Auzentech HomeTheater HD Preview: Bitstreaming True HD/DTS-HD MA
by Anand Lal Shimpi on September 2, 2009 12:00 AM EST- Posted in
- GPUs
Last year ASUS released the Xonar HDAV; it’s a sound card. The Xonar HDAV’s claim to fame was its ability to bitstream Dolby TrueHD and DTS-HD MA over HDMI. Don’t have any idea what that means? I wrote a primer here last year, but I’ll give you the quick rundown.
Blu-ray discs are huge, you can store up to 50GB on a dual-layer disc. That’s not enough to store lossless video, but it’s enough to store lossless audio. In other words, you can have a bit-for-bit reproduction of the audio track that was mastered at a movie studio in your own home. For most consumers it’s cool as hell just for bragging rights, but for some super high end home theater enthusiasts it’s a perceived necessity.
These audio tracks are stored using one of two lossless compression algorithms: Dolby TrueHD or DTS-HD Master Audio. The content owners however were very nervous about putting these audio tracks on BDs, specifically allowing PC users access to them. After all, if you had unencrypted access to one of these tracks you could potentially...uh...idunno, turn them into MP3s? Stop going to the movies? I have no idea. Regardless, the studios were nervous and the result was a ridiculous requirement for security.
In order to play one of these tracks you have to properly implement what’s called a Protected Audio Path (PAP). I go into much greater detail about the encryption/decryption requirements for a PAP but you need OS, software, driver and hardware support for it. Windows Vista gave us OS support, ArcSoft and Cyberlink gave us software support and the GPU vendors gave us driver support - all we were lacking was the hardware.
The GPU vendors didn’t include support in their designs for a number of reasons, so no integrated or discrete graphics currently support sending these compressed audio streams over HDMI. Next year that will change, but for now it is what it is.
The only hope was for sound card makers to tackle the problem, but the sound card market isn’t what it was back in the 1990s. ASUS was the first to take it seriously, because, well, ASUS takes everything it does seriously.
The Xonar HDAV launched and as you’ll see, I haven’t reviewed it. When it first hit, driver support wasn’t there. Despite the hardware support, you couldn’t send TrueHD or DTS-HD MA over HDMI because the driver didn’t allow it. This part took months to fix, it took some more months to work out a number of other bugs and in that period I just gave up on it. I went back to it not too long ago and while it worked, I’d lost my interest.
Before I ever heard of the ASUS card I heard that Creative Labs and Auzentech were working on one. I even wrote about it. I actually expected it to be out first, but for whatever reason it got pushed back. The card finally launched this year and today it finally received support from Cyberlink to bitstream these codecs without any loss in quality. The PowerDVD 9 patch notes tell you right here:
You do need PowerDVD 9 for this to work, no it doesn’t come bundled with the card, yes the latest patch is needed for it to work.
Auzentech sent me a card and I went to testing it. Perhaps it would be my one last hurrah with high end HTPCs before I accept fate and build a modest XBMC box for my needs.
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Jaybus - Friday, September 4, 2009 - link
This is true. I think this should be a software option. It seems they limit bitstream output to 6.144 Mbs, which is the maximum allowed for DVD-Video. This only allows 16-bit 48 kHz sampling for 7.1 surround. Perhaps, with the exception of these high-end audio cards, it is the hardware itself that can't handle more than a 6.144 Mbs audio bitstream over HDMI? Makes the software more compatible with various HDMI implementations? License only allows for DVD-Video quality audio? Not sure.mczak - Wednesday, September 2, 2009 - link
Err, there's no point in using "specialist" high quality hardware for decoding. This is a lossless format, so any decoder adhering to specification will in fact decode it to the exact same uncompressed data. D/A conversion will happen in the receiver anyway so it really doesn't matter where you decode the lossless format.But audiophiles might argue about "better bits" and whatnot whispering words like "jitter"...
micksh - Wednesday, September 2, 2009 - link
Thanks a lot for the article. The essence of the problem is very well formulated.This is exactly what I gathered from months of reading AVSForum. LCPM over HDMI provides you enough resolution for most blu-ray disks even if it is downsampled to 48KHz/16 bit. It is still lossless and can be provided by cheap video cards or motherboards. Not many disks have greater than 48 KHz sample rate and 24 vs 16 bit is like 114 vs 92 db detail level. The difference can't be heard in most environments anyway.
Current Blu-ray PC players just can't get it right with bitstreaming so there is no need to pay ridiculous price for audio hardware. With release of SlyPlayer there will be no need to pay for crap software either.
It is great that the article is appeared on such respectable site.
One question regarding roadmap for motherboard bitstreaming over HDMI. I've heard opposite rumours - LPCM over HDMI can be discontinued because of the need to pay for license. Example - new ATI Radeon 5xxx series are going to lose LPCM over HDMI. Is it true about ATI?
recon300 - Thursday, September 3, 2009 - link
I have to agree. Thanks for the writeup, the issues you highlighted definitely need to be addressed. Great article.Procurion - Wednesday, September 2, 2009 - link
I beg to differ. In a movie room, one built for this environment and set up for it, there is a difference. $250 is high-end which is the emphasis of the article. Subsonics are one of the first thing to go in a compressed format and obvious when compared. There are a lot of people who remember and still listen to lossless-only music and recognize what we're losing when they are converted to what the industry tries to pass off as "indistinguishable" differences in a less than full reproduction.In essence, you can't HEAR the difference, you FEEL the difference. Subsonics and ultra high frequencies can't be heard, true. They are felt.
snarfbot - Wednesday, September 2, 2009 - link
it ultimately depends on your receiver and speakers right?compressed audio does clip the very low and very high frequencies, but most consumer level audio equipment cant even reproduce that part so you wouldnt feel it anyway, even if you could, which im not convinced of, at least in the high range. my mediocre speakers can reproduce painfully high frequencies as it is.
also a good sub can only do around 20hz at best anyway, which is covered just fine by regular dvd's.
so i cant really see what your missing, unless you are talking about bass shakers, you know the things that physically shake the chair your sitting in, which also work just fine with regular compressed audio.
my particular ass for example probably couldn't tell the difference between standard and high definition vibrations.
lol
LTG - Wednesday, September 2, 2009 - link
"you can't HEAR the difference, you FEEL the difference. Subsonics and ultra high frequencies can't be heard, true. They are felt."I'm not that confident in your ability to "feel" ultra high frequencies.
Are you sure they can do anything other than give you a headache or upset your dog?
Fallen Kell - Wednesday, September 2, 2009 - link
"I'm not that confident in your ability to "feel" ultra high frequencies.Are you sure they can do anything other than give you a headache or upset your dog?"
There were several scientific studies on just this subject, and in all of them the answer was yes, we do interpret many of the frequencies that we can not audibly hear. Multiple studies in the infra-sonic frequency ranges have all produces extremely high correlation that humans most certainly do detect infra-sound and interpret it. The high frequency results have not been studied as much, but the studies that I have seen have all shown that there is a very large percentage of people do somehow detect the frequency ranges (one particular study had subjects listening to music which contained a clipped frequency range and music where those clipped frequency ranges were still intact and brain scans were taken during the time. The music with the full range frequency showed much more activity in the brain, which showed that even though the frequency ranges were outside normal audible range, the brain was still interpreting the frequencies).
jigglywiggly - Friday, September 4, 2009 - link
Just get a ps3 and put linux on it, rip it to a smb windows computer. No encrpytion if using anydvd + way freaking easier.MrPoletski - Wednesday, September 2, 2009 - link
It's more than that. You brain identifies the sound as a guitar sound, so you hear a guitar sound - the missing frequencies be damned. As far as you brain is concerned the missing frequencies are just distortion and will require your brain to do a little more work to decipher that it is a guitar sound. But in the end, you will always hear the guitar.That runs with the idea that you dont see and hear the things around you. You see and hear the sights and sounds your brain believes to be around you based on the input it gets from its ears and eyes - i.e. it's interpretation of that.
Having lossy formats wont sound any worse until you have heard the real recording and even then, the difference will be far more noticable ion the experienced fatigue from listening to the music for a length of time.
A tinny radio turned up too loud will tire you out if you are trying to listen to it, a high end hifi would not. In fact, it would be a joy to listen to. Try that tinny radio turned up too loud. You'll soon want to turn it off.