/* putvlc.c, generation of variable length codes                            *//* 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"#include "vlc.h"/* private prototypes */static void putDC _ANSI_ARGS_((sVLCtable *tab, int val));/* generate variable length code for luminance DC coefficient */void putDClum(val)int val;{  putDC(DClumtab,val);}/* generate variable length code for chrominance DC coefficient */void putDCchrom(val)int val;{  putDC(DCchromtab,val);}/* generate variable length code for DC coefficient (7.2.1) */static void putDC(tab,val)sVLCtable *tab;int val;{  int absval, size;  absval = (val<0) ? -val : val; /* abs(val) */  if (absval>2047 || (mpeg1 && absval>255))  {    /* should never happen */    sprintf(errortext,"DC value out of range (%d)\n",val);    error(errortext);  }  /* compute dct_dc_size */  size = 0;  while (absval)  {    absval >>= 1;    size++;  }  /* generate VLC for dct_dc_size (Table B-12 or B-13) */  putbits(tab[size].code,tab[size].len);  /* append fixed length code (dc_dct_differential) */  if (size!=0)  {    if (val>=0)      absval = val;    else      absval = val + (1<<size) - 1; /* val + (2 ^ size) - 1 */    putbits(absval,size);  }}/* generate variable length code for first coefficient * of a non-intra block (7.2.2.2) */void putACfirst(run,val)int run,val;{  if (run==0 && (val==1 || val==-1)) /* these are treated differently */    putbits(2|(val<0),2); /* generate '1s' (s=sign), (Table B-14, line 2) */  else    putAC(run,val,0); /* no difference for all others */}/* generate variable length code for other DCT coefficients (7.2.2) */void putAC(run,signed_level,vlcformat)int run,signed_level,vlcformat;{  int level, len;  VLCtable *ptab;  level = (signed_level<0) ? -signed_level : signed_level; /* abs(signed_level) */  /* make sure run and level are valid */  if (run<0 || run>63 || level==0 || level>2047 || (mpeg1 && level>255))  {    sprintf(errortext,"AC value out of range (run=%d, signed_level=%d)\n",      run,signed_level);    error(errortext);  }  len = 0;  if (run<2 && level<41)  {    /* vlcformat selects either of Table B-14 / B-15 */    if (vlcformat)      ptab = &dct_code_tab1a[run][level-1];    else      ptab = &dct_code_tab1[run][level-1];    len = ptab->len;  }  else if (run<32 && level<6)  {    /* vlcformat selects either of Table B-14 / B-15 */    if (vlcformat)      ptab = &dct_code_tab2a[run-2][level-1];    else      ptab = &dct_code_tab2[run-2][level-1];    len = ptab->len;  }  if (len!=0) /* a VLC code exists */  {    putbits(ptab->code,len);    putbits(signed_level<0,1); /* sign */  }  else  {    /* no VLC for this (run, level) combination: use escape coding (7.2.2.3) */    putbits(1l,6); /* Escape */    putbits(run,6); /* 6 bit code for run */    if (mpeg1)    {      /* ISO/IEC 11172-2 uses a 8 or 16 bit code */      if (signed_level>127)        putbits(0,8);      if (signed_level<-127)        putbits(128,8);      putbits(signed_level,8);    }    else    {      /* ISO/IEC 13818-2 uses a 12 bit code, Table B-16 */      putbits(signed_level,12);    }  }}/* generate variable length code for macroblock_address_increment (6.3.16) */void putaddrinc(addrinc)int addrinc;{  while (addrinc>33)  {    putbits(0x08,11); /* macroblock_escape */    addrinc-= 33;  }  putbits(addrinctab[addrinc-1].code,addrinctab[addrinc-1].len);}/* generate variable length code for macroblock_type (6.3.16.1) */void putmbtype(pict_type,mb_type)int pict_type,mb_type;{  putbits(mbtypetab[pict_type-1][mb_type].code,          mbtypetab[pict_type-1][mb_type].len);}/* generate variable length code for motion_code (6.3.16.3) */void putmotioncode(motion_code)int motion_code;{  int abscode;  abscode = (motion_code>=0) ? motion_code : -motion_code; /* abs(motion_code) */  putbits(motionvectab[abscode].code,motionvectab[abscode].len);  if (motion_code!=0)    putbits(motion_code<0,1); /* sign, 0=positive, 1=negative */}/* generate variable length code for dmvector[t] (6.3.16.3), Table B-11 */void putdmv(dmv)int dmv;{  if (dmv==0)    putbits(0,1);  else if (dmv>0)    putbits(2,2);  else    putbits(3,2);}/* generate variable length code for coded_block_pattern (6.3.16.4) * * 4:2:2, 4:4:4 not implemented */void putcbp(cbp)int cbp;{  putbits(cbptable[cbp].code,cbptable[cbp].len);}