if(s->pict_type==B_TYPE && s->picture_structure == PICT_FRAME){
if(s->pict_type==B_TYPE && s->picture_structure == PICT_FRAME && s->out_format != FMT_H264){
void ff_draw_horiz_band(MpegEncContext *s, int y, int h){    if (s->avctx->draw_horiz_band) {        uint8_t *src_ptr[3];        int offset[4];        h= FFMIN(h, s->height - y);        if(s->pict_type==B_TYPE && s->picture_structure == PICT_FRAME){            offset[0]=            offset[1]=            offset[2]=            offset[3]= 0;        }else{            offset[0]= y * s->linesize;;            offset[1]=             offset[2]= (y>>1) * s->uvlinesize;;            offset[3]= 0;        }        emms_c();        s->avctx->draw_horiz_band(s->avctx, (AVFrame*)s->current_picture_ptr, offset,                               y, s->width, h);    }}