[Morguito]

Hey guys,

So, I need some help here. I'm running KODI on the latest LibreELEC on Odroid C2.

In KODI, I have two audio output devices which I can select:

-ALSA: Default (AML-M8AUDIO, Analog)

-ALSA: AML-M8AUDIO, HDMI

Ideally, I always want to use my HDMI output because it then leaves all audio decoding tasks to my AVR (Denon s930h), which has a much better DAC (digital to analog converter) than my Odroid C2. 

Really, I'm not being picky here. The difference in audio quality is actually quite noticeable.

The problem is, HDMI works most of the time, but it simply doesn't work with MP4 files.

When this happens, if I change the output to Default (Analog), the audio comes back, but with reduced quality, since it gets decoded by C2 instead of my AVR.

Anyway, my AVR should be capable of decoding pretty much anything, and I'm fairly sure it can decode MP4 files.

Do you have any idea about what's happening? Maybe I'm missing some other configuration?

Here's the log file. I try to play an MP4 movie via HDMI and there's no sound. Then I change to Default (Analog) and the sound comes back. Then change back to HDMI and no sound again.

https://paste.kodi.tv/erucasacos

Thanks in advance for the help,

M.

[pkscout]

On thing to check is to make sure that Kodi is set to passthough audio so that your AVR gets the "raw" audio from the video file instead of something processed by Kodi first.  Go to SETTINGS > SYSTEM SETTINGS -> AUDIO.  At the bottom of that section is a group of settings for AUDIO PASSTHROUGH.  Enable it (if it isn't) and select the formats your AVR understands.

[Morguito]

On thing to check is to make sure that Kodi is set to passthough audio so that your AVR gets the "raw" audio from the video file instead of something processed by Kodi first.  Go to SETTINGS > SYSTEM SETTINGS -> AUDIO.  At the bottom of that section is a group of settings for AUDIO PASSTHROUGH.  Enable it (if it isn't) and select the formats your AVR understands.

Hey man. Thanks for the reply.

Sure, passthrough is definitely enabled, and all formats checked.

The only format that isn't working at all (except when changing output to analog) is .mp4.

M.

[Karellen]

Your audio stream is aac

Very few AVR's decode aac audio format. You need to allow Kodi to decode it and pass the raw signal to the AVR.

You can check that via a google search, or some comments in this thread... https://forum.kodi.tv/showthread.php?tid=330738

I have the Denon AVR-X7200WA and it won't decode aac. I see Multi-Channel In on the AVR display. But the surround works fine.

[Morguito]

Your audio stream is aac

Very few AVR's decode aac audio format. You need to allow Kodi to decode it and pass the raw signal to the AVR.

You can check that via a google search, or some comments in this thread... https://forum.kodi.tv/showthread.php?tid=330738

I have the Denon AVR-X7200WA and it won't decode aac. I see Multi-Channel In on the AVR display. But the surround works fine.

Thanks for the reply man,

Yes, I've read this thread, but I couldn't get any info on how to "make Kodi decode it and pass the raw signal to the AVR", like you said. Could you give me a hand here?

By the way, even if I select "multi-channel" in the AVR, no audio passes through, except, like I said, if I turn my output from HDMI to analog, but then it messes with the audio quality of everything else that was previously working.

I would really appreciate some instructions on how to make it work, man. I mean it.

Thanks again.

M.

[Karellen]

Sure. You are on Linux and I don't know much about the system- audio drivers, settings etc and what their capabilities and limitations are. You may need to check that. I use Windows.

Here are screenshots of my settings. Hope you can see a difference that will fix the problem...

[Karellen]

Also just noticed you have Superrepo installed. Please remove that to receive assistance here as it is on our Banned Add-ons (wiki) list.

[Morguito]

Sure. You are on Linux and I don't know much about the system- audio drivers, settings etc and what their capabilities and limitations are. You may need to check that. I use Windows.

Here are screenshots of my settings. Hope you can see a difference that will fix the problem...
 

Hey there,

The parts that matter really look all the same.

Anyway, I don't think this is a superficial configuration issue. I think this might be one of those things that require edition of deeper configuration files.

[Morguito]

Also just noticed you have Superrepo installed. Please remove that to receive assistance here as it is on our Banned Add-ons (wiki) list.

I didn't even remind it was installed. Actually, no addon from it was installed, as you can see in the log.

Anyway, thanks for reminding me. Already removed it.

[Morguito]

Found a partial fix (more like a workaround, actually).

AAC/mp4 audio works via HDMI when "stereo upmix" is enabled.

The problem is that Kodi will then upmix all my stereo music files, which isn't good because its upmixing capabilities aren't great (in fact I'm yet to find any upmixing process that sounds natural)

So far, either I submit all my non-passthrough files to quality loss via analog output or via upmixing.

Kodi should have an option to "convert aac/mp4 files on the fly", or something like that.

I really believe there's some sort of feature missing in this regard. I've read a lot of threads reporting the same issue, with with apparently no solution (that isn't a compromise).

A third option is to set the number of channels to 2, which enables the option "Dolby Digital Transcoding" under "passthrough" settings, and then enable "upmixing".

This allows the AAC 5.1 audio to be properly processed by the AVR, and in theory, wouldn't upsample my music files (since the number of channels is set to 2). However, it does affect the quality of music files, even though technically it isn't supposed to upsample it.

[Morguito]

UPDATE:

It was all a LibreELEC bug.

Changed to CoreELEC and it all works fine now.

Thanks!

[Karellen]

Thread marked solved.