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/*
SMPEG - SDL MPEG Player Library
Copyright (C) 1999 Loki Entertainment Software
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdlib.h>
#include <string.h>
#include "SDL.h"
#include "MPEGfilter.h"
/* General filter cleanup function */
static void filter_destroy(SMPEG_Filter *filter)
{
if ( filter ) {
if ( filter->data ) {
free(filter->data);
}
free(filter);
}
}
/**************************************************/
/* The null filter. Copies source rect to overlay */
/**************************************************/
static void filter_null_callback(SDL_Overlay * dst, SDL_Overlay * src, SDL_Rect * region, SMPEG_FilterInfo * info, void * data)
{
register Uint32 y;
register Uint8 * s, * d;
/* Y component */
s = src->pixels[0];
d = dst->pixels[0];
/* Go to the top left corner of the source rectangle */
s += region->y * src->pitches[0] + region->x;
for(y = 0; y < region->h; y++)
{
/* Copy lines */
memcpy(d, s, region->w);
s += src->pitches[0];
d += dst->pitches[0];
}
/* V component */
s = src->pixels[1];
d = dst->pixels[1];
s += (region->y >> 1) * src->pitches[1] + (region->x >> 1);
for(y = 0; y < region->h; y+=2)
{
memcpy(d, s, region->w >> 1);
s += src->pitches[1];
d += dst->pitches[1];
}
/* U component */
s = src->pixels[2];
d = dst->pixels[2];
s += (region->y >> 1) * src->pitches[2] + (region->x >> 1);
for(y = 0; y < region->h; y+=2)
{
memcpy(d, s, region->w >> 1);
s += src->pitches[2];
d += dst->pitches[2];
}
}
SMPEG_Filter *SMPEGfilter_null(void)
{
SMPEG_Filter *filter;
filter = (SMPEG_Filter *)malloc(sizeof(*filter));
if ( filter ) {
/* the null filter requires no extra info */
filter->flags = 0;
/* no private data */
filter->data = 0;
/* set the function pointers to the callback and destroy functions */
filter->callback = filter_null_callback;
filter->destroy = filter_destroy;
}
return filter;
}
/************************************************************************************/
/* The bilinear filter. A basic low-pass filter that will produce a smoother image. */
/* It uses the following convolution matrix: [0 1 0] */
/* [1 4 1] */
/* [0 1 0] */
/************************************************************************************/
static void filter_bilinear_callback(SDL_Overlay * dst, SDL_Overlay * src, SDL_Rect * region, SMPEG_FilterInfo * info, void * data)
{
register int x, y;
register Uint8 * s, * d;
s = src->pixels[0];
d = dst->pixels[0];
s += region->y * src->pitches[0] + region->x;
/* Skip first line */
memcpy(d, s, region->w);
d += dst->pitches[0];
s += src->pitches[0];
for(y = 1; y < region->h - 1; y++)
{
/* Skip first pixel */
*d++ = *s++;
for(x = 1; x < region->w - 1; x++)
{
*d++ =
(((*s) << 2) + // 4*(x,y) +
*(s - src->pitches[0]) + // (x,y-1) +
*(s - 1) + // (x-1,y) +
*(s + 1) + // (x+1,y) +
*(s + src->pitches[0])) // (x,y+1)
>> 3; // / 8
s++;
}
/* Skip last pixel */
*d++ = *s++;
/* Go to next line */
d += dst->pitches[0] - region->w;
s += src->pitches[0] - region->w;
}
/* Skip last line */
memcpy(d, s, region->w);
d += dst->pitches[0];
s += src->pitches[0];
/* V component (unfiltered) */
s = src->pixels[1];
d = dst->pixels[1];
s += (region->y >> 1) * src->pitches[1] + (region->x >> 1);
for(y = 0; y < region->h; y+=2)
{
memcpy(d, s, region->w >> 1);
s += src->pitches[1];
d += dst->pitches[1];
}
/* U component (unfiltered) */
s = src->pixels[2];
d = dst->pixels[2];
s += (region->y >> 1) * src->pitches[2] + (region->x >> 1);
for(y = 0; y < region->h; y+=2)
{
memcpy(d, s, region->w >> 1);
s += src->pitches[2];
d += dst->pitches[2];
}
}
SMPEG_Filter *SMPEGfilter_bilinear(void)
{
SMPEG_Filter *filter;
filter = (SMPEG_Filter *)malloc(sizeof(*filter));
if ( filter ) {
/* the bilinear filter requires no extra info */
filter->flags = 0;
/* no private data */
filter->data = 0;
/* set the function pointers to the callback and destroy functions */
filter->callback = filter_bilinear_callback;
filter->destroy = filter_destroy;
}
return filter;
}
/***************************************************************************************************/
/* The deblocking filter. It filters block borders and non-intra coded blocks to reduce blockiness */
/***************************************************************************************************/
static void filter_deblocking_callback(SDL_Overlay * dst, SDL_Overlay * src, SDL_Rect * region, SMPEG_FilterInfo * info, void * data)
{
int x, y;
Uint32 dL, dU, dR, dD;
Uint32 aL, aU, aR, aD;
Uint32 Q;
Uint16 * coeffs;
register Uint8 * s, * d;
/* retrieve the coeffs from private data */
coeffs = (Uint16 *) data;
/* Y component */
s = src->pixels[0];
d = dst->pixels[0];
s += region->y * src->pitches[0] + region->x;
/* Skip first line */
memcpy(d, s, region->w);
d += dst->pitches[0];
s += src->pitches[0];
for(y = 1; y < region->h - 1; y++)
{
/* Skip first pixel */
*d++ = *s++;
for(x = 1; x < region->w - 1; x++)
{
/* get current block quantization error from the info structure provided by the video decoder */
Q = info->yuv_mb_square_error[((region->y + y) >> 4) * (src->w >> 4) + ((region->x + x) >> 4)];
if(!Q)
*d++ = *s++; /* block is intra coded, don't filter */
else
{
/* compute differences with up, left, right and down neighbors */
dL = *s - *(s - 1) + 256;
dR = *s - *(s + 1) + 256;
dU = *s - *(s - src->pitches[0]) + 256;
dD = *s - *(s + src->pitches[0]) + 256;
/* get the corresponding filter coefficients from the lookup table */
aU = coeffs[(y & 7) + (Q << 12) + (dU << 3)];
aD = coeffs[(y & 7) + (Q << 12) + (dD << 3)];
aL = coeffs[(x & 7) + (Q << 12) + (dL << 3)];
aR = coeffs[(x & 7) + (Q << 12) + (dR << 3)];
/* apply the filter on current pixel */
*d++ =
((*s)*(4 * 65536 - aL - aR - aU - aD) + // (4-aL-aR-aU-aD)*(x,y) +
(*(s - src->pitches[0]))*aU + // aU*(x,y-1) +
(*(s - 1))*aL + // aL*(x-1,y) +
(*(s + 1))*aR + // aR*(x+1,y) +
(*(s + src->pitches[0]))*aD) // aU*(x,y+1)
>> 18; // remove fixed point and / 4
s++;
}
}
/* Skip last pixel */
*d++ = *s++;
/* Go to next line */
d += dst->pitches[0] - region->w;
s += src->pitches[0] - region->w;
}
/* Skip last line */
memcpy(d, s, region->w);
d += dst->pitches[0];
s += src->pitches[0];
/* V component (unfiltered) */
s = src->pixels[1];
d = dst->pixels[1];
s += (region->y >> 1) * src->pitches[1] + (region->x >> 1);
for(y = 0; y < region->h; y+=2)
{
memcpy(d, s, region->w >> 1);
s += src->pitches[1];
d += dst->pitches[1];
}
/* U component (unfiltered) */
s = src->pixels[2];
d = dst->pixels[2];
s += (region->y >> 1) * src->pitches[2] + (region->x >> 1);
for(y = 0; y < region->h; y+=2)
{
memcpy(d, s, region->w >> 1);
s += src->pitches[2];
d += dst->pitches[2];
}
}
static void *allocate_deblocking_data(void)
{
void * data;
Uint16 * c;
Uint32 q, q1, q5, q9, d;
/* precalc table is 256Kb long */
data = malloc(sizeof(*c)*8*32*512);
c = (Uint16 *)data;
/* precalc filter coefficients: */
/* 1 */
/* coeffs(Q,d,x,y) = _____________________ */
/* d(x,y)*d(x,y) */
/* 1 + _____________ */
/* Q*Q*k(x,y) */
/* where */
/* k(x,y) = [ 9 9 9 9 9 9 9 9 ] */
/* [ 9 5 5 5 5 5 5 9 ] */
/* [ 9 5 1 1 1 1 5 9 ] */
/* [ 9 5 1 1 1 1 5 9 ] */
/* [ 9 5 1 1 1 1 5 9 ] */
/* [ 9 5 1 1 1 1 5 9 ] */
/* [ 9 5 5 5 5 5 5 9 ] */
/* [ 9 9 9 9 9 9 9 9 ] */
/* and Q is the quantization error for the block */
/* and d is the difference between current pixel and neighbor pixel */
/* */
/* this is for the math :), now some additional tricks: */
/* */
/* all coeffs are multiplied by 65536 for precision (fixed point) */
/* and d is translated from [-128,127] to [0,255] (array indexation)*/
for(d = 0; d < 512*8; d++)
*c++ = 0;
for(q = 1; q < 32; q++)
{
q1 = q*q;
q9 = (q1 << 3) + q1;
q5 = (q1 << 2) + q1;
for(d = 0; d < 256; d++)
{
*c++ = (Uint16) ((q9 << 16) / ((256 - d)*(256 - d) + q9));
*c++ = (Uint16) ((q5 << 16) / ((256 - d)*(256 - d) + q5));
*c++ = (Uint16) ((q1 << 16) / ((256 - d)*(256 - d) + q1));
*c++ = (Uint16) ((q1 << 16) / ((256 - d)*(256 - d) + q1));
*c++ = (Uint16) ((q1 << 16) / ((256 - d)*(256 - d) + q1));
*c++ = (Uint16) ((q1 << 16) / ((256 - d)*(256 - d) + q1));
*c++ = (Uint16) ((q5 << 16) / ((256 - d)*(256 - d) + q5));
*c++ = (Uint16) ((q9 << 16) / ((256 - d)*(256 - d) + q9));
}
for(d = 0; d < 256; d++)
{
*c++ = (Uint16) ((q9 << 16) / (d*d + q9));
*c++ = (Uint16) ((q5 << 16) / (d*d + q5));
*c++ = (Uint16) ((q1 << 16) / (d*d + q1));
*c++ = (Uint16) ((q1 << 16) / (d*d + q1));
*c++ = (Uint16) ((q1 << 16) / (d*d + q1));
*c++ = (Uint16) ((q1 << 16) / (d*d + q1));
*c++ = (Uint16) ((q5 << 16) / (d*d + q5));
*c++ = (Uint16) ((q9 << 16) / (d*d + q9));
}
}
return data;
}
SMPEG_Filter *SMPEGfilter_deblocking(void)
{
SMPEG_Filter *filter;
filter = (SMPEG_Filter *)malloc(sizeof(*filter));
if ( filter ) {
/* Ask the video decoder to provide per-block quantization error */
filter->flags = SMPEG_FILTER_INFO_MB_ERROR;
/* allocate private data */
filter->data = allocate_deblocking_data();
if ( ! filter->data ) {
free(filter);
return (SMPEG_Filter *)0;
}
/* set the function pointers to the callback and destroy functions */
filter->callback = filter_deblocking_callback;
filter->destroy = filter_destroy;
}
return filter;
}
|
