7.1 Channel FLAC/AAC wrong channels
#16
how do we make this into a trac ticket?
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#17
I'd say by registering at trac and submitting a ticket? ;-)
I almost always forget that xbmc uses trac and tend to falsely post bugs on git o.O
The question is who is going to open the ticket?
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#18
http://trac.xbmc.org/ticket/13758

there we go. please add stuff if you can.
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#19
There's not much I can add. Just tested LAV and got the following mapping:
Left and Right are actually mapped as flc and frc from looking at the output channel levels (in the status tab).
this is quite consistent with the ffdshow result as the mapping looks like:
left -> left + center
center -> center
right -> right + center
right surround -> right
left surround -> left
right rear surround -> right rear surround
left rear surround -> left rear surround
lfe -> lfe

Thanks to looking at the lav output I can at least tell for sure that the front channels are falsely outputted as front right center and front left center (not sure if that's the right labeling).
Now maybe we should also take a look IF by any chance the channel layout during the encoding is wrong even though vlc outputs the correct channel order.

At least we can tell for sure that the the 7.1 aac are "falsely" mapped as follows:
left -> flc
right -> frc
srl -> left
srl -> right

center, lfe, br, bl are correct. At least now in my eyes the behaviour is consistent and makes a lot of sense Smile cause if the front channels are really marked as frc and flc than it's correct that they are mixed into left, center and right on downmix ^-^;


edit:
take a look at:
http://developer.apple.com/library/mac/#...ag_AAC_7_1

so it is an output issue Smile the channels are encoded correctly, but for 7.0 AAC the channel order is
Center, Left, Right, Left surround, Right surround, Left rear surround, Right rear surround

while for 7.1 it is
Center, Left center, Right center, Left, Right, Left surround, Right surround, Low-frequency effects

edit2:
I just posted a hint in the AE development thread... hopefully they'll not behead me for pushing this issue a bit ^-^;

edit3:
For lav I already got a postiive response for a fix! See: http://code.google.com/p/lavfilters/issu...ail?id=304
Now let's hope that the we'll get a fix for xbmc, too Smile
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#20
(2012-12-18, 17:38)Crayden Wrote: edit2:
I just posted a hint in the AE development thread... hopefully they'll not behead me for pushing this issue a bit ^-^;

Beheadings are a feature-request Wink
System: XBMC HTPC with HDMI WASAPI & AudioEngine - Denon  AVR-3808CI  - Denon DVD-5900 Universal Player  - Denon DCM-27 CD-Changer
- Sony BDP-S580 Blu-Ray  - X-Box 360  - Android tablet wireless remote - 7.1 Streem/Axiom/Velodyne Surround System
If I have been able to help feel free to add to my reputation +/- below - thanks!
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#21
I use HDMI out on my nVidia ION chipset. I had to implement the following ALSA remap in my .asoundrc file to get the channels right.

Code:
pcm.hdmi-remap {                                                                                                                                       [80/1938]
  type route
  slave.pcm hdmi
  ttable.0.0 1
  ttable.1.1 1
  ttable.2.4 1
  ttable.3.5 1
  ttable.4.2 1
  ttable.5.3 1
  ttable.6.6 1
  ttable.7.7 1
}
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#22
But since the channel mapping for 7.1 flac files is totally correct in my case this would not fix the issue Wink
the best solution is still a remap-fix in the AE for 7.1 aac files. Maybe offer a switch via the advancedsettings.xml to enable or disable it. But since this issue is so persistent across all systems I've tested I would advise to enable it per default. I still wonder why they chose a different naming scheme for the 7.1 aac case while all others (6.1, 6.1, 7.0 and 8 cahnnel) use the more "common" naming scheme ^-^;
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#23
I wonder if others will follow and fix this issue. I also wonder if it wouldn't be better to fix this in the decoder itself. At least this way only the (for example) avcodec would need a fix instead of all depending projects. But then the decoder would of course devirate from the specifications for 7.1 aac streams.
I still hope this issue will be fixed for the stable release of xbmc even though I think the chances are small Undecided


Edit:
I've fixed this issue via overlay on my gentoo system using the following diff:
http://git.1f0.de/gitweb?p=ffmpeg.git;a=...1dc936a211
( thanks @hendrik Leppkes )
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#24
We think to have that long standing issue solved by a more intelligent Channel Mapping via: 3744 (PR) (especially the latest one)

Sadly the sample from the bugreport is not available anymore and the original report did not respond with 7 days - so no with 7.1 system can actually test.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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#25
Well it's almost solved ;-)
Due to my current job I'm unable to test builds during the week as I am not at home ^-^;
But I'm still closely following the issue.
http://trac.xbmc.org/ticket/13758#comment:23
Again thanks for your work!
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#26
As this is my first post, the first thing I'd like to say is how grateful I am to all of the XBMC developers who have poured hours upon hours of time into this project. Thanks you =)

I am also having issues with a video file which contains a 7.1 FLAC audio track. I upgraded to 12.3, but this has not solved my issue.

I have an 7.1 capable HDMI receiver (Sony STR-DN1040) with a 5.1 speaker setup. I tried various settings to get the audio track to work, but no success:

-If I leave System > Audio output > speaker configuration to 5.1, the video file plays very slow (about 1 frame a second) with no sound
- If I change the speaker configuration to 7.1, the audio channels are mapped incorrectly (I'm guessing - it sounds like the center speaker is being played out of my sub)

Any help to solve this issue would be greatly appreciated.
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#27
Upgrade to gotham. Flac 5.1 won't work with Frodo at all.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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#28
Thanks for the reply!

I upgraded to Gotham. The video stuttering issue is no longer present with speaker configuration set to 5.1, but now the channels seem to be mapped incorrectly, the same as setting the audio configuration to 7.1, as I wrote earlier.
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#29
ION-1 has a kernel bug - won't work without a custom remapping. For anything else: my crystal ball is absent, e.g. No log no problem.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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