Hidden Messages in The Halo Bulletin

After much head scratching me and some intrepid Halo fans have uncovered this video from the Halo Bulletin.




This is the writing at the end:

This wasn't the only hidden trinket, as with the last three weeks, there other hidden messages too.

Clicking on the full stop after //CLASSIFIED/  takes you to this page

/START FILE/ 
//CLASSIFIED/ 
//ALERT: RETURN FROM BASE-LXIV IMMEDIATELY!/ 
// 
// 
//ADDITIONAL DATA RECOVERED: 

 /END FILE/

In the HTML of that page is the following:

TVRoZAAAAAYAAAABA8BNVHJrAAAAbQD/IAEAAP8DFS8vQ0xBU1NJRklFRC8vRT1tYzMvLwDAWwCQNECWQIA0AACQNkCHQIA2AACQN0CHQIA3AACQNkCHQIA2AACQOUCHQIA5AACQN0CHQIA3AACQNkCWQIA2AACQNECeAIA0AAD/LwA

Using a base64 decode (Thanks @Si_Lumb!) we get this:

"MThd MTrkm //CLASSIFIED//E=mc3//[4@@46@@67@@76@@69@@97@@76@@64@4/"


Hidden in the page HTML of the Bulletin is this image:

ENHANCE (Photoshop wizardry):

And this PDF:

@cnorthwood Recognised that the decoded text could be played as a midi audio file - The Halo theme! Taking the midi note numbers and entering them in place of the question marks in the URL above took us to the video at the top of the article. 

It's been a crazy day and my brain hurts. 

Huge thanks to @Haloathon, @cnorthwood, @Si_Lumb, @Seb_Long and me! @EnglishHaloBlog

- Cowboy Out.