/* putmpg.c, block and motion vector encoding routines                      *//* 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"/* generate variable length codes for an intra-coded block (6.2.6, 6.3.17) */void putintrablk(blk,cc)short *blk;int cc;{  int n, dct_diff, run, signed_level;  /* DC coefficient (7.2.1) */  dct_diff = blk[0] - dc_dct_pred[cc]; /* difference to previous block */  dc_dct_pred[cc] = blk[0];  if (cc==0)    putDClum(dct_diff);  else    putDCchrom(dct_diff);  /* AC coefficients (7.2.2) */  run = 0;  for (n=1; n<64; n++)  {    /* use appropriate entropy scanning pattern */    signed_level = blk[(altscan ? alternate_scan : zig_zag_scan)[n]];    if (signed_level!=0)    {      putAC(run,signed_level,intravlc);      run = 0;    }    else      run++; /* count zero coefficients */  }  /* End of Block -- normative block punctuation */  if (intravlc)    putbits(6,4); /* 0110 (Table B-15) */  else    putbits(2,2); /* 10 (Table B-14) */}/* generate variable length codes for a non-intra-coded block (6.2.6, 6.3.17) */void putnonintrablk(blk)short *blk;{  int n, run, signed_level, first;  run = 0;  first = 1;  for (n=0; n<64; n++)  {    /* use appropriate entropy scanning pattern */    signed_level = blk[(altscan ? alternate_scan : zig_zag_scan)[n]];    if (signed_level!=0)    {      if (first)      {        /* first coefficient in non-intra block */        putACfirst(run,signed_level);        first = 0;      }      else        putAC(run,signed_level,0);      run = 0;    }    else      run++; /* count zero coefficients */  }  /* End of Block -- normative block punctuation  */  putbits(2,2);}/* generate variable length code for a motion vector component (7.6.3.1) */void putmv(dmv,f_code)int dmv,f_code;{  int r_size, f, vmin, vmax, dv, temp, motion_code, motion_residual;  r_size = f_code - 1; /* number of fixed length code ('residual') bits */  f = 1<<r_size;  vmin = -16*f; /* lower range limit */  vmax = 16*f - 1; /* upper range limit */  dv = 32*f;  /* fold vector difference into [vmin...vmax] */  if (dmv>vmax)    dmv-= dv;  else if (dmv<vmin)    dmv+= dv;  /* check value */  if (dmv<vmin || dmv>vmax)    if (!quiet)      fprintf(stderr,"invalid motion vector\n");  /* split dmv into motion_code and motion_residual */  temp = ((dmv<0) ? -dmv : dmv) + f - 1;  motion_code = temp>>r_size;  if (dmv<0)    motion_code = -motion_code;  motion_residual = temp & (f-1);  putmotioncode(motion_code); /* variable length code */  if (r_size!=0 && motion_code!=0)    putbits(motion_residual,r_size); /* fixed length code */}