DLNA in the real world

In my very first post of 2007 I talked about the promise of DLNA and that with compliant devices you could enjoy freedom to consume your digital media wherever or however you wanted. Unfortunately, as I have experienced first hand, the reality is far from the convenient ideal that DLNA professes to provide.

I currently have a Linksys Media Hub NMH410 and a Sony Bravia 32V5500 television connected to my network. Both are DLNA-compliant devices and support streaming pictures, audio and video over the network. The Media Hub runs Twonky Media Server which, to all intents and purposes, is the reference implementation of a DLNA server. The Bravia has a DLNA compatible renderer, similar to the PS3 which can also stream content over a network.

The trouble is that, while I can view photos from the Media Hub on the TV fine, both audio and video fail to work. I can browse audio files on the Media Hub however only the first 20 seconds of each file will play and after that I get a "Playback not available" error. Video files on the other hand are a non-starter and can't be browsed or played.

I suspected my network or the format of files I was trying to stream may have been to blame but after a (lengthy) process of elimination I took both out of the equation. Installing Twonky Media Manager on my PC, which acts as both a server and client, I was able to stream all the content types off the Media Hub fine and was also able to stream content to the TV fine. It was just the particular version of Twonky on the Media Hub and the renderer in the TV that didn't like each other.

Threads on a fair few forums across the net show that lots of folk are experiencing the same issues:

• Playback not available on Sony KDL-37V5500 on Linksys' forum
• KDL40W5500 and NAS on AVForums
• Sony Bravia TVs and Twonky on NAS not working together on Twonky's forum

I found this all very odd as surely the DLNA badge on both devices ensures that they're compatible and will have no trouble in streaming the content. This is apparently not the case and Sony themselves confirmed this to me by e-mail saying:

Unfortunately the KDL-32V5500 Media compatibility results with DLNA Media servers are as follows for Twonky Media 1.0.0.115 you can play back JPG formats. This information is the result of tests performed in Sony laboratories.

In other words their DLNA-compliance for that particular server only extends to pictures. Quite how they can call this compliance I don't know but luckily they have a nice get out clause:

Unfortunately the Twonky Media software versions you are currently using are not guaranteed to work, as third party software developers are susceptible to modify the features of their software.

So basically, "even though we're DLNA-compliant and you're using a DLNA-compliant server we give you no guarantees they'll work together whatsoever". If this is the way companies behave with their DLNA certification, if they can just get around any non-compliance issues by saying "it's the other guy's problem" then one really does wonder what the point of DLNA is.