WebSVN - shark - Rev 2 - /shark/branches/pj/ports/mpeg/hybriderr.c

/*
* hybriderr.c --
*
* Procedures dealing with hybrid2 dithering, which is hybrid
* dithering with error propagation among pixels.
*
*/

/*
* 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.
*/

/* This file contains C code to implement an ordered dither in the
luminance channel and F-S error diffusion on chrominance.
*/

#include "video.h"
#include "proto.h"
#include "dither.h"

#define DITH_SIZE 16

/* Structures used for hybrid dither with errors propogated. */

static unsigned char *l_darrays[DITH_SIZE];
static unsigned char *l_darrays0, *l_darrays1, *l_darrays2, *l_darrays3;
static unsigned char *l_darrays4, *l_darrays5, *l_darrays6, *l_darrays7;
static unsigned char *l_darrays8, *l_darrays9, *l_darrays10, *l_darrays11;
static unsigned char *l_darrays12, *l_darrays13, *l_darrays14, *l_darrays15;
static unsigned char cr_fsarray[256*256][4];
static unsigned char cb_fsarray[256*256][4];
static unsigned short c_fserr[256*256][2];

/*
*--------------------------------------------------------------
*
* InitHybridErrorDither--
*
* Initializes structures used for hybrid dither algorithm
* with errors propogated on Cr and Cb.
*
* Results:
* None.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/

void
InitHybridErrorDither()
{
int i, j, k, err_range, threshval;
unsigned char *lmark;

for (i=0; i<DITH_SIZE; i++) {
lmark = l_darrays[i] = (unsigned char *) malloc(256);

for (j=0; j<lum_values[0]; j++) {
*lmark++ = 0;
}

for (j=0; j<(LUM_RANGE-1); j++) {
err_range = lum_values[j+1] - lum_values[j];
threshval = ((i * err_range) / DITH_SIZE)+lum_values[j];

for (k=lum_values[j]; k<lum_values[j+1]; k++) {
if (k > threshval) *lmark++ = ((j+1) * (CR_RANGE * CB_RANGE));
else *lmark++ = (j * (CR_RANGE * CB_RANGE));
}
}

for (j=lum_values[LUM_RANGE-1]; j <256; j++) {
*lmark++ = (LUM_RANGE-1)*(CR_RANGE * CB_RANGE);
}
}
l_darrays0 = l_darrays[0]; l_darrays8 = l_darrays[8];
l_darrays1 = l_darrays[1]; l_darrays9 = l_darrays[9];
l_darrays2 = l_darrays[2]; l_darrays10 = l_darrays[10];
l_darrays3 = l_darrays[3]; l_darrays11 = l_darrays[11];
l_darrays4 = l_darrays[4]; l_darrays12 = l_darrays[12];
l_darrays5 = l_darrays[5]; l_darrays13 = l_darrays[13];
l_darrays6 = l_darrays[6]; l_darrays14 = l_darrays[14];
l_darrays7 = l_darrays[7]; l_darrays15 = l_darrays[15];
{
int cr1, cr2, cr3, cr4, err1, err2;
int cb1, cb2, cb3, cb4, val, nval;
int outerr1, outerr2, outerr3, outerr4;
int inerr1, inerr2, inerr3, inerr4;
unsigned short oe1, oe2, oe3, oe4;

for (j=0; j<65536; j+= 256) {

inerr1 = (((j & 0xc000) >> 14)*8) - 12;
inerr2 = (((j & 0x3000) >> 12)*8) - 12;
inerr3 = (((j & 0x0c00) >> 10)*8) - 12;
inerr4 = (((j & 0x0300) >> 8) *8) - 12;

for (i=0; i<256; i++) {
val = i;

nval = val+inerr1+inerr3;
if (nval < 0) nval = 0; else if (nval > 255) nval = 255;
cr1 = ((nval) * CR_RANGE) / 256;
err1 = ((nval) - cr_values[cr1])/2;
err2 = ((nval) - cr_values[cr1]) - err1;

nval = val+err1+inerr2;
if (nval < 0) nval = 0; else if (nval > 255) nval = 255;
cr2 = ((nval) * CR_RANGE) / 256;
err1 = ((nval) - cr_values[cr2])/2;
outerr3 = ((nval) - cr_values[cr2])-err1;

nval = val+err2+inerr4;
if (nval < 0) nval = 0; else if (nval > 255) nval = 255;
cr3 = ((nval) * CR_RANGE) / 256;
err2 = ((nval) - cr_values[cr3])/2;
outerr1 = ((nval) - cr_values[cr3]) - err2;

nval = val+err1+err2;
if (nval < 0) nval = 0; else if (nval > 255) nval = 255;
cr4 = ((nval) * CR_RANGE) / 256;
outerr2 = ((nval) - cr_values[cr4])/2;
outerr4 = ((nval) - cr_values[cr4])-outerr2;

cr_fsarray[i+j][0] = cr1*CB_RANGE;
cr_fsarray[i+j][1] = cr2*CB_RANGE;
cr_fsarray[i+j][2] = cr3*CB_RANGE;
cr_fsarray[i+j][3] = cr4*CB_RANGE;

if (outerr1 < -16) outerr1++;
else if (outerr1 > 15) outerr1--;
if (outerr2 < -16) outerr2++;
else if (outerr2 > 15) outerr2--;
if (outerr3 < -16) outerr3++;
else if (outerr3 > 15) outerr3--;
if (outerr4 < -16) outerr4++;
else if (outerr4 > 15) outerr4--;

oe1 = (outerr1 + 16) / 8;
oe2 = (outerr2 + 16) / 8;
oe3 = (outerr3 + 16) / 8;
oe4 = (outerr4 + 16) / 8;

/* This is a debugging check and should be removed if not needed. */
if ((oe1 > 3) || (oe2 > 3) || (oe3 > 3) || (oe4 > 3))
fprintf(stderr, "OE error!!!!\n");

c_fserr[i+j][0] = ((oe1 << 14) | (oe2 << 12));

c_fserr[i+j][1] = ((oe3 << 10) | (oe4 << 8));
}

for (i=0; i<256; i++) {
val = i;
nval = val+inerr1+inerr3;
if (nval < 0) nval = 0; else if (nval > 255) nval = 255;
cb1 = ((nval) * CB_RANGE) / 256;
err1 = ((nval) - cb_values[cb1])/2;
err2 = ((nval) - cb_values[cb1]) - err1;

nval = val+err1+inerr2;
if (nval < 0) nval = 0; else if (nval > 255) nval = 255;
cb2 = ((nval) * CB_RANGE) / 256;
err1 = ((nval) - cb_values[cb2])/2;

nval = val+err2+inerr4;
if (nval < 0) nval = 0; else if (nval > 255) nval = 255;
cb3 = ((nval) * CB_RANGE) / 256;
err2 = ((nval) - cb_values[cb3])/2;

nval = val+err1+err2;
if (nval < 0) nval = 0; else if (nval > 255) nval = 255;
cb4 = ((nval) * CB_RANGE) / 256;

cb_fsarray[i+j][0] = cb1;
cb_fsarray[i+j][1] = cb2;
cb_fsarray[i+j][2] = cb3;
cb_fsarray[i+j][3] = cb4;
}
}
}
}

/*
*--------------------------------------------------------------
*
* HybridErrorDitherImage --
*
* Dithers an image using a hybrid ordered/floyd-steinberg dither.
* Assumptions made:
* 1) The color space is allocated y:cr:cb = 8:4:4
* 2) The spatial resolution of y:cr:cb is 4:1:1
* This dither is almost exactly like the dither implemented in the
* file odith.c (i.e. hybrid dithering) except a quantized amount of
* error is propogated between 2x2 pixel areas in Cr and Cb.
*
* Results:
* None.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void
HybridErrorDitherImage (lum, cr, cb, out, h, w)
unsigned char *lum;
unsigned char *cr;
unsigned char *cb;
unsigned char *out;
int w, h;
{
unsigned char *l, *r, *b, *o1, *o2;
unsigned char *l2;
static int *cr_row_errs;
static int *cb_row_errs;
int *cr_r_err;
int *cb_r_err;
int cr_c_err;
int cb_c_err;
unsigned char *cr_fsptr;
unsigned char *cb_fsptr;
static int first = 1;
int cr_code, cb_code;

int i, j;
int row_advance, row_advance2;
int half_row_advance, half_row_advance2;

/* If first time called, allocate error arrays. */

if (first) {
cr_row_errs = (int *) malloc((w+5)*sizeof(int));
cb_row_errs = (int *) malloc((w+5)*sizeof(int));
first = 0;
}

row_advance = (w << 1) - 1;
row_advance2 = row_advance+2;
half_row_advance = (w>>1)-1;
half_row_advance2 = half_row_advance+2;

l = lum;
l2 = lum+w;
r = cr;
b = cb;
o1 = out;
o2 = out+w;

memset( (char *) cr_row_errs, 0, (w+5)*sizeof(int));
cr_r_err = cr_row_errs;
cr_c_err = 0;
memset( (char *) cb_row_errs, 0, (w+5)*sizeof(int));
cb_r_err = cb_row_errs;
cb_c_err = 0;

for (i=0; i<h; i+=4) {

for (j=w; j>0; j-=4) {

cr_code = (*cr_r_err | cr_c_err | *r++);
cb_code = (*cb_r_err | cb_c_err | *b++);

cr_fsptr = cr_fsarray[cr_code];
cb_fsptr = cb_fsarray[cb_code];

*o1++ = pixel[(l_darrays0[*l++] | *cr_fsptr++ | *cb_fsptr++)];
*o1++ = pixel[(l_darrays8[*l++] | *cr_fsptr++ | *cb_fsptr++)];
*o2++ = pixel[(l_darrays12[*l2++] | *cr_fsptr++ | *cb_fsptr++)];
*o2++ = pixel[(l_darrays4[*l2++] | *cr_fsptr++ | *cb_fsptr++)];

cr_c_err = c_fserr[cr_code][1];
cb_c_err = c_fserr[cb_code][1];
*cr_r_err++ = c_fserr[cr_code][0];
*cb_r_err++ = c_fserr[cb_code][0];
cr_code = (*cr_r_err | cr_c_err | *r++);
cb_code = (*cb_r_err | cb_c_err | *b++);

cr_fsptr = cr_fsarray[cr_code];
cb_fsptr = cb_fsarray[cb_code];

*o1++ = pixel[(l_darrays2[*l++] | *cr_fsptr++ | *cb_fsptr++)];
*o1++ = pixel[(l_darrays10[*l++] | *cr_fsptr++ | *cb_fsptr++)];
*o2++ = pixel[(l_darrays14[*l2++] | *cr_fsptr++ | *cb_fsptr++)];
*o2++ = pixel[(l_darrays6[*l2++] | *cr_fsptr++ | *cb_fsptr++)];

cr_c_err = c_fserr[cr_code][1];
cb_c_err = c_fserr[cb_code][1];
*cr_r_err++ = c_fserr[cr_code][0];
*cb_r_err++ = c_fserr[cb_code][0];
}

l += row_advance; l2 += row_advance;
o1 += row_advance; o2 += row_advance;
cr_c_err = 0;
cb_c_err = 0;
cr_r_err--; cb_r_err--;
r += half_row_advance; b += half_row_advance;

for (j=w; j>0; j-=4) {

cr_code = (*cr_r_err | cr_c_err | *r--);
cb_code = (*cb_r_err | cb_c_err | *b--);
cr_fsptr = cr_fsarray[cr_code];
cb_fsptr = cb_fsarray[cb_code];

*o1-- = pixel[(l_darrays9[*l--] | *cr_fsptr++ | *cb_fsptr++)];
*o1-- = pixel[(l_darrays1[*l--] | *cr_fsptr++ | *cb_fsptr++)];
*o2-- = pixel[(l_darrays5[*l2--] | *cr_fsptr++ | *cb_fsptr++)];
*o2-- = pixel[(l_darrays13[*l2--] | *cr_fsptr++ | *cb_fsptr++)];

cr_c_err = c_fserr[cr_code][1];
cb_c_err = c_fserr[cb_code][1];
*cr_r_err-- = c_fserr[cr_code][0];
*cb_r_err-- = c_fserr[cb_code][0];
cr_code = (*cr_r_err | cr_c_err | *r--);
cb_code = (*cb_r_err | cb_c_err | *b--);
cr_fsptr = cr_fsarray[cr_code];
cb_fsptr = cb_fsarray[cb_code];

*o1-- = pixel[(l_darrays11[*l--] | *cr_fsptr++ | *cb_fsptr++)];
*o1-- = pixel[(l_darrays3[*l--] | *cr_fsptr++ | *cb_fsptr++)];
*o2-- = pixel[(l_darrays7[*l2--] | *cr_fsptr++ | *cb_fsptr++)];
*o2-- = pixel[(l_darrays15[*l2--] | *cr_fsptr++ | *cb_fsptr++)];

cr_c_err = c_fserr[cr_code][1];
cb_c_err = c_fserr[cb_code][1];
*cr_r_err-- = c_fserr[cr_code][0];
*cb_r_err-- = c_fserr[cb_code][0];

}

l += row_advance2; l2 += row_advance2;
o1 += row_advance2; o2 += row_advance2;
cr_c_err = 0; cb_c_err = 0;
cr_r_err++; cb_r_err++;
r += half_row_advance2; b += half_row_advance2;
}
}

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