Certain Videos When i Play them Sound Doesn't work...

[AC Question]

Some movies, when I play them, the sound is very low, and it sounds like a train going by and crappy, But when I plug the headphones in, the sound is fine, My speakers are fine, nothing wrong at all, I thought it might have been the equalizer or something but I set it back to regular, and it is still the Same.. Also when I cast the Movie to my TV through A Casting App, still has that same crappy very low buzzing volume.. I have no clue why this would be when everything else is fine.. Also there is a Slight possibility that it's happening with .MKV files but not totally sure because when this happened I thought it was the file being messed up so I deleted them.. Any help would be greatly appreciated..