TrueHD
#1
I have blueray rip (around 38GB) with supposedly 5.1TrueHD sound track.
VLC on Windows box shows 2 sound streams:
id 4353 codec trhd
id 4352 codec bpcm stereo

XBMC on Live distro shows 3 audio streams:
AC3 5.1, Stereo and 5.1 (without AC3 prefixed).
AC3 5.1 sound is the best, my amplifier displays regular Dolby Digital symbol (not LPCM expected for TrueHD). When Stereo is played amplifier displays stereo as expected, when 5.1 without AC3 is selected amplifier still displays "stereo".
So - any idea what I get here ? Is AC3 5.1 track is truehd or regular dolby ? and what are 2 other tracks ?
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#2
i guess we could need a sticky for this topic.

please see the various threads: http://forum.xbmc.org/search.php?searchid=6133042
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#3
einhänder Wrote:i guess we could need a sticky for this topic.

please see the various threads: http://forum.xbmc.org/search.php?searchid=6133042
Read them, but don't see something like my situation.
I don't have any "audio initialization problem".
I get perfect sound, at least when playing AC3 5.1 stream.
I just don't know what is the other 5.1 stream without AC3 - its sound is worse than AC3 5.1.
On other side many people complain about don't getting sound at all, but moderator tells there "9.04 milestone has full TrueHD support".
If in VLC the only 5.1 stream that I see is TrueHD - can I assume AC3 5.1 is actually TrueHD stream ?

But why it is displayed as Dolby Digital ?

I read before current sound cards on ASRock can't send truehd as-is, they decode it and and I should see LPCM on the AVR, not DolbyDigital ?

:confused2:
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#4
5.1 is the True-HD stream. If your HDMI passhrough is setup properly you should get the message multich LPCM on your AVR. This is what I get on my Onkyo. Make sure your AVR is set to multi channel. The sound quality is excellent.
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#5
ylagace Wrote:5.1 is the True-HD stream. If your HDMI passhrough is setup properly you should get the message multich LPCM on your AVR. This is what I get on my Onkyo. Make sure your AVR is set to multi channel. The sound quality is excellent.
This is what I thought.
When playing AC3 5.1 channel AVR displays dolby digital 48KHz 5.1 channels, not LPCM (and obviously truehd marker doesn't light up - as expected).
My AVR is Denon 1910, and if I get it correctly it should recognize input signal format automatically. XBMC is connected to it only through HDMI, and I don't have any menu command on AVR to tell him "this is multi channel signal".

So, or it is real truehd that somehow gets "labeled" by AVR as Dolby Digital, and not LPCM, or it is actual Dolby Digital - but who produced it ? VLC doesn't see such stream.
Can it be XBMC re-encoding TrueHD 5.1.into Dolby Digital 5.1 ? Doesn't seem logical, though.

And what is about non AC3 5.1 stream (VLC doesn't show it at all) - AVR recognizes it as stereo, and it may be the same "surround only" bad truehd decoding outcome that people complain about on the forum.
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#6
dumalkin,

i guess i have to apologize for my post above. Smile but i was totally convinced xbmc would not handle truehd streams in any way.
i did some tests on my xbmc system. for this purpose i downloaded dts-hd ma and dolby truehd samples from the url below:

samples: http://www.demo-world.eu/trailers/high-definition-trailers.php

my experience:

- dts-hd ma:
xbmc passes through the signal to my avr. the avr detects it as a normal dts signal. xbmc shows "dca" in the info dialog. vlc shows "dts" in the info dialog.

- dolby truehd:
xbmc behaves just like the ps3. it passes a lpcm stream to my avr. so my avr doesn't recognize whether this is a dts, ac3 or whatever signal. but it shows me the channels that are currently in use. this is correct. xbmc itself shows "truehd" in the info dialog. same does vlc.

i created screenshots of the playback of each file, info dialog is in the foreground showing information about the streams:

dts hd-ma: http://emberapp.com/makaimura/images/xbmc-dts-hd-ma/sizes/o
dolby truehd: http://emberapp.com/makaimura/images/xbm...hd/sizes/o

p.s. both dts hd-ma and dolby true-hd samples sound awesome.
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#7
einhänder,
I tried those samples ...
Good news - I see the same figures on XBMC. TrueHD is detected and displayed, TrueHD 7.1 is displayed as 8 channels stream ...
Instead of TS-HD Core DTS is played (at least it seems so) - DTS HD is not supported by XBMC for now.
Bad news - when I play TrueHD 7.1 sample my AVR detects it as PCM 2/0/0 stream, not 3/4/1. The same file has Dolby 5.1 stream - if I select this one it is detected as Dolby Digital 5.1, as expected.
I have another streamer, Popcorn A200. Don't remember if it supposed to decode TrueHD, if yes - I'll try to test my AVR with it. Honestly - I suspect XBMC configuration is messed up and AVR is OK.
I have audio playback configured this way:
Receiver supports Dolby+DTS. Output device and passthrough device - hdmi. Rest of options - off.
Any ideas ?
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#8
Doesn't what the AVR sees depend not only on the XBMC software that is running but also the platforms hardware capabilities that it is running on?

For example I am running on an Asrock IOn-330 using the XBMClive v 9.11. My AVR never reports True HD or DTS MA but does play 5.1 channels very nicely. The same rip file when sent to a Dune player causes the AVR to report True HD or HD Master Audio whatever the file contains. One of the test cases I use is the BR version of Avatar
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#9
I too was under the impression that TrueHD was a no-go for Linux! However if it can be spat out the HDMI port and the receiver allowed to decode it that would rock. would it be possible for XBMC to play a secondary AC3 channel or extract AC3 on the fly if the receiver wasn't selected as being TrueHD capable? I know on the new code there's a ton of new output options to include DTS which I thought Linux wasn't capable of either. This is pretty exciting but since I'll be using both a receiver than cannot handle DTS and TrueHD and one that can how best to setup my MKV files? Honestly just DTS with an AC3 fallback if the output isn't enabled would rock even if I have to put both soundtracks in my files.

The hardware question is also obviously a big one - I too am running an ASROCK ION 330 as well as a Zotac ND01 with the same older ION chipset. These should be capable shouldn't they? The software just throws the bitstream out the HDMI port right? Is there some version of ALSA where this became available - I too had been under the impression it wasn't doable! :-O
Openelec Gotham, MCE remote(s), Intel i3 NUC, DVDs fed from unRAID cataloged by DVD Profiler. HD-DVD encoded with Handbrake to x.264. Yamaha receiver(s)
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#10
True HD does not bitstream in Linux, nor can most Nvidia hardware support HDMI HD audio bitstreaming in any OS. You MUST have bitstreaming support in order for the "True HD" and "DTS HD" lights on receivers to light up.

What DOES happen in Linux with True HD is that if you have everything setup properly, then it will decode on your True HD tracks and output them as 8 channel LPCM audio to your receiver.

Decoding on the Linux box gives you the same uncompressed sound in most cases, you just don't get the ego satisfaction of having the correct light glow on your receiver. The only exception is if you have an INSANELY expensive receiver that adds effects to True HD tracks (and ONLY True HD tracks), but such a situation is rare.

Here is how to get things working:

http://forum.xbmc.org/showthread.php?tid=74778

Final Note: Under no circumstance in Linux does DTS HD tracks get decoded. With those the best you get by default is passing through the massive DTS core of the track. To get optimal sound from these DTS HD-laden files, you must decode the tracks beforehand and re-encode them into multi-channel FLAC. This process gives you full audio quality from all Blu Rays.

Here is the guide I use to do that:

http://www.curtpalme.com/forum/viewtopic.php?t=17002
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#11
A200 doesn't seem to be able to decode TrueHD, so I have no reference to compare with, and can't know for sure problem is in ASRock/XBMC or in AVR.

barrygordon:
I have the same hardware - ASRock 330. It is connected through HDMI to Denon 1910. And I expect to see multichannel LPCM sent to AVR, instead of this I see only 2 channels.

poofyhairguy: I know.
I do not want to see TrueHD lights on AVR, I want to hear 7.1 HD sound ...
The key phrase is :"if you have everything setup properly, then it will decode on your True HD tracks and output them as 8 channel LPCM audio to your receiver" - and what I see on my receiver is 2 channel LPCM, not 8 channel. So apparently not everything is setup properly. The questions is - what exactly is messed up and how to fix it ?
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#12
I have some questions about this guide:
http://forum.xbmc.org/showthread.php?tid=74778
1. I see here "The next two files will fix the wrong channel mapping of multi-channel PCM and makes the menu sound working.". On my ASRock menu sound is working, so this is uneeded fix XBMC if installed on Live ? Or it should be applied anyway ?
2. "f you want PCM multichannel, for example FLAC (HD audio) and let XBMC directly bitstream this over HDMI turn off the Dolby digital capable receiver in audio settings." - So if I want Dolby sound in movie with normal, non-HD, sound track I have to turn it on, to get 8 channel LPCM to AVR I have to turn it off ?
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#13
Steps:
1. Downloaded latest (256.25) nvidia drivers according to the guide from here. Before running installation do "kill xinit", else driver installation program will exit. I didn't select the option "make nvidia driver default", and didn't rebuild xorg.conf file, just rebooted the machine.
2. Upgraded to Alsa 1.0.23 according to guide from here
3. Got upgraded alsa config files (HDA-Intel.conf and asound.conf) according steps from here. I am not sure it is required for the latest alsa/nvidia combination
4. Optional - removed tons of stuff installed for Alsa compilation to get disk space back
XBMC setup - as it was. AVR supports DTS/Dolby, device/passthrough device - hdmi both, no downsampling audio to stereo, use audio clock
AVR displays correct LPCM marker when streamed TrueHD 5.1 or 7.1 channels, Dolby/DTS/Flac stereo/MP3 streams continue to work normally.
Sound test program strange effect - somehow volume level of front left/right channels is way too low. When playing normal content movies/trailers from HD audio sample server) everything is OK.
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