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/* 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 "mpeg2enc_config.h"
#include "mpeg2enc_global.h"
/* generate variable length codes for an intra-coded block (6.2.6, 6.3.17) */
void MPEG2_putintrablk(blk,cc,mpeg2_struct)
short *blk;
int cc;
struct MPEG2_structure *mpeg2_struct;
{
int n, dct_diff, run, signed_level;
/* DC coefficient (7.2.1) */
dct_diff = blk[0] - mpeg2_struct->dc_dct_pred[cc]; /* difference to previous block */
mpeg2_struct->dc_dct_pred[cc] = blk[0];
if (cc==0)
MPEG2_putDClum(dct_diff,mpeg2_struct);
else
MPEG2_putDCchrom(dct_diff,mpeg2_struct);
/* AC coefficients (7.2.2) */
run = 0;
for (n=1; n<64; n++)
{
/* use appropriate entropy scanning pattern */
signed_level = blk[(mpeg2_struct->altscan ? MPEG2_alternate_scan : MPEG2_zig_zag_scan)[n]];
if (signed_level!=0)
{
MPEG2_putAC(run,signed_level,mpeg2_struct->intravlc,mpeg2_struct);
run = 0;
}
else
run++; /* count zero coefficients */
}
/* End of Block -- normative block punctuation */
if (mpeg2_struct->intravlc)
MPEG2_putbits(6,4,mpeg2_struct); /* 0110 (Table B-15) */
else
MPEG2_putbits(2,2,mpeg2_struct); /* 10 (Table B-14) */
}
/* generate variable length codes for a non-intra-coded block (6.2.6, 6.3.17) */
void MPEG2_putnonintrablk(blk,mpeg2_struct)
short *blk;
struct MPEG2_structure *mpeg2_struct;
{
int n, run, signed_level, first;
run = 0;
first = 1;
for (n=0; n<64; n++)
{
/* use appropriate entropy scanning pattern */
signed_level = blk[(mpeg2_struct->altscan ? MPEG2_alternate_scan : MPEG2_zig_zag_scan)[n]];
if (signed_level!=0)
{
if (first)
{
/* first coefficient in non-intra block */
MPEG2_putACfirst(run,signed_level,mpeg2_struct);
first = 0;
}
else
MPEG2_putAC(run,signed_level,0,mpeg2_struct);
run = 0;
}
else
run++; /* count zero coefficients */
}
/* End of Block -- normative block punctuation */
MPEG2_putbits(2,2,mpeg2_struct);
}
/* generate variable length code for a motion vector component (7.6.3.1) */
void MPEG2_putmv(dmv,f_code,mpeg2_struct)
int dmv,f_code;
struct MPEG2_structure *mpeg2_struct;
{
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 (!mpeg2_struct->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);
MPEG2_putmotioncode(motion_code,mpeg2_struct); /* variable length code */
if (r_size!=0 && motion_code!=0)
MPEG2_putbits(motion_residual,r_size,mpeg2_struct); /* fixed length code */
}
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