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So I'm having trouble with my Apple TV/XBMC/AV Receiver setup. Files encoded with either AC3 or DTS send the encoded audio stream directly to the AV receiver and it decodes it perfectly, showing "Dolby Digital" and "DTS" in its display.

However, movie files with AAC 5.1 audio do not. I don't get any sound out of my receiver until I select the "Downmix multichannel audio to stereo" box. I have to set my AV receiver to convert the (now downmixed) stereo signal back to either Pro Logic or Pro Logic II to get some sort of 5.1 audio.

Is there a way to fix this? I know my decoder probably can't handle or doesn't understand AAC 5.1, but maybe there's a way I can set XBMC to convert it to AC3 on the fly before passing it to the AVR.

The box is an STR-K1500 by Sony (the first revision, without HDMI). I'm passing audio to it from the Apple TV via optical.

Thanks!

Guille779 Wrote:So I'm having trouble with my Apple TV/XBMC/AV Receiver setup. Files encoded with either AC3 or DTS send the encoded audio stream directly to the AV receiver and it decodes it perfectly, showing "Dolby Digital" and "DTS" in its display.

However, movie files with AAC 5.1 audio do not. I don't get any sound out of my receiver until I select the "Downmix multichannel audio to stereo" box. I have to set my AV receiver to convert the (now downmixed) stereo signal back to either Pro Logic or Pro Logic II to get some sort of 5.1 audio.

Is there a way to fix this? I know my decoder probably can't handle or doesn't understand AAC 5.1, but maybe there's a way I can set XBMC to convert it to AC3 on the fly before passing it to the AVR.

The box is an STR-K1500 by Sony (the first revision, without HDMI). I'm passing audio to it from the Apple TV via optical.

Thanks!

* davilla sings the xbmc version song.

davilla Wrote:/me sings the xbmc version song.

Oops. Sorry about that. Version is 9.11 r26018

Guille779 Wrote:Oops. Sorry about that. Version is 9.11 r26018

Dharma beta1 just tagged (http://mirrors.xbmc.org/nightlies/osx/) give it a try.

I'm having a very similar problem. AC3/Dolby/DTS multi-channel audio (as well as traditional stereo sources) all play fine and are passed to my receiver. However AAC encoded multi-channel audio isn't coming across correctly. The receiver detects stereo, but I seem to be getting one or two random channels coming from the wrong speakers - not even a downmix.

I'm using the latest stable Live CD release downloaded yesterday. Dharma 10.0.

Ati HD5400 via HDMI to an Onkyo HT-RC160.

Any suggestions?

Apparently, as documented in this thread there is an undocumented "feature" in xbmc where transcoding from AAC to AC3 occurs for SPDIF, but not for HDMI.

Changing the audio output from HDMI to Optical/Coax aka SPDIF while leaving the other two audio output options on hdmi resolves the problem.

Just to note, the fix seems unintuitive since I am using an HDMI audio connection, but have set my audio setting to Optical/Coax instead of HDMI to enable proper audio processing. It would be my opinion that the same code path/logic should be used for both HDMI and optical/coax and a separate option be created to transcode AAC to AC3*.

I did see a boolean option under guisettings.xml for passthrough of AAC, unfortunately setting this to TRUE resulted in no audio.

Thanx blakewry. This was driving me nuts and that fix is totally not intuitive. Glad to have it working again.

If you get two random channels from a 5.1 aac please try the speaker configuration in audio-midi-setup ( utilities folder ). It is standard stereo and must set to 5.1 manually.

(2010-12-29, 07:36)blakerwry Wrote: [ -> ]Apparently, as documented in this thread there is an undocumented "feature" in xbmc where transcoding from AAC to AC3 occurs for SPDIF, but not for HDMI.

Changing the audio output from HDMI to Optical/Coax aka SPDIF while leaving the other two audio output options on hdmi resolves the problem.

Just to note, the fix seems unintuitive since I am using an HDMI audio connection, but have set my audio setting to Optical/Coax instead of HDMI to enable proper audio processing. It would be my opinion that the same code path/logic should be used for both HDMI and optical/coax and a separate option be created to transcode AAC to AC3*.

THANK YOU! I was really annoyed that AAC 5.1 was getting downmixed to stereo (albeit with Dolby Pro-Logic II, which was of course quite muddy), and this has enabled AC3 transcoding for me in XBMC Live 10.1 Dharma.

Quote:I did see a boolean option under guisettings.xml for passthrough of AAC, unfortunately setting this to TRUE resulted in no audio.

I wonder if this is only the case for receivers that don't know how to decode AAC?

In case anyone is wondering, the official Eden release still requires setting Optical/Coax instead of HDMI in order to make 5.1 AAC->AC3 transcoding work.

And AAC passthrough isn't supported on OSX/IOS (dunno for other plattforms)...

I wish I could get this working 100%, the HTPC that my Apple TV 2 replaced could send any audio format with no hiccups.

Wishing doesn't produce code. So go get on it

Gah!!!

Okay so it seems I have the same problem here but the fix doesn't seem to work for me.

I have the following set up in "System -> Audio Output"
Audio Output: Optical/Coax
Speaker Config: 5.1
Boost Volume level on Downmix: True
Dolby Digital (AC#) capable receiver: True
DTS capable receiver: True
Audio Output Device: Defaults
Passthrough Output Device: iec958

Currently all of the following still work: MP3 2.0 / AAC 2.0 / AC3 2.0
However, it doesn't seem to allow ANY 5.1 sound.

I've tried putting the AOD and POD to "hdmi" but then I get a "Failed to initial audio device" when I play ANY file.

I currently have XBMC 10.1 running on a ZBox ID41 connected to a receiver via HDMI.
If I change the output to Analog and the Speaker Config to 2.0, everything works but it's all being downmixed. Meh!!!
Sure, I can get the receiver to do a Pro-Logic 5.1 upmix but obviously that's not the same as having the real thing.

Any idea what I'm doing wrong?

(2012-05-14, 17:15)Kheiron2711 Wrote: [ -> ]Gah!!!

Okay so it seems I have the same problem here but the fix doesn't seem to work for me.

I have the following set up in "System -> Audio Output"
Audio Output: Optical/Coax
Speaker Config: 5.1
Boost Volume level on Downmix: True
Dolby Digital (AC#) capable receiver: True
DTS capable receiver: True
Audio Output Device: Defaults
Passthrough Output Device: iec958

Currently all of the following still work: MP3 2.0 / AAC 2.0 / AC3 2.0
However, it doesn't seem to allow ANY 5.1 sound.

I've tried putting the AOD and POD to "hdmi" but then I get a "Failed to initial audio device" when I play ANY file.

What choices do you have for the AO, AOD and POD settings?