Gapless playback
As far as I know gapless playback is not part of the DLNA standard.
UPnP does (the magic word seems to be the SetNextAVTransport).
DLNA iincoperates UPnP so go figure!
A lot of streaming audio players today do support gapless.
Always check if gapless is supported as nothing as annoying as a white space in a live concert
If gapless is not supported a trick is not play from your receiver but to use a media player on a PC that support gapless.
Capture the gapless audio stream and push this to your receiver.
Firstly there's the free foo_UPnP plugin component available for Foobar2000 music player I mentioned, that gives Fb2k full UPnP/DLNA streaming capabilities, providing a UPnP/DLNA controller, server and renderer. However, what's relevant here is it also has the option of creating a UPnP/DLNA streamable file from the playlist of music tracks that's currently being played by Fb2k.
The other application to investigate is a UPnP/DLNA music server that captures the sound of the current application to create a UPnP/DLNA streamable file with, ie, it can be used for ANY music playing application. This is the free ('donation ware') Stream What You Hear UPnP/DLNA server.