There was a metal version of Koi no Mikuru Densetsu that was done, and it was supposedly done by X Japan, but it turns out it was done by some other group (arranged by psycho and sung by J -
http://speedfreaks.blog.shinobi.jp/ ) and placed over a concert recording that closely matched the song as far as lip movements and instruments. I want to say the same was done here, since parts of that video don't look right. The song is at least an interesting take though, and well done on placing it over the concert. ^^
I think that Tori no Uta cover was done by the same guys too... I can't read it, but the kanji (forgive me if it's not actually kanji but one of the other writing forms - I'm ignorant on such things at the moment) looks the same on one of the songs on their download list.
EDIT: Downloaded the song - yeah, it's the same song.