Based on the latest comments from VLC media player lead developer Rémi Denis-Courmont, it seems likely that the iOS version of the app probably won't be available much longer. Denis-Courmont claims that Apple is violating the GNU public license (GPL) under which VLC is released by applying DRM to it.
While VLC is available free of charge for the iPhone, iPod touch, and iPad on the App Store, it's not possible to copy it from one device to another. Every copy of an iOS app is tied to a specific user account when it is downloaded, regardless of whether you pay f