5.1 audio encoding problem on AMP.

  • 18 December 2022
  • 17 replies
  • 249 views
McCallister
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Hi everyone, through an HDMI switch connected to AMP, I stream content from different sources to the TV, ps4, intel NUC 7th generation, satellite decoder and more.
When I use Netflix on the NUC, even though 5.1 audio is enabled in the PC audio settings, the PCM stereo audio format icon appears in the smartphone Sonos app.
One would think there might be an audio driver issue however if I connect the PC to the ARC, the data stream is recognized correctly and the PCM 5.1 icon appears on the app.
Could this be an AMP firmware issue?

Thanks

17 replies

Ken_Griffiths

@McCallister, 
Forgive me, I’m just seeking some clarification ..do you mean that the ‘HDMI Switch’ is connected to your TV (HDMI port) and your Sonos AMP is connected to the TV’s HDMI-ARC/eARC port? Otherwise I’m confused with your opening sentence?

You then mention if your PC is connected to the ARC … is that the ‘Audio Return Channel’, or do you mean a Sonos Arc (as listed in your profile)?

Sorry to seek clarification from you, but I find your post a little confusing, but maybe it’s me.🤷‍♂️

McCallister
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Hello,

I attach this very explanatory image.
Connecting the ARC soundbar on port 1 no problem, on the Sonos app I see 5.1 encoding.
If I connect AMP to port 1 instead of ARC, the app displays stereo PCM audio encoding.

 

 

Ken_Griffiths

Ah you have a combined audio extractor/switch not just an HDMI-Switch - I understand now. Thanks for clarifying🙏. It sounds like your Netflix App audio is somehow being transcoded to stereo somewhere en-route to the soundbar. I would try a few things - a different HDMI cable between the Intel NUC and your extractor and also check the settings on your extractor. Try it with eARC disabled, so that it switches to ARC and check its output and see if either 5.1/7.1 output works for you.

Hope that assists you to resolve the matter. If not, I would speak to the support desk of your manufacturers (Feintech) switch/extractor and see if they can assist… sometimes a firmware update for the extractor can resolve these type of issues.

McCallister
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I don't think the switch is the problem, because when I connect the ARC soundbar, the audio is encoded correctly, while by connecting the AMP amplifier in home theater configuration (FR/FR, SUB, SR/SL) I get stereo pcm signal.

Ken_Griffiths

I don't think the switch is the problem, because when I connect the ARC soundbar, the audio is encoded correctly, while by connecting the AMP amplifier in home theater configuration (FR/FR, SUB, SR/SL) I get stereo pcm signal.

The port on the Sonos Amp is HDMI-ARC and the port on the Sonos Arc is HDMI-eARC - that’s why I suggested you switch the Feintech device to use ARC - iIRC it’s the button on the far right to disable eARC. You may just need to setup the handshake again - but it could still be a problem caused by the extractor and if the problem persists you might need the latest firmware update for the Feintech extractor. Anyhow try my suggestion first and then speak to Feintech Support (if necessary).

McCallister
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Perfect, I'll do these tests later.

Thank you.

McCallister
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So there should be two problems:

1) Apparently AMP only supports two audio formats, PCM stereo and Dolby Digital.

2) The NUC7 supports several audio formats (PCM multichannel, DTS, DTS-hd, etc.) but not Dolby Digital.

A firmware update of AMP would be desirable in order to support some other multi-channel audio formats.

Ken_Griffiths

So there should be two problems:

1) Apparently AMP only supports two audio formats, PCM stereo and Dolby Digital.

2) The NUC7 supports several audio formats (PCM multichannel, DTS, DTS-hd, etc.) but not Dolby Digital.

A firmware update of AMP would be desirable in order to support some other multi-channel audio formats.

I thought the AMP supported the DTS 5.1 codec? …but absolutely none of the Sonos products support DTS:X/HD.

Also the AMP/Beam (gen1) also do not support the multichannel LPCM codec as that needs an eARC connection.

I’m quite surprised that the Intel NUC does not support Dolby Digital codecs as they are rather popular with the streaming services like Netflix etc.

edit: Maybe try forcing the audio output codec on the Intel NUC as DTS 5.1 and see if that works for you, although the App you’re using might just fallback to PCM stereo anyway unfortunately, but worth a quick try perhaps.

McCallister
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I spent some time tinkering with the NUC, updated the bios and display port chip firmware to the latest version but nothing to do.

In the audio properties I see the 5.1 channels and the supported formats (DTS and Dolby Digital) but when I run the audio test, I hear the sound coming only from the two front left and right channels.

I just have to try with another PC.

McCallister
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Just tried with the notebook, nothing! At this point I think there may be some compatibility bug between AMP and Windows 10…

If I use PS4 as source, 5.1 audio is encoded correctly.

Ken_Griffiths

Just tried with the notebook, nothing! At this point I think there may be some compatibility bug between AMP and Windows 10…

If I use PS4 as source, 5.1 audio is encoded correctly.

Others seem to have it working on Windows 10, but perhaps see if this link might assist you:

https://www.partitionwizard.com/partitionmagic/how-to-set-up-5-1-surround-sound-on-pc-win10.html

McCallister
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Ken, everything is set up correctly :(

Ken_Griffiths

Ken, everything is set up correctly :(

When you had the Arc connected the Intel NUC, it was sending the audio ‘uncompressed’ to the Arc as multichannel LPCM - you need to get the Intel NUC (or your laptop) to transcode the audio-out to ‘compressed’ Dolby Digital 5.1 - so I’m guessing there is a setting somewhere to do that. The Amp will not handle uncompressed LPCM 5.1 audio as that codec requires eARC on the audio receiver, hence its falling back to PCM 2.0 stereo only.

So perhaps look for a setting to transcode the digital audio-out in your audio card driver settings to DD 5.1 or even DTS 5.1 in windows.

 

McCallister
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Update: today I did some other tests with a laptop where win11 is installed. The situation has not changed even if many dolby codecs would be available. Audio coming from PC to AMP is always encoded to PCM stereo :(

 

Ken_Griffiths

Well it shows support for the DTS and Dolby Digital codecs, so you just need the Intel NUC/chosen App to play either one of those codecs, I suspect - I’m not sure though where in windows you change those settings. Perhaps someone who uses that device/OS might chime in and be able to assist you, or perhaps check with the Intel NUC community. See below link…

https://community.intel.com/t5/Intel-NUCs/NUC-11-audio-DTS-Dolby/m-p/1430741

Airgetlam

You may want to double check the settings on your sound card as well, and not what appears to be, based on the image you’ve attached, the monitor itself. And potentially whatever player you’re using on Windows 11 might also impact the type of signal being sent to the sound card, which then would pass that on to the monitor/TV set. 

Because you’re using a PC, there’s a lot of things that can affect the signal type. most people tend not to use PCs as their source, but instead blueray players, cable boxes, satellite boxes, most of which also have (sometimes) sound settings, although many work with CEC, which the PC likely won’t. 

Bruce
McCallister
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Happy New Year to all.

Problem solved by simply reinstalling the Netflix app again. Unbelievable... Thanks anyway for the support.

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