[firstofthewinterale]

I was given a surround sound music file in .ac3 format. Kodi 21 plays the music itself without problem; however, Kodi doesn't seem to actually recognize it's playing an audio file since the music visualizer doesn't display as with other music. Therefore, I'm guessing there isn't anything in the code telling it to treat .ac3 files as music. I'll leave this for a dev to decide whether to report it as a bug or otherwise how to handle it.

[jjd-uk]

It's because it's a passthrough format, the music visualisations only work with audio decoded by Kodi. Turn off AC3 passthrough in settings and the visualisation will work.

[firstofthewinterale]

Since it's a "surround sound music file" turning off passthrough would defect the purpose since it would no longer play in surround sound. Also, I don't understand the assertion that "the music visualisations only work with audio decoded by Kodi." I have a couple other surround sound music albumss which are Dolby TrueHD and Atmos in mka and m4a formats and all those files DO show the music visualization when playing even though passthrough is enabled in Kodi. That's why I thought the issue was that Kodi just wasn't recognizing the ac3 file as music. So, what could explain this discrepancy?

[jjd-uk]

Is you disable AC3 it will be decoded to LPCM and depending on the capabilities of what you are connecting to the 5.1 channels will be kept. Are 100% sure the TrueHD is being bitstreamed via passthrough and is not being decoded?

[HomerJau]

Since it's a "surround sound music file" turning off passthrough would defect the purpose since it would no longer play in surround sound.

That’s not correct, when not using pass-through Kodi decodes multi-channel formats to 5.1 or 7.1 so it’s still surround.

However, for Atmos and DTS:X Kodi only decodes to 8 channels (7.1) max as its decodes the backward compatible ‘core’ layer only. If you don’t have more than 8 channels you’ll hear same as if your AVR decoded Atmos or DTS:X. If you do have > 8 channels then pass-through is the only way to hear the full mix.

[firstofthewinterale]

When I disable passthrough, my various surround sound test files confirm there is no surround. However, when passthrough is enabled, those same test files (including a Dolby TrueHD 7.1 mkv) do produce surround. However, I will note that my surround system can only do Dolby and DTS 5.1. Therefore, I presume there's some sort of fallback stream or core that's being used. So, I think that's why there is surround correctly going to each of the speakers using the TrueHD 7.1 test with Kodi passthrough enabled to my 5.1 system. But, that being said, we are getting near the edge of my knowledge on this subject.

[jjd-uk]

What type of connection? SPDIF or HDMI as Multichannel LPCM is only possible with HDMI, and even then not all devices support Multichannel LPCM.

[firstofthewinterale]

Since it's a "surround sound music file" turning off passthrough would defect the purpose since it would no longer play in surround sound.

That’s not correct...

It is correct *in my situation* because I don't make claims without testing them first and I have already confirmed it using multiple different surround test files = when passthrough is turned off in Kodi none of them produce surround sound. Since the connection used in my setup is SPDIF, the correctness of my statement that I don't get surround without passthrough has also been confirmed by @jjd-uk stating above: "Multichannel LPCM is only possible with HDMI"

[HomerJau]

You didn’t mention you were using SPDIF. I assumed pass-through meant HDMI.