If you just want to do a straight burn, no conversion necessary. All you need is burning software that can burn to BD media:
Nero Burning ROM is what I use for all burning tasks, CD, DVD, DVD DL, BD - it does 'em all:
http
/www.nero.com/eng/products/nero-burning-rom/whats-new.php
What I don't get is why you converted it to MP4 with the quality loss that such conversion imposes. Nero can write BDMV direct to BD media.