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Adventures in Google Cast development: Day 1

Google's developer preview SDK for Google Cast -- the streaming technology that's powering the Chromecast hardware -- is up and running. It looks like adding Google Cast support will be ridiculously easy with little coding overhead for anyone who wants to jump on the bandwagon.

Although the Chromecast stick we ordered here at TUAW will take a couple of weeks (at least) to arrive, the iOS SDK is already live and an iOS-specific project can be found over at Github.

It consists of an app that more or less runs (you may want to comment out the bits about the playProgressSlider) and transmits arbitrary media to a Chromecast receiver.

Unfortunately, as far as I can tell, you can't immediately use the receiver HTML on your local network to test transmission. Google writes in its Xcode README:

Getting Whitelisted: App IDs and receiver location. You will have to be whitelisted as a developer before you can specify your own App ID and receiver URL, or test the included receiver. For whitelisting instructions, see https://developers.google.com/cast/whitelisting.

You send along details about your testing device for whitelisting for your app.

In all, it's a bit disappointing that you can't just simulate a receiver for immediate development and testing -- assuming I'm reading all the pages correctly -- without whitelisting a receiver URL and an app. Once you have a receiver URL set up and whitelisted for an app, you can use the receiver.html code included with the sample. I'd been hoping you could just use the built-in OS X Apache server without all the fuss and bother.

The sample is remarkably simple even if it is a bit hard to read. You start listening for a device. If one is found, you establish a media protocol message stream; that is, you begin talking to the device. You point the media content to a URL and set yourself to listen for updates. At any point, you can push request like pause and play to the device or listen for status updates from the device using a delegate protocol.

You can learn more about Google's developer preview at the Google Cast site.

Fun facts:

  • Google Cast uses SSDP for device discovery. Details are in the GCKDevice.h header file. You receive notifications as device appear online or disappear.

  • You can buy an inexpensive router if your Wi-Fi reception is iffy. This one is cheap and reasonably well reviewed. You should also be able to create a network if you have a Mac along with you.