Stutters/Pauses with Video in S5 Active


After several years as an iphone user I decided to switch over to the Galaxy S5 Active. I transferred a video from my Windows system which seemed to go flawlessly. When I play the video which plays smoothly on my computer and also played smoothly on my last iphone, there are quick pauses or stutters every few seconds or so. it may be fine for up to a minute, then the quick pauses resume.
It was suggested I try another video player than the default Android one but it plays the same. Any ideas ??? I do like playing videos so it is important to me. Thanks. Tom