When I got my Galaxy S5 from Verizon last month, the first thing I wanted to add in was VLC, since I love that program on all my computers.
I downloaded and installed the VLC app. But it would not play any videos which were all MP4 and which played fine on my PC's, & iPad2. The default player in the S5 played everything, but I prefer the performance of VLC.
I have to believe that the version I installed did not have the necessary codecs for the Galaxy S5. I don't know what version I installed, as I removed it from the S5.
Is there a "good" version which is available and will play everything on the Galaxy S5, just as it does on my PC's