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jedioutcast/utils/roq2/mpeg/motion.c
James Monroe b2f9cf6f08 Jedi Outcast v056
2013-04-04 13:07:40 -05:00

472 lines
7.6 KiB
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/* motion.c, motion vector 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"
/* private prototypes */
static void decode_motion_vector _ANSI_ARGS_((int *pred, int r_size, int motion_code,
int motion_residualesidual, int full_pel_vector));
/* ISO/IEC 13818-2 sections 6.2.5.2, 6.3.17.2, and 7.6.3: Motion vectors */
void motion_vectors(PMV,dmvector,
motion_vertical_field_select,s,motion_vector_count,mv_format,h_r_size,v_r_size,dmv,mvscale)
int PMV[2][2][2];
int dmvector[2];
int motion_vertical_field_select[2][2];
int s, motion_vector_count, mv_format, h_r_size, v_r_size, dmv, mvscale;
{
if (motion_vector_count==1)
{
if (mv_format==MV_FIELD && !dmv)
{
motion_vertical_field_select[1][s] = motion_vertical_field_select[0][s] = Get_Bits(1);
#ifdef TRACE
if (Trace_Flag)
{
printf("motion_vertical_field_select[][%d] (%d): %d\n",s,
motion_vertical_field_select[0][s],motion_vertical_field_select[0][s]);
}
#endif /* TRACE */
}
motion_vector(PMV[0][s],dmvector,h_r_size,v_r_size,dmv,mvscale,0);
/* update other motion vector predictors */
PMV[1][s][0] = PMV[0][s][0];
PMV[1][s][1] = PMV[0][s][1];
}
else
{
motion_vertical_field_select[0][s] = Get_Bits(1);
#ifdef TRACE
if (Trace_Flag)
{
printf("motion_vertical_field_select[0][%d] (%d): %d\n",s,
motion_vertical_field_select[0][s],motion_vertical_field_select[0][s]);
}
#endif /* TRACE */
motion_vector(PMV[0][s],dmvector,h_r_size,v_r_size,dmv,mvscale,0);
motion_vertical_field_select[1][s] = Get_Bits(1);
#ifdef TRACE
if (Trace_Flag)
{
printf("motion_vertical_field_select[1][%d] (%d): %d\n",s,
motion_vertical_field_select[1][s],motion_vertical_field_select[1][s]);
}
#endif /* TRACE */
motion_vector(PMV[1][s],dmvector,h_r_size,v_r_size,dmv,mvscale,0);
}
}
/* get and decode motion vector and differential motion vector
for one prediction */
void motion_vector(PMV,dmvector,
h_r_size,v_r_size,dmv,mvscale,full_pel_vector)
int *PMV;
int *dmvector;
int h_r_size;
int v_r_size;
int dmv; /* MPEG-2 only: get differential motion vectors */
int mvscale; /* MPEG-2 only: field vector in frame pic */
int full_pel_vector; /* MPEG-1 only */
{
int motion_code, motion_residual;
/* horizontal component */
/* ISO/IEC 13818-2 Table B-10 */
motion_code = Get_motion_code();
motion_residual = (h_r_size!=0 && motion_code!=0) ? Get_Bits(h_r_size) : 0;
#ifdef TRACE
if (Trace_Flag)
{
if (h_r_size!=0 && motion_code!=0)
{
printf("motion_residual (");
Print_Bits(motion_residual,h_r_size,h_r_size);
printf("): %d\n",motion_residual);
}
}
#endif /* TRACE */
decode_motion_vector(&PMV[0],h_r_size,motion_code,motion_residual,full_pel_vector);
if (dmv)
dmvector[0] = Get_dmvector();
/* vertical component */
motion_code = Get_motion_code();
motion_residual = (v_r_size!=0 && motion_code!=0) ? Get_Bits(v_r_size) : 0;
#ifdef TRACE
if (Trace_Flag)
{
if (v_r_size!=0 && motion_code!=0)
{
printf("motion_residual (");
Print_Bits(motion_residual,v_r_size,v_r_size);
printf("): %d\n",motion_residual);
}
}
#endif /* TRACE */
if (mvscale)
PMV[1] >>= 1; /* DIV 2 */
decode_motion_vector(&PMV[1],v_r_size,motion_code,motion_residual,full_pel_vector);
if (mvscale)
PMV[1] <<= 1;
if (dmv)
dmvector[1] = Get_dmvector();
#ifdef TRACE
if (Trace_Flag)
printf("PMV = %d,%d\n",PMV[0],PMV[1]);
#endif /* TRACE */
}
/* calculate motion vector component */
/* ISO/IEC 13818-2 section 7.6.3.1: Decoding the motion vectors */
/* Note: the arithmetic here is more elegant than that which is shown
in 7.6.3.1. The end results (PMV[][][]) should, however, be the same. */
static void decode_motion_vector(pred,r_size,motion_code,motion_residual,full_pel_vector)
int *pred;
int r_size, motion_code, motion_residual;
int full_pel_vector; /* MPEG-1 (ISO/IEC 11172-1) support */
{
int lim, vec;
lim = 16<<r_size;
vec = full_pel_vector ? (*pred >> 1) : (*pred);
if (motion_code>0)
{
vec+= ((motion_code-1)<<r_size) + motion_residual + 1;
if (vec>=lim)
vec-= lim + lim;
}
else if (motion_code<0)
{
vec-= ((-motion_code-1)<<r_size) + motion_residual + 1;
if (vec<-lim)
vec+= lim + lim;
}
*pred = full_pel_vector ? (vec<<1) : vec;
}
/* ISO/IEC 13818-2 section 7.6.3.6: Dual prime additional arithmetic */
void Dual_Prime_Arithmetic(DMV,dmvector,mvx,mvy)
int DMV[][2];
int *dmvector; /* differential motion vector */
int mvx, mvy; /* decoded mv components (always in field format) */
{
if (picture_structure==FRAME_PICTURE)
{
if (top_field_first)
{
/* vector for prediction of top field from bottom field */
DMV[0][0] = ((mvx +(mvx>0))>>1) + dmvector[0];
DMV[0][1] = ((mvy +(mvy>0))>>1) + dmvector[1] - 1;
/* vector for prediction of bottom field from top field */
DMV[1][0] = ((3*mvx+(mvx>0))>>1) + dmvector[0];
DMV[1][1] = ((3*mvy+(mvy>0))>>1) + dmvector[1] + 1;
}
else
{
/* vector for prediction of top field from bottom field */
DMV[0][0] = ((3*mvx+(mvx>0))>>1) + dmvector[0];
DMV[0][1] = ((3*mvy+(mvy>0))>>1) + dmvector[1] - 1;
/* vector for prediction of bottom field from top field */
DMV[1][0] = ((mvx +(mvx>0))>>1) + dmvector[0];
DMV[1][1] = ((mvy +(mvy>0))>>1) + dmvector[1] + 1;
}
}
else
{
/* vector for prediction from field of opposite 'parity' */
DMV[0][0] = ((mvx+(mvx>0))>>1) + dmvector[0];
DMV[0][1] = ((mvy+(mvy>0))>>1) + dmvector[1];
/* correct for vertical field shift */
if (picture_structure==TOP_FIELD)
DMV[0][1]--;
else
DMV[0][1]++;
}
}
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