/*===========================================================================*
* block.c
*
* Block routines
*
* NOTES: MAD = Mean Absolute Difference
*===========================================================================*/
/* Copyright information is at end of file */
#include <assert.h>
#include "pm_c_util.h"
#include "all.h"
#include "mtypes.h"
#include "frames.h"
#include "bitio.h"
#include "prototypes.h"
#include "fsize.h"
#include "opts.h"
#include "postdct.h"
#include "block.h"
#define TRUNCATE_UINT8(x) ((x < 0) ? 0 : ((x > 255) ? 255 : x))
/*==================*
* GLOBAL VARIABLES *
*==================*/
extern Block **dct, **dctb, **dctr;
static vector
halfVector(vector const v) {
vector half;
half.y = v.y/2;
half.x = v.x/2;
return half;
}
/*===========================*
* COMPUTE DCT OF DIFFERENCE *
*===========================*/
/*===========================================================================*
*
* compute current-motionBlock, take the DCT, and put the difference
* back into current
*
* RETURNS: current block modified
*
* SIDE EFFECTS: none
*
*===========================================================================*/
void
ComputeDiffDCTBlock(Block current,
Block dest,
Block motionBlock,
boolean * const significantDifferenceP) {
unsigned int y;
int diff;
diff = 0; /* initial value */
for (y = 0; y < 8; ++y) {
unsigned int x;
for (x = 0; x < 8; ++x) {
current[y][x] -= motionBlock[y][x];
diff += ABS(current[y][x]);
}
}
/* Kill the block if change is too small */
/* (block_bound defaults to 128, see opts.c) */
if (diff < block_bound)
*significantDifferenceP = FALSE;
else {
mp_fwd_dct_block2(current, dest);
*significantDifferenceP = TRUE;
}
}
/*===========================================================================*
*
* appropriate (according to pattern, the coded block pattern) blocks
* of 'current' are diff'ed and DCT'd.
*
* RETURNS: current blocks modified
*
* SIDE EFFECTS: Can remove too-small difference blocks from pattern
*
* PRECONDITIONS: appropriate blocks of 'current' have not yet been
* modified
*
*===========================================================================*/
void
ComputeDiffDCTs(MpegFrame * const current,
MpegFrame * const prev,
int const by,
int const bx,
vector const m,
int * const patternP) {
Block motionBlock;
if (collect_quant && (collect_quant_detailed & 1))
fprintf(collect_quant_fp, "l\n");
if (*patternP & 0x20) {
boolean significantDiff;
ComputeMotionBlock(prev->ref_y, by, bx, m, &motionBlock);
ComputeDiffDCTBlock(current->y_blocks[by][bx], dct[by][bx],
motionBlock, &significantDiff);
if (!significantDiff)
*patternP ^= 0x20;
}
if (*patternP & 0x10) {
boolean significantDiff;
ComputeMotionBlock(prev->ref_y, by, bx+1, m, &motionBlock);
ComputeDiffDCTBlock(current->y_blocks[by][bx+1], dct[by][bx+1],
motionBlock, &significantDiff);
if (!significantDiff)
*patternP ^= 0x10;
}
if (*patternP & 0x8) {
boolean significantDiff;
ComputeMotionBlock(prev->ref_y, by+1, bx, m, &motionBlock);
ComputeDiffDCTBlock(current->y_blocks[by+1][bx], dct[by+1][bx],
motionBlock, &significantDiff);
if (!significantDiff)
*patternP ^= 0x8;
}
if (*patternP & 0x4) {
boolean significantDiff;
ComputeMotionBlock(prev->ref_y, by+1, bx+1, m, &motionBlock);
ComputeDiffDCTBlock(current->y_blocks[by+1][bx+1], dct[by+1][bx+1],
motionBlock, &significantDiff);
if (!significantDiff)
*patternP ^= 0x4;
}
if (collect_quant && (collect_quant_detailed & 1))
fprintf(collect_quant_fp, "c\n");
if (*patternP & 0x2) {
boolean significantDiff;
ComputeMotionBlock(prev->ref_cb, by/2, bx/2, halfVector(m),
&motionBlock);
ComputeDiffDCTBlock(current->cb_blocks[by/2][bx/2],
dctb[by/2][bx/2], motionBlock,
&significantDiff);
if (!significantDiff)
*patternP ^= 0x2;
}
if (*patternP & 0x1) {
boolean significantDiff;
ComputeMotionBlock(prev->ref_cr, by/2, bx/2, halfVector(m),
&motionBlock);
ComputeDiffDCTBlock(current->cr_blocks[by/2][bx/2],
dctr[by/2][bx/2], motionBlock,
&significantDiff);
if (!significantDiff)
*patternP ^= 0x1;
}
}
static void
computePrevFyFx(MpegFrame * const prevFrame,
int const by,
int const bx,
vector const m,
uint8 *** const prevP,
int * const fyP,
int * const fxP) {
boolean const xHalf = (ABS(m.x) % 2 == 1);
boolean const yHalf = (ABS(m.y) % 2 == 1);
MotionToFrameCoord(by, bx, m.y/2, m.x/2, fyP, fxP);
assert(*fyP >= 0); assert(*fxP >= 0);
/* C integer arithmetic rounds toward zero. But what we need is a
"floor" -- i.e. round down. So we adjust now for where the dividend
in the above divide by two was negative.
*/
if (xHalf) {
if (m.x < 0)
--*fxP;
if (yHalf) {
if (m.y < 0)
--*fyP;
*prevP = prevFrame->halfBoth;
} else
*prevP = prevFrame->halfX;
} else if (yHalf) {
if (m.y < 0)
--*fyP;
*prevP = prevFrame->halfY;
} else
*prevP = prevFrame->ref_y;
}
/*======================*
* COMPUTE MOTION BLOCK *
*======================*/
/*===========================================================================*
*
* compute the motion-compensated block
*
* RETURNS: motionBlock
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: motion vector MUST be valid
*
* NOTE: could try to speed this up using halfX, halfY, halfBoth,
* but then would have to compute for chrominance, and it's just
* not worth the trouble (this procedure is not called relatively
* often -- a constant number of times per macroblock)
*
*===========================================================================*/
void
ComputeMotionBlock(uint8 ** const prev,
int const by,
int const bx,
vector const m,
Block * const motionBlockP) {
int fy, fx;
boolean xHalf, yHalf;
xHalf = (ABS(m.x) % 2 == 1);
yHalf = (ABS(m.y) % 2 == 1);
MotionToFrameCoord(by, bx, m.y/2, m.x/2, &fy, &fx);
if (xHalf && yHalf) {
unsigned int y;
/* really should be fy+y-1 and fy+y so do (fy-1)+y = fy+y-1 and
(fy-1)+y+1 = fy+y
*/
if (m.y < 0)
--fy;
if (m.x < 0)
--fx;
for (y = 0; y < 8; ++y) {
int16 * const destPtr = (*motionBlockP)[y];
uint8 * const srcPtr = &(prev[fy+y][fx]);
uint8 * const srcPtr2 = &(prev[fy+y+1][fx]);
unsigned int x;
for (x = 0; x < 8; ++x)
destPtr[x] =
(srcPtr[x]+srcPtr[x+1]+srcPtr2[x]+srcPtr2[x+1]+2) >> 2;
}
} else if (xHalf) {
unsigned int y;
if (m.x < 0)
--fx;
for (y = 0; y < 8; ++y) {
int16 * const destPtr = (*motionBlockP)[y];
uint8 * const srcPtr = &(prev[fy+y][fx]);
unsigned int x;
for (x = 0; x < 8; ++x)
destPtr[x] = (srcPtr[x]+srcPtr[x+1]+1) >> 1;
}
} else if (yHalf) {
unsigned int y;
if ( m.y < 0 )
fy--;
for (y = 0; y < 8; ++y) {
int16 * const destPtr = (*motionBlockP)[y];
uint8 * const srcPtr = &(prev[fy+y][fx]);
uint8 * const srcPtr2 = &(prev[fy+y+1][fx]);
unsigned int x;
for (x = 0; x < 8; ++x)
destPtr[x] = (srcPtr[x]+srcPtr2[x]+1) >> 1;
}
} else {
unsigned int y;
for (y = 0; y < 8; ++y) {
int16 * const destPtr = (*motionBlockP)[y];
uint8 * const srcPtr = &(prev[fy+y][fx]);
unsigned int x;
for (x = 0; x < 8; ++x)
destPtr[x] = srcPtr[x];
}
}
}
/*===========================================================================*
*
* compute the motion-compensated luminance block
*
* RETURNS: motionBlock
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: motion vector MUST be valid
*
* NOTE: see ComputeMotionBlock
*
*===========================================================================*/
void
ComputeMotionLumBlock(MpegFrame * const prevFrame,
int const by,
int const bx,
vector const m,
LumBlock * const motionBlockP) {
unsigned int y;
uint8 ** prev;
int fy, fx;
computePrevFyFx(prevFrame, by, bx, m, &prev, &fy, &fx);
for (y = 0; y < 16; ++y) {
uint8 * const across = &(prev[fy+y][fx]);
int32 * const macross = motionBlockP->l[y];
unsigned int x;
for (x = 0; x < 16; ++x)
macross[x] = across[x];
}
/* this is what's really happening, in slow motion:
*
* for (y = 0; y < 16; ++y, ++py)
* for (x = 0; x < 16; ++x, ++px)
* motionBlock[y][x] = prev[fy+y][fx+x];
*
*/
}
/*=======================*
* BASIC ERROR FUNCTIONS *
*=======================*/
/*===========================================================================*
*
* return the MAD of two luminance blocks
*
* RETURNS: the MAD, if less than bestSoFar, or some number bigger if not
*
* SIDE EFFECTS: none
*
*===========================================================================*/
int32
LumBlockMAD(const LumBlock * const currentBlockP,
const LumBlock * const motionBlockP,
int32 const bestSoFar) {
int32 diff; /* max value of diff is 255*256 = 65280 */
unsigned int y;
diff = 0; /* initial value */
for (y = 0; y < 16; ++y) {
const int32 * const currentRow = currentBlockP->l[y];
const int32 * const motionRow = motionBlockP->l[y];
unsigned int x;
for (x = 0; x < 16; ++x)
diff += ABS(currentRow[x] - motionRow[x]);
if (diff > bestSoFar)
/* We already know the MAD won't be less than bestSoFar;
Caller doesn't care by how much we missed, so just return
this.
*/
return diff;
}
/* Return the actual MAD */
return diff;
}
/*===========================================================================*
*
* return the MAD of the currentBlock and the motion-compensated block
* (without TUNEing)
*
* (by, bx) is the location of the block in the frame
* (block number coordinates). 'm' is the motion of the block in pixels.
* The moved block must be wholly within the frame.
*
* RETURNS: the MAD, if less than bestSoFar, or
* some number bigger if not
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: motion vector MUST be valid
*
* NOTES: this is the procedure that is called the most, and should therefore
* be the most optimized!!!
*
*===========================================================================*/
int32
LumMotionError(const LumBlock * const currentBlockP,
MpegFrame * const prevFrame,
int const by,
int const bx,
vector const m,
int32 const bestSoFar) {
int32 adiff;
int32 diff; /* max value of diff is 255*256 = 65280 */
int y;
uint8 **prev;
int fy, fx;
computePrevFyFx(prevFrame, by, bx, m, &prev, &fy, &fx);
assert(fy >= 0); assert(fx >= 0);
adiff = 0; /* initial value */
diff = 0; /* initial value */
switch (SearchCompareMode) {
case DEFAULT_SEARCH: /* Default. */
for (y = 0; y < 16; ++y) {
const int32 * const cacross = currentBlockP->l[y];
uint8 * const across = &prev[fy+y][fx];
unsigned int x;
for (x = 0; x < 16; ++x) {
int32 const localDiff = across[x]-cacross[x];
diff += ABS(localDiff);
}
if (diff > bestSoFar)
return diff;
}
break;
case LOCAL_DCT: {
Block dctdiff[4], dctquant[4];
FlatBlock quant;
int x, i, tmp;
int distortion=0, datarate=0;
int pq = GetPQScale();
for (y = 0; y < 16; ++y) {
const int32 * const cacross = currentBlockP->l[y];
uint8 * const across = &(prev[fy+y][fx]);
for (x = 0; x < 16; ++x) {
dctdiff[(x>7)+2*(y>7)][y%8][x%8] = cacross[x]-across[x];
}}
/* Calculate rate */
for (i = 0; i < 4; ++i) {
mp_fwd_dct_block2(dctdiff[i], dctdiff[i]);
if (Mpost_QuantZigBlock(dctdiff[i], quant, pq, FALSE) ==
MPOST_ZERO) {
/* no sense in continuing */
memset((char *)dctquant[i], 0, sizeof(Block));
} else {
Mpost_UnQuantZigBlock(quant, dctquant[i], pq, FALSE);
mpeg_jrevdct((int16 *)dctquant[i]);
datarate += CalcRLEHuffLength(quant);
}
}
/* Calculate distortion */
for (y = 0; y < 16; ++y) {
const int32 * const cacross = currentBlockP->l[y];
uint8 * const across = &(prev[fy+y][fx]);
for (x = 0; x < 16; ++x) {
tmp = across[x] - cacross[x] +
dctquant[(x>7)+2*(y>7)][y%8][x%8];
distortion += tmp*tmp;
}}
distortion /= 256;
distortion *= LocalDCTDistortScale;
datarate *= LocalDCTRateScale;
diff = (int) sqrt(distortion*distortion + datarate*datarate);
break;
}
case NO_DC_SEARCH: {
extern int32 niqtable[];
int pq = niqtable[0]*GetPQScale();
unsigned int y;
for (y = 0; y < 16; ++y) {
const int32 * const cacross = currentBlockP->l[y];
uint8 * const across = &(prev[fy+y][fx]);
unsigned int x;
for (x = 0; x < 16; ++x) {
int32 const localDiff = across[x]-cacross[x];
diff += localDiff;
adiff += ABS(localDiff);
}
}
diff /= 64*pq; /* diff is now the DC difference (with QSCALE 1) */
adiff -= 64*pq*ABS(diff);
diff = adiff;
}
break;
case DO_Mean_Squared_Distortion:
for (y = 0; y < 16; ++y) {
const int32 * const cacross = currentBlockP->l[y];
uint8 * const across = &(prev[fy+y][fx]);
unsigned int x;
for (x = 0; x < 16; ++x) {
int32 const localDiff = across[x] - cacross[x];
diff += localDiff * localDiff;
}
if (diff > bestSoFar)
return diff;
}
break;
} /* End of Switch */
return diff;
}
/*===========================================================================*
*
* return the MAD of the currentBlock and the average of the blockSoFar
* and the motion-compensated block (this is used for B-frame searches)
*
* RETURNS: the MAD, if less than bestSoFar, or
* some number bigger if not
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: motion vector MUST be valid
*
*===========================================================================*/
int32
LumAddMotionError(const LumBlock * const currentBlockP,
const LumBlock * const blockSoFarP,
MpegFrame * const prevFrame,
int const by,
int const bx,
vector const m,
int32 const bestSoFar) {
int32 diff; /* max value of diff is 255*256 = 65280 */
int y;
uint8 **prev;
int fy, fx;
computePrevFyFx(prevFrame, by, bx, m, &prev, &fy, &fx);
diff = 0; /* initial value */
/* do we add 1 before dividing by two? Yes -- see MPEG-1 doc page 46 */
for (y = 0; y < 16; ++y) {
unsigned int x;
const uint8 * const across = &prev[fy+y][fx];
const int32 * const bacross = blockSoFarP->l[y];
const int32 * const cacross = currentBlockP->l[y];
for (x = 0; x < 16; ++x) {
int32 const localDiff =
((across[x] + bacross[x] + 1) / 2) - cacross[x];
diff += ABS(localDiff);
}
if (diff > bestSoFar)
return diff;
}
/* This is what's happening:
*
* ComputeMotionLumBlock(prevFrame, by, bx, my, mx, lumMotionBlock);
*
* for (y = 0; y < 16; ++y)
* for (x = 0; x < 16; ++x) {
* localDiff = currentBlock[y][x] - lumMotionBlock[y][x];
* diff += ABS(localDiff);
* }
*/
return diff;
}
/*===========================================================================*
*
* adds the motion-compensated block to the given block
*
* RETURNS: block modified
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: motion vector MUST be valid
*
*===========================================================================*/
void
AddMotionBlock(Block block,
uint8 ** const prev,
int const by,
int const bx,
vector const m) {
int fy, fx;
boolean xHalf, yHalf;
xHalf = (ABS(m.x) % 2 == 1);
yHalf = (ABS(m.y) % 2 == 1);
MotionToFrameCoord(by, bx, (m.y/2), (m.x/2), &fy, &fx);
if (xHalf && yHalf) {
unsigned int y;
/* really should be fy+y-1 and fy+y so do (fy-1)+y = fy+y-1 and
(fy-1)+y+1 = fy+y
*/
if (m.y < 0)
--fy;
if (m.x < 0)
--fx;
for (y = 0; y < 8; ++y) {
unsigned int x;
for (x = 0; x < 8; ++x)
block[y][x] += (prev[fy+y][fx+x]+prev[fy+y][fx+x+1]+
prev[fy+y+1][fx+x]+prev[fy+y+1][fx+x+1]+2)>>2;
}
} else if (xHalf) {
unsigned int y;
if (m.x < 0)
--fx;
for (y = 0; y < 8; ++y) {
unsigned int x;
for (x = 0; x < 8; ++x) {
block[y][x] += (prev[fy+y][fx+x]+prev[fy+y][fx+x+1]+1)>>1;
}
}
} else if ( yHalf ) {
unsigned int y;
if (m.y < 0)
--fy;
for (y = 0; y < 8; ++y) {
unsigned int x;
for (x = 0; x < 8; ++x) {
block[y][x] += (prev[fy+y][fx+x]+prev[fy+y+1][fx+x]+1)>>1;
}
}
} else {
unsigned int y;
for (y = 0; y < 8; ++y) {
unsigned int x;
for (x = 0; x < 8; ++x) {
block[y][x] += (int16)prev[fy+y][fx+x];
}
}
}
}
/*===========================================================================*
*
* adds the motion-compensated B-frame block to the given block
*
* RETURNS: block modified
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: motion vectors MUST be valid
*
*===========================================================================*/
void
AddBMotionBlock(Block block,
uint8 ** const prev,
uint8 ** const next,
int const by,
int const bx,
int const mode,
motion const motion) {
unsigned int y;
Block prevBlock, nextBlock;
switch (mode) {
case MOTION_FORWARD:
AddMotionBlock(block, prev, by, bx, motion.fwd);
break;
case MOTION_BACKWARD:
AddMotionBlock(block, next, by, bx, motion.bwd);
break;
default:
ComputeMotionBlock(prev, by, bx, motion.fwd, &prevBlock);
ComputeMotionBlock(next, by, bx, motion.bwd, &nextBlock);
}
for (y = 0; y < 8; ++y) {
unsigned int x;
for (x = 0; x < 8; ++x) {
block[y][x] += (prevBlock[y][x] + nextBlock[y][x] + 1) / 2;
}
}
}
/*===========================================================================*
*
* copies the given block into the appropriate data area
*
* RETURNS: data modified
*
* SIDE EFFECTS: none
*
*===========================================================================*/
void
BlockToData(uint8 ** const data,
Block block,
int const by,
int const bx) {
int x, y;
int fy, fx;
int16 blockItem;
BLOCK_TO_FRAME_COORD(by, bx, fy, fx);
for ( y = 0; y < 8; y++ ) {
for ( x = 0; x < 8; x++ ) {
blockItem = block[y][x];
data[fy+y][fx+x] = TRUNCATE_UINT8(blockItem);
}
}
}
/*===========================================================================*
*
* copies data into appropriate blocks
*
* RETURNS: mf modified
*
* SIDE EFFECTS: none
*
* NOTES: probably shouldn't be in this file
*
*===========================================================================*/
void
BlockifyFrame(MpegFrame * const frameP) {
int dctx, dcty;
int x, y;
int bx, by;
int fy, fx;
int16 *destPtr;
uint8 *srcPtr;
int16 *destPtr2;
uint8 *srcPtr2;
Block *blockPtr;
Block *blockPtr2;
dctx = Fsize_x / DCTSIZE;
dcty = Fsize_y / DCTSIZE;
/*
* copy y data into y_blocks
*/
for (by = 0; by < dcty; by++) {
fy = by*DCTSIZE;
for (bx = 0; bx < dctx; bx++) {
fx = bx*DCTSIZE;
blockPtr = (Block *) &(frameP->y_blocks[by][bx][0][0]);
for (y = 0; y < DCTSIZE; y++) {
destPtr = &((*blockPtr)[y][0]);
srcPtr = &(frameP->orig_y[fy+y][fx]);
for (x = 0; x < DCTSIZE; x++) {
destPtr[x] = srcPtr[x];
}
}
}
}
/*
* copy cr/cb data into cr/cb_blocks
*/
for (by = 0; by < (dcty >> 1); by++) {
fy = by*DCTSIZE;
for (bx = 0; bx < (dctx >> 1); bx++) {
fx = bx*DCTSIZE;
blockPtr = (Block *) &(frameP->cr_blocks[by][bx][0][0]);
blockPtr2 = (Block *) &(frameP->cb_blocks[by][bx][0][0]);
for (y = 0; y < DCTSIZE; y++) {
destPtr = &((*blockPtr)[y][0]);
srcPtr = &(frameP->orig_cr[fy+y][fx]);
destPtr2 = &((*blockPtr2)[y][0]);
srcPtr2 = &(frameP->orig_cb[fy+y][fx]);
for (x = 0; x < DCTSIZE; x++) {
destPtr[x] = srcPtr[x];
destPtr2[x] = srcPtr2[x];
}
}
}
}
}
/*===========================================================================*
* *
* UNUSED PROCEDURES *
* *
* The following procedures are all unused by the encoder *
* *
* They are listed here for your convenience. You might want to use *
* them if you experiment with different search techniques *
* *
*===========================================================================*/
#ifdef UNUSED_PROCEDURES
/* this procedure calculates the subsampled motion block (obviously)
*
* for speed, this procedure is probably not called anywhere (it is
* incorporated directly into LumDiffA, LumDiffB, etc.
*
* but leave it here anyway for clarity
*
* (startY, startX) = (0,0) for A....(0,1) for B...(1,0) for C...(1,1) for D
*
*/
void
ComputeSubSampledMotionLumBlock(MpegFrame * const prevFrame,
int const by,
int const bx,
int const my,
int const mx,
LumBlock const motionBlock,
int const startY,
int const startX) {
uint8 *across;
int32 *macross;
int32 *lastx;
int y;
uint8 **prev;
int fy, fx;
boolean xHalf, yHalf;
xHalf = (ABS(mx) % 2 == 1);
yHalf = (ABS(my) % 2 == 1);
MotionToFrameCoord(by, bx, my/2, mx/2, &fy, &fx);
if ( xHalf ) {
if ( mx < 0 ) {
fx--;
}
if ( yHalf ) {
if ( my < 0 ) {
fy--;
}
prev = prevFrame->halfBoth;
} else {
prev = prevFrame->halfX;
}
} else if ( yHalf ) {
if ( my < 0 ) {
fy--;
}
prev = prevFrame->halfY;
} else {
prev = prevFrame->ref_y;
}
for ( y = startY; y < 16; y += 2 ) {
across = &(prev[fy+y][fx+startX]);
macross = &(motionBlock[y][startX]);
lastx = &(motionBlock[y][16]);
while ( macross < lastx ) {
(*macross) = (*across);
across += 2;
macross += 2;
}
}
/* this is what's really going on in slow motion:
*
* for ( y = startY; y < 16; y += 2 )
* for ( x = startX; x < 16; x += 2 )
* motionBlock[y][x] = prev[fy+y][fx+x];
*
*/
}
/*===========================================================================*
*
* return the MAD of the currentBlock and the motion-compensated block,
* subsampled 4:1 with given starting coordinates (startY, startX)
*
* RETURNS: the MAD
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: motion vector MUST be valid
*
* NOTES: this procedure is never called. Instead, see subsample.c. This
* procedure is provided only for possible use in extensions
*
*===========================================================================*/
int32
LumMotionErrorSubSampled(LumBlock const currentBlock,
MpegFrame * const prevFrame,
int const by,
int const bx,
int const my,
int const mx,
int const startY,
int const startX) {
int32 diff; /* max value of diff is 255*256 = 65280 */
int32 localDiff;
int32 *cacross;
uint8 *macross;
int32 *lastx;
int y;
uint8 **prev;
int fy, fx;
boolean xHalf, yHalf;
xHalf = (ABS(mx) % 2 == 1);
yHalf = (ABS(my) % 2 == 1);
motionToFrameCoord(by, bx, my/2, mx/2, &fy, &fx);
if ( xHalf ) {
if ( mx < 0 ) {
fx--;
}
if ( yHalf ) {
if ( my < 0 ) {
fy--;
}
prev = prevFrame->halfBoth;
} else {
prev = prevFrame->halfX;
}
} else if ( yHalf ) {
if ( my < 0 ) {
fy--;
}
prev = prevFrame->halfY;
} else {
prev = prevFrame->ref_y;
}
diff = 0; /* initial value */
for ( y = startY; y < 16; y += 2 ) {
macross = &(prev[fy+y][fx+startX]);
cacross = &(currentBlock[y][startX]);
lastx = &(currentBlock[y][16]);
while ( cacross < lastx ) {
localDiff = (*cacross)-(*macross);
diff += ABS(localDiff);
macross += 2;
cacross += 2;
}
}
/* this is what's really happening:
*
* ComputeSubSampledMotionLumBlock(prevFrame, by, bx, my, mx,
* lumMotionBlock, startY, startX);
*
* for ( y = startY; y < 16; y += 2 )
* for ( x = startX; x < 16; x += 2 )
* {
* localDiff = currentBlock[y][x] - lumMotionBlock[y][x];
* diff += ABS(localDiff);
* }
*
*/
return (int32)diff;
}
#endif /* UNUSED_PROCEDURES */
/*
* Copyright (c) 1995 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.
*/