of any kind whatsoever

 * arising from the use of these programs.

 *

 * This disclaimer of warranty extends to the user of these programs and user's

 * customers, employees, agents, transferees, successors, and assigns.

 *

 * The MPEG Software Simulation Group does not represent or warrant that the

 * programs furnished hereunder are free of infringement of any third-party

 * patents.

 *

 * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,

 * are subject to royalty fees to patent holders.  Many of these patents are

 * general enough such that they are unavoidable regardless of implementation

 * design.

 *

 */



#include <stdio.h>



#include "config.h"

#include "global.h"





/* defined in getvlc.h */

typedef struct {

  char run, level, len;

} DCTtab;



extern DCTtab DCTtabfirst[],DCTtabnext[],DCTtab0[],DCTtab1[];

extern DCTtab DCTtab2[],DCTtab3[],DCTtab4[],DCTtab5[],DCTtab6[];

extern DCTtab DCTtab0a[],DCTtab1a[];





/* decode one intra coded MPEG-1 block */



void Decode_MPEG1_Intra_Block(comp,dc_dct_pred)

int comp;

int dc_dct_pred[];

{

  int val, i, j, sign;

  unsigned int code;

  DCTtab *tab;

  short *bp;



  bp = ld->block[comp];



  /* ISO/IEC 11172-2 section 2.4.3.7: Block layer. */

  /* decode DC coefficients */

  if (comp<4)

    bp[0] = (dc_dct_pred[0]+=Get_Luma_DC_dct_diff()) << 3;

  else if (comp==4)

    bp[0] = (dc_dct_pred[1]+=Get_Chroma_DC_dct_diff()) << 3;

  else

    bp[0] = (dc_dct_pred[2]+=Get_Chroma_DC_dct_diff()) << 3;



  if (Fault_Flag) return;



  /* D-pictures do not contain AC coefficients */

  if(picture_coding_type == D_TYPE)

    return;



  /* decode AC coefficients */

  for (i=1; ; i++)

  {

    code = Show_Bits(16);

    if (code>=16384)

      tab = &DCTtabnext[(code>>12)-4];

    else if (code>=1024)

      tab = &DCTtab0[(code>>8)-4];

    else if (code>=512)

      tab = &DCTtab1[(code>>6)-8];

    else if (code>=256)

      tab = &DCTtab2[(code>>4)-16];

    else if (code>=128)

      tab = &DCTtab3[(code>>3)-16];

    else if (code>=64)

      tab = &DCTtab4[(code>>2)-16];

    else if (code>=32)

      tab = &DCTtab5[(code>>1)-16];

    else if (code>=16)

      tab = &DCTtab6[code-16];

    else

    {

      if (!Quiet_Flag)

        printf("invalid Huffman code in Decode_MPEG1_Intra_Block()\n");

      Fault_Flag = 1;

      return;

    }



    Flush_Buffer(tab->len);



    if (tab->run==64) /* end_of_block */

      return;



    if (tab->run==65) /* escape */

    {

      i+= Get_Bits(6);



      val = Get_Bits(8);

      if (val==0)

        val = Get_Bits(8);

      else if (val==128)

        val = Get_Bits(8) - 256;

      else if (val>128)

        val -= 256;



      if (sign = (val<0))

        val = -val;

    }

    else

    {

      i+= tab->run;

      val = tab->level;

      sign = Get_Bits(1);

    }



    if (i>=64)

    {

      if (!Quiet_Flag)

        fprintf(stderr,"DCT coeff index (i) out of bounds (intra)\n");

      Fault_Flag = 1;

      return;

    }



    j = scan[ZIG_ZAG][i];

    val = (val*ld->quantizer_scale*ld->intra_quantizer_matrix[j]) >> 3;



    /* mismatch control ('oddification') */

    if (val!=0) /* should always be true, but it's not guaranteed */

      val = (val-1) | 1; /* equivalent to: if ((val&1)==0) val = val - 1; */



    /* saturation */

    if (!sign)

      bp[j] = (val>2047) ?  2047 :  val; /* positive */

    else

      bp[j] = (val>2048) ? -2048 : -val; /* negative */

  }

}





/* decode one non-intra coded MPEG-1 block */



void Decode_MPEG1_Non_Intra_Block(comp)

int comp;

{

  int val, i, j, sign;

  unsigned int code;

  DCTtab *tab;

  short *bp;



  bp = ld->block[comp];



  /* decode AC coefficients */

  for (i=0; ; i++)

  {

    code = Show_Bits(16);

    if (code>=16384)

    {

      if (i==0)

        tab = &DCTtabfirst[(code>>12)-4];

      else

        tab = &DCTtabnext[(code>>12)-4];

    }

    else if (code>=1024)

      tab = &DCTtab0[(code>>8)-4];

    else if (code>=512)

      tab = &DCTtab1[(code>>6)-8];

    else if (code>=256)

      tab = &DCTtab2[(code>>4)-16];

    else if (code>=128)

      tab = &DCTtab3[(code>>3)-16];

    else if (code>=64)

      tab = &DCTtab4[(code>>2)-16];

    else if (code>=32)

      tab = &DCTtab5[(code>>1)-16];

    else if (code>=16)

      tab = &DCTtab6[code-16];

    else

    {

      if (!Quiet_Flag)

        printf("invalid Huffman code in Decode_MPEG1_Non_Intra_Block()\n");

      Fault_Flag = 1;

      return;

    }



    Flush_Buffer(tab->len);



    if (tab->run==64) /* end_of_block */

      return;



    if (tab->run==65) /* escape */

    {

      i+= Get_Bits(6);



      val = Get_Bits(8);

      if (val==0)

        val = Get_Bits(8);

      else if (val==128)

        val = Get_Bits(8) - 256;

      else if (val>128)

        val -= 256;



      if (sign = (val<0))

        val = -val;

    }

    else

    {

      i+= tab->run;

      val = tab->level;

      sign = Get_Bits(1);

    }



    if (i>=64)

    {

      if (!Quiet_Flag)

        fprintf(stderr,"DCT coeff index (i) out of bounds (inter)\n");

      Fault_Flag = 1;

      return;

    }



    j = scan[ZIG_ZAG][i];

    val = (((val<<1)+1)*ld->quantizer_scale*ld->non_intra_quantizer_matrix[j]) >> 4;



    /* mismatch control ('oddification') */

    if (val!=0) /* should always be true, but it's not guaranteed */

      val = (val-1) | 1; /* equivalent to: if ((val&1)==0) val = val - 1; */



    /* saturation */

    if (!sign)

      bp[j] = (val>2047) ?  2047 :  val; /* positive */

    else

      bp[j] = (val>2048) ? -2048 : -val; /* negative */

  }

}





/* decode one intra coded MPEG-2 block */



void Decode_MPEG2_Intra_Block(comp,dc_dct_pred)

int comp;

int dc_dct_pred[];

{

  int val, i, j, sign, nc, cc, run;

  unsigned int code;

  DCTtab *tab;

  short *bp;

  int *qmat;

  struct layer_data *ld1;



  /* with data partitioning, data always goes to base layer */

  ld1 = (ld->scalable_mode==SC_DP) ? &base : ld;

  bp = ld1->block[comp];



  if (base.scalable_mode==SC_DP)

    if (base.priority_breakpoint<64)

      ld = &enhan;

    else

      ld = &base;



  cc = (comp<4) ? 0 : (comp&1)+1;



  qmat = (comp<4 || chroma_format==CHROMA420)

         ? ld1->intra_quantizer_matrix

         : ld1->chroma_intra_quantizer_matrix;



  /* ISO/IEC 13818-2 section 7.2.1: decode DC coefficients */

  if (cc==0)

    val = (dc_dct_pred[0]+= Get_Luma_DC_dct_diff());

  else if (cc==1)

    val = (dc_dct_pred[1]+= Get_Chroma_DC_dct_diff());

  else

    val = (dc_dct_pred[2]+= Get_Chroma_DC_dct_diff());



  if (Fault_Flag) return;



  bp[0] = val << (3-intra_dc_precision);



  nc=0;



#ifdef TRACE

  if (Trace_Flag)

    printf("DCT(%d)i:",comp);

#endif /* TRACE */



  /* decode AC coefficients */

  for (i=1; ; i++)

  {

    code = Show_Bits(16);

    if (code>=16384 && !intra_vlc_format)

      tab = &DCTtabnext[(code>>12)-4];

    else if (code>=1024)

    {

      if (intra_vlc_format)

        tab = &DCTtab0a[(code>>8)-4];

      else

        tab = &DCTtab0[(code>>8)-4];

    }

    else if (code>=512)

    {

      if (intra_vlc_format)

        tab = &DCTtab1a[(code>>6)-8];

      else

        tab = &DCTtab1[(code>>6)-8];

    }

    else if (code>=256)

      tab = &DCTtab2[(code>>4)-16];

    else if (code>=128)

      tab = &DCTtab3[(code>>3)-16];

    else if (code>=64)

      tab = &DCTtab4[(code>>2)-16];

    else if (code>=32)

      tab = &DCTtab5[(code>>1)-16];

    else if (code>=16)

      tab = &DCTtab6[code-16];

    else

    {

      if (!Quiet_Flag)

        printf("invalid Huffman code in Decode_MPEG2_Intra_Block()\n");

      Fault_Flag = 1;

      return;

    }



    Flush_Buffer(tab->len);



#ifdef TRACE

    if (Trace_Flag)

    {

      printf(" (");

      Print_Bits(code,16,tab->len);

    }

#endif /* TRACE */



    if (tab->run==64) /* end_of_block */

    {

#ifdef TRACE

      if (Trace_Flag)

        printf("): EOB\n");

#endif /* TRACE */

      return;

    }



    if (tab->run==65) /* escape */

    {

#ifdef TRACE

      if (Trace_Flag)

      {

        putchar(' ');

        Print_Bits(Show_Bits(6),6,6);

      }

#endif /* TRACE */



      i+= run = Get_Bits(6);



#ifdef TRACE

      if (Trace_Flag)

      {

        putchar(' ');

        Print_Bits(Show_Bits(12),12,12);

      }

#endif /* TRACE */



      val = Get_Bits(12);

      if ((val&2047)==0)

      {

        if (!Quiet_Flag)

          printf("invalid signed_level (escape) in Decode_MPEG2_Intra_Block()\n");

        Fault_Flag = 1;

        return;

      }

      if (sign = (val>=2048))

        val = 4096 - val;

    }

    else

    {

      i+= run = tab->run;

      val = tab->level;

      sign = Get_Bits(1);



#ifdef TRACE

      if (Trace_Flag)

        printf("%d",sign);

#endif /* TRACE */

    }



    if (i>=64)

    {

      if (!Quiet_Flag)

        fprintf(stderr,"DCT coeff index (i) out of bounds (intra2)\n");

      Fault_Flag = 1;

      return;

    }



#ifdef TRACE

    if (Trace_Flag)

      printf("): %d/%d",run,sign ? -val : val);

#endif /* TRACE */



    j = scan[ld1->alternate_scan][i];

    val = (val * ld1->quantizer_scale * qmat[j]) >> 4;

    bp[j] = sign ? -val : val;

    nc++;



    if (base.scalable_mode==SC_DP && nc==base.priority_breakpoint-63)

      ld = &enhan;

  }

}





/* decode one non-intra coded MPEG-2 block */



void Decode_MPEG2_Non_Intra_Block(comp)

int comp;

{

  int val, i, j, sign, nc, run;

  unsigned int code;

  DCTtab *tab;

  short *bp;

  int *qmat;

  struct layer_data *ld1;



  /* with data partitioning, data always goes to base layer */

  ld1 = (ld->scalable_mode==SC_DP) ? &base : ld;

  bp = ld1->block[comp];



  if (base.scalable_mode==SC_DP)

    if (base.priority_breakpoint<64)

      ld = &enhan;

    else

      ld = &base;



  qmat = (comp<4 || chroma_format==CHROMA420)

         ? ld1->non_intra_quantizer_matrix

         : ld1->chroma_non_intra_quantizer_matrix;



  nc = 0;



#ifdef TRACE

  if (Trace_Flag)

    printf("DCT(%d)n:",comp);

#endif /* TRACE */



  /* decode AC coefficients */

  for (i=0; ; i++)

  {

    code = Show_Bits(16);

    if (code>=16384)

    {

      if (i==0)

        tab = &DCTtabfirst[(code>>12)-4];

      else

        tab = &DCTtabnext[(code>>12)-4];

    }

    else if (code>=1024)

      tab = &DCTtab0[(code>>8)-4];

    else if (code>=512)

      tab = &DCTtab1[(code>>6)-8];

    else if (code>=256)

      tab = &DCTtab2[(code>>4)-16];

    else if (code>=128)

      tab = &DCTtab3[(code>>3)-16];

    else if (code>=64)

      tab = &DCTtab4[(code>>2)-16];

    else if (code>=32)

      tab = &DCTtab5[(code>>1)-16];

    else if (code>=16)

      tab = &DCTtab6[code-16];

    else

    {

      if (!Quiet_Flag)

        printf("invalid Huffman code in Decode_MPEG2_Non_Intra_Block()\n");

      Fault_Flag = 1;

      return;

    }



    Flush_Buffer(tab->len);



#ifdef TRACE

    if (Trace_Flag)

    {

      printf(" (");

      Print_Bits(code,16,tab->len);

    }

#endif /* TRACE */



    if (tab->run==64) /* end_of_block */

    {

#ifdef TRACE

      if (Trace_Flag)

        printf("): EOB\n");

#endif /* TRACE */

      return;

    }



    if (tab->run==65) /* escape */

    {

#ifdef TRACE

      if (Trace_Flag)

      {

        putchar(' ');

        Print_Bits(Show_Bits(6),6,6);

      }

#endif /* TRACE */



      i+= run = Get_Bits(6);



#ifdef TRACE

      if (Trace_Flag)

      {

        putchar(' ');

        Print_Bits(Show_Bits(12),12,12);

      }

#endif /* TRACE */



      val = Get_Bits(12);

      if ((val&2047)==0)

      {

        if (!Quiet_Flag)

          printf("invalid signed_level (escape) in Decode_MPEG2_Intra_Block()\n");

        Fault_Flag = 1;

        return;

      }

      if (sign = (val>=2048))

        val = 4096 - val;

    }

    else

    {

      i+= run = tab->run;

      val = tab->level;

      sign = Get_Bits(1);



#ifdef TRACE

      if (Trace_Flag)

        printf("%d",sign);

#endif /* TRACE */

    }



    if (i>=64)

    {

      if (!Quiet_Flag)

        fprintf(stderr,"DCT coeff index (i) out of bounds (inter2)\n");

      Fault_Flag = 1;

      return;

    }



#ifdef TRACE

    if (Trace_Flag)

      printf("): %d/%d",run,sign?-val:val);

#endif /* TRACE */



    j = scan[ld1->alternate_scan][i];

    val = (((val<<1)+1) * ld1->quantizer_scale * qmat[j]) >> 5;

    bp[j] = sign ? -val : val;

    nc++;



    if (base.scalable_mode==SC_DP && nc==base.priority_breakpoint-63)

      ld = &enhan;

  }

}