Copyright - sound effects

Searching through youtube for music and soundtracks appropriate to my trailer, I found two that would fit in perfectly with my trailer. When playing them over my in-progress trailer, they were extremely relevant and helped to enhance the feel that I wanted my product to have. In order to abide with copyright laws I will ask their permission to use their pieces of music.

I have commented on the sound tracks asking permission to use part of it in my coursework:

 

The other one however is marked as royalty free:

I will not need to ask permission for this piece of music due to this.