motion_est.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

        c->xmax = - x + s->mb_width *16;
        c->ymax = - y + s->mb_height*16;
    } else if (s->out_format == FMT_H261){
        // Search range of H261 is different from other codec standards
        c->xmin = (x > 15) ? - 15 : 0;
        c->ymin = (y > 15) ? - 15 : 0;
        c->xmax = (x < s->mb_width * 16 - 16) ? 15 : 0;
        c->ymax = (y < s->mb_height * 16 - 16) ? 15 : 0;
    } else {
        c->xmin = - x;
        c->ymin = - y;
        c->xmax = - x + s->mb_width *16 - 16;
        c->ymax = - y + s->mb_height*16 - 16;
    }
    if(range){
        c->xmin = FFMAX(c->xmin,-range);
        c->xmax = FFMIN(c->xmax, range);
        c->ymin = FFMAX(c->ymin,-range);
        c->ymax = FFMIN(c->ymax, range);
    }
}

static inline void init_mv4_ref(MotionEstContext *c){
    const int stride= c->stride;

    c->ref[1][0] = c->ref[0][0] + 8;
    c->ref[2][0] = c->ref[0][0] + 8*stride;
    c->ref[3][0] = c->ref[2][0] + 8;
    c->src[1][0] = c->src[0][0] + 8;
    c->src[2][0] = c->src[0][0] + 8*stride;
    c->src[3][0] = c->src[2][0] + 8;
}

static inline int h263_mv4_search(MpegEncContext *s, int mx, int my, int shift)
{
    MotionEstContext * const c= &s->me;
    const int size= 1;
    const int h=8;
    int block;
    int P[10][2];
    int dmin_sum=0, mx4_sum=0, my4_sum=0;
    int same=1;
    const int stride= c->stride;
    uint8_t *mv_penalty= c->current_mv_penalty;

    init_mv4_ref(c);

    for(block=0; block<4; block++){
        int mx4, my4;
        int pred_x4, pred_y4;
        int dmin4;
        static const int off[4]= {2, 1, 1, -1};
        const int mot_stride = s->b8_stride;
        const int mot_xy = s->block_index[block];

        P_LEFT[0] = s->current_picture.motion_val[0][mot_xy - 1][0];
        P_LEFT[1] = s->current_picture.motion_val[0][mot_xy - 1][1];

        if(P_LEFT[0]       > (c->xmax<<shift)) P_LEFT[0]       = (c->xmax<<shift);

        /* special case for first line */
        if (s->first_slice_line && block<2) {
            c->pred_x= pred_x4= P_LEFT[0];
            c->pred_y= pred_y4= P_LEFT[1];
        } else {
            P_TOP[0]      = s->current_picture.motion_val[0][mot_xy - mot_stride             ][0];
            P_TOP[1]      = s->current_picture.motion_val[0][mot_xy - mot_stride             ][1];
            P_TOPRIGHT[0] = s->current_picture.motion_val[0][mot_xy - mot_stride + off[block]][0];
            P_TOPRIGHT[1] = s->current_picture.motion_val[0][mot_xy - mot_stride + off[block]][1];
            if(P_TOP[1]      > (c->ymax<<shift)) P_TOP[1]     = (c->ymax<<shift);
            if(P_TOPRIGHT[0] < (c->xmin<<shift)) P_TOPRIGHT[0]= (c->xmin<<shift);
            if(P_TOPRIGHT[0] > (c->xmax<<shift)) P_TOPRIGHT[0]= (c->xmax<<shift);
            if(P_TOPRIGHT[1] > (c->ymax<<shift)) P_TOPRIGHT[1]= (c->ymax<<shift);

            P_MEDIAN[0]= mid_pred(P_LEFT[0], P_TOP[0], P_TOPRIGHT[0]);
            P_MEDIAN[1]= mid_pred(P_LEFT[1], P_TOP[1], P_TOPRIGHT[1]);

            c->pred_x= pred_x4 = P_MEDIAN[0];
            c->pred_y= pred_y4 = P_MEDIAN[1];
        }
        P_MV1[0]= mx;
        P_MV1[1]= my;

        dmin4 = epzs_motion_search4(s, &mx4, &my4, P, block, block, s->p_mv_table, (1<<16)>>shift);

        dmin4= c->sub_motion_search(s, &mx4, &my4, dmin4, block, block, size, h);

        if(s->dsp.me_sub_cmp[0] != s->dsp.mb_cmp[0]){
            int dxy;
            const int offset= ((block&1) + (block>>1)*stride)*8;
            uint8_t *dest_y = c->scratchpad + offset;
            if(s->quarter_sample){
                uint8_t *ref= c->ref[block][0] + (mx4>>2) + (my4>>2)*stride;
                dxy = ((my4 & 3) << 2) | (mx4 & 3);

                if(s->no_rounding)
                    s->dsp.put_no_rnd_qpel_pixels_tab[1][dxy](dest_y   , ref    , stride);
                else
                    s->dsp.put_qpel_pixels_tab       [1][dxy](dest_y   , ref    , stride);
            }else{
                uint8_t *ref= c->ref[block][0] + (mx4>>1) + (my4>>1)*stride;
                dxy = ((my4 & 1) << 1) | (mx4 & 1);

                if(s->no_rounding)
                    s->dsp.put_no_rnd_pixels_tab[1][dxy](dest_y    , ref    , stride, h);
                else
                    s->dsp.put_pixels_tab       [1][dxy](dest_y    , ref    , stride, h);
            }
            dmin_sum+= (mv_penalty[mx4-pred_x4] + mv_penalty[my4-pred_y4])*c->mb_penalty_factor;
        }else
            dmin_sum+= dmin4;

        if(s->quarter_sample){
            mx4_sum+= mx4/2;
            my4_sum+= my4/2;
        }else{
            mx4_sum+= mx4;
            my4_sum+= my4;
        }

        s->current_picture.motion_val[0][ s->block_index[block] ][0]= mx4;
        s->current_picture.motion_val[0][ s->block_index[block] ][1]= my4;

        if(mx4 != mx || my4 != my) same=0;
    }

    if(same)
        return INT_MAX;

    if(s->dsp.me_sub_cmp[0] != s->dsp.mb_cmp[0]){
        dmin_sum += s->dsp.mb_cmp[0](s, s->new_picture.data[0] + s->mb_x*16 + s->mb_y*16*stride, c->scratchpad, stride, 16);
    }

    if(c->avctx->mb_cmp&FF_CMP_CHROMA){
        int dxy;
        int mx, my;
        int offset;

        mx= ff_h263_round_chroma(mx4_sum);
        my= ff_h263_round_chroma(my4_sum);
        dxy = ((my & 1) << 1) | (mx & 1);

        offset= (s->mb_x*8 + (mx>>1)) + (s->mb_y*8 + (my>>1))*s->uvlinesize;

        if(s->no_rounding){
            s->dsp.put_no_rnd_pixels_tab[1][dxy](c->scratchpad    , s->last_picture.data[1] + offset, s->uvlinesize, 8);
            s->dsp.put_no_rnd_pixels_tab[1][dxy](c->scratchpad+8  , s->last_picture.data[2] + offset, s->uvlinesize, 8);
        }else{
            s->dsp.put_pixels_tab       [1][dxy](c->scratchpad    , s->last_picture.data[1] + offset, s->uvlinesize, 8);
            s->dsp.put_pixels_tab       [1][dxy](c->scratchpad+8  , s->last_picture.data[2] + offset, s->uvlinesize, 8);
        }

        dmin_sum += s->dsp.mb_cmp[1](s, s->new_picture.data[1] + s->mb_x*8 + s->mb_y*8*s->uvlinesize, c->scratchpad  , s->uvlinesize, 8);
        dmin_sum += s->dsp.mb_cmp[1](s, s->new_picture.data[2] + s->mb_x*8 + s->mb_y*8*s->uvlinesize, c->scratchpad+8, s->uvlinesize, 8);
    }

    c->pred_x= mx;
    c->pred_y= my;

    switch(c->avctx->mb_cmp&0xFF){
    /*case FF_CMP_SSE:
        return dmin_sum+ 32*s->qscale*s->qscale;*/
    case FF_CMP_RD:
        return dmin_sum;
    default:
        return dmin_sum+ 11*c->mb_penalty_factor;
    }
}

static inline void init_interlaced_ref(MpegEncContext *s, int ref_index){
    MotionEstContext * const c= &s->me;

    c->ref[1+ref_index][0] = c->ref[0+ref_index][0] + s->linesize;
    c->src[1][0] = c->src[0][0] + s->linesize;
    if(c->flags & FLAG_CHROMA){
        c->ref[1+ref_index][1] = c->ref[0+ref_index][1] + s->uvlinesize;
        c->ref[1+ref_index][2] = c->ref[0+ref_index][2] + s->uvlinesize;
        c->src[1][1] = c->src[0][1] + s->uvlinesize;
        c->src[1][2] = c->src[0][2] + s->uvlinesize;
    }
}

static int interlaced_search(MpegEncContext *s, int ref_index,
                             int16_t (*mv_tables[2][2])[2], uint8_t *field_select_tables[2], int mx, int my, int user_field_select)
{
    MotionEstContext * const c= &s->me;
    const int size=0;
    const int h=8;
    int block;
    int P[10][2];
    uint8_t * const mv_penalty= c->current_mv_penalty;
    int same=1;
    const int stride= 2*s->linesize;
    int dmin_sum= 0;
    const int mot_stride= s->mb_stride;
    const int xy= s->mb_x + s->mb_y*mot_stride;

    c->ymin>>=1;
    c->ymax>>=1;
    c->stride<<=1;
    c->uvstride<<=1;
    init_interlaced_ref(s, ref_index);

    for(block=0; block<2; block++){
        int field_select;
        int best_dmin= INT_MAX;
        int best_field= -1;

        for(field_select=0; field_select<2; field_select++){
            int dmin, mx_i, my_i;
            int16_t (*mv_table)[2]= mv_tables[block][field_select];

            if(user_field_select){
                assert(field_select==0 || field_select==1);
                assert(field_select_tables[block][xy]==0 || field_select_tables[block][xy]==1);
                if(field_select_tables[block][xy] != field_select)
                    continue;
            }

            P_LEFT[0] = mv_table[xy - 1][0];
            P_LEFT[1] = mv_table[xy - 1][1];
            if(P_LEFT[0]       > (c->xmax<<1)) P_LEFT[0]       = (c->xmax<<1);

            c->pred_x= P_LEFT[0];
            c->pred_y= P_LEFT[1];

            if(!s->first_slice_line){
                P_TOP[0]      = mv_table[xy - mot_stride][0];
                P_TOP[1]      = mv_table[xy - mot_stride][1];
                P_TOPRIGHT[0] = mv_table[xy - mot_stride + 1][0];
                P_TOPRIGHT[1] = mv_table[xy - mot_stride + 1][1];
                if(P_TOP[1]      > (c->ymax<<1)) P_TOP[1]     = (c->ymax<<1);
                if(P_TOPRIGHT[0] < (c->xmin<<1)) P_TOPRIGHT[0]= (c->xmin<<1);
                if(P_TOPRIGHT[0] > (c->xmax<<1)) P_TOPRIGHT[0]= (c->xmax<<1);
                if(P_TOPRIGHT[1] > (c->ymax<<1)) P_TOPRIGHT[1]= (c->ymax<<1);

                P_MEDIAN[0]= mid_pred(P_LEFT[0], P_TOP[0], P_TOPRIGHT[0]);
                P_MEDIAN[1]= mid_pred(P_LEFT[1], P_TOP[1], P_TOPRIGHT[1]);
            }
            P_MV1[0]= mx; //FIXME not correct if block != field_select
            P_MV1[1]= my / 2;

            dmin = epzs_motion_search2(s, &mx_i, &my_i, P, block, field_select+ref_index, mv_table, (1<<16)>>1);

            dmin= c->sub_motion_search(s, &mx_i, &my_i, dmin, block, field_select+ref_index, size, h);

            mv_table[xy][0]= mx_i;
            mv_table[xy][1]= my_i;

            if(s->dsp.me_sub_cmp[0] != s->dsp.mb_cmp[0]){
                int dxy;

                //FIXME chroma ME
                uint8_t *ref= c->ref[field_select+ref_index][0] + (mx_i>>1) + (my_i>>1)*stride;
                dxy = ((my_i & 1) << 1) | (mx_i & 1);

                if(s->no_rounding){
                    s->dsp.put_no_rnd_pixels_tab[size][dxy](c->scratchpad, ref    , stride, h);
                }else{
                    s->dsp.put_pixels_tab       [size][dxy](c->scratchpad, ref    , stride, h);
                }
                dmin= s->dsp.mb_cmp[size](s, c->src[block][0], c->scratchpad, stride, h);
                dmin+= (mv_penalty[mx_i-c->pred_x] + mv_penalty[my_i-c->pred_y] + 1)*c->mb_penalty_factor;
            }else
                dmin+= c->mb_penalty_factor; //field_select bits

            dmin += field_select != block; //slightly prefer same field

            if(dmin < best_dmin){
                best_dmin= dmin;
                best_field= field_select;
            }
        }
        {
            int16_t (*mv_table)[2]= mv_tables[block][best_field];

            if(mv_table[xy][0] != mx) same=0; //FIXME check if these checks work and are any good at all
            if(mv_table[xy][1]&1) same=0;
            if(mv_table[xy][1]*2 != my) same=0;
            if(best_field != block) same=0;
        }

        field_select_tables[block][xy]= best_field;
        dmin_sum += best_dmin;
    }

    c->ymin<<=1;
    c->ymax<<=1;
    c->stride>>=1;
    c->uvstride>>=1;

    if(same)
        return INT_MAX;

    switch(c->avctx->mb_cmp&0xFF){
    /*case FF_CMP_SSE:
        return dmin_sum+ 32*s->qscale*s->qscale;*/
    case FF_CMP_RD:
        return dmin_sum;
    default:
        return dmin_sum+ 11*c->mb_penalty_factor;
    }
}

static void clip_input_mv(MpegEncContext * s, int16_t *mv, int interlaced){
    int ymax= s->me.ymax>>interlaced;
    int ymin= s->me.ymin>>interlaced;

    if(mv[0] < s->me.xmin) mv[0] = s->me.xmin;
    if(mv[0] > s->me.xmax) mv[0] = s->me.xmax;
    if(mv[1] <       ymin) mv[1] =       ymin;
    if(mv[1] >       ymax) mv[1] =       ymax;
}

static inline int check_input_motion(MpegEncContext * s, int mb_x, int mb_y, int p_type){
    MotionEstContext * const c= &s->me;
    Picture *p= s->current_picture_ptr;
    int mb_xy= mb_x + mb_y*s->mb_stride;
    int xy= 2*mb_x + 2*mb_y*s->b8_stride;
    int mb_type= s->current_picture.mb_type[mb_xy];
    int flags= c->flags;
    int shift= (flags&FLAG_QPEL) + 1;
    int mask= (1<<shift)-1;
    int x, y, i;
    int d=0;
    me_cmp_func cmpf= s->dsp.sse[0];
    me_cmp_func chroma_cmpf= s->dsp.sse[1];

    if(p_type && USES_LIST(mb_type, 1)){
        av_log(c->avctx, AV_LOG_ERROR, "backward motion vector in P frame\n");
        return INT_MAX/2;
    }
    assert(IS_INTRA(mb_type) || USES_LIST(mb_type,0) || USES_LIST(mb_type,1));

    for(i=0; i<4; i++){
        int xy= s->block_index[i];
        clip_input_mv(s, p->motion_val[0][xy], !!IS_INTERLACED(mb_type));
        clip_input_mv(s, p->motion_val[1][xy], !!IS_INTERLACED(mb_type));
    }

    if(IS_INTERLACED(mb_type)){
        int xy2= xy  + s->b8_stride;
        s->mb_type[mb_xy]=CANDIDATE_MB_TYPE_INTRA;
        c->stride<<=1;
        c->uvstride<<=1;

        if(!(s->flags & CODEC_FLAG_INTERLACED_ME)){
            av_log(c->avctx, AV_LOG_ERROR, "Interlaced macroblock selected but interlaced motion estimation disabled\n");
            return INT_MAX/2;
        }

        if(USES_LIST(mb_type, 0)){
            int field_select0= p->ref_index[0][xy ];
            int field_select1= p->ref_index[0][xy2];
            assert(field_select0==0 ||field_select0==1);