error_resilience.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

/*
 * Error resilience / concealment
 *
 * Copyright (c) 2002 Michael Niedermayer <[e-mail]>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
 
/**
 * @file error_resilience.c
 * Error resilience / concealment.
 */

#include <limits.h>
 
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#include "common.h"

static void decode_mb(MpegEncContext *s){
    s->dest[0] = s->current_picture.data[0] + (s->mb_y * 16* s->linesize  ) + s->mb_x * 16;
    s->dest[1] = s->current_picture.data[1] + (s->mb_y * 8 * s->uvlinesize) + s->mb_x * 8;
    s->dest[2] = s->current_picture.data[2] + (s->mb_y * 8 * s->uvlinesize) + s->mb_x * 8;

    MPV_decode_mb(s, s->block);    
}

/**
 * replaces the current MB with a flat dc only version.
 */
static void put_dc(MpegEncContext *s, uint8_t *dest_y, uint8_t *dest_cb, uint8_t *dest_cr, int mb_x, int mb_y)
{
    int dc, dcu, dcv, y, i;
    for(i=0; i<4; i++){
        dc= s->dc_val[0][mb_x*2+1 + (i&1) + (mb_y*2+1 + (i>>1))*(s->mb_width*2+2)];
        if(dc<0) dc=0;
        else if(dc>2040) dc=2040;
        for(y=0; y<8; y++){
            int x;
            for(x=0; x<8; x++){
                dest_y[x + (i&1)*8 + (y + (i>>1)*8)*s->linesize]= dc/8;
            }
        }
    }
    dcu = s->dc_val[1][mb_x+1 + (mb_y+1)*(s->mb_width+2)];
    dcv = s->dc_val[2][mb_x+1 + (mb_y+1)*(s->mb_width+2)];
    if     (dcu<0   ) dcu=0;
    else if(dcu>2040) dcu=2040;
    if     (dcv<0   ) dcv=0;
    else if(dcv>2040) dcv=2040;
    for(y=0; y<8; y++){
        int x;
        for(x=0; x<8; x++){
            dest_cb[x + y*(s->uvlinesize)]= dcu/8;
            dest_cr[x + y*(s->uvlinesize)]= dcv/8;
        }
    }
}

static void filter181(int16_t *data, int width, int height, int stride){
    int x,y;

    /* horizontal filter */
    for(y=1; y<height-1; y++){
        int prev_dc= data[0 + y*stride];

        for(x=1; x<width-1; x++){
            int dc;
            
            dc= - prev_dc 
                + data[x     + y*stride]*8
                - data[x + 1 + y*stride];
            dc= (dc*10923 + 32768)>>16;
            prev_dc= data[x + y*stride];
            data[x + y*stride]= dc;
        }
    }
    
    /* vertical filter */
    for(x=1; x<width-1; x++){
        int prev_dc= data[x];

        for(y=1; y<height-1; y++){
            int dc;
            
            dc= - prev_dc 
                + data[x +  y   *stride]*8
                - data[x + (y+1)*stride];
            dc= (dc*10923 + 32768)>>16;
            prev_dc= data[x + y*stride];
            data[x + y*stride]= dc;
        }
    }
}

/**
 * guess the dc of blocks which dont have a undamaged dc
 * @param w	width in 8 pixel blocks
 * @param h	height in 8 pixel blocks
 */
static void guess_dc(MpegEncContext *s, int16_t *dc, int w, int h, int stride, int is_luma){
    int b_x, b_y;

    for(b_y=0; b_y<h; b_y++){
        for(b_x=0; b_x<w; b_x++){
            int color[4]={1024,1024,1024,1024};
            int distance[4]={9999,9999,9999,9999};
            int mb_index, error, j;
            int64_t guess, weight_sum;
            
            mb_index= (b_x>>is_luma) + (b_y>>is_luma)*s->mb_stride;
            
            error= s->error_status_table[mb_index];
            
            if(IS_INTER(s->current_picture.mb_type[mb_index])) continue; //inter
            if(!(error&DC_ERROR)) continue;           //dc-ok
            
            /* right block */
            for(j=b_x+1; j<w; j++){
                int mb_index_j= (j>>is_luma) + (b_y>>is_luma)*s->mb_stride;
                int error_j= s->error_status_table[mb_index_j];
                int intra_j= IS_INTRA(s->current_picture.mb_type[mb_index_j]);
                if(intra_j==0 || !(error_j&DC_ERROR)){
                    color[0]= dc[j + b_y*stride];
                    distance[0]= j-b_x;
                    break;
                }
            }
            
            /* left block */
            for(j=b_x-1; j>=0; j--){
                int mb_index_j= (j>>is_luma) + (b_y>>is_luma)*s->mb_stride;
                int error_j= s->error_status_table[mb_index_j];
                int intra_j= IS_INTRA(s->current_picture.mb_type[mb_index_j]);
                if(intra_j==0 || !(error_j&DC_ERROR)){
                    color[1]= dc[j + b_y*stride];
                    distance[1]= b_x-j;
                    break;
                }
            }

            /* bottom block */
            for(j=b_y+1; j<h; j++){
                int mb_index_j= (b_x>>is_luma) + (j>>is_luma)*s->mb_stride;
                int error_j= s->error_status_table[mb_index_j];
                int intra_j= IS_INTRA(s->current_picture.mb_type[mb_index_j]);
                if(intra_j==0 || !(error_j&DC_ERROR)){
                    color[2]= dc[b_x + j*stride];
                    distance[2]= j-b_y;
                    break;
                }
            }

            /* top block */
            for(j=b_y-1; j>=0; j--){
                int mb_index_j= (b_x>>is_luma) + (j>>is_luma)*s->mb_stride;
                int error_j= s->error_status_table[mb_index_j];
                int intra_j= IS_INTRA(s->current_picture.mb_type[mb_index_j]);
                if(intra_j==0 || !(error_j&DC_ERROR)){
                    color[3]= dc[b_x + j*stride];
                    distance[3]= b_y-j;
                    break;
                }
            }
            
            weight_sum=0;
            guess=0;
            for(j=0; j<4; j++){
                int64_t weight= 256*256*256*16/distance[j];
                guess+= weight*(int64_t)color[j];
                weight_sum+= weight;
            }
            guess= (guess + weight_sum/2) / weight_sum;

            dc[b_x + b_y*stride]= guess;
        }
    }
}

/**
 * simple horizontal deblocking filter used for error resilience
 * @param w	width in 8 pixel blocks
 * @param h	height in 8 pixel blocks
 */
static void h_block_filter(MpegEncContext *s, uint8_t *dst, int w, int h, int stride, int is_luma){
    int b_x, b_y;
    uint8_t *cm = cropTbl + MAX_NEG_CROP;

    for(b_y=0; b_y<h; b_y++){
        for(b_x=0; b_x<w-1; b_x++){
            int y;
            int left_status = s->error_status_table[( b_x   >>is_luma) + (b_y>>is_luma)*s->mb_stride];
            int right_status= s->error_status_table[((b_x+1)>>is_luma) + (b_y>>is_luma)*s->mb_stride];
            int left_intra=   IS_INTRA(s->current_picture.mb_type      [( b_x   >>is_luma) + (b_y>>is_luma)*s->mb_stride]);
            int right_intra=  IS_INTRA(s->current_picture.mb_type      [((b_x+1)>>is_luma) + (b_y>>is_luma)*s->mb_stride]);
            int left_damage =  left_status&(DC_ERROR|AC_ERROR|MV_ERROR);
            int right_damage= right_status&(DC_ERROR|AC_ERROR|MV_ERROR);
            int offset= b_x*8 + b_y*stride*8;
            int16_t *left_mv=  s->motion_val[s->block_wrap[0]*((b_y<<(1-is_luma)) + 1) + ( b_x   <<(1-is_luma))];
            int16_t *right_mv= s->motion_val[s->block_wrap[0]*((b_y<<(1-is_luma)) + 1) + ((b_x+1)<<(1-is_luma))];
            
            if(!(left_damage||right_damage)) continue; // both undamaged
            
            if(   (!left_intra) && (!right_intra) 
               && ABS(left_mv[0]-right_mv[0]) + ABS(left_mv[1]+right_mv[1]) < 2) continue;
            
            for(y=0; y<8; y++){
                int a,b,c,d;
                
                a= dst[offset + 7 + y*stride] - dst[offset + 6 + y*stride];
                b= dst[offset + 8 + y*stride] - dst[offset + 7 + y*stride];
                c= dst[offset + 9 + y*stride] - dst[offset + 8 + y*stride];
                
                d= ABS(b) - ((ABS(a) + ABS(c) + 1)>>1);
                d= FFMAX(d, 0);
                if(b<0) d= -d;
                
                if(d==0) continue;

                if(!(left_damage && right_damage))
                    d= d*16/9;
                
                if(left_damage){
                    dst[offset + 7 + y*stride] = cm[dst[offset + 7 + y*stride] + ((d*7)>>4)];
                    dst[offset + 6 + y*stride] = cm[dst[offset + 6 + y*stride] + ((d*5)>>4)];
                    dst[offset + 5 + y*stride] = cm[dst[offset + 5 + y*stride] + ((d*3)>>4)];
                    dst[offset + 4 + y*stride] = cm[dst[offset + 4 + y*stride] + ((d*1)>>4)];
                }
                if(right_damage){
                    dst[offset + 8 + y*stride] = cm[dst[offset + 8 + y*stride] - ((d*7)>>4)];
                    dst[offset + 9 + y*stride] = cm[dst[offset + 9 + y*stride] - ((d*5)>>4)];
                    dst[offset + 10+ y*stride] = cm[dst[offset +10 + y*stride] - ((d*3)>>4)];
                    dst[offset + 11+ y*stride] = cm[dst[offset +11 + y*stride] - ((d*1)>>4)];
                }
            }
        }
    }
}

/**
 * simple vertical deblocking filter used for error resilience
 * @param w	width in 8 pixel blocks
 * @param h	height in 8 pixel blocks
 */
static void v_block_filter(MpegEncContext *s, uint8_t *dst, int w, int h, int stride, int is_luma){
    int b_x, b_y;
    uint8_t *cm = cropTbl + MAX_NEG_CROP;

    for(b_y=0; b_y<h-1; b_y++){
        for(b_x=0; b_x<w; b_x++){
            int x;
            int top_status   = s->error_status_table[(b_x>>is_luma) + ( b_y   >>is_luma)*s->mb_stride];
            int bottom_status= s->error_status_table[(b_x>>is_luma) + ((b_y+1)>>is_luma)*s->mb_stride];
            int top_intra=     IS_INTRA(s->current_picture.mb_type      [(b_x>>is_luma) + ( b_y   >>is_luma)*s->mb_stride]);
            int bottom_intra=  IS_INTRA(s->current_picture.mb_type      [(b_x>>is_luma) + ((b_y+1)>>is_luma)*s->mb_stride]);
            int top_damage =      top_status&(DC_ERROR|AC_ERROR|MV_ERROR);
            int bottom_damage= bottom_status&(DC_ERROR|AC_ERROR|MV_ERROR);
            int offset= b_x*8 + b_y*stride*8;
            int16_t *top_mv=    s->motion_val[s->block_wrap[0]*(( b_y   <<(1-is_luma)) + 1) + (b_x<<(1-is_luma))];
            int16_t *bottom_mv= s->motion_val[s->block_wrap[0]*(((b_y+1)<<(1-is_luma)) + 1) + (b_x<<(1-is_luma))];
            
            if(!(top_damage||bottom_damage)) continue; // both undamaged
            
            if(   (!top_intra) && (!bottom_intra) 
               && ABS(top_mv[0]-bottom_mv[0]) + ABS(top_mv[1]+bottom_mv[1]) < 2) continue;
            
            for(x=0; x<8; x++){
                int a,b,c,d;
                
                a= dst[offset + x + 7*stride] - dst[offset + x + 6*stride];
                b= dst[offset + x + 8*stride] - dst[offset + x + 7*stride];
                c= dst[offset + x + 9*stride] - dst[offset + x + 8*stride];
                
                d= ABS(b) - ((ABS(a) + ABS(c)+1)>>1);
                d= FFMAX(d, 0);
                if(b<0) d= -d;
                
                if(d==0) continue;

                if(!(top_damage && bottom_damage))
                    d= d*16/9;
                
                if(top_damage){
                    dst[offset + x +  7*stride] = cm[dst[offset + x +  7*stride] + ((d*7)>>4)];
                    dst[offset + x +  6*stride] = cm[dst[offset + x +  6*stride] + ((d*5)>>4)];
                    dst[offset + x +  5*stride] = cm[dst[offset + x +  5*stride] + ((d*3)>>4)];
                    dst[offset + x +  4*stride] = cm[dst[offset + x +  4*stride] + ((d*1)>>4)];
                }
                if(bottom_damage){
                    dst[offset + x +  8*stride] = cm[dst[offset + x +  8*stride] - ((d*7)>>4)];
                    dst[offset + x +  9*stride] = cm[dst[offset + x +  9*stride] - ((d*5)>>4)];
                    dst[offset + x + 10*stride] = cm[dst[offset + x + 10*stride] - ((d*3)>>4)];
                    dst[offset + x + 11*stride] = cm[dst[offset + x + 11*stride] - ((d*1)>>4)];
                }
            }
        }
    }
}

static void guess_mv(MpegEncContext *s){
    uint8_t fixed[s->mb_stride * s->mb_height];
#define MV_FROZEN    3
#define MV_CHANGED   2
#define MV_UNCHANGED 1
    const int mb_stride = s->mb_stride;
    const int mb_width = s->mb_width;
    const int mb_height= s->mb_height;
    int i, depth, num_avail;
    int mb_x, mb_y;
   
    num_avail=0;
    for(i=0; i<s->mb_num; i++){
        const int mb_xy= s->mb_index2xy[ i ];
        int f=0;
        int error= s->error_status_table[mb_xy];

        if(IS_INTRA(s->current_picture.mb_type[mb_xy])) f=MV_FROZEN; //intra //FIXME check
        if(!(error&MV_ERROR)) f=MV_FROZEN;           //inter with undamaged MV
        
        fixed[mb_xy]= f;
        if(f==MV_FROZEN)
            num_avail++;
    }