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Author Topic: ALSA .. Pulse ....settings?  (Read 2384 times)

pepar

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ALSA .. Pulse ....settings?
« on: July 13, 2021, 03:54:32 pm »

So I am poking around settings on my Debian/Intel NUC (where I have the correct ALSA HDMI device selected) and I see a Pulse panel where I can select the format/output channels .. so I select "7.1 HDMI (Plugged in)."

Puzzling as I have been watching The Expanse and noticed my pre/pro had been receiving 5.1 PCM while the Pulse setting was to 2.0 and unplugged. Nothing souinded amiss. A bit later today I will have an opportunity for another home theater session to see/hear if anything has changed.

Is there a Dummies Guide To Linux Audio ... Windows Edition?

Thanks,
Jeff
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mwillems

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Re: ALSA .. Pulse ....settings?
« Reply #1 on: July 13, 2021, 04:03:50 pm »

ALSA is the lowest layer of linux audio, and the pulseaudio sound server sits on top of the ALSA devices in much the same way that direct sound sits on top of WASAPI on windows.   Picking a hardware direct ALSA output in MC (outputs with names that begin "front:" or "hdmi:" or "surround:")  will bypass pulseaudio entirely, but you can also choose to have MC talk to pulseaudio by choosing the "pulse" output device in JRiver.  Folks might choose to do the latter if they want to be able to have sound from other sources and JRiver at the same time, for example.  Generally if you only use JRiver for audio output and your devices are well-beheaved, it's better to use the hardware direct output devices to avoid resampling and/or the pulse mixer.

So it's most likely that you previously picked a hardware direct output option and JRiver was just bypassing pulse.  If you want MC to use the settings in the pulse panel, you'll need to select pulse as your output device in JRiver, but be aware that pulse may be doing various things under the hood that you might or might not want.  All are configurable, but usually require modifying config files.
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pepar

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Re: ALSA .. Pulse ....settings?
« Reply #2 on: July 13, 2021, 04:20:15 pm »

Ahhh, whew, thanks! I have an "ALSA" HDMI device selected in MC. Apparently, the nefarious PulseAudio is sidelined.
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pepar

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Re: ALSA .. Pulse ....settings?
« Reply #3 on: July 20, 2021, 05:42:23 pm »

I am still struggling with my Debian/Intel NUC not bitstreaming, i.e. outputting the audio codec, to my prepro. The JRiver app correctly shows the source audio, DTS, DTS-HD MA and DSD/DSF so far. My prepro shows only 5.1 PCM regardless.

I have every setting I could find - there aren't many - in Debian set to what seems correct. There is an ALSAMixer that doesn't seem to have any relevant settings. There is a PulseAudio something or other which, as I understand it, isn't in the chain if I select an "ALSA" HDMI device in MC.

To MC now, I have bitstreaming selected and have an ALSA HDMI Dev=0 device selected. There must be over twenty options there, so the odds of me having mis-selected something seems high. But I just don't see it. I have tried an "hw" HDMI that specifically has in parentheses something about direct, no conversions. Nothing I have tried has worked.

First, perhaps my hardware isn't capable of outputting the audio directly? How would I determine that?

Beyond that, is there a Linux Audio for (Windows) Dummies? I am accustomed to directly controlling my audio in, out, yadda yadda, and Linux' "controls" appear to be for everything but audio.

Jeff

Adding on here - the kit is Intel-NUC-D34010WYK w/audio listed as " 7.1 digital + analog stereo headset". It is further listed as having Intel HD Audio. That sounds capable, doesn't it?

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mwillems

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Re: ALSA .. Pulse ....settings?
« Reply #4 on: July 20, 2021, 07:42:24 pm »

So I've never actually used the bitstreaming functionality in JRiver, but have a look at the audio path in JRiver during to see what's going on (the little gear or faders just down and to the right of the search box).

It's possible you might need to disable volume control or output format to get bitstreaming to work as expected, but I'm not sure as I've never used it.  Audio path should tell if the issue is in JRiver.
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pepar

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Re: ALSA .. Pulse ....settings?
« Reply #5 on: July 21, 2021, 06:59:23 am »

Wow, what a feature-rich piece of software ..

I took your advice and came up with this. Puzzling. I have no idea where "32-bit" came from; the codec is 24-bit. Plus the DTS-HD MA is 7.1. On the positive side, the path is "direct."

So there are extra bits and two missing channels. Any ideas what is happening?

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mwillems

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Re: ALSA .. Pulse ....settings?
« Reply #6 on: July 21, 2021, 08:33:57 am »

So my understanding is that you can't use volume control or DSP with bitstreaming (I actually thought the bitstreaming option automatically disabled them?), but your screenshot shows that you're using internal volume so some setting somewhere isn't working as expected.  I assume your current bitstreaming setting under the audio options is "HDMI"?  As an experiment, try changing the bitstreaming setting to "Custom" and check all the boxes that your output device supports, then start playback and look at the audio path and see if that changes anything.

If that doesn't change anything, then, as an experiment, try going into audio settings and disabling volume control (Volume Mode:Disabled).  Then open the "DSP & output format" sub-menu from the audio options menu.  In the DSP & Output format menu try unchecking *all* the boxes (including output format!).  Then, with those settings in place, try playing something and see what audio path says.

If that doesn't make a difference, I'm at a loss, but report back and maybe someone else will have some ideas!
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pepar

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Re: ALSA .. Pulse ....settings?
« Reply #7 on: July 21, 2021, 10:13:52 pm »

I returned MC’s device to ALSA HDMI DEV=0 something or other. Select Disable Volume. Watched a movie with 7.1 DTS-HD MA. Prepro still reports 7.1 PCM. With that input my prepro has limited modes available to select. I selected Direct.

The JRiver apps shows 0 for output volume, but I could tell that the volume was maxed as I needed to turn down my prepro.

Audio Path now reports 48KHz 64bits 8-channel.

I will try the DSP & Output settings you suggest but I am not optimistic. With my prepro receiving PCM the modes I can select are limited. I will say that The Bourne Legacy sounded as good as ever, maybe a bit better.

My next move is to image the Debian installation, wipe the SSD, install Windows and try MC. If that allows me to properly bitstream the codecs to my prepro, that’s will be my path forward. Regrettably, Windows of course will be a huge PITA .. overkill for a simple MC server and clients.

Edited: Sorry for the grousing. If I get the operation I need in Windows I will be back to work on getting it to work in Debian. Thanks for your help!
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pepar

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Re: ALSA .. Pulse ....settings?
« Reply #8 on: August 04, 2021, 04:32:30 pm »

I am back with more data. To recap, I am using a 4th generation embedded i3 with Intel HD Graphics 4400. I tried another media player in Debian and played a 7.1 DTS-HD MA movie file directly. I was never able to pass the native codec to my pre/pro; 7.1 PCM is what it listed as incoming. I was going to install and try VLC but decided to install Win 10 and MC next. With that combo I could pass the 7.1 DTS-HD MA to my pre/pro. So it can be done with the hardware I have.

I really do not want to use Windows for Media Center/Library Server. What the heck do I need to do to get MC/Debian to pass the codecs? Is it a Linux driver issue perhaps?

Jeff
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bob

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Re: ALSA .. Pulse ....settings?
« Reply #9 on: August 05, 2021, 10:44:36 am »

Did some querying the dev group on this.
Only DSD bitstreaming is implemented on Linux at this time.

Until we get time to do that on Linux, I'm going to remove those options.
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pepar

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Re: ALSA .. Pulse ....settings?
« Reply #10 on: August 05, 2021, 11:54:17 am »

Alrighty, that is progress!

I get the impression that most MC users let it decode as well as handle a boatload of other processing, even room correction. My usage seems like an outlier. So Iíd guess bitstreaming audio codecs isnít going to be added any time soon?

Jeff
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bob

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Re: ALSA .. Pulse ....settings?
« Reply #11 on: August 05, 2021, 11:58:25 am »

Alrighty, that is progress!

I get the impression that most MC users let it decode as well as handle a boatload of other processing, even room correction. My usage seems like an outlier. So Iíd guess bitstreaming audio codecs isnít going to be added any time soon?

Jeff
I can't say for sure. We talked about it a bit just now but there are other projects ahead of it.
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