Music / Video stops when audjusting volume

[AC Question]

Whenever I am watching a video, or listening music, I sometimes turn up the volume for when its too silent, or turn down the volume if its too loud. But when I do it, the video pauses it self, same with the music. I have had my S7 for about 6 weeks now, and has happened every since. I do have a case on, but it still happens without the case.