Chromecast Audio as endpoint? [Delivered; B333]

I’m streaming FLAC to one right now, using bubbleupnp on an android phone (accessing a minimserver on a NAS), and if I understand this UI right (?), it’s delivering 24 192 (to the internal DAC; this is using the line-out)?

Not sure I trust the UI–it could just be decoding 192/24 and displaying the file stats.

I should have all the bits and pieces to get the Chromecast Audio here plugged in via optical to a DAC with a frontpanel display. I’ll try when I have a chance.

The word on the street is that there’s no Cast SDK for desktop apps. Google requires mobile or Chrome browser casting only. The Spotify desktop client doesn’t even support casting to the new Chromecast Audio, but the Spotify iOS app does.

Hopefully the Roon team can talk to Google about getting an exception.

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Google Cast support would greatly expand Roons speaker and remote system options. With iOS and Android as main mobile platforms and the operating systems most used for the remote software, most if not all new wireless speakers (except maybe big brands like Denon and Sonos) will probably support one or both in the future, especially after the streamingbattledust settles down.

My understanding, at least with the original Chromecast, is that you’re not streaming to the dongle from the device you are casting from, you’re sending it enough info so that it can manage the streaming with the cloud-based service. (Casting a tab in chrome is different, obviously.) From the article above, it doesn’t seem like this has changed for the Chromecast Audio.

I’m not sure if there’s any (public) way, even with the SDK, to send it an audio stream from RoonCore. Happy to be wrong.


When you “cast”, you’re directing the cast device to load an app, which is really just a web page (js+html) to be run on the chrome engine. The app is delivered from the cloud. You can also pass some additional information, and there’s a control channel over the LAN so Roon could get messages to its “other half” running on the cast device.

The app can do whatever it wants within the bounds of HTML5 + the additional stuff google has exposed for Cast. Loading a PCM stream from a URL on the local network should be no problem. Playing it using HTML5 Audio should be no problem either.

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Yup, that makes sense, thanks for clarifying!

So it sounds like answer to my original question is “yes”, then?

Sorry, I can’t find which question you’re referring to.

Title and first post.

Nothing is 100% until it’s done, but yeah, I think it’s feasible.

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Now with official support for 96KHz/24bit lossless audio playback (and multiroom sync)

What about going the other direction? Any way for your guys to have Roon act as a chromecast endpoint, so that i can chromecast from apps on my iphone (e.g. podcast app) to my htpc running Roon?

I think that is something for hobbyists to create, like Shairport and Airfoil did for Airplay. It doesn’t make sense from a Roon point of view.

What about going the other direction? Any way for your guys to have Roon act as a chromecast endpoint, so that i can chromecast from apps on my iphone (e.g. podcast app) to my htpc running Roon?

Chromecast isn’t an audio streaming protocol like AirPlay–it’s an entire platform with apps, a runtime engine, a rich set of platform APIs, and so on (plus HTML5/js/normal stuff).

So this question is roughly equivalent to asking “Can you make iOS/Android apps within Roon and route their audio output?”. It would require replicating the whole ChromeCast platform within Roon–not something we are planning to do.

We’ve discussed the possibility of making an “input device” that allows audio to be routed into Roon and then back out through our various streaming backends. This is practical, assuming you don’t care about latency. Some technologies like RAAT are built in a way that could allow for low-latency operation, but it still won’t be perfect. That’s a hard problem–there’s a reason you don’t see a lot of products trying to sling around audio with extremely low latency on consumer/home networks.

@brian thanks for the thoughtful response. Totally understand that this would be beyond the scope of Roon. Hopefully someone (Google!?) will take a stab at doing something similar to this but for chromecast. Then it would make sense for Roon to do the input device route (with the latency caveat you mention).

This is a great idea, especially if you can have it emulate an AirPlay endpoint.


From the CA front page:

“CA readers will also be happy to know that Roon will support Chromecast Audio devices in the coming months. What’s not to like about $35 Roon endpoints?”

This sounds fantastic news. I was initially worried about how Tidal would fit into this but as I understand @brian’s comments above, Roon will be “casting” or delivering it’s audio stream via a URL that the Chromecast Audio can access after Tidal has been processed through Roon.

Think you can synchronise them Brian ? That would put whole home audio in everyone’s pocket.


Would you care to comment on this @brian? Are you working on, or planning to implement Chromecast audio support at some point? I’ve been experimenting with the chromecast audio for the last couple of weeks and find the casting very stable in my densely populated environment, as compared to using Airplay endpoints.


Chromecast support is on our roadmap, and has been for a while.

We haven’t set a timeframe/dates for it yet. I’m not sure where that part of the press coverage came from.

Whether or not we synchronize multiple Chromecasts, or enable them to synchronize with RAAT devices is an open question that will likely not be resolved until we’re into the implementation process.

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