HD audio to 7.1 LPCM in Gotham
#1
I just installed Gotham build from yesterday on my ATV1. I wanted to test Audio Engine and the new FFMPEG.

ATV1 does not bitstream HD audio, so I wanted to test transcoding to LPCM. I have some movies with 5.1 and 7.1 HD sound. I have a 7.1 speaker setup.

These are my findings;

- 7.1 DTS-MA tracks are still recognized as 5.1 tracks. Dolby TrueHD are detected as 7.1. This was the same in Frodo.
- Enabling DTS, AC3 and LPCM in Xbmc I would expect Xbmc, with the new FFMPEG, to see and decode all 7.1 channels and be able to encode them as LPCM and output that. However for DTS-MA I get the core track on the receiver and for TrueHD I get only 2 channels (not a downmix as center sound is gone) and receiver shows PCM in display (not LPCM).

Perhaps this is too early to expect this stuff to work correctly? Smile
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#2
Why are you posting in development?

Moving...
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#3
i wanted to ask the op a quick question:

are u using the hdmi as the audi pass thru or are u connected thru the optical port to ur receiver? im not sure, but i believe the at1 will not do the pass thru with hdmi but possibley w optical it will? i my be wrong, but the atv 1 is a legacy product, so it may not pass thru specific adio thru thet there hdmi?
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#4
I'm using HDMI. It passes the legacy formats just fine but cannot pass HD audio since the HDMI version is too old etc. LPCM is supported since HDMI 1.0, so that should be possible with the ATV.
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#5
ok but is there an optical port on the original atv? i forget... if so, plug that sucker into the receiver and see if it works for the audi options ur looking for,

OR

in the add ons, i forget where, there is the xbmc audio mixer of some sort... might give it a go and see if it helps n this situation at all as well?
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#6
This should in theory work with HDMI. I can test it with S/PDIF but it is not a solution in the long run. Hopefully we can get Xbmc to properly support LPCM over both.
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#7
yes hopefully as it is a very sound home theater solution, but try that and also try the xbmc audio mixer i believe is what it is called and let us know how they both wok out for u,

and what receiver are u currently using?

also check out this post a few below urs and look specifically at post #6 from glorious1, his settings may help in this case as well?

and perhaps there is a hack or drivers we can use to update the hdmi??
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#8
Martijn, it's cool you moved the thread, but I think it was not correct to place it under MacOSX since the ATV uses Ubuntu Linux (at least for the image most are using - CrystualBuntu).

j2048b, there are other nVidia drivers for Ubuntu, but I don't think that is the problem here (I might be wrong). This seems like a FFMPEG issue on one end (decoding audio) and Audio Engine on the other (encoding audio as LPCM).
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#9
OK, it's under Linux support now.
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#10
There are no software decoders for DTS-HD Master Audio, that's why XBMC passes through the core track only. For TrueHD there is, that's why it is properly decoded to 7.1 LPCM.
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#11
hmm, I was sure that the new ffmpeg was able to decode DTS HD. I cannot find anything about this, so I guess you're right. Bummer
TrueHD does not work for me. I get only the front channels and receiver says PCM. Any idea why rest of channels are gone?
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#12
http://ffmpeg.org/pipermail/ffmpeg-devel...41557.html

Seems there's only partial decoding support.
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#13
I actually have a DTS-HD HR test file I could play with.

But right now I'm interested in getting TrueHD to be properly transcoded to 7.1 LPCM. Does anyone have an idea what can be wrong?
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#14
@bleze: http://forum.xbmc.org/showthread.php?tid...pid1321164
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#15
Did u happen to try the audi mixer within xbmc? Just an idea to try before u do something more complicated?
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