ffmpeg/libavcodec/motion_est.c

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/*
* Motion estimation
* Copyright (c) 2000,2001 Gerard Lantau.
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* new Motion Estimation (X1/EPZS) by Michael Niedermayer <michaelni@gmx.at>
*/
#include <stdlib.h>
#include <stdio.h>
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#define ABS(a) ((a)>0 ? (a) : -(a))
#define INTER_BIAS 257
static void halfpel_motion_search(MpegEncContext * s,
int *mx_ptr, int *my_ptr, int dmin,
int xmin, int ymin, int xmax, int ymax,
int pred_x, int pred_y);
/* config it to test motion vector encoding (send random vectors) */
//#define CONFIG_TEST_MV_ENCODE
static int pix_sum(UINT8 * pix, int line_size)
{
int s, i, j;
s = 0;
for (i = 0; i < 16; i++) {
for (j = 0; j < 16; j += 8) {
s += pix[0];
s += pix[1];
s += pix[2];
s += pix[3];
s += pix[4];
s += pix[5];
s += pix[6];
s += pix[7];
pix += 8;
}
pix += line_size - 16;
}
return s;
}
static int pix_dev(UINT8 * pix, int line_size, int mean)
{
int s, i, j;
s = 0;
for (i = 0; i < 16; i++) {
for (j = 0; j < 16; j += 8) {
s += ABS(pix[0]-mean);
s += ABS(pix[1]-mean);
s += ABS(pix[2]-mean);
s += ABS(pix[3]-mean);
s += ABS(pix[4]-mean);
s += ABS(pix[5]-mean);
s += ABS(pix[6]-mean);
s += ABS(pix[7]-mean);
pix += 8;
}
pix += line_size - 16;
}
return s;
}
static int pix_norm1(UINT8 * pix, int line_size)
{
int s, i, j;
UINT32 *sq = squareTbl + 256;
s = 0;
for (i = 0; i < 16; i++) {
for (j = 0; j < 16; j += 8) {
s += sq[pix[0]];
s += sq[pix[1]];
s += sq[pix[2]];
s += sq[pix[3]];
s += sq[pix[4]];
s += sq[pix[5]];
s += sq[pix[6]];
s += sq[pix[7]];
pix += 8;
}
pix += line_size - 16;
}
return s;
}
static int pix_norm(UINT8 * pix1, UINT8 * pix2, int line_size)
{
int s, i, j;
UINT32 *sq = squareTbl + 256;
s = 0;
for (i = 0; i < 16; i++) {
for (j = 0; j < 16; j += 8) {
s += sq[pix1[0] - pix2[0]];
s += sq[pix1[1] - pix2[1]];
s += sq[pix1[2] - pix2[2]];
s += sq[pix1[3] - pix2[3]];
s += sq[pix1[4] - pix2[4]];
s += sq[pix1[5] - pix2[5]];
s += sq[pix1[6] - pix2[6]];
s += sq[pix1[7] - pix2[7]];
pix1 += 8;
pix2 += 8;
}
pix1 += line_size - 16;
pix2 += line_size - 16;
}
return s;
}
static void no_motion_search(MpegEncContext * s,
int *mx_ptr, int *my_ptr)
{
*mx_ptr = 16 * s->mb_x;
*my_ptr = 16 * s->mb_y;
}
static int full_motion_search(MpegEncContext * s,
int *mx_ptr, int *my_ptr, int range,
int xmin, int ymin, int xmax, int ymax)
{
int x1, y1, x2, y2, xx, yy, x, y;
int mx, my, dmin, d;
UINT8 *pix;
xx = 16 * s->mb_x;
yy = 16 * s->mb_y;
x1 = xx - range + 1; /* we loose one pixel to avoid boundary pb with half pixel pred */
if (x1 < xmin)
x1 = xmin;
x2 = xx + range - 1;
if (x2 > xmax)
x2 = xmax;
y1 = yy - range + 1;
if (y1 < ymin)
y1 = ymin;
y2 = yy + range - 1;
if (y2 > ymax)
y2 = ymax;
pix = s->new_picture[0] + (yy * s->linesize) + xx;
dmin = 0x7fffffff;
mx = 0;
my = 0;
for (y = y1; y <= y2; y++) {
for (x = x1; x <= x2; x++) {
d = pix_abs16x16(pix, s->last_picture[0] + (y * s->linesize) + x,
s->linesize, 16);
if (d < dmin ||
(d == dmin &&
(abs(x - xx) + abs(y - yy)) <
(abs(mx - xx) + abs(my - yy)))) {
dmin = d;
mx = x;
my = y;
}
}
}
*mx_ptr = mx;
*my_ptr = my;
#if 0
if (*mx_ptr < -(2 * range) || *mx_ptr >= (2 * range) ||
*my_ptr < -(2 * range) || *my_ptr >= (2 * range)) {
fprintf(stderr, "error %d %d\n", *mx_ptr, *my_ptr);
}
#endif
return dmin;
}
static int log_motion_search(MpegEncContext * s,
int *mx_ptr, int *my_ptr, int range,
int xmin, int ymin, int xmax, int ymax)
{
int x1, y1, x2, y2, xx, yy, x, y;
int mx, my, dmin, d;
UINT8 *pix;
xx = s->mb_x << 4;
yy = s->mb_y << 4;
/* Left limit */
x1 = xx - range;
if (x1 < xmin)
x1 = xmin;
/* Right limit */
x2 = xx + range;
if (x2 > xmax)
x2 = xmax;
/* Upper limit */
y1 = yy - range;
if (y1 < ymin)
y1 = ymin;
/* Lower limit */
y2 = yy + range;
if (y2 > ymax)
y2 = ymax;
pix = s->new_picture[0] + (yy * s->linesize) + xx;
dmin = 0x7fffffff;
mx = 0;
my = 0;
do {
for (y = y1; y <= y2; y += range) {
for (x = x1; x <= x2; x += range) {
d = pix_abs16x16(pix, s->last_picture[0] + (y * s->linesize) + x, s->linesize, 16);
if (d < dmin || (d == dmin && (abs(x - xx) + abs(y - yy)) < (abs(mx - xx) + abs(my - yy)))) {
dmin = d;
mx = x;
my = y;
}
}
}
range = range >> 1;
x1 = mx - range;
if (x1 < xmin)
x1 = xmin;
x2 = mx + range;
if (x2 > xmax)
x2 = xmax;
y1 = my - range;
if (y1 < ymin)
y1 = ymin;
y2 = my + range;
if (y2 > ymax)
y2 = ymax;
} while (range >= 1);
#ifdef DEBUG
fprintf(stderr, "log - MX: %d\tMY: %d\n", mx, my);
#endif
*mx_ptr = mx;
*my_ptr = my;
return dmin;
}
static int phods_motion_search(MpegEncContext * s,
int *mx_ptr, int *my_ptr, int range,
int xmin, int ymin, int xmax, int ymax)
{
int x1, y1, x2, y2, xx, yy, x, y, lastx, d;
int mx, my, dminx, dminy;
UINT8 *pix;
xx = s->mb_x << 4;
yy = s->mb_y << 4;
/* Left limit */
x1 = xx - range;
if (x1 < xmin)
x1 = xmin;
/* Right limit */
x2 = xx + range;
if (x2 > xmax)
x2 = xmax;
/* Upper limit */
y1 = yy - range;
if (y1 < ymin)
y1 = ymin;
/* Lower limit */
y2 = yy + range;
if (y2 > ymax)
y2 = ymax;
pix = s->new_picture[0] + (yy * s->linesize) + xx;
mx = 0;
my = 0;
x = xx;
y = yy;
do {
dminx = 0x7fffffff;
dminy = 0x7fffffff;
lastx = x;
for (x = x1; x <= x2; x += range) {
d = pix_abs16x16(pix, s->last_picture[0] + (y * s->linesize) + x, s->linesize, 16);
if (d < dminx || (d == dminx && (abs(x - xx) + abs(y - yy)) < (abs(mx - xx) + abs(my - yy)))) {
dminx = d;
mx = x;
}
}
x = lastx;
for (y = y1; y <= y2; y += range) {
d = pix_abs16x16(pix, s->last_picture[0] + (y * s->linesize) + x, s->linesize, 16);
if (d < dminy || (d == dminy && (abs(x - xx) + abs(y - yy)) < (abs(mx - xx) + abs(my - yy)))) {
dminy = d;
my = y;
}
}
range = range >> 1;
x = mx;
y = my;
x1 = mx - range;
if (x1 < xmin)
x1 = xmin;
x2 = mx + range;
if (x2 > xmax)
x2 = xmax;
y1 = my - range;
if (y1 < ymin)
y1 = ymin;
y2 = my + range;
if (y2 > ymax)
y2 = ymax;
} while (range >= 1);
#ifdef DEBUG
fprintf(stderr, "phods - MX: %d\tMY: %d\n", mx, my);
#endif
/* half pixel search */
*mx_ptr = mx;
*my_ptr = my;
return dminy;
}
#define Z_THRESHOLD 256
#define CHECK_MV(x,y)\
{\
d = pix_abs16x16(new_pic, old_pic + (x) + (y)*pic_stride, pic_stride, 16);\
d += (mv_penalty[((x)<<shift)-pred_x] + mv_penalty[((y)<<shift)-pred_y])*quant;\
if(d<dmin){\
best[0]=x;\
best[1]=y;\
dmin=d;\
}\
}
#define CHECK_MV_DIR(x,y,new_dir)\
{\
d = pix_abs16x16(new_pic, old_pic + (x) + (y)*pic_stride, pic_stride, 16);\
d += (mv_penalty[((x)<<shift)-pred_x] + mv_penalty[((y)<<shift)-pred_y])*quant;\
if(d<dmin){\
best[0]=x;\
best[1]=y;\
dmin=d;\
next_dir= new_dir;\
}\
}
#define check(x,y,S,v)\
if( (x)<(xmin<<(S)) ) printf("%d %d %d %d xmin" #v, (x), (y), s->mb_x, s->mb_y);\
if( (x)>(xmax<<(S)) ) printf("%d %d %d %d xmax" #v, (x), (y), s->mb_x, s->mb_y);\
if( (y)<(ymin<<(S)) ) printf("%d %d %d %d ymin" #v, (x), (y), s->mb_x, s->mb_y);\
if( (y)>(ymax<<(S)) ) printf("%d %d %d %d ymax" #v, (x), (y), s->mb_x, s->mb_y);\
static inline int small_diamond_search(MpegEncContext * s, int *best, int dmin,
UINT8 *new_pic, UINT8 *old_pic, int pic_stride,
int pred_x, int pred_y, UINT16 *mv_penalty, int quant,
int xmin, int ymin, int xmax, int ymax, int shift)
{
int next_dir=-1;
for(;;){
int d;
const int dir= next_dir;
const int x= best[0];
const int y= best[1];
next_dir=-1;
//printf("%d", dir);
if(dir!=2 && x>xmin) CHECK_MV_DIR(x-1, y , 0)
if(dir!=3 && y>ymin) CHECK_MV_DIR(x , y-1, 1)
if(dir!=0 && x<xmax) CHECK_MV_DIR(x+1, y , 2)
if(dir!=1 && y<ymax) CHECK_MV_DIR(x , y+1, 3)
if(next_dir==-1){
return dmin;
}
}
/* for(;;){
int d;
const int x= best[0];
const int y= best[1];
const int last_min=dmin;
if(x>xmin) CHECK_MV(x-1, y )
if(y>xmin) CHECK_MV(x , y-1)
if(x<xmax) CHECK_MV(x+1, y )
if(y<xmax) CHECK_MV(x , y+1)
if(x>xmin && y>ymin) CHECK_MV(x-1, y-1)
if(x>xmin && y<ymax) CHECK_MV(x-1, y+1)
if(x<xmax && y>ymin) CHECK_MV(x+1, y-1)
if(x<xmax && y<ymax) CHECK_MV(x+1, y+1)
if(x-1>xmin) CHECK_MV(x-2, y )
if(y-1>xmin) CHECK_MV(x , y-2)
if(x+1<xmax) CHECK_MV(x+2, y )
if(y+1<xmax) CHECK_MV(x , y+2)
if(x-1>xmin && y-1>ymin) CHECK_MV(x-2, y-2)
if(x-1>xmin && y+1<ymax) CHECK_MV(x-2, y+2)
if(x+1<xmax && y-1>ymin) CHECK_MV(x+2, y-2)
if(x+1<xmax && y+1<ymax) CHECK_MV(x+2, y+2)
if(dmin==last_min) return dmin;
}
*/
}
static inline int snake_search(MpegEncContext * s, int *best, int dmin,
UINT8 *new_pic, UINT8 *old_pic, int pic_stride,
int pred_x, int pred_y, UINT16 *mv_penalty, int quant,
int xmin, int ymin, int xmax, int ymax, int shift)
{
int dir=0;
int c=1;
static int x_dir[8]= {1,1,0,-1,-1,-1, 0, 1};
static int y_dir[8]= {0,1,1, 1, 0,-1,-1,-1};
int fails=0;
int last_d[2]={dmin, dmin};
/*static int good=0;
static int bad=0;
static int point=0;
point++;
if(256*256*256*64%point==0)
{
printf("%d %d %d\n", good, bad, point);
}*/
for(;;){
int x= best[0];
int y= best[1];
int d;
x+=x_dir[dir];
y+=y_dir[dir];
if(x>=xmin && x<=xmax && y>=ymin && y<=ymax){
d = pix_abs16x16(new_pic, old_pic + (x) + (y)*pic_stride, pic_stride, 16);
d += (mv_penalty[((x)<<shift)-pred_x] + mv_penalty[((y)<<shift)-pred_y])*quant;
}else{
d = dmin + 10000; //FIXME smarter boundary handling
}
if(d<dmin){
best[0]=x;
best[1]=y;
dmin=d;
if(last_d[1] - last_d[0] > last_d[0] - d) c= -c;
dir+=c;
fails=0;
//good++;
last_d[1]=last_d[0];
last_d[0]=d;
}else{
//bad++;
if(fails){
if(fails>=3) return dmin;
}else{
c= -c;
}
dir+=c*2;
fails++;
}
dir&=7;
}
}
static int epzs_motion_search(MpegEncContext * s,
int *mx_ptr, int *my_ptr,
int P[5][2], int pred_x, int pred_y,
int xmin, int ymin, int xmax, int ymax)
{
int best[2]={0, 0};
int d, dmin;
UINT8 *new_pic, *old_pic;
const int pic_stride= s->linesize;
const int pic_xy= (s->mb_y*pic_stride + s->mb_x)*16;
UINT16 *mv_penalty= s->mv_penalty[s->f_code] + MAX_MV; // f_code of the prev frame
int quant= s->qscale; // qscale of the prev frame
const int shift= 1+s->quarter_sample;
new_pic = s->new_picture[0] + pic_xy;
old_pic = s->last_picture[0] + pic_xy;
dmin = pix_abs16x16(new_pic, old_pic, pic_stride, 16);
if(dmin<Z_THRESHOLD){
*mx_ptr= 0;
*my_ptr= 0;
//printf("Z");
return dmin;
}
/* first line */
if ((s->mb_y == 0 || s->first_slice_line || s->first_gob_line)) {
CHECK_MV(P[1][0]>>shift, P[1][1]>>shift)
}else{
CHECK_MV(P[4][0]>>shift, P[4][1]>>shift)
if(dmin<Z_THRESHOLD){
*mx_ptr= P[4][0]>>shift;
*my_ptr= P[4][1]>>shift;
//printf("M\n");
return dmin;
}
CHECK_MV(P[1][0]>>shift, P[1][1]>>shift)
CHECK_MV(P[2][0]>>shift, P[2][1]>>shift)
CHECK_MV(P[3][0]>>shift, P[3][1]>>shift)
}
CHECK_MV(P[0][0]>>shift, P[0][1]>>shift)
//check(best[0],best[1],0, b0)
if(s->full_search==ME_EPZS)
dmin= small_diamond_search(s, best, dmin, new_pic, old_pic, pic_stride,
pred_x, pred_y, mv_penalty, quant, xmin, ymin, xmax, ymax, shift);
else
dmin= snake_search(s, best, dmin, new_pic, old_pic, pic_stride,
pred_x, pred_y, mv_penalty, quant, xmin, ymin, xmax, ymax, shift);
//check(best[0],best[1],0, b1)
*mx_ptr= best[0];
*my_ptr= best[1];
// printf("%d %d %d \n", best[0], best[1], dmin);
return dmin;
}
#define CHECK_HALF_MV(suffix, x, y) \
d= pix_abs16x16_ ## suffix(pix, ptr+((x)>>1), s->linesize, 16);\
d += (mv_penalty[pen_x + x] + mv_penalty[pen_y + y])*quant;\
if(d<dminh){\
dminh= d;\
mx= mx1 + x;\
my= my1 + y;\
}
/* The idea would be to make half pel ME after Inter/Intra decision to
save time. */
static inline void halfpel_motion_search(MpegEncContext * s,
int *mx_ptr, int *my_ptr, int dmin,
int xmin, int ymin, int xmax, int ymax,
int pred_x, int pred_y)
{
UINT16 *mv_penalty= s->mv_penalty[s->f_code] + MAX_MV; // f_code of the prev frame
const int quant= s->qscale;
int pen_x, pen_y;
int mx, my, mx1, my1, d, xx, yy, dminh;
UINT8 *pix, *ptr;
mx = *mx_ptr;
my = *my_ptr;
ptr = s->last_picture[0] + (my * s->linesize) + mx;
xx = 16 * s->mb_x;
yy = 16 * s->mb_y;
pix = s->new_picture[0] + (yy * s->linesize) + xx;
dminh = dmin;
if (mx > xmin && mx < xmax &&
my > ymin && my < ymax) {
mx= mx1= 2*(mx - xx);
my= my1= 2*(my - yy);
if(dmin < Z_THRESHOLD && mx==0 && my==0){
*mx_ptr = 0;
*my_ptr = 0;
return;
}
pen_x= pred_x + mx;
pen_y= pred_y + my;
ptr-= s->linesize;
CHECK_HALF_MV(xy2, -1, -1)
CHECK_HALF_MV(y2 , 0, -1)
CHECK_HALF_MV(xy2, +1, -1)
ptr+= s->linesize;
CHECK_HALF_MV(x2 , -1, 0)
CHECK_HALF_MV(x2 , +1, 0)
CHECK_HALF_MV(xy2, -1, +1)
CHECK_HALF_MV(y2 , 0, +1)
CHECK_HALF_MV(xy2, +1, +1)
}else{
mx= 2*(mx - xx);
my= 2*(my - yy);
}
*mx_ptr = mx;
*my_ptr = my;
}
#ifndef CONFIG_TEST_MV_ENCODE
int estimate_motion(MpegEncContext * s,
int mb_x, int mb_y,
int *mx_ptr, int *my_ptr)
{
UINT8 *pix, *ppix;
int sum, varc, vard, mx, my, range, dmin, xx, yy;
int xmin, ymin, xmax, ymax;
int rel_xmin, rel_ymin, rel_xmax, rel_ymax;
int pred_x=0, pred_y=0;
int P[5][2];
const int shift= 1+s->quarter_sample;
range = 8 * (1 << (s->f_code - 1));
/* XXX: temporary kludge to avoid overflow for msmpeg4 */
if (s->out_format == FMT_H263 && !s->h263_msmpeg4)
range = range * 2;
if (s->unrestricted_mv) {
xmin = -16;
ymin = -16;
if (s->h263_plus)
range *= 2;
if(s->avctx==NULL || s->avctx->codec->id!=CODEC_ID_MPEG4){
xmax = s->mb_width*16;
ymax = s->mb_height*16;
}else {
/* XXX: dunno if this is correct but ffmpeg4 decoder wont like it otherwise
(cuz the drawn edge isnt large enough))*/
xmax = s->width;
ymax = s->height;
}
} else {
xmin = 0;
ymin = 0;
xmax = s->mb_width*16 - 16;
ymax = s->mb_height*16 - 16;
}
switch(s->full_search) {
case ME_ZERO:
default:
no_motion_search(s, &mx, &my);
dmin = 0;
break;
case ME_FULL:
dmin = full_motion_search(s, &mx, &my, range, xmin, ymin, xmax, ymax);
break;
case ME_LOG:
dmin = log_motion_search(s, &mx, &my, range / 2, xmin, ymin, xmax, ymax);
break;
case ME_PHODS:
dmin = phods_motion_search(s, &mx, &my, range / 2, xmin, ymin, xmax, ymax);
break;
case ME_X1:
case ME_EPZS:
{
static const int off[4]= {2, 1, 1, -1};
const int mot_stride = s->mb_width*2 + 2;
const int mot_xy = (s->mb_y*2 + 1)*mot_stride + s->mb_x*2 + 1;
rel_xmin= xmin - s->mb_x*16;
rel_xmax= xmax - s->mb_x*16;
rel_ymin= ymin - s->mb_y*16;
rel_ymax= ymax - s->mb_y*16;
P[0][0] = s->motion_val[mot_xy ][0];
P[0][1] = s->motion_val[mot_xy ][1];
P[1][0] = s->motion_val[mot_xy - 1][0];
P[1][1] = s->motion_val[mot_xy - 1][1];
if(P[1][0] > (rel_xmax<<shift)) P[1][0]= (rel_xmax<<shift);
/* special case for first line */
if ((s->mb_y == 0 || s->first_slice_line || s->first_gob_line)) {
P[4][0] = P[1][0];
P[4][1] = P[1][1];
} else {
P[2][0] = s->motion_val[mot_xy - mot_stride ][0];
P[2][1] = s->motion_val[mot_xy - mot_stride ][1];
P[3][0] = s->motion_val[mot_xy - mot_stride + off[0] ][0];
P[3][1] = s->motion_val[mot_xy - mot_stride + off[0] ][1];
if(P[2][1] > (rel_ymax<<shift)) P[2][1]= (rel_ymax<<shift);
if(P[3][0] < (rel_xmin<<shift)) P[3][0]= (rel_xmin<<shift);
if(P[3][1] > (rel_ymax<<shift)) P[3][1]= (rel_ymax<<shift);
P[4][0]= mid_pred(P[1][0], P[2][0], P[3][0]);
P[4][1]= mid_pred(P[1][1], P[2][1], P[3][1]);
}
if(s->out_format == FMT_H263){
pred_x = P[4][0];
pred_y = P[4][1];
}else { /* mpeg1 at least */
pred_x= P[1][0];
pred_y= P[1][1];
}
}
dmin = epzs_motion_search(s, &mx, &my, P, pred_x, pred_y, rel_xmin, rel_ymin, rel_xmax, rel_ymax);
mx+= s->mb_x*16;
my+= s->mb_y*16;
break;
}
/* intra / predictive decision */
xx = mb_x * 16;
yy = mb_y * 16;
pix = s->new_picture[0] + (yy * s->linesize) + xx;
/* At this point (mx,my) are full-pell and the absolute displacement */
ppix = s->last_picture[0] + (my * s->linesize) + mx;
sum = pix_sum(pix, s->linesize);
varc = pix_dev(pix, s->linesize, (sum+128)>>8);
vard = pix_abs16x16(pix, ppix, s->linesize, 16);
s->mb_var[s->mb_width * mb_y + mb_x] = varc;
s->avg_mb_var += varc;
s->mc_mb_var += vard;
#if 0
printf("varc=%4d avg_var=%4d (sum=%4d) vard=%4d mx=%2d my=%2d\n",
varc, s->avg_mb_var, sum, vard, mx - xx, my - yy);
#endif
if (vard <= 64 || vard < varc + INTER_BIAS) {
if (s->full_search != ME_ZERO) {
halfpel_motion_search(s, &mx, &my, dmin, xmin, ymin, xmax, ymax, pred_x, pred_y);
} else {
mx -= 16 * s->mb_x;
my -= 16 * s->mb_y;
}
// check(mx + 32*s->mb_x, my + 32*s->mb_y, 1, end)
*mx_ptr = mx;
*my_ptr = my;
return 0;
} else {
*mx_ptr = 0;
*my_ptr = 0;
return 1;
}
}
#else
/* test version which generates valid random vectors */
int estimate_motion(MpegEncContext * s,
int mb_x, int mb_y,
int *mx_ptr, int *my_ptr)
{
int xx, yy, x1, y1, x2, y2, range;
if ((random() % 10) >= 5) {
range = 8 * (1 << (s->f_code - 1));
if (s->out_format == FMT_H263 && !s->h263_msmpeg4)
range = range * 2;
xx = 16 * s->mb_x;
yy = 16 * s->mb_y;
x1 = xx - range;
if (x1 < 0)
x1 = 0;
x2 = xx + range - 1;
if (x2 > (s->width - 16))
x2 = s->width - 16;
y1 = yy - range;
if (y1 < 0)
y1 = 0;
y2 = yy + range - 1;
if (y2 > (s->height - 16))
y2 = s->height - 16;
*mx_ptr = (random() % (2 * (x2 - x1 + 1))) + 2 * (x1 - xx);
*my_ptr = (random() % (2 * (y2 - y1 + 1))) + 2 * (y1 - yy);
return 0;
} else {
*mx_ptr = 0;
*my_ptr = 0;
return 1;
}
}
#endif