Only stereo surround channels when playing 5.1 AAC audio
#1
Yesterday I've tried to play a video containing an 5.1 AAC audio stream and the only thing I was hearing on my front speakers was the sound that sould be played on the rear speakers. (No voices, just background sound) According to my receiver just an 2.0 PCM audio signal is transfered. I've tried to ajust the audio settings but nothing worked, but when I change the audio settings from 5.1 to 2.0 I can hear all channels mixed together on my front speakers. But clearly this cannot be the solution to this problem. This is the first video file i've found that is causing such problems. I think the problem is the audio codec. Most of my video files have ac3, dts or HD audio streams and they are played correctly on my receiver.

Here are the specs of my homecinema:
- XBMC 12.3 runs on a Workstation under Ubuntu 13.10.
- Zotac GeForce GT 610 Zone Edition - 1GB
- Onkyo TX-NR818 (connected over HDMI, passthrough enabled)

I've also enabled the debug log and found some interessting entries:
DEBUG: FactoryCodec - Audio: passthrough - Opening
DEBUG: FactoryCodec - Audio: passthrough - Failed
DEBUG: FactoryCodec - Audio: FFmpeg - Opening
DEBUG: FactoryCodec - Audio: FFmpeg - Opened
NOTICE: Creating audio stream (codec id: 86018, channels: 6, sample rate: 48000, no pass-through)
ERROR: CAESinkALSA::HandleError(snd_pcm_wait) - underrun

I've uploaded the complete log from play to stop on pastebin: http://pastebin.com/6Sm6Z0ZJ
Does anyone have an idea why this audio signal cannot be sent using passthrough? I've enabled the option that my receiver supports AAC and it sould be able to decode this codec according to the specs.
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#2
Quote:Does anyone have an idea why this audio signal cannot be sent using passthrough? I've enabled the option that my receiver supports AAC and it sould be able to decode this codec according to the specs.

AAC passthrough did never work, the option in settings was a fake. I case of any audio issues please try a Gotham nightly. Audio engine is completely rewritten and there won't be any fixes for 12.x
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#3
I've updated my XBMC to the latest nightly build and tried to play the video again and it works! 5.1 AAC audio is transfered and played on my receiver! (I had to enter the audio settings of ubuntu first an set the audio output to 5.1 and then the 5.1 audio device appeared in XBMC)

Thanks for the hint!
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Only stereo surround channels when playing 5.1 AAC audio0