What Files can OneDrive Play Online?

Supported audio and video formats in OneDrive:

The following audio/video files can be played directly from your OneDrive in most browsers: .3g2, .3gp, .3gp2, .3gpp, .aac, .adts, .asf, .avi, .mp3, .m4a, .m4v, .mov, .mp4, .sami, .smi, .wav, .wma, .wmv

If you have videos in a different format, you can still upload them to OneDrive, but they might not play directly in a browser. To view them on a mobile device, you’ll need to download them first.

If a file doesn’t play, the format might be one that either OneDrive or your mobile device doesn't support. 

Microsoft has additional helps for playing videos on iOS devices (like your iPad or iPhone) on the same site.  You are encouraged to check there if you still cannot play videos on these devices from the OneDrive App!