Google Cast target (formerly Chromecast Audio reciever) as Music Provider inside Music Assistant?

[Hedda]

Any chance future roadmap is to make it possible to have Music Assistant act and present as Google Cast reciever / Chromecast Audio target?

What I would like to achieve is to use Music Assistant as a virtual "Chromecast Audio" device to make it be seen as Google Cast speaker(s). As it will then be able to act as a middleware to present any other player/speaker as a Google Cast / Chromecast Audio compatible receiver.

https://en.wikipedia.org/wiki/Chromecast#Chromecast_Audio

That is, have a Music Provider for MA that is presenting virtual Google Nest speakers / Google Home speakers / Chromecast Audio recievers?

If so then could stream audio from all cast apps and devices that support sending Google Audio Casting protocol to Music Assistant, including the official Google Home app.

Is such a Google Cast reciever even techically possible? Is there any Google Cast for Audio / Chromecast Audio receiver source code?

Google does have standalone receiver code but it then depend on manufacturer registering to get a peer certificate for authentication:

• https://chromium.googlesource.com/openscreen/+/refs/heads/main/cast/standalone_receiver/

Can not tell if Music Assistant's custom "cast-receiver" (CastReceiver) was meant to become a Google Cast receiver app in Music Assistant?

• https://github.com/music-assistant/cast-receiver

  • https://github.com/googlecast/CastReceiver

    • https://developers.google.com/cast/docs/web_receiver

      • https://github.com/THEOplayer/samples-google-cast-v3-receiver

Have recieving/target end of Google Cast for Audio (GC4A) protocol been reverse engineered so possible to make DIY Google Cast recievers?

Clients are using challenge-response protocol to authenticate the Chromecast receiver, and these are the relevant messages from the protocol:

• https://chromium.googlesource.com/openscreen/+/refs/heads/main/cast/common/channel/proto/cast_channel.proto

I only read that the original Chromecast Audio receiver devices operate on a heavily modified variant of the DIAL protocol.

Unfortunatly libraries such as pychromecast only seem to work as sender to communicate with Google's officially certified Chromecast targets.

• https://github.com/home-assistant-libs/pychromecast

[sandymac]

i think DRM is the real hurdle.

[dunxd]

This would be great for enabling playing of podcasts from a podcast player app such as Podcast Addict.

Also, in the UK the BBC Sounds player only supports casting to Chromecast from its Android app (presumably it supports Airplay from iOS).

Being able to stream to Music Assistant via Chromecast and Airplay would add lots of flexibility such as being able to stream to speaker groups, control volume centrally, playing from sources that Music Assistant doesn't yet support as Music Providers.

[debackerl]

Today, I use my Chromecast compatible amp as default audio sink for Google Assistant. Problem is that ant announcement from Home Assistant is breaking to playback. If Music Assistant could be a Chromecast receiver, it could sit in the middle, and allow the usage of announcements, pausing the Chromecast playback, and resuming it after the announcement.

But I don't know if the protocol is reversed engineered. I'm just exposing a use case.

[benklop]

There's at least one implementation that I'm aware of - https://chromium.googlesource.com/openscreen/ - obviously not specific to music, but I would expect it to work fine for music..

[huggenknubbel]

Since I have a Denon amp and most of the apps doesn't support they're stupid Denon heos, I would love to see a chromecast receiver.

[spudje]

This would be great indeed. Or at least be able to use individual non-native Google Cast devices like the Voice PE as chromecast receivers.

[marcelveldt]

This is not possible. Cast is closed source

[Borrower543]

Spotify connect is too but there is an emulator for that

[Hedda]

Is that only because of DRM applied preventing media playback? What if stream media that is not DRM protected to it? Could it be done then?

I seen some people have at least found workarounds for Google Cast receiver authentication, see example "Project Shanocast":

• https://xakcop.com/post/shanocast/

  • https://github.com/rgerganov/shanocast

    • https://github.com/rgerganov/shanocast/blob/master/shanocast.patch

There in "Project Shanocast" he has reverse engineered an Android app from Softmedia (which still make their AirReceiver app which can act as Chromecast receivers) to hack togheter a solution that implements Chromecast reciever protocol without using “official” certificates and keys.

I understand that approach is normally a "cat and mouse" game in which Google will try to patch their sender SDK to block non-official certs.

[FX7]

Wouldnt it be possible to achive the same with dlna/upnp? I mean that music assist would act Like a "dlna Receiver" and then redirects the audio to any configured Player?

[Borrower543]

Unfortunatley dlna recievers don't appear in the streaming menus of pretty much all popular media apps.