DLNA/UPnP AV DMSs and Playlists

Yet another old and only-half-finished article, which I am publishing anyway. On the topic, I ended up using Playlist Creator on the file system from which our primary DMS serves its contents. Using relative paths, of course.

It turns out that the DLNA/UPnP AV standards do not provide systematic support for server-side playlist management, which I find utterly surprising. Aren’t there obvious needs for that?

Some DMSs pick it up if there’s a playlist file while scanning their media libraries in file systems, but there does not seem to be any predefined protocol through which you can manage playlists; you can only do that on the file system you are exposing to DMSs. For example, here is a way to do it for MiniDLNA servers. Also, here’s a list of playlist creation tools.

Some DMPs, DMRs and DMCs do support playlists, but not in a collaborative way. Normally those playlists are never propagated elsewhere and stay isolated, confined only inside that particular device/app.

If they should be propagated at all, that happens only between, say, a DMS and a DMC that are designed to work together from the get-go, but not between other devices/apps. Since there is no support for it from the DLNA standards themselves, the interoperability does not exist.

That is why I was very much intrigued by BubbleUPnP Server. It is not a DMS by itself, but it works as a proxy to existing DMSs and provides additional functionality, such as transcoding and remote access.

I am sure some would consider it useful enough for those additional benefits, but I was more interested in the fact that it can also create an OpenHome compliant renderer, acting as a proxy to an existing DMR .

I’ll be honest here — I am not still quite sure what OpenHome is. My first impression was that it is a home automation framework (on a related note, I wrote “Home Automation Systems and Intercoms” before). iControl Networks does present it that way. At any rate, OpenHome includes an arm on home media management called OhMedia, which supposedly addresses the flaws of the UPnP AV standard. Each of the claims seems legitimate, but my take on it is that they should be addressed by augmenting the UPnP standard, not by creating a separate standard. At any rate, OhMedia offers the playlist management functionality, and that is the additional benefit you get by creating a OpenHome compliant DMR with BubbleUPnP Server.

Initially, I thought that was exactly what I wanted, but then realized it wasn’t. The server maintains playlists on its side on the per-renderer basis. Is this what people normally want? Don’t we rather want playlists that are not bound with a particular renderer?

Sure, since you can start playing a playlist on a renderer and then switch the renderer midway, you could potentially create playlists for a “catch-all” renderer and use its playlists as “renderer-unbound” playlists. But I find this solution conceptually unnecessarily complicated and methodically awkward. (I’d also think the initial renderer needs to be present at all times for this scheme to work.)

So, okay, the verdict is in: BubbleUPnP Server is not for me. At least with regards to the server-side playlist management, that is. I might use it for its transcoding and remote access capabilities.

The other option I considered is Twonky Server (Packet Video’s explanation of Twonky Server) combined with Twonky Manger.

You can create playlists with Twonky Manager running on your Windows PC or Mac (no Linux) for Twonky Server. Those playlists will be shown on your DMC/DMP in a Playlists folder. If you are running Twonky Server on a Windows PC, the playlists made on that PC in Windows Media Player will be shown alongside.

The fact

The Android app Twonky Beam’s UI is not quite user friendly. It does not allow playing videos on an external player, thus limiting the codecs it can handle.

In the Windows version, those playlist data are stored at a specific place. Since Twonky Server offers WebDAV access, I wonder why you cannot just place those playlist files directly in such a way that those playlists can be utilized even when the media contents are served by other servers.

One interesting feature of Twonky Server is to aggregate media content from other DLNA servers. I was surprised to learn that it can download DTCP-IP mpegs from the over-the-air digital TV tuner with recording capabilities.

Comparison of UPnP AV media servers

Universal Media Player, derivative of PS3 Media Server




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