For my first post I thought I'd start with something thats been bugging me for a while. I've searched the forums here and I've done the Google thing and found nothing particularly enlightening.

What I want to do is very simple, I want to output TrueHD/DTS-HDMA from a HTPC. From my research, as I understand it, theres 2 ways to do it. One is to pass a bitstream out of the PC into something like the Onkyo which whould decode the stream for you or secondly to decode within the HTPC and pass out an analog stream via 6 or 7 analog cables.

That is as far as I've managed to glean from reading for a few weeks. What I basically have been looking for is quite simply "Buy any of the following cards, with the following software, and the following hardware and you can listen to the HD streams" but I've yet to find anything concrete.

So questions

1. How are people currently listening to HD streams from their HTPC
2. What is the preferred/most flexible/most capable method.
3. Which method gives the highest sound quality

Any help with this would be great - I'm not one to post to forums unless I'm right on edge of insanity.



Active Member
By chance, I've just been tinkering with my PC to do just the same.

I achieved it by using PowerDVD Ultra, running on Vista, set to 6 speakers on the audio config tab. Then, I connected the analogue audio outputs from my sound card (a Creative Audigy 2 - shortly to be replaced with the X-Fi PCI-E card) to the 5.1 input of my Denon amp.

Hoo baby! Proper True HD (on Superman Returns HD-DVD, playing on the 360 HD-DVD drive connected via USB) caused things to fall off the walls and shelves during the "you might just hear the sonic boom" sequence. Likewise, uncompressed PCM on Blu-ray (via a Pioneer BD-ROM drive) sounds equally impressive (a newly arrived Replacement Killers - the opening nightclub sequence, to be precise)

Hardware breakdown -

XFX Nvidia 650i motherboard
2GB of 800mhz DDR2 RAM
XFX Geforce 8800 GTS 320mb
Creative Audigy 2ZS
Pioneer BCD202 BD-ROM Drive
Xbox 360 HD-DVD drive
Antec P182 case (weighs slightly less than me)*
numerous HDD's recycled from previous PC.

*One gently cooling credit card not shown.


Thanks for the very quick response, very interesting indeed. So whats doing the decoding, PowerDVD? Thats is one option (which I assume requires some pretty hefty CPU time) but is there any way to pass the untouched bitstream to an Onkyo so it can do the decoding work?



Distinguished Member
PowerDVD downsamples all Hi Res audio formats to a maximum of 48hz 16bit to comply with AACS, so what you are looking for cannot yet be done. Cyberlink are currently working with Microsoft to complete a software path that will comply with AACS.

Some people claim that the analogue audio method mentioned by MrSynner makes an audiable difference. In my experience it does not, at least not when comparing Dolby TruHeD and a DD+ track on the same discs. Sometimes there is a volume increase that tends to give tghe impresiion of an improvement but that is all.

We will just have to wait for Cyberlink to sort this out :(

Check out my thread on AVSforum in the HTPC forum.

Using same method as MrSynner, have Audigy 2 ZS in one PC and X-FI Xtreme Music in other, 5.1 analogue output from card to 5.1 analogue in of Logitech Z-5500 Speakers, Amazing Sound Quality..., You really do hear the sound difference of Dolby True HD over DD Plus, due to the higher bit rate, take for example Superman Returns, at the start where asteroid comes crashing to earth, and everything starts shaking in the Kent Home, never heard audio so good..

Tried using the same method with Power DVD Ultra and onboard HD Audio from Realtek, but does not even compare to using a Creative Soundcard, those who still favour onboard sound over a dedicated soundblaster are still in the old ages..., sounds are much more sharper and louder, and more detail to them with the soundblaster, have heard the the Auzuntech Prelude sounds even better than the Soundblasters, but not tested one myself, cannot notice a difference between Audigy 2 Zs and X--Fi though when playing back HD-DVD/BD Audio...


Distinguished Member
I use an X-Fi myself and on the highest bitrate BD disk I have Pirates, Dead man's chest which is 7mb/s or something mental, I can hear no difference on my kit except for an increase in volume.

I suppose it is possible that the disk will make a difference, a well mastered DD+ track may be similiar in quality to a TrueHD track but the fact that Cyberlink state they downsample all audio from BD sources to 16bit / 48hz should significantly reduce any differences in quality between the two tracks.


Distinguished Member
Ok, so I made a typo :p

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