Thank you very much MikeCash!
Actually, I used a database more than 200.000 words and phrases but this seem not enough. For example, the first sentence of the song Yuki no Hana is (のびた人陰を舗道に並べ, 夕闇のなかをキミと歩いてる). RomajiDesu converter produces (no bita jin(tari,to,nin,hito,ri) in(kage,hoto) wo hodou ni nami be , yuuyami no nakawo kimi to kachi(fu,ho) iteru), while the correct lyrics should be (Nobita kake wo hodou ni narabe,Yuuyami no naka wo KIMI to aruiteru)
I wonder why there is no (人) in the official pronunciation, and is "並べ" (narabe) and 歩いてる(aruiteru) is some special phrase that should be in my database?