Maturing DLNA
There is a proliferation of the ways in which music is streamed from device to device, but for the broadest support, DLNA is the way to go, says Stephen Dawson
Conceptually, playing music used to be easy. You had music on some media – an LP, a cassette tape, a CD. You would place that item of media in a suitable player attached to (or perhaps part of) your music system. You would start it playing, and music would emerge.
Increasingly these days your music ‘media’ is a digital storage – on hard disk or flash memory, or even the cloud – and there are a proliferation of ways in which the music is delivered to a playback device.
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However, one way is dominant, and looks to remain so. That is the way of the Digital Living Network Alliance, or DLNA.
Dominant? Various media reports suggest that as of the start of this year more than 20,000 various devices have been DLNA-certified and some three billion individual DLNA devices have been sold.
What is it
DLNA has two meanings. One is the actual organisation, the ‘Alliance’ behind it. This was started by Sony and Intel a dozen years ago, and these days the main players (called ‘promoter members’ of the Alliance) additionally include Samsung, LG, Panasonic, Microsoft, Dolby and DTS.
Notable is that the most dominant consumer electronics companies are represented there. Except one: Apple.
The Alliance’s main role is essentially to control a set of standards designed to ensure that various DLNA devices will work together reasonably smoothly, to allow consumers to effortlessly stream their digital media from their network storage to network-attached players. In addition to setting the standards, the DLNA also provides certification services.
From here on out, I’ll be using DLNA to refer to the products of those standards, not the organisation. Note that some brands use other names for DLNA. LG, for example, calls it ‘Smart Share’. Samsung calls it ‘All Share’.
In addition, it is remarkably similar to something called uPnP (Universal Plug and Play). uPnP not actually a very good name. It isn’t universal, and PnP has other meanings in the computing context. In reality, though, DLNA is in large part a subset of uPnP, with restrictions designed to keep things easier for consumers.
Both uPnP and DLNA support music, video and still photo streaming. But not all devices are required to support all three. I will be mostly talking about music here to streamline things, but DLNA-capable TVs will typically also run video and photos via DLNA.
Servers and players and renderers
Conceptually a DLNA system is divided up into four parts, although some of the parts might be physically located in the same device. First, there’s the Digital Media Server. This has two jobs: it stores your music, and it also ‘serves’ it up to the network. The storage side of things is obvious, but the serving thing is less so. Your music is just a collection of files. The server software examines each file and creates indexes based on such things as album, artist, genre, possibly composer and various other things. This is based on the identifying metadata tags in the music files (so it’s worthwhile to have a consistent tagging system for your music).
Any Windows computer from recent years is a DMS. These typically have the DLNA server function switched on, earlier ones uses Windows Media Player for that service. Network attached storage isn’t a DMS necessarily, but most models comes with DMS software. I run two different sets of software – MinimServer and Media Server on my Synology NAS because they have different and complementary capabilities. An Android tablet or phone also acts as a DMS for any music in its storage.
Next, we have two functions which are related, but subtly different: the Digital Media Player and the Digital Media Renderer. The Renderer is the engine that turns the digital data into actual music: it ‘renders’ the music, in the same way that a graphics program ‘renders’ a final image. A DMP includes a DMR, but it also adds all the necessary stuff to actually make use of the music. It reads the lists of artists and whatnot served up by the DMS and presents them to you, the user, for you to choose the music to be played.
The DMP was for quite a few years the main way that one would interact with DLNA content. Your home theatre receiver would have an input setting called ‘Network’. From that you’d select ‘Media Server’ or some such, then choose ‘Music’, then drill down through the lists presented. How effective all this was depended a great deal on whether your receiver’s remote had a way of jumping you quickly through long lists to find the items that you wanted to play. When you selected a song, the receiver would ‘render’ it into music.
But a DMR can exist independently of a DMP. Increasingly the most efficient way of using DLNA is to use a DMC to send music from the DMS to the DMR. Let me explain!
The DMC is a Digital Media Controller. In just about all cases, this is software on a tablet or phone: iOS, Android or Windows. It talks to both the DMS and the DMR. It reads the lists served up by a DMS and presents them to you to choose what you want to hear. When you make a selection the DMC tells the DMS to send the digital music to the DMR, and hence it plays.
The point of this is two-fold. First, the digital audio streams directly from server to renderer, not through the tablet or phone. So if your music is high resolution FLAC or DSD, there won’t be WiFi bottlenecks (at least between your phone and your other devices). Second, you have a greater choice of controller.
These days most good gear capable of streaming network audio supports DMP and DMR functions, and also has available an app which acts as a DMC. Mostly the app is locked to that brand (or other brands in the same family). The Denon Hi-Fi Remote app won’t stream music to my Cabasse Stream Source. However the Awox Cabasse Stream Control DMC will stream to the Denon DNP-730AE network streamer. But there are lots of third party DMCs as well. I generally like to use BubbleUPnP on Android for this purpose because it populates long lists quickly and allows me a degree of control not provided may other apps. If, however, you’re using an iPad or iPhone, there aren’t many third party DMCs, so you may be stuck with the proprietary app.
Gaplessness
One important consideration with DLNA devices is whether they support gapless playback. Music files are computer data. Computer data is always organised in blocks at some level or other. These bock boundaries usually don’t align precisely with the end of a musical track. So in playing back an album where each track merges into the next without a pause, you may find yourself experiencing irritating brief pauses between each track.
Gapless playback is a feature in which such pauses are eliminated so that the music flows smoothly from track to track. However for this to work it has to be supported by the music itself, by the server, by the player and by the renderer. In general FLAC is capable of being rendered gaplessly, along with iTunes-style AAC and MP3 encoded using iTunes or the LAME encoder.
My Synology NAS’s Media Server software originally did not support gapless playback, and after one of its occasional updates it suddenly did. The Denon DNP-730AE network media player does, but the previous model (DNP-720AE ) reportedly only provided partial support. It would support gapless playback when used as a Digital Media Player (that is, when it was pulling music from the server), but not when being used as a Digital Media Renderer (that is, a controller was being used to push music to it from the server).
If all this is confusing, don’t consider yourself alone. There are an enormous number of combinations in which any single weak link can stop gapless playback. If you’re buying, the best advice is to have the store demonstrate that whichever device you are purchasing is, in fact, gapless (take an album with run-on music with you on a flash drive, preferably in FLAC format, so that you can check. If it’s a player, make sure that it is gapless not only with its own internal interface (ie. it’s acting as a DMP), but also when music is pushed to it by a Digital Media Controller.
Conclusion
All this might make it seem hard. But it’s worth it. I have all my music sitting on a NAS, able to be dialled up in an instant and delivered at full resolution using a tablet as a controller. No switching of discs. If an album is coming towards the end, I can en-queue another before the currently playing content comes to an end.
We do live in wondrous times for the music lover.
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