Three-Minute Tech: DLNA
If you've ever wanted to stream music or video around your house—say, from your laptop or your smartphone to your HDTV—you know it can be a bit of a pain. It's often complicated enough that we have to write articles to help you, say, move audio around the house. Wouldn't it be a lot simpler if it moving media around your home network were standardized?
It turns out, it sort of is standardized. At least, there's a dominant standard to allow digital devices to talk to one another for the purposes of streaming video and audio around your home network. That standard is DLNA, or Digital Living Network Alliance.
DLNA isn't so much a standard as it is a trade organization. The non-profit group was founded primarily by Sony about nine years ago, and now includes a couple doezen promoter members and nearly 200 contributor members. The promoter members, the big dogs, include companies like Microsoft, AT&T, Comcast, Motorola, Intel, Hewlett-Packard, Dolby, Samsung, Verizon, and more. Notably absent from the list? Apple. Apple uses its own protocols for device discovery and streaming. So while a lot of people say a device "supports DLNA", what they really mean is "it is DLNA Certified."
The DLNA group establishes some standards for how compatible devices will be discovered on your home network, how they'll control each other, and how they'll communicate. When you go to the Video menu on your PlayStation 3, then choose Search for Media Servers, it's using the Universal Plug and Play (UPnP) networking protocols to look for devices on your network that are essentially rasing their hands and saying, "Hey! We speak the same language!"
What it is, and isn't
What does it mean to be DLNA Certified? Unfortunately, that gets a little confusing. There are different classes of DLNA devices. Some are servers (devices that hold the content you're trying to stream, like your PC) and others are what the DLNA refers to as renderers (devices that will play back the audio, video, or photos, like your HDTV). The third class of device is the controller, which is sort of a traffic cop that finds the servers and tells it where to send data. For example, you may have a phone that will find the video files on your DLNA server and tell it to play one to your HDTV—that's a controller. These days, a lot of devices fulfill multiple roles; a modern tablet could be a DLNA server, controller, and renderer.
If your products are DLNA Certified, they should be able to find each other on your local home network, and send music, video, and photos to each other. That's about all the specifications are really meant to guarantee. Devices are supposed to communicate to each other about which file formats they support, but it doesn't always work right. Similarly, it's not uncommon for some devices to list music or video that you have deleted, or not to find newly added files, simply because they haven't refreshed their indexes.
The DLNA group doesn't mandate any particular interface, either. That means different devices might present all your music and videos in a different way, which can be confusing and annoying.
That's not meant to scare you off. DLNA Certified devices usually work together quite well, and allow you to stream your media around your home network without any complicated setup.
How to get DLNA devices and software
I'm not kidding when I say there are far too many DLNA Certified devices. DLNA Certified products may have their flaws, but the program has been generally a huge success. There have been around 10,000 products to be DLNA Certified over the years. The DLNA site has a product search page that can help you find one, and a mobile app if you want to do a product search while walking around a big box electronics store.
If you have a Windows PC, the version of Windows Media Player included in Windows 7 and 8 supports DLNA. It can stream to DLNA devices, control them with the "Play To" function, and be remote-controlled by other DLNA Certified controllers. On Mac, there's no built-in support, but you can use well-regarded applications like Twonky. An app like media:connect can add DLNA support to your iPhone or iPad. Many Android phones are already DLNA Certified. The official DLNA product search page uses annoying model numbers that are hard to understand, but the manufacturer's web pages will often list DLNA Certification in the specs. The Google Play store has several apps that support DLNA, too.