/* getblk.c, DCT 編碼                                             */#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 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 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;  }}