[SOLVED] AAC multichannel doesnt work


#1

Odroid C2, CoreELEC 8.95.7.

When I have Audio output setuped to the 2.0, AAC multichannel (tested 2.1, 7.1) doesnt work as multichannel on passthrough. AVR shows and play it like stereo. DTS/DD etc. works fine, when passthrough, which is expected behauviour (output settings shouldnt matter when passthrough).

When I setuped Audio output to the 5.1, AAC multichannel works in both passthrough/decode (and AVR shows PCM).

For the record, AVR is Pioneer VSX-930 and it knows AAC by specifications.


#2

As far as I understand AAC pass-thru is not supported by Kodi.
There are only two options:

Audio output 5.1…etc.
With this Kodi decodes AAC internally and transmits resulting raw multichannel PCM to AVR

Audio output 2.0
Here more than 2.0 is only possible by enabling DD transcode.
AAC is converted to DD which is not a lossless conversion.


#3

Ah, didnt know that. Thank you for information, I will try adress this to the Kodi team then…


#4

There is no such thing as passthrough for AAC since no existing reference amps support it.


#5

hmm, thats strange.

But anyway, then would make sense to differentiate AAC and rest of DD/DTS…, and make option passthrough avaible only for audio streams, which are in fact possible to send through passthrough.

I will adress this to the Kodi community anyway, I understand this is offtopic here. Main thing is that workaround exists :slight_smile: (switch temporarily to decode, for those whose prefer passthrough in other cases)


#6

Maybe I understand how it is…

AAC is not possible to passthrough, so Enable passthrough option doesnt have affect on this particular codec. So even when I have “passthrough enabled”, it doesnt means all audio goes passthrough (not as I though: global passthrough), but only supported audio goes passthrough. Guessing that supported codecs are those, who have option in Passthrough settings… (?)

Because that AAC just got decode all times, and when I setuped 2.0/5.1 pass/not pass? Just guessing, as I think when I enabled 5.1 output and use 7.1 AAC, AVR shows PCM, and shows it gets 8 channels (not practical problem, as AVR has setuped correct number of speakers connected, but worth mention/question this)