snow.c

从FFMPEG转换而来的H264解码程序,VC下编译..

        b2[i] += (W_BM*(b1[i] + b3[i])+W_BO)>>W_BS;
#else
        b2[i] += (W_BM*(b1[i] + b3[i])+4*b2[i]+W_BO)>>W_BS;
#endif
        b1[i] += (W_AM*(b0[i] + b2[i])+W_AO)>>W_AS;
    }
}

static void spatial_compose97i_buffered_init(dwt_compose_t *cs, slice_buffer * sb, int height, int stride_line){
    cs->b0 = slice_buffer_get_line(sb, mirror(-3-1, height-1) * stride_line);
    cs->b1 = slice_buffer_get_line(sb, mirror(-3  , height-1) * stride_line);
    cs->b2 = slice_buffer_get_line(sb, mirror(-3+1, height-1) * stride_line);
    cs->b3 = slice_buffer_get_line(sb, mirror(-3+2, height-1) * stride_line);
    cs->y = -3;
}

static void spatial_compose97i_init(dwt_compose_t *cs, DWTELEM *buffer, int height, int stride){
    cs->b0 = buffer + mirror(-3-1, height-1)*stride;
    cs->b1 = buffer + mirror(-3  , height-1)*stride;
    cs->b2 = buffer + mirror(-3+1, height-1)*stride;
    cs->b3 = buffer + mirror(-3+2, height-1)*stride;
    cs->y = -3;
}

static void spatial_compose97i_dy_buffered(DSPContext *dsp, dwt_compose_t *cs, slice_buffer * sb, int width, int height, int stride_line){
    int y = cs->y;

    DWTELEM *b0= cs->b0;
    DWTELEM *b1= cs->b1;
    DWTELEM *b2= cs->b2;
    DWTELEM *b3= cs->b3;
    DWTELEM *b4= slice_buffer_get_line(sb, mirror(y + 3, height - 1) * stride_line);
    DWTELEM *b5= slice_buffer_get_line(sb, mirror(y + 4, height - 1) * stride_line);

    if(y>0 && y+4<height){
        dsp->vertical_compose97i(b0, b1, b2, b3, b4, b5, width);
    }else{
        if(y+3<(unsigned)height) vertical_compose97iL1(b3, b4, b5, width);
        if(y+2<(unsigned)height) vertical_compose97iH1(b2, b3, b4, width);
        if(y+1<(unsigned)height) vertical_compose97iL0(b1, b2, b3, width);
        if(y+0<(unsigned)height) vertical_compose97iH0(b0, b1, b2, width);
    }

        if(y-1<(unsigned)height) dsp->horizontal_compose97i(b0, width);
        if(y+0<(unsigned)height) dsp->horizontal_compose97i(b1, width);

    cs->b0=b2;
    cs->b1=b3;
    cs->b2=b4;
    cs->b3=b5;
    cs->y += 2;
}

static void spatial_compose97i_dy(dwt_compose_t *cs, DWTELEM *buffer, int width, int height, int stride){
    int y = cs->y;
    DWTELEM *b0= cs->b0;
    DWTELEM *b1= cs->b1;
    DWTELEM *b2= cs->b2;
    DWTELEM *b3= cs->b3;
    DWTELEM *b4= buffer + mirror(y+3, height-1)*stride;
    DWTELEM *b5= buffer + mirror(y+4, height-1)*stride;

        if(y+3<(unsigned)height) vertical_compose97iL1(b3, b4, b5, width);
        if(y+2<(unsigned)height) vertical_compose97iH1(b2, b3, b4, width);
        if(y+1<(unsigned)height) vertical_compose97iL0(b1, b2, b3, width);
        if(y+0<(unsigned)height) vertical_compose97iH0(b0, b1, b2, width);

        if(y-1<(unsigned)height) ff_snow_horizontal_compose97i(b0, width);
        if(y+0<(unsigned)height) ff_snow_horizontal_compose97i(b1, width);

    cs->b0=b2;
    cs->b1=b3;
    cs->b2=b4;
    cs->b3=b5;
    cs->y += 2;
}

static void spatial_compose97i(DWTELEM *buffer, int width, int height, int stride){
    dwt_compose_t cs;
    spatial_compose97i_init(&cs, buffer, height, stride);
    while(cs.y <= height)
        spatial_compose97i_dy(&cs, buffer, width, height, stride);
}

static void ff_spatial_idwt_buffered_init(dwt_compose_t *cs, slice_buffer * sb, int width, int height, int stride_line, int type, int decomposition_count){
    int level;
    for(level=decomposition_count-1; level>=0; level--){
        switch(type){
        case DWT_97: spatial_compose97i_buffered_init(cs+level, sb, height>>level, stride_line<<level); break;
        case DWT_53: spatial_compose53i_buffered_init(cs+level, sb, height>>level, stride_line<<level); break;
        /* not slicified yet */
        case DWT_X: /*spatial_composeX(buffer, width>>level, height>>level, stride<<level); break;*/
          av_log(NULL, AV_LOG_ERROR, "spatial_composeX neither buffered nor slicified yet.\n"); break;
        }
    }
}

static void ff_spatial_idwt_init(dwt_compose_t *cs, DWTELEM *buffer, int width, int height, int stride, int type, int decomposition_count){
    int level;
    for(level=decomposition_count-1; level>=0; level--){
        switch(type){
        case DWT_97: spatial_compose97i_init(cs+level, buffer, height>>level, stride<<level); break;
        case DWT_53: spatial_compose53i_init(cs+level, buffer, height>>level, stride<<level); break;
        /* not slicified yet */
        case DWT_X: spatial_composeX(buffer, width>>level, height>>level, stride<<level); break;
        }
    }
}

static void ff_spatial_idwt_slice(dwt_compose_t *cs, DWTELEM *buffer, int width, int height, int stride, int type, int decomposition_count, int y){
    const int support = type==1 ? 3 : 5;
    int level;
    if(type==2) return;

    for(level=decomposition_count-1; level>=0; level--){
        while(cs[level].y <= FFMIN((y>>level)+support, height>>level)){
            switch(type){
            case DWT_97: spatial_compose97i_dy(cs+level, buffer, width>>level, height>>level, stride<<level);
                    break;
            case DWT_53: spatial_compose53i_dy(cs+level, buffer, width>>level, height>>level, stride<<level);
                    break;
            case DWT_X: break;
            }
        }
    }
}

static void ff_spatial_idwt_buffered_slice(DSPContext *dsp, dwt_compose_t *cs, slice_buffer * slice_buf, int width, int height, int stride_line, int type, int decomposition_count, int y){
    const int support = type==1 ? 3 : 5;
    int level;
    if(type==2) return;

    for(level=decomposition_count-1; level>=0; level--){
        while(cs[level].y <= FFMIN((y>>level)+support, height>>level)){
            switch(type){
            case DWT_97: spatial_compose97i_dy_buffered(dsp, cs+level, slice_buf, width>>level, height>>level, stride_line<<level);
                    break;
            case DWT_53: spatial_compose53i_dy_buffered(cs+level, slice_buf, width>>level, height>>level, stride_line<<level);
                    break;
            case DWT_X: break;
            }
        }
    }
}

static void ff_spatial_idwt(DWTELEM *buffer, int width, int height, int stride, int type, int decomposition_count){
    if(type==2){
        int level;
        for(level=decomposition_count-1; level>=0; level--)
            spatial_composeX  (buffer, width>>level, height>>level, stride<<level);
    }else{
        dwt_compose_t cs[MAX_DECOMPOSITIONS];
        int y;
        ff_spatial_idwt_init(cs, buffer, width, height, stride, type, decomposition_count);
        for(y=0; y<height; y+=4)
            ff_spatial_idwt_slice(cs, buffer, width, height, stride, type, decomposition_count, y);
    }
}

static int encode_subband_c0run(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *parent, int stride, int orientation){
    const int w= b->width;
    const int h= b->height;
    int x, y;

    if(1){
        int run=0;
        int runs[w*h];
        int run_index=0;
        int max_index;

        for(y=0; y<h; y++){
            for(x=0; x<w; x++){
                int v, p=0;
                int l=0, lt=0, t=0, rt=0;
                v= src[x + y*stride];

                if(y){
                    t= src[x + (y-1)*stride];
                    if(x){
                        lt= src[x - 1 + (y-1)*stride];
                    }
                    if(x + 1 < w){
                        rt= src[x + 1 + (y-1)*stride];
                    }
                }
                if(x){
                    l= src[x - 1 + y*stride];
                }
                if(parent){
                    int px= x>>1;
                    int py= y>>1;
                    if(px<b->parent->width && py<b->parent->height)
                        p= parent[px + py*2*stride];
                }
                if(!(l|lt|t|rt|p)){
                    if(v){
                        runs[run_index++]= run;
                        run=0;
                    }else{
                        run++;
                    }
                }
            }
        }
        max_index= run_index;
        runs[run_index++]= run;
        run_index=0;
        run= runs[run_index++];

        put_symbol2(&s->c, b->state[30], max_index, 0);
        if(run_index <= max_index)
            put_symbol2(&s->c, b->state[1], run, 3);

        for(y=0; y<h; y++){
            if(s->c.bytestream_end - s->c.bytestream < w*40){
                av_log(s->avctx, AV_LOG_ERROR, "encoded frame too large\n");
                return -1;
            }
            for(x=0; x<w; x++){
                int v, p=0;
                int l=0, lt=0, t=0, rt=0;
                v= src[x + y*stride];

                if(y){
                    t= src[x + (y-1)*stride];
                    if(x){
                        lt= src[x - 1 + (y-1)*stride];
                    }
                    if(x + 1 < w){
                        rt= src[x + 1 + (y-1)*stride];
                    }
                }
                if(x){
                    l= src[x - 1 + y*stride];
                }
                if(parent){
                    int px= x>>1;
                    int py= y>>1;
                    if(px<b->parent->width && py<b->parent->height)
                        p= parent[px + py*2*stride];
                }
                if(l|lt|t|rt|p){
                    int context= av_log2(3*FFABS(l) + FFABS(lt) + 2*FFABS(t) + FFABS(rt) + FFABS(p));

                    put_rac(&s->c, &b->state[0][context], !!v);
                }else{
                    if(!run){
                        run= runs[run_index++];

                        if(run_index <= max_index)
                            put_symbol2(&s->c, b->state[1], run, 3);
                        assert(v);
                    }else{
                        run--;
                        assert(!v);
                    }
                }
                if(v){
                    int context= av_log2(3*FFABS(l) + FFABS(lt) + 2*FFABS(t) + FFABS(rt) + FFABS(p));
                    int l2= 2*FFABS(l) + (l<0);
                    int t2= 2*FFABS(t) + (t<0);

                    put_symbol2(&s->c, b->state[context + 2], FFABS(v)-1, context-4);
                    put_rac(&s->c, &b->state[0][16 + 1 + 3 + quant3bA[l2&0xFF] + 3*quant3bA[t2&0xFF]], v<0);
                }
            }
        }
    }
    return 0;
}

static int encode_subband(SnowContext *s, SubBand *b, DWTELEM *src, DWTELEM *parent, int stride, int orientation){
    return encode_subband_c0run(s, b, src, parent, stride, orientation);
}

static inline void unpack_coeffs(SnowContext *s, SubBand *b, SubBand * parent, int orientation){
    const int w= b->width;
    const int h= b->height;
    int x,y;

    if(1){
        int run, runs;
        x_and_coeff *xc= b->x_coeff;
        x_and_coeff *prev_xc= NULL;
        x_and_coeff *prev2_xc= xc;
        x_and_coeff *parent_xc= parent ? parent->x_coeff : NULL;
        x_and_coeff *prev_parent_xc= parent_xc;

        runs= get_symbol2(&s->c, b->state[30], 0);
        if(runs-- > 0) run= get_symbol2(&s->c, b->state[1], 3);
        else           run= INT_MAX;

        for(y=0; y<h; y++){
            int v=0;
            int lt=0, t=0, rt=0;

            if(y && prev_xc->x == 0){
                rt= prev_xc->coeff;
            }
            for(x=0; x<w; x++){
                int p=0;
                const int l= v;

                lt= t; t= rt;

                if(y){
                    if(prev_xc->x <= x)
                        prev_xc++;
                    if(prev_xc->x == x + 1)
                        rt= prev_xc->coeff;
                    else
                        rt=0;
                }
                if(parent_xc){
                    if(x>>1 > parent_xc->x){
                        parent_xc++;
                    }
                    if(x>>1 == parent_xc->x){
                        p= parent_xc->coeff;
                    }
                }
                if(l|lt|t|rt|p){
                    int context= av_log2(3*(l>>1) + (lt>>1) + (t&~1) + (rt>>1) + (p>>1));

                    v=get_rac(&s->c, &b->state[0][context]);
                    if(v){
                        v= 2*(get_symbol2(&s->c, b->state[context + 2], context-4) + 1);
                        v+=get_rac(&s->c, &b->state[0][16 + 1 + 3 + quant3bA[l&0xFF] + 3*quant3bA[t&0xFF]]);

                        xc->x=x;
                        (xc++)->coeff= v;
                    }
                }else{
                    if(!run){
                        if(runs-- > 0) run= get_symbol2(&s->c, b->state[1], 3);
                        else           run= INT_MAX;
                        v= 2*(get_symbol2(&s->c, b->state[0 + 2], 0-4) + 1);
                        v+=get_rac(&s->c, &b->state[0][16 + 1 + 3]);

                        xc->x=x;
                        (xc++)->coeff= v;
                    }else{
                        int max_run;
                        run--;
                        v=0;

                        if(y) max_run= FFMIN(run, prev_xc->x - x - 2);
                        else  max_run= FFMIN(run, w-x-1);
                        if(parent_xc)
                            max_run= FFMIN(max_run, 2*parent_xc->x - x - 1);
                        x+= max_run;
                        run-= max_run;
                    }
                }
            }
            (xc++)->x= w+1; //end marker
            prev_xc= prev2_xc;
            prev2_xc= xc;

            if(parent_xc){
                if(y&1){
                    while(parent_xc->x != parent->width+1)
                        parent_xc++;
                    parent_xc++;
                    prev_parent_xc= parent_xc;
                }else{
                    parent_xc= prev_parent_xc;
                }
            }