uvdxy = dxy | (motion_y & 2) | ((motion_x & 2) >> 1); uvsrc_x = src_x>>1; uvsrc_y = src_y>>1;
if((s->workaround_bugs & FF_BUG_HPEL_CHROMA) && field_based){ mx = (motion_x>>1)|(motion_x&1); my = motion_y >>1; uvdxy = ((my & 1) << 1) | (mx & 1); uvsrc_x = s->mb_x* 8               + (mx >> 1); uvsrc_y = s->mb_y*(8>>field_based) + (my >> 1); }else{ uvdxy = dxy | (motion_y & 2) | ((motion_x & 2) >> 1); uvsrc_x = src_x>>1; uvsrc_y = src_y>>1; }
static inline void mpeg_motion(MpegEncContext *s,                               uint8_t *dest_y, uint8_t *dest_cb, uint8_t *dest_cr,                               int field_based, int bottom_field, int field_select,                               uint8_t **ref_picture, op_pixels_func (*pix_op)[4],                               int motion_x, int motion_y, int h){    uint8_t *ptr_y, *ptr_cb, *ptr_cr;    int dxy, uvdxy, mx, my, src_x, src_y, uvsrc_x, uvsrc_y, v_edge_pos, uvlinesize, linesize;    #if 0    if(s->quarter_sample){    motion_x>>=1;    motion_y>>=1;}#endif    v_edge_pos = s->v_edge_pos >> field_based;    linesize   = s->current_picture.linesize[0] << field_based;    uvlinesize = s->current_picture.linesize[1] << field_based;    dxy = ((motion_y & 1) << 1) | (motion_x & 1);    src_x = s->mb_x* 16               + (motion_x >> 1);    src_y = s->mb_y*(16>>field_based) + (motion_y >> 1);    if (s->out_format == FMT_H263) {        uvdxy = dxy | (motion_y & 2) | ((motion_x & 2) >> 1);        uvsrc_x = src_x>>1;        uvsrc_y = src_y>>1;    } else {        mx = motion_x / 2;        my = motion_y / 2;        uvdxy = ((my & 1) << 1) | (mx & 1);        uvsrc_x = s->mb_x* 8               + (mx >> 1);        uvsrc_y = s->mb_y*(8>>field_based) + (my >> 1);    }    ptr_y  = ref_picture[0] + src_y * linesize + src_x;    ptr_cb = ref_picture[1] + uvsrc_y * uvlinesize + uvsrc_x;    ptr_cr = ref_picture[2] + uvsrc_y * uvlinesize + uvsrc_x;    if(   (unsigned)src_x > s->h_edge_pos - (motion_x&1) - 16       || (unsigned)src_y >    v_edge_pos - (motion_y&1) - h){            ff_emulated_edge_mc(s->edge_emu_buffer, ptr_y, s->linesize, 17, 17+field_based,                             src_x, src_y<<field_based, s->h_edge_pos, s->v_edge_pos);            ptr_y = s->edge_emu_buffer;            if(!(s->flags&CODEC_FLAG_GRAY)){                uint8_t *uvbuf= s->edge_emu_buffer+18*s->linesize;                ff_emulated_edge_mc(uvbuf  , ptr_cb, s->uvlinesize, 9, 9+field_based,                                  uvsrc_x, uvsrc_y<<field_based, s->h_edge_pos>>1, s->v_edge_pos>>1);                ff_emulated_edge_mc(uvbuf+16, ptr_cr, s->uvlinesize, 9, 9+field_based,                                  uvsrc_x, uvsrc_y<<field_based, s->h_edge_pos>>1, s->v_edge_pos>>1);                ptr_cb= uvbuf;                ptr_cr= uvbuf+16;            }    }    if(bottom_field){ //FIXME use this for field pix too instead of the obnoxious hack which changes picture.data        dest_y += s->linesize;        dest_cb+= s->uvlinesize;        dest_cr+= s->uvlinesize;    }    if(field_select){        ptr_y += s->linesize;        ptr_cb+= s->uvlinesize;        ptr_cr+= s->uvlinesize;    }    pix_op[0][dxy](dest_y, ptr_y, linesize, h);        if(!(s->flags&CODEC_FLAG_GRAY)){        pix_op[1][uvdxy](dest_cb, ptr_cb, uvlinesize, h >> 1);        pix_op[1][uvdxy](dest_cr, ptr_cr, uvlinesize, h >> 1);    }}