High-Bandwidth Digital Copy Protection (HDCP)
Source: Tom's Guide | Keywords: HD, PC, Audio | Themes: Digital Entertainment
- 1. Following the PC Audio Chain for Blu-Ray Playback
- 2. PC Blu-ray Drives and Decoders
- 3. Commercial Blu-Ray Disk Decoders and HDMI Versions
- 4. High-Bandwidth Digital Copy Protection (HDCP)
- 5. Onward Through the Audio Chain!
4. High-Bandwidth Digital Copy Protection (HDCP)
HDCP stands for High-bandwidth Digital Content Protection, and represents copy protection technology developed by Intel and licensed through Digital Content Protection LLC. It’s specifically designed to protect encrypted data as it moves through the signal processing chain from player to display. Blu-ray and HD DVD require a secure connection when using DVI or HDMI interfaces, which must support HDCP through the entire chain.
HDCP is designed to foil unauthorized access to digital content while it’s “on the wire” between the player and the display, and gets the backing of most major movie studios and other creators of high-definition video source material. If any component in the processing chain doesn’t support HDCP, no HDCP handshake will complete end-to-end, and you won’t be able to play back protected content, including any Blu-ray discs you might want to watch.
These days, most vendors whose hardware can handle high-definition content—including set-top boxes for cable or satellite video, DVD players, HDTV sets and so forth—choose to license HDCP, and typically also require it to be accessed using an HDMI connection. That’s why you see an increasing number of HDMI- and HDCP-capable graphics cards and motherboards coming to market these days. It also explains why you must have the right version of HDMI to get high-definition audio out of a PC: only it provides the right combination of copy protection and audio bandwidth handling capability to meet combined HDMI/HDCP requirements.
Content publishers—movie and TV studios, and other outfits that produce copyrighted high-def content—haven’t yet turned on the AACS Image Constraint Token (ICT). Think of the ICT as a flag that tells the display gear to downscale content if it senses the lack of the right transmission and decoding chain for output of high resolution (1080i and 1080p) content. For the time being, the ICT isn’t turned on in any commercially available pre-recorded materials right now, either for Blu-ray or HD-DVD. That’s because these fledgling technologies and markets don’t want to alienate the vast majority of HDTV owners whose equipment doesn’t meet the AACS interface and decryption requirements. That’s why you can use component video, older HDMI (1.1 or 1.2), VGA or even DVI-I links from player to display (and other points between, where applicable) and still get 1080 output, specifications and copy protection notwithstanding.
Today, movie studios get to choose whether they use the flag or not, and so far, they’ve chosen not to do so, for eminently practical reasons. The issue with high-def audio such as Dolby Digital Plus, Dolby True HD, DTS-HD High Resolution, and DTS-HD Master Audio is that only HDMI 1.3 is able to recognize and forward those formats unaltered from the player to the next link in the processing chain. Lower versions of HDMI will happily handle LPCM, even at high bitrates, which is why you can use that approach as a workaround, by decoding any of those formats into their uncompressed LPCM counterpart (raw audio channels, essentially) then emitting that format from your PC via HDMI or DVI-I instead.
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Ed,
On page 7, when you talk about the Asus HDAV1.3, you say the output opamps can be swapped and then refer to the Burr-Frown (should be Burr-Brown) PCM1796. The BB PCM1796 is a stereo DAC not an opamp. Someone might get confused and think they can swap the DACs. You should fix this.
So why doesn't some company bite the bullet and design a solution that has a protected audio path that can work outside of MS PAP, instead of waiting for MS to get their act together on their PAP drivers? This would probably help those of us with XP as well, since PAP appears to be Vista only.
Oddly enough it turns out that mis-spelling is taken directly from the ASUSTek site and it explicitly states that the DAC is replaceable. While rather odd seeming, and clearly incorrect insofar as the spelling of Burr-Brown goes, it is consistent with the press release...
All this to protect from ripping the raw audio/video streams. HDCP is the creator of all the trouble, and still quite easily circumvented by the end user, or the hardcore pirate. HDCP is going to stop NOONE from pirating the works that are being placed on Blu-Ray, and is only serving to frustrate not only customers but the manufacturers of both hardware and software.
The only benefactors of HDCP are those who are making it, IE Digital Content Protection LLC. and their ilk. Too bad the executives at the MPAA are too focused on screwing their customers to actually work at MAKING money rather than "protecting" a possible future of milking money from old works.
Thanks for part 2. I've been waiting on this for a while.
"Likewise, the Radeon 4x000 graphics cards appear to promise a fuller melding of 7.1 LPCM and high-definition video in their circuitry through a single HDMI output, but they aren’t due to hit the market until around the same time, perhaps as early as late summer."
Do you mean Radeon 4x00 / 4000 series? And they're out now.
Thanks for part 2. I've been waiting on this for a while.
"Likewise, the Radeon 4x000 graphics cards appear to promise a fuller melding of 7.1 LPCM and high-definition video in their circuitry through a single HDMI output, but they aren’t due to hit the market until around the same time, perhaps as early as late summer."
Do you mean Radeon 4x00 / 4000 series? And they're out now.
sorry, double post! :|
AMD/ATI products from the 2000 series on (excepting the 2900) have all had connectorless input for HDMI sound. No SPDIF cable is required, as is the case for nVidia products. Plug in your 2000, HD 3000, or HD 4000 product, install the drivers, and voila sound at the HDMi interface. SPDIF cable bandwidth is not an issue. Other issues however do exist (as the article points out).
What exactly is wrong with using the analog-outs on your sound card??
This is a great article. I was considering the purchase of an HP s3500t to use as a compact HTPC. The current model allows for a Q9300 CPU, Blu-ray drive, 512MB 9500GS with HDMI out and an ATSC tuner with remote. It's a good-looking, compact, feature-packed box. I'm not too concerned with obtaining digital audio because the analog from the onboard 5.1 is fine and I'm only connecting the built-in speakers on the display. I'm assuming the only thing I need to get BD movies playing with this PC is the right playback software.
Perhaps THG should investigate the quality of the Motherboard amplifiers.
If the preamp in the PC was as good as the first stage of my Reciever/Amp, then the only downside of using the MB analog outputs would be the number of wires which to me is not a big deal.
When I asked ASUS Support what the SNR for the P5K MB outputs are, they said they didn't know.
I like many am buying new hardware now that is supposed to be HDCP compliant. However, if the Bluray disks don't currently have HDCP enabled, then we all may have a rude awakening some day when we find the HW that was supposed to work doesn't.
Does anyone know of a Bluray disk that is using HDCP now so I can verify HW works before the return policy expires!!!
I said it already but, can't find it in previous article. There's no real 7.1 thru analog connetion from PC, (PDVD/TMT) player software is a problem, try to play some HD DVD /Blu-ray 7.1 sound test with right sounds separation then you will know it by yourself, if it would be not enough all analog/SPDIF sounds are downsampled in player to 48khz/16bit because of lack of PAP implementation. And more : GFX cards like AMD/ATI HD2xxx/3xxx and all Geforce even 260/280 supports only LPCM 2.0 & DTS/DD 5.1 mode , so right now only AMD4xxx has LPCM 7.1 support. Go to avsforum to find more ...
I said it already but, can't find it in previous article. There's no real 7.1 thru analog connetion from PC, (PDVD/TMT) player software is a problem, try to play some HD DVD /Blu-ray 7.1 sound test with right sounds separation then you will know it by yourself, if it would be not enough all analog/SPDIF sounds are downsampled in player to 48khz/16bit because of lack of PAP implementation. And more : GFX cards like AMD/ATI HD2xxx/3xxx and all Geforce even 260/280 supports only LPCM 2.0 & DTS/DD 5.1 mode , so right now only AMD4xxx has LPCM 7.1 support. Go to avsforum to find more ...
Thanks to one and all for the feedback. I'll get the Burr-Brown/Frown typo and the incorrect DAC mention fixed ASAP (and yes, it did come straight from the Asus press release, so far my only completely reliable source of information on the Xonar HDAV--that said, I'm supposed to review this as soon as Asus can furnish me with one, so look to these page for a *LOT* more information as soon as I can lay hands on one).
As for player software, I continue to enjoy great results in my testing with the ArcSoft Total Media Theatre product (which has now risen in my estimation as the best of the software codecs for PC, and which offers the best Media Center integratino around, IMO).
The citation of AVSforum is right on the money: it remains one of the best and most reliable sources of information on handling high-def audio around, both from the PC and the consumer/prosumer player perspectives.
If anybody else has questions, or suggestions for additional coverage in this area, I'm interested in shedding as much bright light into this space as possible. Thanks again to all for your feedback so far.
--Ed--
I have an Auzentec Cinema Sound Explosion 7.1 sound card w/upgraded op-amps, a Nvidia 8800GTX video card, several HD monitor choices, Cyberlink Power Dvd software and a Onkyo THX certified 7.1 home theater sound system. The Onkyo sound system does not have HDMI inputs/outputs. It does have 7.1 direct analog RCA inputs. As I understand what you wrote if I add a Blu-ray drive to my PC I can have the Cyberlink software decode the HD loss-less sound formats and send them to the Auzentech sound card which will do the D/A conversion and pass the resulting 7.1 analog channels to the Onkyo's direct analog inputs and the receiver becomes simply 8 amplifiers for my speakers. You are not sure if the actual output from the speakers will be correct in quality, fidelity and positioning etc. Is this correct? I have already determined I can use the DVI output on the video card to connect to a couple of different HD monitors and televisions I own. If the sound path I have described will work then for as little as $130 I can potentially enjoy all of the HD sound/video content currently available.
Response to Dmac225's question/assertion: Indeed the issue is the uncertainty of how well your proposed signal chain will deliver the high-def digital audio goods. It should work, but the real question remains: will it work well enough to be listenable. As long as the your rig can handle your sound scheme of choice you should be OK. That said, I'm pretty sure there will be issues with either the Cyberlink or Auzentech component for Dolby TrueHD and/or DTS Master Audio--you might want to consider obtaining the ArcSoft Total Media Theatre codecs as well, just to be on the safe side.
Please keep us posted on how things turn out, and what bumps in the road to success you may encounter. Such stories are an important part of learning this brave new audio world for all of us, including me!
--Ed--
More on the Asus Xonar HDAV1.3:
1. Looks like only the op-amps are socketed and thus the only items that users can switch out if they like
2. the DAC and the A2D converters offer very high signal-to-noise rations (120 dB SNR or better) but may not be swapped out. My mistake in conflating these items: I should have double checked the part numbers/IDs
3. There's some interesting coverage of the card at Nordic Hardware at http://www.nordichardware.com/news,7838.html, where you can see that Asus offers very high SNR for all of its analog outputs, which may make this card more suitable even for those who can only go analog from PC to receiver/processor.
HTH,
--Ed--
I installed a Blu-Ray drive into the PC described in my previous post and I must say other than the wife being pissed off (loading a movie off of a PC with dual monitor/TV is a bit much for her.) it seems to work very well. I have not had the opportunity to watch a movie recorded in Dolby TruHD yet but I did watch one recorded in DTS Master HD and it sounded very, very good. One issue I have is there does not seem to be a way to verify that what I am listening to is the actual HD audio track or a standard 5.1 stream with matrixed surround back channels. Also since I have never heard anything in TruHD or DTS Mater HD I have no reference to what it should sound like. So at this point I can only report that the system setup as described in my previous post does work and does sound very good. I am going to go try to rent a movie that allows you to specify what audio stream you want to verify that it handles the HD audio formats. I will let you know what I find out.
About verifying audio streams:
The only way I know of to do this is to pipe the stream via HDMI into an HDMI 1.3 capable receiver or pre-amp/pre-proc. These units will invariably tell you what kind of audio stream they sense incoming on the HDMI channel of which the audio is a part. There are probably HDMI testers out there that will tell you this, but my guess is that they cost even more than the aforementioned equipment!
HTH,
--Ed--
From what I see it's not a good moment to build a HTPC if you want the full specs of HD audio. At least thats what I gonna say to some friends of mine if they ask me about it.
Besides some true hardcore (not in a bad way) fans of Home Theater , I think most people wont use the full potential of HD Audio nor will they know how to do a correct setup to their speakers or even have enough quality in their speakers to notice the true difference.
Anyway great article, write more in the future, and btw whats the point in having HD audio if people don't know how to setup their own systems, so I hope you write a nice detailed article about the correct way to put different kinds of speakers in different rooms, just an ideia.
Best wishes
Rafael Lino