[LINUX/MAC/WINDOWS] 5.1 Analog Output (6 Channel Discrete, not mirrored) Option?

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Freddo Offline
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Question  [LINUX/MAC/WINDOWS] 5.1 Analog Output (6 Channel Discrete, not mirrored) Option?
Post: #1
I've just spent all day having a great time ripping a load of my HD-DVD's and blu-rays, no problems there I now have a nice collection of h264/VC1 with 6 channel flac included, which seem to playback great in 2 channel stereo (down mixing) so far as I can tell. What I'm wondering is, does anyone know if XBMC will let me use 6 channel analog output to send the audio straight to my amplifier without having to downsample it to dolby digital, or upgrade my amp to one that supports E-AC3 or Dolby TrueHD? I'm curious to know if this is supported before I spend a lot of money on hardware.
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Freddo Offline
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Post: #2
well, from my own rather crude testing (look at me, 3 sets of headphones at once!) I've found that XBMC does appear to correctly pass 6 channel flac to 6 channal analog output, so yay, at least on windows this seems to work. Now to pull the trigger and build a proper HTPC.
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Bahndit Offline
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Post: #3
Freddo,
I would love to hear what kind of results you get after you build your new rig.

-Bahndit
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elupus Offline
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Post: #4
we currently don't support 6ch analog output.

Always read the XBMC online-manual, FAQ and search the forum before posting.
Do not e-mail XBMC-Team members directly asking for support. Read/follow the forum rules.
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Freddo Offline
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Post: #5
no, in the end I couldn't get it to work on linux, I don't know if it was alsa or drivers or xbmc or just sheer idiocy on my part.

it worked basicly out of the box on the windows port though, a teency bit of configuration in the realtek sound control panel and it worked right away.
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rikbrown Offline
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Post: #6
elupus Wrote:we currently don't support 6ch analog output.

It is in the code though, just it's been manually forced to downmix to 2 channel because there's no GUI frontend. I've been able to get 5.1 to work fine simply by commenting this line out. Or at least it was in the last version I tried.

I hope to have a bit more of a look into how to write for xbmc and see if I can patch some sort of frontend addition. Never done anything with an oss project before though heh.
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elupus Offline
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Post: #7
you need to comment out stuff in a few places actually. dts/ac3/aac decoder and alsa audio rendererer.

Always read the XBMC online-manual, FAQ and search the forum before posting.
Do not e-mail XBMC-Team members directly asking for support. Read/follow the forum rules.
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Gamester17 Offline
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Post: #8
New feature request ticket on trac would be welcomed http://trac.xbmc.org see guidelines:
http://wiki.xbmc.org/?title=What_is_XBMC...to_XBMC.3F

Wink

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dellis86 Offline
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Lightbulb  5.1 Multi-Channel Analog Output (discrete 6-channel PCM) for all non-Xbox versions
Post: #9
First off, I just found out that XBMC is being ported to Windows. I about pooped myself. I love everything about XBMC, it is exactly what I want/need.

I have searched the forums several times now and I'm not finding anyone talking about Multichannel OUTPUT. Many receivers have this feature, where you simply send every individual 5.1 channel to the receiver using stereo RCA cables, and all it does is amplify the signal. I use this setup since my receiver does not do matrixing well, and does not support ac3 (I dont think. when I tried all i got was PCM stereo).

Am I alone? did I miss something in the SPDIF settings that would allow me to pass 5.1 from AC3 MKVs to the receiver?

If I am not alone, would it be possible to add this audio output to the non XBOX versions of XBMC? I am assuming it doesnt currently exist because the XBOX only had optical/stereo analog outputs. but with PC sound cards, you have this multichannel option.

Thanks in advance, and keep up the good work!
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Freddo Offline
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Post: #10
This isn't currently officially supported, all audio is either down sampled to 2 channel analog or passed through for external decoding. However I have found that on the windows build at least, 6 channel flac is correctly passed through the 6 channel analog outputs, although to my knowledge this is infact a bug (6ch flac should be down mixed to 2ch stereo), I haven't dared raise it with the devs 'cos I don't want them to fix it lol.


.....shhhhh!
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Freddo Offline
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Post: #11
oh ps: I wholeheartedly endorse this feature request, since I intend to use 6 channel analog output as my principle method of outputting audio, and I prefer to have XBMC (which is software and thus updatable to support new formats) do the hard work since my amp is just a teency bit on the old side and doesn't support 6ch PCM via HDMI or anything fancy.
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dellis86 Offline
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Post: #12
Thanks for the response. So FLAC is just another codec? Meaning if I had content encoded in FLAC then the 6 channel analog output (multichannel) would work, but not if its AC3, which is the case with my files. Also, it sounds like to get the "passthrough" to work I need a fancier receiver? There isnt a way to get my receiver to read an AC3 track as a DD 5.1? People on the forums keep mentioning "ac3 capable receiver" but when I google that, nothing really comes up. What should I be looking for? HDMI 1.3? LPCM?

The reason I have been using the multichannel output on my HTPC is that its just easier, i don't have to be changing sound modes on my receiver, or fooling with the menu system, it just amplifies the signal. I do my leveling and equalizing on the PC.
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Freddo Offline
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Post: #13
naw ac3 is just a fancy way of saying dolby digital 5.1 , most any reciever will support that so if you enable passthrough and connect to your amp with a digital connection such as spdif optical or coaxial then you should get dd5.1 aka ac3 no problem. It's also possible to pass DTS this way.
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dellis86 Offline
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Post: #14
Wait what? OK now I can't wait to get home! Thanks!
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dellis86 Offline
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Post: #15
It worked, the only immediate problem was that the subwoofer level was way too high, so I adjusted it in the receiver. Thanks again.
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