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/*
* Copyright (c) 1992 The Regents of the University of California.
* All rights reserved.
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without written agreement is
* hereby granted, provided that the above copyright notice and the following
* two paragraphs appear in all copies of this software.
*
* IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
* OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
* CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#include "video.h"
#include "util.h"
/*
*--------------------------------------------------------------
*
* 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.
*
*--------------------------------------------------------------
*/
static void
ComputeVector(recon_right_ptr, recon_down_ptr,
recon_right_prev_ptr, recon_down_prev_ptr,
f, full_pel_vector,
motion_h_code, motion_v_code,
motion_h_r, motion_v_r)
int *recon_right_ptr, *recon_down_ptr;
int *recon_right_prev_ptr, *recon_down_prev_ptr;
unsigned int f;
BOOLEAN full_pel_vector;
int motion_h_code, motion_v_code;
unsigned int motion_h_r, 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_ptr + right_little;
if (new_vector <= max && new_vector >= min)
*recon_right_ptr = *recon_right_prev_ptr + right_little;
/* just new_vector */
else
*recon_right_ptr = *recon_right_prev_ptr + right_big;
*recon_right_prev_ptr = *recon_right_ptr;
if (full_pel_vector)
*recon_right_ptr = *recon_right_ptr << 1;
new_vector = *recon_down_prev_ptr + down_little;
if (new_vector <= max && new_vector >= min)
*recon_down_ptr = *recon_down_prev_ptr + down_little;
/* just new_vector */
else
*recon_down_ptr = *recon_down_prev_ptr + down_big;
*recon_down_prev_ptr = *recon_down_ptr;
if (full_pel_vector)
*recon_down_ptr = *recon_down_ptr << 1;
}
/*
*--------------------------------------------------------------
*
* ComputeForwVector --
*
* Computes forward motion vector by calling ComputeVector
* with appropriate parameters.
*
* Results:
* Reconstructed motion vector placed in recon_right_for_ptr and
* recon_down_for_ptr.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void
ComputeForwVector(recon_right_for_ptr, recon_down_for_ptr)
int *recon_right_for_ptr;
int *recon_down_for_ptr;
{
Pict *picture;
Macroblock *mblock;
picture = &(curVidStream->picture);
mblock = &(curVidStream->mblock);
ComputeVector(recon_right_for_ptr, recon_down_for_ptr,
&(mblock->recon_right_for_prev),
&(mblock->recon_down_for_prev),
picture->forw_f, picture->full_pel_forw_vector,
mblock->motion_h_forw_code, mblock->motion_v_forw_code,
mblock->motion_h_forw_r, mblock->motion_v_forw_r);
}
/*
*--------------------------------------------------------------
*
* ComputeBackVector --
*
* Computes backward motion vector by calling ComputeVector
* with appropriate parameters.
*
* Results:
* Reconstructed motion vector placed in recon_right_back_ptr and
* recon_down_back_ptr.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void
ComputeBackVector(recon_right_back_ptr, recon_down_back_ptr)
int *recon_right_back_ptr;
int *recon_down_back_ptr;
{
Pict *picture;
Macroblock *mblock;
picture = &(curVidStream->picture);
mblock = &(curVidStream->mblock);
ComputeVector(recon_right_back_ptr, recon_down_back_ptr,
&(mblock->recon_right_back_prev),
&(mblock->recon_down_back_prev),
picture->back_f, picture->full_pel_back_vector,
mblock->motion_h_back_code, mblock->motion_v_back_code,
mblock->motion_h_back_r, mblock->motion_v_back_r);
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.