If your Roku is playing from a source on the network, it's either DLNA or a proprietary streaming method, i.e. Plex or Emby. If it's coming from an app on an Android device, my guess it's still DLNA. And no, I don't believe RMP can index DLNA sources. It takes whatever information the DLNA source provides, but maintains no local index or file list. The Roku just doesn't have the memory storage for something like that. Yes, it does now maintain an index for attached USB devices, but I would guess it's limited to just the titles and file structure of the USB device. There just isn't enough internal storage for anything more.
Dan
Roku Community Streaming Expert
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