From OpenHome
What is ohMedia?
ohMedia is an open standard for networked audio devices. Devices can implement it in place of or in addition to the UPnP Forum’s AV standards. It offers a number of advantages over basic UPnP:
- Playlists are stored on the renderer, allowing playback to continue when the control point leaves the network (e.g. the control point application closes or its host device powers down).
- Storing playlists on the renderer also allows for gapless playback, avoiding gaps between tracks that were intended to merge seamlessly. This is particularly important for live albums and classical music.
- Multiple control points are better supported. Storing a playlist on the renderer allows multiple control points to edit the order of tracks and display metadata (including track name and album art) for the entire playlist.
- Share music between renderers. The Songcast protocol allows an ohMedia renderer to share its content with any other ohMedia device or listen to content from another device. Synchronised audio can be played between any number of devices. Desktop songcast applications plus mobile support (Songcast app for Android; Airplay receiver for iOS) allows content from many other devices to be shared.
- Internet radio and a receiver for Apple's AirPlay are also natively supported.
- Playlists can be more easily & reliably saved and reused. Many popular UPnP media servers change track URIs whenever they rebuild their database (e.g. every time new content is added to the database). ohMedia’s reference server - Songbox - guarantees to retain track URIs across rebuilds, allowing saving and repeated reuse of playlists.
- Support for multi-product hi-fi systems. E.g. a media renderer with a separate pre-amp. ohMedia topology algorithms allow a control point to select the volume control on the pre-amp.