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/* transfrm.c, forward / inverse transformation */
/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
/*
* Disclaimer of Warranty
*
* These software programs are available to the user without any license fee or
* royalty on an "as is" basis. The MPEG Software Simulation Group disclaims
* any and all warranties, whether express, implied, or statuary, including any
* implied warranties or merchantability or of fitness for a particular
* purpose. In no event shall the copyright-holder be liable for any
* incidental, punitive, or consequential damages of any kind whatsoever
* arising from the use of these programs.
*
* This disclaimer of warranty extends to the user of these programs and user's
* customers, employees, agents, transferees, successors, and assigns.
*
* The MPEG Software Simulation Group does not represent or warrant that the
* programs furnished hereunder are free of infringement of any third-party
* patents.
*
* Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
* are subject to royalty fees to patent holders. Many of these patents are
* general enough such that they are unavoidable regardless of implementation
* design.
*
*/
#include <stdio.h>
#include <math.h>
#include "mpeg2enc_config.h"
#include "mpeg2enc_global.h"
/* private prototypes*/
static void add_pred _ANSI_ARGS_((unsigned char *pred, unsigned char *cur,
int lx, short *blk,struct MPEG2_structure *mpeg2_struct));
static void sub_pred _ANSI_ARGS_((unsigned char *pred, unsigned char *cur,
int lx, short *blk));
/* subtract prediction and transform prediction error */
void MPEG2_transform( unsigned char *pred[], unsigned char *cur[],
struct mbinfo *mbi,
short blocks[][64],
struct MPEG2_structure *mpeg2_struct)
{
int i, j, i1, j1, k, n, cc, offs, lx;
k = 0;
for (j=0; j<mpeg2_struct->height2; j+=16)
for (i=0; i<mpeg2_struct->width; i+=16)
{
for (n=0; n<mpeg2_struct->block_count; n++)
{
cc = (n<4) ? 0 : (n&1)+1; /* color component index */
if (cc==0)
{
/* luminance */
if ((mpeg2_struct->pict_struct==FRAME_PICTURE) && mbi[k].dct_type)
{
/* field DCT */
offs = i + ((n&1)<<3) + mpeg2_struct->width*(j+((n&2)>>1));
lx = mpeg2_struct->width<<1;
}
else
{
/* frame DCT */
offs = i + ((n&1)<<3) + mpeg2_struct->width2*(j+((n&2)<<2));
lx = mpeg2_struct->width2;
}
if (mpeg2_struct->pict_struct==BOTTOM_FIELD)
offs += mpeg2_struct->width;
}
else
{
/* chrominance */
/* scale coordinates */
i1 = (mpeg2_struct->chroma_format==CHROMA444) ? i : i>>1;
j1 = (mpeg2_struct->chroma_format!=CHROMA420) ? j : j>>1;
if ((mpeg2_struct->pict_struct==FRAME_PICTURE) && mbi[k].dct_type
&& (mpeg2_struct->chroma_format!=CHROMA420))
{
/* field DCT */
offs = i1 + (n&8) + mpeg2_struct->chrom_width*(j1+((n&2)>>1));
lx = mpeg2_struct->chrom_width<<1;
}
else
{
/* frame DCT */
offs = i1 + (n&8) + mpeg2_struct->chrom_width2*(j1+((n&2)<<2));
lx = mpeg2_struct->chrom_width2;
}
if (mpeg2_struct->pict_struct==BOTTOM_FIELD)
offs += mpeg2_struct->chrom_width;
}
sub_pred(pred[cc]+offs,cur[cc]+offs,lx,blocks[k*mpeg2_struct->block_count+n]);
MPEG2_fdct(blocks[k*mpeg2_struct->block_count+n]);
}
k++;
}
}
/* inverse transform prediction error and add prediction */
void MPEG2_itransform( unsigned char *pred[], unsigned char *cur[],
struct mbinfo *mbi,
short blocks[][64],
struct MPEG2_structure *mpeg2_struct)
{
int i, j, i1, j1, k, n, cc, offs, lx;
k = 0;
for (j=0; j<mpeg2_struct->height2; j+=16)
for (i=0; i<mpeg2_struct->width; i+=16)
{
for (n=0; n<mpeg2_struct->block_count; n++)
{
cc = (n<4) ? 0 : (n&1)+1; /* color component index */
if (cc==0)
{
/* luminance */
if ((mpeg2_struct->pict_struct==FRAME_PICTURE) && mbi[k].dct_type)
{
/* field DCT */
offs = i + ((n&1)<<3) + mpeg2_struct->width*(j+((n&2)>>1));
lx = mpeg2_struct->width<<1;
}
else
{
/* frame DCT */
offs = i + ((n&1)<<3) + mpeg2_struct->width2*(j+((n&2)<<2));
lx = mpeg2_struct->width2;
}
if (mpeg2_struct->pict_struct==BOTTOM_FIELD)
offs += mpeg2_struct->width;
}
else
{
/* chrominance */
/* scale coordinates */
i1 = (mpeg2_struct->chroma_format==CHROMA444) ? i : i>>1;
j1 = (mpeg2_struct->chroma_format!=CHROMA420) ? j : j>>1;
if ((mpeg2_struct->pict_struct==FRAME_PICTURE) && mbi[k].dct_type
&& (mpeg2_struct->chroma_format!=CHROMA420))
{
/* field DCT */
offs = i1 + (n&8) + mpeg2_struct->chrom_width*(j1+((n&2)>>1));
lx = mpeg2_struct->chrom_width<<1;
}
else
{
/* frame DCT */
offs = i1 + (n&8) + mpeg2_struct->chrom_width2*(j1+((n&2)<<2));
lx = mpeg2_struct->chrom_width2;
}
if (mpeg2_struct->pict_struct==BOTTOM_FIELD)
offs += mpeg2_struct->chrom_width;
}
MPEG2_idct(blocks[k*mpeg2_struct->block_count+n]);
add_pred(pred[cc]+offs,cur[cc]+offs,lx,blocks[k*mpeg2_struct->block_count+n],mpeg2_struct);
}
k++;
}
}
/* add prediction and prediction error, saturate to 0...255 */
static void add_pred( unsigned char *pred, unsigned char *cur,
int lx,
short *blk,
struct MPEG2_structure *mpeg2_struct)
{
int i, j;
for (j=0; j<8; j++)
{
for (i=0; i<8; i++)
cur[i] = mpeg2_struct->clp[blk[i] + pred[i]];
blk+= 8;
cur+= lx;
pred+= lx;
}
}
/* subtract prediction from block data */
static void sub_pred(pred,cur,lx,blk)
unsigned char *pred, *cur;
int lx;
short *blk;
{
int i, j;
for (j=0; j<8; j++)
{
for (i=0; i<8; i++)
blk[i] = cur[i] - pred[i];
blk+= 8;
cur+= lx;
pred+= lx;
}
}
/*
* select between frame and field DCT
*
* preliminary version: based on inter-field correlation
*/
void MPEG2_dct_type_estimation( unsigned char *pred, unsigned char *cur,
struct mbinfo *mbi,struct MPEG2_structure *mpeg2_struct)
{
short blk0[128], blk1[128];
int i, j, i0, j0, k, offs, s0, s1, sq0, sq1, s01;
double d, r;
k = 0;
for (j0=0; j0<mpeg2_struct->height2; j0+=16)
for (i0=0; i0<mpeg2_struct->width; i0+=16)
{
if (mpeg2_struct->frame_pred_dct || mpeg2_struct->pict_struct!=FRAME_PICTURE)
mbi[k].dct_type = 0;
else
{
/* interlaced frame picture */
/*
* calculate prediction error (cur-pred) for top (blk0)
* and bottom field (blk1)
*/
for (j=0; j<8; j++)
{
offs = mpeg2_struct->width*((j<<1)+j0) + i0;
for (i=0; i<16; i++)
{
blk0[16*j+i] = cur[offs] - pred[offs];
blk1[16*j+i] = cur[offs+mpeg2_struct->width] - pred[offs+mpeg2_struct->width];
offs++;
}
}
/* correlate fields */
s0=s1=sq0=sq1=s01=0;
for (i=0; i<128; i++)
{
s0+= blk0[i];
sq0+= blk0[i]*blk0[i];
s1+= blk1[i];
sq1+= blk1[i]*blk1[i];
s01+= blk0[i]*blk1[i];
}
d = (sq0-(s0*s0)/128.0)*(sq1-(s1*s1)/128.0);
if (d>0.0)
{
r = (s01-(s0*s1)/128.0)/sqrt(d);
if (r>0.5)
mbi[k].dct_type = 0; /* frame DCT */
else
mbi[k].dct_type = 1; /* field DCT */
}
else
mbi[k].dct_type = 1; /* field DCT */
}
k++;
}
}
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