home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
DP Tool Club 9
/
CD_ASCQ_09_1193.iso
/
news
/
4441
/
mpegcode
/
src
/
pframe.c
< prev
next >
Wrap
C/C++ Source or Header
|
1993-09-27
|
27KB
|
942 lines
/*===========================================================================*
* pframe.c *
* *
* Procedures concerned with generation of P-frames *
* *
* EXPORTED PROCEDURES: *
* GenPFrame *
* ResetPFrameStats *
* ShowPFrameSummary *
* EstimateSecondsPerPFrame *
* ComputeHalfPixelData *
* SetPQScale *
* GetPQScale *
* *
* NOTE: when motion vectors are passed as arguments, they are passed as *
* twice their value. In other words, a motion vector of (3,4) will *
* be passed as (6,8). This allows half-pixel motion vectors to be *
* passed as integers. This is true throughout the program. *
* *
*===========================================================================*/
/*
* Copyright (c) 1993 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.
*/
/*
* $Header: /n/picasso/users/keving/encode/src/RCS/pframe.c,v 1.5 1993/07/22 22:23:43 keving Exp keving $
* $Log: pframe.c,v $
* Revision 1.5 1993/07/22 22:23:43 keving
* nothing
*
* Revision 1.4 1993/06/30 20:06:09 keving
* nothing
*
* Revision 1.3 1993/06/03 21:08:08 keving
* nothing
*
* Revision 1.2 1993/03/02 23:03:42 keving
* nothing
*
* Revision 1.1 1993/02/19 19:14:12 keving
* nothing
*
*/
/*==============*
* HEADER FILES *
*==============*/
#include <sys/times.h>
#include "all.h"
#include "mtypes.h"
#include "bitio.h"
#include "frames.h"
#include "prototypes.h"
#include "param.h"
#include "mheaders.h"
#include "fsize.h"
#include "postdct.h"
/*==================*
* STATIC VARIABLES *
*==================*/
static int32 zeroDiff;
static int numPIBlocks = 0;
static int numPPBlocks = 0;
static int numPSkipped = 0;
static int numPIBits = 0;
static int numPPBits = 0;
static int numFrames = 0;
static int numFrameBits = 0;
static time_t totalTime = 0;
static int qscaleP;
static float totalSNR = 0.0;
static float totalPSNR = 0.0;
/*===============================*
* INTERNAL PROCEDURE prototypes *
*===============================*/
static boolean ZeroMotionBetter _ANSI_ARGS_((LumBlock currentBlock,
MpegFrame *prev, int by, int bx,
int my, int mx));
static boolean DoIntraCode _ANSI_ARGS_((LumBlock currentBlock,
MpegFrame *prev, int by, int bx,
int motionY, int motionX));
static boolean ZeroMotionSufficient _ANSI_ARGS_((LumBlock currentBlock,
MpegFrame *prev,
int by, int bx));
#ifdef BLEAH
static void ComputeAndPrintPframeMAD _ANSI_ARGS_((LumBlock currentBlock,
MpegFrame *prev,
int by, int bx,
int my, int mx,
int numBlock));
#endif
/*=====================*
* EXPORTED PROCEDURES *
*=====================*/
/*===========================================================================*
*
* GenPFrame
*
* generate a P-frame from previous frame, adding the result to the
* given bit bucket
*
* RETURNS: frame appended to bb
*
* SIDE EFFECTS: none
*
*===========================================================================*/
void
GenPFrame(bb, current, prev)
BitBucket *bb;
MpegFrame *current;
MpegFrame *prev;
{
FlatBlock fba[6], fb[6];
Block dec[6];
int32 y_dc_pred, cr_dc_pred, cb_dc_pred;
int x, y;
int motionX = 0, motionY = 0;
int oldMotionX = 0, oldMotionY = 0;
int offsetX, offsetY;
int tempX, tempY;
int motionXrem, motionXquot;
int motionYrem, motionYquot;
int pattern;
int mbAddrInc = 1;
boolean useMotion;
int numIBlocks = 0;
int numPBlocks = 0;
int numSkipped = 0;
int numIBits = 0;
int numPBits = 0;
int totalBits;
int totalFrameBits;
time_t startTime, endTime;
int numBlocks = -1;
int lastBlockX, lastBlockY;
int lastX, lastY;
int fy, fx;
LumBlock currentBlock;
register int ix, iy;
int frameBlocks;
int slicePos;
register int index;
float snr[3], psnr[3];
numFrames++;
totalFrameBits = bb->cumulativeBits;
time(&startTime);
DBG_PRINT(("Generating pframe\n"));
Mhead_GenPictureHeader(bb, P_FRAME, current->id, fCode);
DBG_PRINT(("Slice Header\n"));
Mhead_GenSliceHeader(bb, 1, qscaleP, NULL, 0);
if ( referenceFrame == DECODED_FRAME ) {
Frame_AllocDecoded(current, TRUE);
} else if ( printSNR ) {
Frame_AllocDecoded(current, FALSE);
}
/* don't do dct on blocks yet */
Frame_AllocBlocks(current);
BlockifyFrame(current);
/* for I-blocks */
y_dc_pred = cr_dc_pred = cb_dc_pred = 128;
totalBits = bb->cumulativeBits;
if ( (! pixelFullSearch) && (! prev->halfComputed) ) {
ComputeHalfPixelData(prev);
}
lastBlockX = Fsize_x/8;
lastBlockY = Fsize_y/8;
lastX = lastBlockX-2;
lastY = lastBlockY-2;
frameBlocks = 0;
for (y = 0; y < lastBlockY; y += 2) {
for (x = 0; x < lastBlockX; x += 2) {
slicePos = (frameBlocks % blocksPerSlice);
if ( (slicePos == 0) && (frameBlocks != 0) ) {
Mhead_GenSliceEnder(bb);
Mhead_GenSliceHeader(bb, 1+(y/2), qscaleP, NULL, 0);
/* reset everything */
oldMotionX = 0; oldMotionY = 0;
y_dc_pred = cr_dc_pred = cb_dc_pred = 128;
mbAddrInc = 1+(x/2);
}
numBlocks++;
frameBlocks++;
/* compute currentBlock */
BLOCK_TO_FRAME_COORD(y, x, fy, fx);
for ( iy = 0; iy < 16; iy++ ) {
for ( ix = 0; ix < 16; ix++ ) {
currentBlock[iy][ix] = (int16)current->orig_y[fy+iy][fx+ix];
}
}
/* see if we should use motion vectors, and if so, what those
* vectors should be
*/
if ( ZeroMotionSufficient(currentBlock, prev, y, x) ) {
motionX = 0;
motionY = 0;
pattern = 63;
useMotion = TRUE;
} else {
useMotion = PMotionSearch(currentBlock, prev, y, x,
&motionY, &motionX);
pattern = 63;
if ( useMotion ) {
if ( ZeroMotionBetter(currentBlock, prev, y, x, motionY,
motionX) ) {
motionX = 0;
motionY = 0;
pattern = 63;
}
useMotion = (! DoIntraCode(currentBlock, prev, y, x,
motionY, motionX));
}
}
if ( ! useMotion ) {
/* output I-block inside a P-frame */
numIBlocks++;
/* calculate forward dct's */
mp_fwd_dct_block(current->y_blocks[y][x]);
mp_fwd_dct_block(current->y_blocks[y][x+1]);
mp_fwd_dct_block(current->y_blocks[y+1][x]);
mp_fwd_dct_block(current->y_blocks[y+1][x+1]);
mp_fwd_dct_block(current->cb_blocks[y >> 1][x >> 1]);
mp_fwd_dct_block(current->cr_blocks[y >> 1][x >> 1]);
GEN_I_BLOCK(P_FRAME, current, bb, mbAddrInc, qscaleP);
mbAddrInc = 1;
numIBits += (bb->cumulativeBits-totalBits);
totalBits = bb->cumulativeBits;
/* reset because intra-coded */
oldMotionX = 0; oldMotionY = 0;
if ( decodeRefFrames ) {
/* need to decode block we just encoded */
Mpost_UnQuantZigBlock(fb[0], dec[0], qscaleP, TRUE);
Mpost_UnQuantZigBlock(fb[1], dec[1], qscaleP, TRUE);
Mpost_UnQuantZigBlock(fb[2], dec[2], qscaleP, TRUE);
Mpost_UnQuantZigBlock(fb[3], dec[3], qscaleP, TRUE);
Mpost_UnQuantZigBlock(fb[4], dec[4], qscaleP, TRUE);
Mpost_UnQuantZigBlock(fb[5], dec[5], qscaleP, TRUE);
/* now, reverse the DCT transform */
for ( index = 0; index < 6; index++ ) {
j_rev_dct((int16 *)dec[index]);
}
/* now, unblockify */
BlockToData(current->decoded_y, dec[0], y, x);
BlockToData(current->decoded_y, dec[1], y, x+1);
BlockToData(current->decoded_y, dec[2], y+1, x);
BlockToData(current->decoded_y, dec[3], y+1, x+1);
BlockToData(current->decoded_cb, dec[4], y>>1, x>>1);
BlockToData(current->decoded_cr, dec[5], y>>1, x>>1);
}
} else {
/* USE MOTION VECTORS */
numPBlocks++;
/* reset because non-intra-coded */
y_dc_pred = cr_dc_pred = cb_dc_pred = 128;
#ifdef BLEAH
ComputeAndPrintPframeMAD(currentBlock, prev, y, x, motionY, motionX, numBlocks);
#endif
ComputeDiffDCTs(current, prev, y, x, motionY, motionX,
pattern);
if ( pixelFullSearch ) { /* should be even */
motionY /= 2;
motionX /= 2;
}
/* transform the motion vector into the appropriate values */
offsetX = motionX - oldMotionX;
offsetY = motionY - oldMotionY;
ENCODE_MOTION_VECTOR(offsetX, offsetY, motionXquot,
motionYquot, motionXrem, motionYrem,
FORW_F);
#ifdef BLEAH
if ( (motionX != 0) || (motionY != 0) ) {
fprintf(stdout, "FRAME (y, x) %d, %d (block %d)\n", y, x, numBlocks);
fprintf(stdout, "motionX = %d, motionY = %d\n", motionX, motionY);
fprintf(stdout, " mxq, mxr = %d, %d myq, myr = %d, %d\n",
motionXquot, motionXrem, motionYquot, motionYrem);
}
#endif
oldMotionX = motionX;
oldMotionY = motionY;
if ( pixelFullSearch ) {/* reset for use with PMotionSearch */
motionY *= 2;
motionX *= 2;
}
/* create flat blocks and update pattern if necessary */
if ( (pattern & 0x20) &&
(! Mpost_QuantZigBlock(current->y_blocks[y][x], fba[0],
qscaleP, FALSE)) ) {
pattern ^= 0x20;
}
if ( (pattern & 0x10) &&
(! Mpost_QuantZigBlock(current->y_blocks[y][x+1], fba[1],
qscaleP, FALSE)) ) {
pattern ^= 0x10;
}
if ( (pattern & 0x8) &&
(! Mpost_QuantZigBlock(current->y_blocks[y+1][x], fba[2],
qscaleP, FALSE)) ) {
pattern ^= 0x8;
}
if ( (pattern & 0x4) &&
(! Mpost_QuantZigBlock(current->y_blocks[y+1][x+1], fba[3],
qscaleP, FALSE)) ) {
pattern ^= 0x4;
}
if ( (pattern & 0x2) &&
(! Mpost_QuantZigBlock(current->cb_blocks[y >> 1][x >> 1], fba[4],
qscaleP, FALSE)) ) {
pattern ^= 0x2;
}
if ( (pattern & 0x1) &&
(! Mpost_QuantZigBlock(current->cr_blocks[y >> 1][x >> 1], fba[5],
qscaleP, FALSE)) ) {
pattern ^= 0x1;
}
if ( decodeRefFrames ) {
if ( pattern & 0x20 ) {
Mpost_UnQuantZigBlock(fba[0], dec[0], qscaleP, FALSE);
} else {
bzero((char *)dec[0], sizeof(Block));
}
if ( pattern & 0x10 ) {
Mpost_UnQuantZigBlock(fba[1], dec[1], qscaleP, FALSE);
} else {
bzero((char *)dec[1], sizeof(Block));
}
if ( pattern & 0x8 ) {
Mpost_UnQuantZigBlock(fba[2], dec[2], qscaleP, FALSE);
} else {
bzero((char *)dec[2], sizeof(Block));
}
if ( pattern & 0x4 ) {
Mpost_UnQuantZigBlock(fba[3], dec[3], qscaleP, FALSE);
} else {
bzero((char *)dec[3], sizeof(Block));
}
if ( pattern & 0x2 ) {
Mpost_UnQuantZigBlock(fba[4], dec[4], qscaleP, FALSE);
} else {
bzero((char *)dec[4], sizeof(Block));
}
if ( pattern & 0x1 ) {
Mpost_UnQuantZigBlock(fba[5], dec[5], qscaleP, FALSE);
} else {
bzero((char *)dec[5], sizeof(Block));
}
/* now, reverse the DCT transform */
for ( index = 0; index < 6; index++ ) {
if ( GET_ITH_BIT(pattern, 5-index) ) {
j_rev_dct((int16 *)dec[index]);
}
}
/* now add the motion block */
AddMotionBlock(dec[0], prev->decoded_y, y, x, motionY, motionX);
AddMotionBlock(dec[1], prev->decoded_y, y, x+1, motionY, motionX);
AddMotionBlock(dec[2], prev->decoded_y, y+1, x, motionY, motionX);
AddMotionBlock(dec[3], prev->decoded_y, y+1, x+1, motionY, motionX);
AddMotionBlock(dec[4], prev->decoded_cb, y>>1, x>>1, motionY/2, motionX/2);
AddMotionBlock(dec[5], prev->decoded_cr, y>>1, x>>1, motionY/2, motionX/2);
/* now, unblockify */
BlockToData(current->decoded_y, dec[0], y, x);
BlockToData(current->decoded_y, dec[1], y, x+1);
BlockToData(current->decoded_y, dec[2], y+1, x);
BlockToData(current->decoded_y, dec[3], y+1, x+1);
BlockToData(current->decoded_cb, dec[4], y>>1, x>>1);
BlockToData(current->decoded_cr, dec[5], y>>1, x>>1);
}
if ( (motionX == 0) && (motionY == 0) ) {
if ( pattern == 0 ) {
/* don't skip if last frame of slice */
if ( ((y < lastY) || (x < lastX)) &&
(slicePos+1 != blocksPerSlice) ) {
mbAddrInc++; /* skipped macroblock */
numSkipped++;
numPBlocks--;
} else { /* last macroblock */
Mhead_GenMBHeader(bb, 2 /* pict_code_type */, mbAddrInc /* addr_incr */,
0 /* mb_quant */, 0 /* q_scale */,
fCode /* forw_f_code */, 1 /* back_f_code */,
0 /* horiz_forw_r */, 0 /* vert_forw_r */,
0 /* horiz_back_r */, 0 /* vert_back_r */,
0 /* motion_forw */, 0 /* m_horiz_forw */,
0 /* m_vert_forw */, 0 /* motion_back */,
0 /* m_horiz_back */, 0 /* m_vert_back */,
1 /* mb_pattern */, 0 /* mb_intra */);
mbAddrInc = 1;
Bitio_Write(bb, 0x2, 2); /* first coeff */
Bitio_Write(bb, 0x2, 2); /* end of block */
}
} else {
DBG_PRINT(("MB Header(%d,%d)\n", x, y));
Mhead_GenMBHeader(bb, 2 /* pict_code_type */, mbAddrInc /* addr_incr */,
0 /* mb_quant */, 0 /* q_scale */,
fCode /* forw_f_code */, 1 /* back_f_code */,
0 /* horiz_forw_r */, 0 /* vert_forw_r */,
0 /* horiz_back_r */, 0 /* vert_back_r */,
0 /* motion_forw */, 0 /* m_horiz_forw */,
0 /* m_vert_forw */, 0 /* motion_back */,
0 /* m_horiz_back */, 0 /* m_vert_back */,
pattern /* mb_pattern */, 0 /* mb_intra */);
mbAddrInc = 1;
}
} else {
DBG_PRINT(("MB Header(%d,%d)\n", x, y));
Mhead_GenMBHeader(bb, 2 /* pict_code_type */, mbAddrInc /* addr_incr */,
0 /* mb_quant */, 0 /* q_scale */,
fCode /* forw_f_code */, 1 /* back_f_code */,
motionXrem /* horiz_forw_r */, motionYrem /* vert_forw_r */,
0 /* horiz_back_r */, 0 /* vert_back_r */,
1 /* motion_forw */, motionXquot /* m_horiz_forw */,
motionYquot /* m_vert_forw */, 0 /* motion_back */,
0 /* m_horiz_back */, 0 /* m_vert_back */,
pattern /* mb_pattern */, 0 /* mb_intra */);
mbAddrInc = 1;
}
/* now output the difference */
for ( tempX = 0; tempX < 6; tempX++ ) {
if ( GET_ITH_BIT(pattern, 5-tempX) ) {
Mpost_RLEHuffPBlock(fba[tempX], bb);
}
}
numPBits += (bb->cumulativeBits-totalBits);
totalBits = bb->cumulativeBits;
}
}
}
if ( printSNR ) {
ComputeSNR(current->orig_y, current->decoded_y, Fsize_y, Fsize_x,
&snr[0], &psnr[0]);
ComputeSNR(current->orig_cb, current->decoded_cb, Fsize_y/2, Fsize_x/2,
&snr[1], &psnr[1]);
ComputeSNR(current->orig_cr, current->decoded_cr, Fsize_y/2, Fsize_x/2,
&snr[2], &psnr[2]);
totalSNR += snr[0];
totalPSNR += psnr[0];
}
Mhead_GenSliceEnder(bb);
/* UPDATE STATISTICS */
time(&endTime);
totalTime += (endTime-startTime);
if ( (! childProcess) && frameSummary ) {
fprintf(stdout, "FRAME %d (P): I BLOCKS: %d; P BLOCKS: %d SKIPPED: %d (%ld seconds)\n",
current->id, numIBlocks, numPBlocks, numSkipped, (long)(totalTime));
if ( printSNR ) {
fprintf(stdout, "FRAME %d: SNR: %.1f\t%.1f\t%.1f\tPSNR: %.1f\t%.1f\t%.1f\n",
current->id, snr[0], snr[1], snr[2],
psnr[0], psnr[1], psnr[2]);
}
}
numFrameBits += (bb->cumulativeBits-totalFrameBits);
numPIBlocks += numIBlocks;
numPPBlocks += numPBlocks;
numPSkipped += numSkipped;
numPIBits += numIBits;
numPPBits += numPBits;
#ifdef BLEAH
if ( decodeRefFrames ) {
FILE *fpointer;
char fileName[256];
int width, height;
/* output the decoded frame */
width = Fsize_x;
height = Fsize_y;
sprintf(fileName, "/tmp/decoded%d.yuv", current->id);
fprintf(stdout, "outputting to %s\n", fileName);
fpointer = fopen(fileName, "wb");
for ( y = 0; y < height; y++ ) {
fwrite(current->decoded_y[y], 1, width, fpointer);
}
for (y = 0; y < height / 2; y++) { /* U */
fwrite(current->decoded_cb[y], 1, width / 2, fpointer);
}
for (y = 0; y < height / 2; y++) { /* V */
fwrite(current->decoded_cr[y], 1, width / 2, fpointer);
}
fclose(fpointer);
}
#endif
}
/*===========================================================================*
*
* ResetPFrameStats
*
* reset the P-frame statistics
*
* RETURNS: nothing
*
* SIDE EFFECTS: none
*
*===========================================================================*/
void
ResetPFrameStats()
{
numPIBlocks = 0;
numPPBlocks = 0;
numPSkipped = 0;
numPIBits = 0;
numPPBits = 0;
numFrames = 0;
numFrameBits = 0;
totalTime = 0;
}
/*===========================================================================*
*
* SetPQScale
*
* set the P-frame Q-scale
*
* RETURNS: nothing
*
* SIDE EFFECTS: qscaleP
*
*===========================================================================*/
void
SetPQScale(qP)
int qP;
{
qscaleP = qP;
}
/*===========================================================================*
*
* GetPQScale
*
* return the P-frame Q-scale
*
* RETURNS: the P-frame Q-scale
*
* SIDE EFFECTS: none
*
*===========================================================================*/
int
GetPQScale()
{
return qscaleP;
}
/*===========================================================================*
*
* ShowPFrameSummary
*
* print a summary of information on encoding P-frames
*
* RETURNS: nothing
*
* SIDE EFFECTS: none
*
*===========================================================================*/
void
ShowPFrameSummary(inputFrameBits, totalBits, fpointer)
int inputFrameBits;
int32 totalBits;
FILE *fpointer;
{
if ( numFrames == 0 ) {
return;
}
fprintf(fpointer, "-------------------------\n");
fprintf(fpointer, "*****P FRAME SUMMARY*****\n");
fprintf(fpointer, "-------------------------\n");
if ( numPIBlocks != 0 ) {
fprintf(fpointer, " I Blocks: %5d (%6d bits) (%5d bpb)\n",
numPIBlocks, numPIBits, numPIBits/numPIBlocks);
} else {
fprintf(fpointer, " I Blocks: %5d\n", 0);
}
if ( numPPBlocks != 0 ) {
fprintf(fpointer, " P Blocks: %5d (%6d bits) (%5d bpb)\n",
numPPBlocks, numPPBits, numPPBits/numPPBlocks);
} else {
fprintf(fpointer, " P Blocks: %5d\n", 0);
}
fprintf(fpointer, " Skipped: %5d\n", numPSkipped);
fprintf(fpointer, " Frames: %5d (%6d bits) (%5d bpf) (%2.1f%% of total)\n",
numFrames, numFrameBits, numFrameBits/numFrames,
100.0*(float)numFrameBits/(float)totalBits);
fprintf(fpointer, " Compression: %3d:1\n",
numFrames*inputFrameBits/numFrameBits);
if ( printSNR )
fprintf(fpointer, " Avg Y SNR/PSNR: %.1f %.1f\n",
totalSNR/(float)numFrames, totalPSNR/(float)numFrames);
fprintf(fpointer, " Seconds: %9ld (%9ld spf) (%9ld bps)\n",
(long)(totalTime), (long)(totalTime/(numFrames)),
(long)((float)numFrames*(float)inputFrameBits/(float)totalTime));
}
/*===========================================================================*
*
* EstimateSecondsPerPFrame
*
* compute an estimate of the number of seconds required per P-frame
*
* RETURNS: the estimate, in seconds
*
* SIDE EFFECTS: none
*
*===========================================================================*/
float
EstimateSecondsPerPFrame()
{
if ( numFrames == 0 ) {
return 10.0;
} else {
return (float)totalTime/((float)numFrames);
}
}
/*===========================================================================*
*
* ComputeHalfPixelData
*
* compute all half-pixel data required for half-pixel motion vector
* search (luminance only)
*
* RETURNS: frame->halfX, ->halfY, and ->halfBoth modified
*
* SIDE EFFECTS: none
*
*===========================================================================*/
void
ComputeHalfPixelData(frame)
MpegFrame *frame;
{
register int x, y;
/* we add 1 before dividing by 2 because .5 is supposed to be rounded up
* (see MPEG-1, page D-31)
*/
if ( frame->halfX == NULL ) { /* need to allocate memory */
Frame_AllocHalf(frame);
}
/* compute halfX */
for ( y = 0; y < Fsize_y; y++ ) {
for ( x = 0; x < Fsize_x-1; x++ ) {
frame->halfX[y][x] = (frame->ref_y[y][x]+
frame->ref_y[y][x+1]+1)/2;
}
}
/* compute halfY */
for ( y = 0; y < Fsize_y-1; y++ ) {
for ( x = 0; x < Fsize_x; x++ ) {
frame->halfY[y][x] = (frame->ref_y[y][x]+
frame->ref_y[y+1][x]+1)/2;
}
}
/* compute halfBoth */
for ( y = 0; y < Fsize_y-1; y++ ) {
for ( x = 0; x < Fsize_x-1; x++ ) {
frame->halfBoth[y][x] = (frame->ref_y[y][x]+
frame->ref_y[y][x+1]+
frame->ref_y[y+1][x]+
frame->ref_y[y+1][x+1]+2)/4;
}
}
frame->halfComputed = TRUE;
}
/*=====================*
* INTERNAL PROCEDURES *
*=====================*/
/*===========================================================================*
*
* USER-MODIFIABLE
*
* ZeroMotionBetter
*
* decide if (0,0) motion is better than the given motion vector
*
* RETURNS: TRUE if (0,0) is better, FALSE if (my,mx) is better
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: The relevant block in 'current' is valid (it has not
* been dct'd). 'zeroDiff' has already been computed
* as the LumMotionError() with (0,0) motion
*
* NOTES: This procedure follows the algorithm described on
* page D-48 of the MPEG-1 specification
*
*===========================================================================*/
static boolean
ZeroMotionBetter(currentBlock, prev, by, bx, my, mx)
LumBlock currentBlock;
MpegFrame *prev;
int by;
int bx;
int my;
int mx;
{
int bestDiff;
bestDiff = LumMotionError(currentBlock, prev, by, bx, my, mx, 0x7fffffff);
if ( zeroDiff < 256*3 ) {
if ( 2*bestDiff >= zeroDiff ) {
return TRUE;
}
} else {
if ( 11*bestDiff >= 10*zeroDiff ) {
return TRUE;
}
}
return FALSE;
}
/*===========================================================================*
*
* USER-MODIFIABLE
*
* DoIntraCode
*
* decide if intra coding is necessary
*
* RETURNS: TRUE if intra-block coding is better; FALSE if not
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: The relevant block in 'current' is valid (it has not
* been dct'd).
*
* NOTES: This procedure follows the algorithm described on
* page D-49 of the MPEG-1 specification
*
*===========================================================================*/
static boolean
DoIntraCode(currentBlock, prev, by, bx, motionY, motionX)
LumBlock currentBlock;
MpegFrame *prev;
int by;
int bx;
int motionY;
int motionX;
{
int x, y;
int32 sum = 0, vard = 0, varc = 0, dif;
int32 currPixel, prevPixel;
LumBlock motionBlock;
int fy, fx;
ComputeMotionLumBlock(prev, by, bx, motionY, motionX, motionBlock);
MOTION_TO_FRAME_COORD(by, bx, 0, 0, fy, fx);
for ( y = 0; y < 16; y++ ) {
for ( x = 0; x < 16; x++ ) {
currPixel = currentBlock[y][x];
prevPixel = motionBlock[y][x];
sum += currPixel;
varc += currPixel*currPixel;
dif = currPixel - prevPixel;
vard += dif*dif;
}
}
vard /= 256; /* assumes mean is close to zero */
varc = varc/256 - (sum/256)*(sum/256);
if ( vard <= 64 ) {
return FALSE;
} else if ( vard < varc ) {
return FALSE;
} else {
return TRUE;
}
}
/*===========================================================================*
*
* USER-MODIFIABLE
*
* ZeroMotionSufficient
*
* decide if zero motion is sufficient without DCT correction
*
* RETURNS: TRUE no DCT required; FALSE otherwise
*
* SIDE EFFECTS: none
*
* PRECONDITIONS: The relevant block in 'current' is raw YCC data
*
*===========================================================================*/
static boolean
ZeroMotionSufficient(currentBlock, prev, by, bx)
LumBlock currentBlock;
MpegFrame *prev;
int by;
int bx;
{
LumBlock motionBlock;
register int fy, fx;
register int x, y;
fy = by*DCTSIZE;
fx = bx*DCTSIZE;
for ( y = 0; y < 16; y++ ) {
for ( x = 0; x < 16; x++ ) {
motionBlock[y][x] = prev->ref_y[fy+y][fx+x];
}
}
zeroDiff = LumBlockMAD(currentBlock, motionBlock, 0x7fffffff);
return (zeroDiff <= 256);
}
#ifdef UNUSED_PROCEDURES
static void
ComputeAndPrintPframeMAD(currentBlock, prev, by, bx, my, mbx, numBlock)
LumBlock currentBlock;
MpegFrame *prev;
int by;
int bx;
int my;
int mx;
int numBlock;
{
LumBlock lumMotionBlock;
int32 mad;
ComputeMotionLumBlock(prev, by, bx, my, mx, lumMotionBlock);
mad = LumBlockMAD(currentBlock, lumMotionBlock, 0x7fffffff);
fprintf(stdout, "%d %d\n", numBlock, mad);
}
#endif