class function CreateFromFile(const URL: string): TSoundFile;
Load a sound data, given an URL. This just opens the file as stream and then calls CreateFromStream of appropriate class, so see CreateFromStream for more info. For now, file format (which TSoundFile to use) is decided by the URL extension.
procedure PrepareOpenAL; virtual;
Call this on this sound always after OpenAL is initialized and before passing this sound data to OpenAL. This may fix or check some things for this sound, checking e.g. whether some OpenAL extensions are supported.