DIALing up the competition
Last week, as I was fiddling around in the lab, I realized just how many of the devices in our lab were quietly using the DIAL protocol.
Example: I opened YouTube on my phone and tapped the “Cast” button, only to see a long list of devices including the TiVo Roamio, Roku 3, Chromecast, and even two generations of Google TV.
DIAL, or Discovery And Launch, is the protocol used for Chromecast, and, increasingly, other devices. It was developed by Netflix and YouTube, with a little help from Sony and Samsung, and has gained support from a number of other big players in both content and hardware.
In a nutshell, DIAL enables apps on 2nd-screen devices (such as your mobile phone) to discover and send content to 1st-screen devices (i.e. Chromecast or Roku) on the same network.
How does it work?
From the user’s perspective, you launch an app. Let’s say it’s Netflix. You launch it from your mobile device and choose an output device on the same wireless network.* Let’s say it’s Chromecast. Then, you can start playing content from your mobile device, and it sends a signal to the Chromecast to go and retrieve that content.
This means that the content streams directly from The Cloud to the DIAL-enabled device — not from the mobile device. This frees up your phone for checking email, browsing the web, searching out other titles to play, texting people, and all the other things we do with our phones/tablets.
Most importantly, it means that the second-screen experience won’t drain your battery life and then grind to a halt. Even with the phone powered off, the video plays on.
*Because the devices need to be able to talk to one another over the wireless network, DIAL won’t work on networks with Access Point(AP)/Client isolation – i.e. don’t bother bringing your Chromecast for the hotel room.
Here’s the tech talk of it. DIAL relies on UPnP (Universal Plug n Play), SSDP (Simple Service Discovery Protocol), and HTTP (Hypertext Transfer Protocol).
DIAL consists of two parts: DIAL Service Discovery and DIAL REST (REpresentational State Transfer). In the first part, the DIAL client device (i.e. your phone) discovers DIAL servers (i.e. a Roku, Chromecast, etc.) and obtains access to DIAL REST on those devices. DIAL REST then allows the client device to query, launch, and stop apps on the DIAL server.
DIAL-enabled Devices (and how Chromecast differs)
Several of the devices in our lab already support DIAL, even though some of those devices are a couple years old. And because DIAL is based on UPnP, it may be possible to add DIAL support to other existing boxes through a software update.
Chromecast is a little different in that it uses Google Cast, which is based on DIAL but includes a few extras (of course it does) in the way of playback controls. It also has a more stable YouTube implementation than the other devices (it seems that way to us, anyway).
Chromecast also carries the distinction of using HDMI-CEC (Consumer Electronics Control), for controlling your TV through the HDMI port. All you need to do is find a piece of content on your phone and send it to the Chromecast – it’ll then turn on your TV, switch to the right input, let you change the TV volume, and so on. This is a great feature and we wish more of the devices in the lab had it.
What apps support DIAL?
Currently, only a handful of apps use DIAL – on most devices it’s Netflix and YouTube only. Chromecast currently has a handful of other apps such as HBO Go, Pandora, and Hulu Plus.
More interesting is the DIAL name registry, which shows us which apps may be using DIAL in the future. Not surprisingly, Turner Broadcasting has entries for all or most of its apps, and Comcast is on the list as well. In the OTT space, Aereo, Redbox Instant, and Crackle are all on the registry. And as a heavy Spotify user, I was thrilled to see it listed there too.
However, just because a name is on the DIAL registry doesn’t mean that it will ever end up on Chromecast, or even have a working DIAL implementation – just that the app maker has started tinkering with DIAL in some capacity. As of this writing, the Google Cast SDK is still being finalized and Google is keeping the Chromecast partners to a select few. However, Google promises a busy 2014 on the Chromecast front, with a goal of bringing as many apps to the device as possible. Needless to say, we’ll be watching.