VLC media player for iOS

VLC is a free and open source cross-platform multimedia player.
It can play all your movies, shows and music in most formats directly without conversion.
It allows file synchronization with Dropbox, GDrive, OneDrive, Box, iCloud Drive, iTunes, direct downloads and through Wi-Fi sharing as well as streaming from SMB, FTP, SFTP, NFS, UPnP/DLNA media servers and the web.
VLC offers support for advanced subtitles including full SSA compatibility, multi-track audio, playback speed control and rendering through Chromecast.

VLC is completely free and open source.