Beyond the several meta-contexts of a music video on YouTube linked to a blog post, etc, this video assumes and relies on a couple contexts to tells its story. I'll also ignore the contexts of the audience's and the communicator's time as well the contexts of bodies in space, all being at the choosing all parties.
First, just looking at the background, the scene is dark and gray, dead trees create tension with what appears to be at least some walls of a church (which don't appear to be in poor condition). Churches, which hold strong place and institutional contexts, are usually clean and well kept (including their grounds), contrary to the images from the video; furthermore they're not usually considers as places for metalcore performances.
The next contextual reference comes in the lyrics, starting off with "the concept of fashion is the one to blame". The first half of the song talks to ("megalomania") obsession with fashion and power ("claiming to be kings and queens"), saying "but it's all for nothing." To understand this you need to understand the context of modern pop culture (as most people that would view this video will). This, beyond an institutional context, is more of a societal context that is understood (although not necessarily valued) by a much broader audience.
Another context from the lyrics returns to religion, The Devil Wears Prada being a christian band and providing vindication for the scenery of the church. In the story of the song, even after sinning (killing the bird), "salvation lies within,' and the singer will hope and pray for 'you' (this juxtaposition manifesting itself in the aforementioned tension of the dark scene with the walls of the church). The song ends with "Here's an offering", the boy holding up the dead bird which then hops and flies away. The context of religion provides the understanding of the sin, praying, and subsequent redemption, but more importantly, depending on the audience's personal experiences with and views of religion, this context will hold significant sway in the video's appeal, strengthening it for some and turning some others away.
