Dumb question re how minimserver works

[DavidHB]

Peter's definitions relate to DLNA. The device definitions for UPnP AV are slightly different, but, because DLNA uses the UPnP messaging protocol, the two standards are essentially inter-operable. However, UPnP does not seem to include a device definition like the Digital Media Player, i.e. one that autonomously pulls content from the server; it only has the Control Point which issues instructions for the server to provide content to the renderer using the playlist, which is only active within the control point software.

The issue with UPnP AV is that, for the renderer to continue to function, the control point has to remain active, while devices such as phones and tablets that are the typical hosts for control point software readily go into standby to save power. OpenHome (originally developed as an extension to UPnP AV under the sponsorship of Linn, but fully open and now used by some other manufacturers as well) actually has a 'halfway house' pull feature. The control point is still used to build the playlist but, when it is created or amended, it is saved in the renderer, which then uses the playlist to pull the content from the server. If you put your DS in standby when it has a playlist loaded, the playlist will still be there when the player is active again.

This approach has two advantages. Firstly, the renderer can continue playing even when the control point shuts down, and the user can switch seamlessly between control points while the renderer is still playing. Also, from the user perceptive, the renderer works almost like a CD player with a disc loaded; the user can use the remote control or the front panel to work the 'transport' functions of the renderer (play, pause, track change etc) directly, that is without using or needing a control point.

Apart from this difference, OpenHome also provides other features, in particular it implements gapless playback. This, I believe, is also a feature in UPnP AV, but it is by no means always implemented.

Interestingly, the Linn document to which Peter linked does not mention the difference between UPnP AV and OpenHome. Linn DS and DSM devices offer a UpnP AV compatibility mode (without gapless playback), but there is no reason to use it with MinimServer or control points such as BubbleDS and Kazoo, all of which are fully OpenHome compliant.

David