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/*
class for motionvectors
Copyright (C) 1999 Martin Vogt
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as published by
the Free Software Foundation.
For more information look at the file COPYRIGHT in this package
*/
#include "motionVector.h"
MotionVector::MotionVector() {
}
MotionVector::~MotionVector() {
}
/*
*--------------------------------------------------------------
*
* ComputeVector --
*
* Computes motion vector given parameters previously parsed
* and reconstructed.
*
* Results:
* Reconstructed motion vector info is put into recon_* parameters
* passed to this function. Also updated previous motion vector
* information.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void MotionVector::computeVector(int* recon_right_ptr,
int* recon_down_ptr,
int& recon_right_prev,
int& recon_down_prev,
unsigned int& f,
unsigned int& full_pel_vector,
int& motion_h_code,
int& motion_v_code,
unsigned int& motion_h_r,
unsigned int& motion_v_r) {
int comp_h_r, comp_v_r;
int right_little, right_big, down_little, down_big;
int max, min, new_vector;
/* The following procedure for the reconstruction of motion vectors
is a direct and simple implementation of the instructions given
in the mpeg December 1991 standard draft.
*/
if (f == 1 || motion_h_code == 0)
comp_h_r = 0;
else
comp_h_r = f - 1 - motion_h_r;
if (f == 1 || motion_v_code == 0)
comp_v_r = 0;
else
comp_v_r = f - 1 - motion_v_r;
right_little = motion_h_code * f;
if (right_little == 0)
right_big = 0;
else {
if (right_little > 0) {
right_little = right_little - comp_h_r;
right_big = right_little - 32 * f;
}
else {
right_little = right_little + comp_h_r;
right_big = right_little + 32 * f;
}
}
down_little = motion_v_code * f;
if (down_little == 0)
down_big = 0;
else {
if (down_little > 0) {
down_little = down_little - comp_v_r;
down_big = down_little - 32 * f;
}
else {
down_little = down_little + comp_v_r;
down_big = down_little + 32 * f;
}
}
max = 16 * f - 1;
min = -16 * f;
new_vector = recon_right_prev + right_little;
if (new_vector <= max && new_vector >= min)
*recon_right_ptr = recon_right_prev + right_little;
/* just new_vector */
else
*recon_right_ptr = recon_right_prev + right_big;
recon_right_prev = *recon_right_ptr;
if (full_pel_vector)
*recon_right_ptr = *recon_right_ptr << 1;
new_vector = recon_down_prev + down_little;
if (new_vector <= max && new_vector >= min)
*recon_down_ptr = recon_down_prev + down_little;
/* just new_vector */
else
*recon_down_ptr = recon_down_prev + down_big;
recon_down_prev = *recon_down_ptr;
if (full_pel_vector)
*recon_down_ptr = *recon_down_ptr << 1;
}
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