void ff_init_block_index(MpegEncContext *s){ //FIXME maybe rename const int linesize = s->current_picture.f.linesize[0]; //not s->linesize as this would be wrong for field pics const int uvlinesize = s->current_picture.f.linesize[1]; const int mb_size= 4; s->block_index[0]= s->b8_stride*(s->mb_y*2 ) - 2 + s->mb_x*2; s->block_index[1]= s->b8_stride*(s->mb_y*2 ) - 1 + s->mb_x*2; s->block_index[2]= s->b8_stride*(s->mb_y*2 + 1) - 2 + s->mb_x*2; s->block_index[3]= s->b8_stride*(s->mb_y*2 + 1) - 1 + s->mb_x*2; s->block_index[4]= s->mb_stride*(s->mb_y + 1) + s->b8_stride*s->mb_height*2 + s->mb_x - 1; s->block_index[5]= s->mb_stride*(s->mb_y + s->mb_height + 2) + s->b8_stride*s->mb_height*2 + s->mb_x - 1; //block_index is not used by mpeg2, so it is not affected by chroma_format s->dest[0] = s->current_picture.f.data[0] + ((s->mb_x - 1) << mb_size); s->dest[1] = s->current_picture.f.data[1] + ((s->mb_x - 1) << (mb_size - s->chroma_x_shift)); s->dest[2] = s->current_picture.f.data[2] + ((s->mb_x - 1) << (mb_size - s->chroma_x_shift)); if(!(s->pict_type==AV_PICTURE_TYPE_B && s->avctx->draw_horiz_band && s->picture_structure==PICT_FRAME)) { if(s->picture_structure==PICT_FRAME){ s->dest[0] += s->mb_y * linesize << mb_size; s->dest[1] += s->mb_y * uvlinesize << (mb_size - s->chroma_y_shift); s->dest[2] += s->mb_y * uvlinesize << (mb_size - s->chroma_y_shift); }else{ s->dest[0] += (s->mb_y>>1) * linesize << mb_size; s->dest[1] += (s->mb_y>>1) * uvlinesize << (mb_size - s->chroma_y_shift); s->dest[2] += (s->mb_y>>1) * uvlinesize << (mb_size - s->chroma_y_shift); assert((s->mb_y&1) == (s->picture_structure == PICT_BOTTOM_FIELD)); } } }