Stream Multichanell Audio (5.1) using Dolby Digital or Dolby Digital Plus

[iz8mbw]

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Hello.
Is it possible to set Sunshine to use the Dolby Digital (AC3) codec to stream the Multichanell Audio (5.1)?
My setup can handle Dolby Digital, Dolby Digital Plus or DTS but not Multichanell PCM since my Moonlight Client is connected to my TV via HDMI ARC and not eARC (so ARC doesn't have enough bandwith to support Multichanell PCM/MPCM or LPCM).
My setup:

Sunshine on Windows 11 PC -> Moonlight on NVIDIA Shield -> TV -> ARC -> Onkyo AV (5.1) -> Speaker.

Thanks.

[danschne]

@LizardByte-bot
Is that something that is generally doable? I know too little about streaming latencies and/or license fees at the moment to be able to judge this, but there seems to be a decent amount of requests for it (see below). I would love to help with the implemention, but obvisouly only if the idea/approach itself is viable to begin with.

https://github.com/orgs/LizardByte/discussions/431
https://ideas.moonlight-stream.org/posts/360/add-support-for-5-1-encoded-audio-stream
https://ideas.moonlight-stream.org/posts/59/some-sort-of-ac3-support-for-receivers-with-dd-only

[ReenigneArcher]

LizardByte-bot is not some AI bot or anything that will respond to you.

With that said, I am no expert on audio streaming, but I believe it would be fairly straight forward to implement if you want to take a crack at it. I suspect it would require changes to both Moonlight and Sunshine, with the client requesting the type of audio that it wants from Sunshine.

[MwenDavo]

Hi. I've looked into this, since similar to OP my home theater only supports 5.1 through Dolby Digital (AC3).
There are ways to convert PCM 5.1 to DD through different software, such as the a52 encoder on Alsa-Plugins on Linux and using APO Drivers on Windows to enable real-time AC3 encoding (Windows 11 removed the DD encoders and decoders that came by default so you need to enable them back with this for the APO Driver to work).
It would be a nice feature to allow converting to DD from Sunshine. I think it would need to be implemented with ffmpeg for the cross-platform support.

[danschne]

I was also more thinking of encoding to DD in Sunshine (is that a license fee problem or something?), and just passing that through Moonlight to whatever our audio devices are.