^
Just so you know it...
Linn was originally very snooty about what they perceived as weaknesses in the standard UPnP / DLNA specifications, and when they made their implementation of those standards they deigned that the standards were insufficient to fulfill their needs, so they added their own so called "Linn UPnP Extensions".
Linn has published its extensions, and so they claim that those extensions are now "open standards", but in reality these extensions have not been adopted by the UPnP standardization working group (at
www.upnp.org) nor by the DLNA industry group (at
www.dlna.org), so de facto these are still really proprietary extensions.
MC's implementation supports the official UPnP and DLNA standards, and (IMHO rightly so) they do not support the Linn extensions.
One of the Linn Extensions concerns gapless playback. According to the official standards, the Control Point shall manage the playlist, and it shall use the SetAvTransportUri / SetNextAvTransportUri mechanism to push individual tracks to the renderer "just-in-time" so that the renderer can play each track gaplessly after the other. This is what MC does. On the other hand, in Linn's "solution" they invented a new UPnP Service Action that rather than pushing individual tracks via the SetAvTransportUri / SetNextAvTransportUri mechanism, instead pushes the whole playlist by means of this newly defined proprietary Service Action.
I don't know the Linn DS at all, so I cannot tell you if it falls back to supporting the standard SetAvTransportUri / SetNextAvTransportUri mechanism when the Control Point uses that mechanism rather than the Linn proprietary Service Action.