Dolby TrueHD, Windows 7

V

visionviper

[H]ard|Gawd
Joined
Jul 24, 2007
Messages
1,222
I have ripped my Blu-Ray collection to my media server and I have discovered an issue I have with only rips from movies that use Dolby TrueHD.

When I play a movie with a DTS-MA audio track everything works fine. When I play it in Media Center or in TMT the computer outputs in DTS (my receiver doesn't support DTS-MA) and my receiver clicks over to DTS and everything. When I try to play one of my Dolby TrueHD movies though I get no audio at all from Media Center or TMT. I can get basic stereo audio when I just play it in Media Player though.

What gives? Can DTS-MA be downmixed by Windows and Dolby TrueHD can't? Am I doing something completely wrong?
 
How are you sending the audio over to your receiver?

DTS-MA and TrueHD can only be sent via HDMI on the latest boards (ATI 5xxx series, Intel's chipset, not sure of the model). DTS-MA has a 'core' DTS track that can be sent to your receiver, TrueHD has no equivalent so it must be downsampled.
 
nite0 said:
DTS-MA has a 'core' DTS track that can be sent to your receiver, TrueHD has no equivalent so it must be downsampled.
Click to expand...

Ah, that is the reason then. I thought that it might be something like that. I will just have to remux the mkvs with a different audio track. Thanks for the help.
 
Last edited:
nite0 said:
DTS-MA has a 'core' DTS track that can be sent to your receiver, TrueHD has no equivalent so it must be downsampled.
Click to expand...

TrueHD tracks can have AC3 mixed in the same stream, effectively being a 'core' as you put it. That means that the the AC3 frames can be stripped from the stream to leave either the AC3 or TrueHD track for playback.
 
Snowknight26 said:
TrueHD tracks can have AC3 mixed in the same stream, effectively being a 'core' as you put it. That means that the the AC3 frames can be stripped from the stream to leave either the AC3 or TrueHD track for playback.
Click to expand...

Cool, didn't know that. Are any movies shipping this way?
 
I believe every Blu-ray that has a TrueHD track comes like that. On the other hand, I don't believe any HD DVD TrueHD tracks are like that.
 
Snowknight26 said:
TrueHD tracks can have AC3 mixed in the same stream, effectively being a 'core' as you put it. That means that the the AC3 frames can be stripped from the stream to leave either the AC3 or TrueHD track for playback.
Click to expand...
Snowknight26 said:
I believe every Blu-ray that has a TrueHD track comes like that. On the other hand, I don't believe any HD DVD TrueHD tracks are like that.
Click to expand...

Is there maybe a guide somewhere where I can see how to do this?
 
Actually I'm pretty sure that all TrueHD tracks have an AC3 core. The way DTS-MA and TrueHD work is that they have the "core," which is a lossy codec (AC3/DTS) then they have the extra info that got tossed out by the lossy codec added back in to make them lossless. this makes backwards compatibility pretty easy since they have the legacy codec built right in.

as for how to remux BD rips, my friend wrote this nice little guide right here:
http://sites.google.com/site/xorphdstuff/remuxing
 
There's not core with TrueHD. There is usually a secondary hidden AC3 track.
 
G:\Encoding Tools\eac3to>eac3to.exe "E:\" 1)
M2TS, 1 video track, 10 audio tracks, 16 subtitle tracks, 1:54:32, 24p /1.001
1: Chapters, 44 chapters
2: VC-1, 1080p24 /1.001 (16:9)
3: AC3, English, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB
4: TrueHD/AC3, English, 5.1 channels, 48kHz, dialnorm: -27dB
(embedded: AC3, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB)
5: AC3, French, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB
6: AC3, French, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB
7: AC3, German, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB
8: AC3, Italian, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB
9: AC3, Spanish, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB
10: AC3 Surround, Spanish, 2.0 channels, 192kbps, 48kHz, dialnorm: -27dB
11: AC3 Surround, Portuguese, 2.0 channels, 192kbps, 48kHz, dialnorm: -27dB
12: AC3, Japanese, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB
13: Subtitle (PGS), Japanese
14: Subtitle (PGS), English
15: Subtitle (PGS), French
16: Subtitle (PGS), German
17: Subtitle (PGS), Italian
18: Subtitle (PGS), Italian
19: Subtitle (PGS), Spanish
20: Subtitle (PGS), Chinese
21: Subtitle (PGS), Korean
22: Subtitle (PGS), Spanish
23: Subtitle (PGS), Portuguese
24: Subtitle (PGS), Danish
25: Subtitle (PGS), Finnish
26: Subtitle (PGS), Norwegian
27: Subtitle (PGS), Swedish
28: Subtitle (PGS), Japanese
Click to expand...

I'm sorry, you were saying? Probably want to backup your nonsense statements next time.
 
danman said:
There's not core with TrueHD. There is usually a secondary hidden AC3 track.
Click to expand...

I'll actually have to revise my statement since it seems you are correct. AC3 is mandatory on BD's that use dolby audio because TrueHD does not provide a core. It may act like a core, but it doesn't function the same as DTS/DTS-MA
 
Last edited:
Snowknight26 said:
I'm sorry, you were saying? Probably want to backup your nonsense statements next time.
Click to expand...

I dont care what eac3to says, there's no core AC3 track in TrueHD.

Per Dolby:

http://www.dolby.com/uploadedFiles/Assets/US/Doc/Professional/TrueHD_Tech_Paper_Final.pdf


Different Strategies for Differing Coding Technologies

Other codecs using a lossy core paired with a lossless extension treat them together, with the inevitable result that one or the other suffers. Either the lossy audio is potentially degraded by rematrixing, as explained earlier, or the lossless audio payload is materially increased because of the extra channels it carries. We chose to handle the lossy and lossless codecs independently, thereby elegantly avoiding these compromises by using the optimal method for each codec.

As a result, content providers can include lossless Dolby TrueHD soundtracks for enthusiasts, with ample capacity left over for high-quality, alternative-language tracks and bonus features encoded with Dolby Digital Plus or Dolby Digital. There’s no need to compromise picture quality or minimize additional soundtracks or features, unlike systems that encode the lossy core and lossless extension as a single bitstream. Keeping these elements separate also means that either bitstream can be altered during the production process without requiring
a QC check of the other, a benefit for content creators.
 
danman said:
I dont care what eac3to says, there's no core AC3 track in TrueHD.

Per Dolby:

http://www.dolby.com/uploadedFiles/Assets/US/Doc/Professional/TrueHD_Tech_Paper_Final.pdf


Different Strategies for Differing Coding Technologies

Other codecs using a lossy core paired with a lossless extension treat them together, with the inevitable result that one or the other suffers. Either the lossy audio is potentially degraded by rematrixing, as explained earlier, or the lossless audio payload is materially increased because of the extra channels it carries. We chose to handle the lossy and lossless codecs independently, thereby elegantly avoiding these compromises by using the optimal method for each codec.


As a result, content providers can include lossless Dolby TrueHD soundtracks for enthusiasts, with ample capacity left over for high-quality, alternative-language tracks and bonus features encoded with Dolby Digital Plus or Dolby Digital. There’s no need to compromise picture quality or minimize additional soundtracks or features, unlike systems that encode the lossy core and lossless extension as a single bitstream. Keeping these elements separate also means that either bitstream can be altered during the production process without requiring
a QC check of the other, a benefit for content creators.
Click to expand...
Yea, I looked that up myself as well. I suspect the confusion comes from this;

3: AC3, English, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB
4: TrueHD/AC3, English, 5.1 channels, 48kHz, dialnorm: -27dB
(embedded: AC3, 5.1 channels, 640kbps, 48kHz, dialnorm: -27dB)
Click to expand...

note track 3, which is the same as the track 4 "embedded" data. It seems like eac3to is reporting track 3 as the embedded portion of track 4, probably just as a matter of convenience, even if its technically incorrect.
 
Track 3 is the AC3 track, track 4 is a stream that interleaves both TrueHD and AC3 frames. Neither are dependent on the other (such as in the case of DTS and DTS-HD variants). The quote from Dolby even cements the fact that the AC3 is not a core, but rather just an additional embedded track.

http://forum.doom9.org/showpost.php?p=1415246&postcount=13
http://forum.doom9.org/showthread.php?t=155499

Activate: AMD said:
note track 3, which is the same as the track 4 "embedded" data. It seems like eac3to is reporting track 3 as the embedded portion of track 4, probably just as a matter of convenience, even if its technically incorrect.
Click to expand...

Track 3 and the AC3 portion of track 4 are totally separate and also don't have to share any similarity apart from the codec.
 
Snowknight26 said:
Track 3 is the AC3 track, track 4 is a stream that interleaves both TrueHD and AC3 frames. Neither are dependent on the other (such as in the case of DTS and DTS-HD variants). The quote from Dolby even cements the fact that the AC3 is not a core, but rather just an additional embedded track.

http://forum.doom9.org/showpost.php?p=1415246&postcount=13
http://forum.doom9.org/showthread.php?t=155499



Track 3 and the AC3 portion of track 4 are totally separate and also don't have to share any similarity apart from the codec.
Click to expand...
ok! I admitted i was wrong already! I was just trying to reason out why there were 2 AC3 streams that were at full quality. a lot of director's commentary or bonus audio tracks have lower bitrates so I wasn't sure if thats what track 3 was.

lol it sounds like danman and Snowknight are saying the same things two ways
 
All I'm saying is DTS MA has metadata which allows the endpoint to read only the DTS core track if that is all it can playback - this is a core part of DTS MA.

TrueHD does *not* have this as a part of the spec as a requirement and is not included. What he has posted is that an additional AC3 track can be inter-weaved into the TrueHD track if the encoder chooses to. TrueHD does not have a core AC3 track. And there are some discs that only have TrueHD and not an AC3 track.
 
Last edited:
You must log in or register to reply here.
Back
Top