I am not sure about any other apps but you will get MX player in every other phone that you will see out there.
Basically its job is to play videos and movies but it gets it all done more than perfectly.
I think its the fastest player out there in terms of loading speed.
I supports many formats of video.The list is really huge.
one of the best feature I like about it is pinch and zoom, from it you can adjust the video to your screen size.
Yes the design and user interface is not that wanky but its not bad too.You can adjust its colour scheme and many more.
In audio formats its good too you get the options of HW, HW+ , SW.
At time it shows the message of Aw3 format not supported but dont worry you just have to download a small file.Just google it.
Overall I am really happy with it.Thank you.