DLNA Certification: What It Means for Streaming Video

Four years ago when I wrote about the Digital Living Network Alliance (DLNA) for Home Theater, I explained the basic certifications used in streaming media around a home network. Watching videos streamed from a computer to a media player connected to a TV was still new. DLNA certifications ensured that the computers and devices storing media files could easily be found and stream to a media player.

Over the past four years, digital media streaming has exploded. It’s everywhere—from sharing digital photos (does anyone print photos anymore?), to streaming a missed TV show on Hulu Plus, to watching high-definition movies on Vudu. Internet and router speeds have increased to accommodate streaming high-quality audio and video. Smart TVs have built-in media players.

Tablets and smartphones have become a part of our home network. They stream media from our computers, network attached storage (NAS) drives, and other media servers. We stream media stored on our mobile devices to our TVs and A/V receivers. We use our phones and tablets to control home network streaming.

And TV providers have joined the party. They see the benefit of home network media streaming and will soon be just another part of our home media streaming experience.

DLNA Basics
The purpose of DLNA is to be sure that all the devices in your home can communicate easily, creating a reliable streaming experience. To become DLNA certified, a device must be able to satisfy certain criteria, including: discovery of files stored on devices connected to your home network; control of playback, including play, pause, rewind, and fast-forward; ability to play compatible file formats (MPEG2, JPEG, AAC LC, MP3, and many more); and Quality of Service (QoS) that prioritizes streaming video, giving it more bandwidth (speed) than data files, e-mails, and so forth.

With DLNA-certified devices, you should be able to turn on a media player—whether it’s a Smart TV or a Boxee Box—see a list of your media servers, pick out a file you want to view or hear, and play it using the player’s remote control without getting a message that the file is incompatible and without waiting endlessly for it to play.

DLNA has created specific certifications for the roles of different devices in your home network, including digital media servers, digital media players, digital media controllers, and so on. The required features may be embedded in a devices instruction set—the core firmware for the device—or there may be DLNA software that is added to the device.

The DLNA home network begins with digital media servers (DMS) that store your files and can be searched by media players. You may have saved media files on your computer, but a media player must be able to find the computer on your home network, then find the files on your computer. There is software that can be added to a computer or NAS drive that turns the device into a media server. Routers are increasingly DLNA certified, so you can stream media from a USB external hard drive connected to the router.

A DLNA-certified digital media player can be a standalone device like a WDTV Live player, or it can be a feature built into Blu-ray player or smart TV. The media player will find the files on digital media servers, then play the one you choose.

The DLNA digital media renderer certification is similar to that for a digital media player. I can’t think of any renderers that aren’t also media players. A media renderer cannot find the files on your home network. Instead, you must stream (push) files to it using a digital media controller. A media controller finds files on media servers and then sends the chosen file to a media renderer. Smart TVs, Blu-ray players, and many media players include this certification.

Mobile and Software DLNA Certifications
Four years ago, the concern was to transfer files on mobile devices to a computer or media server. To view the photos we shot on our phones or stream saved videos, we had to transfer and save them to a media player or computer. Or we wanted to transfer files wirelessly from our computers to our smartphones. DLNA mobile certifications were mobile digital media uploaders and mobile digital media downloaders.

Now we are more likely to pull out our tablet or smartphone and stream a video from our NAS drive, or watch a slideshow saved on our computer. Most mobile phones and tablets aren’t DLNA certified, but there are a number of apps that are. DLNA began certifying software in 2009. With DLNA-certified software, these apps will seamlessly fit into a home network. Some play media from your media servers. Others act as media servers so you can play files stored on your phone. Many so-called streaming apps are actually media controllers.

The Twonky media server was one of the first available for computers. The DLNA certification ensures that your computer will be seen by media players and media controllers. Twonky is now one of the DLNA-certified apps available for smartphones and tablets.

Premium Video
The Premium Video certification is an exciting breakthrough in streaming media. DLNA has covered private media streaming of files we own and have saved to our computers, NAS drives, and media servers. Streaming content from TV providers has been another story. The movie and TV studios, as the cable and satellite companies, needed assurance that their streams couldn’t be accessed and copied.