So I have an external hard drive that I'm plugging into my MacBook Pro. Then I'm using an HDMI to play it from a Roku TV. The image of my laptop is coming up fine on the Roku, but none of the audio is playing. When I play the sound of other tabs from my laptop they play on the TV just fine. So what I'm assuming is happening is when I set the audio output to my laptop, it isn't picking up the audio from the blu-ray player because it's an external device. So is there anything I can do about this? Also I'm not very smart so explain everything like I am 8 years old please.