Why is HDMI audio input to Digital Audio Output blocked when allowed by HDCP license? - AVS Forum
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post #1 of 6 Old 01-27-2008, 02:32 PM - Thread Starter
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When I got my new HDTV in August 2007, I hooked it up according to the user manual but could not get more than a couple of seconds of audio from the Digital Audio Optical output for any HDMI source. The manufacturer's website FAQ said:

Quote:


The HDMI input on Samsung TVs can not pass digital 5.1 Surround Sound to the Digital Optical output jack. This is not a limitation of the TV (technically, it could be done), but instead a limitation imposed by laws and regulations. The TV can not pass straight digital signal because to do so would violate copyright laws and copy protection regulations.

So, if you want digital video and digital 5.1 sound, you must connect the video output of your source to your TV using DVI or HDMI, and connect the digital audio output from your source directly to the digital audio input of your Home Theater System or Stereo.

Following these instructions resulted in source switching complexity and very noticeable lip sync error.

On the Internet I found the HDCP license at http://www.digital-cp.com/home/HDCP_...st_21_2005.pdf . Reading thru the license I found a specific exemption that allows copy protected HDMI audio input to be passed to Digital Audio Output as long as the channel status bit 2 in the S/PDIF control word is set to zero in each audio output packet:

Quote:


3.3.2.3 IEC60958 Audio Content may be passed:

3.3.2.3.2 To IEC-60958 or IEC 61937 where SCMS information is properly set and transmitted as Copy-never.

I replied to the FAQ with this information and they changed the web page to remove mention of laws and regulation. But they have been otherwise unresponsive by explaining the reason they are blocking the signal or providing a firmware update. Their hardware is able to pass the digital HDMI input because a couple of seconds of sound can be heard before the firmware begins blocking the signal.

I understand that other manufacturers also block the Digital Audio Output but there is at least one exception. I own a Calibre Vantage-HD2 video processor which does not block the signal. A FAQ on their website, Calibre Vantage-HD FAQ number 6 at http://www.calibreuk.com/vhdfaq.htm#Q6, says:
Quote:


You originally told customers that if the audio input was via HDMI with HDCP then the SPDIF Coaxial and Optical audio outputs would not function. Is this true and why?

We originally believed this was necessary for compliance with the HDMI and HDCP licensing rules but have now found another means to make Vantage-HD comply with the copy protection requirements of HDCP and HDMI without having to disable the coaxial and optical digital audio outputs. This is clearly far more convenient for our customers. Unfortunately there is no such work-around for video signals though, we are not permitted to output RGBHV analog signals if the input is HDMI with HDCP or DVI with HDCP - see FAQ 5 above.

FAQ 5 is:

Quote:


Can I always get an HDMI output? Is HDMI audio always present?

Yes, the HDMI output is always active and it automatically detects whether you have connected it to a true HDMI display device or to a DVI device. It may not always have HDCP encryption present since that is dependent on whether the input signal is HDCP encrypted, but it can always be used. HDMI audio is always output when an HDMI compliant display device is detected, but is not available if the display is detected as a DVI type.

The "means" that they refer to is to set the channel status bit 2 (copy prohibit) in the S/PDIF control word to zero, for Digital Audio Output from an HDMI source. This satisfies the HDCP License Agreement requirement 3.3.2.3.2 which allows digital audio from HDMI to be passed if "SCMS information is properly set and transmitted as Copy-never".

There is no law or license that prevents HDMI audio input from being passed to Digital Audio Output. So my question is, why is HDMI audio input to Digital Audio Output blocked?
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post #2 of 6 Old 01-30-2008, 10:45 PM
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Great question that deserves an answer. Every customer is screwed out of using a simplified audio setup by just connecting to their TV because of some ignorant legal departments.

Just so everyone understands, this would be a big thing to get passed by Samsung. It'd have to be brought up to legal, who'd have to authorize it. Then it would be passed to management, who may/may not send it to development. Fix in development, send to QA, pass to management, pass to legal again to authorize. It may then find its way out to people at that point, but there's miles of red tape to cut in the bureaucracy world of modern day corporations.
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post #3 of 6 Old 02-03-2008, 11:07 AM
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The HDMI slogan needs updating. It should read:

HDMI - The One Connector World, as Long as Everyone in the World is Satisfied with Stereo Audio Over Their TV's Speakers.
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post #4 of 6 Old 04-07-2008, 10:40 AM
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I just got a an LN-T5265 and ran into this very problem. This total crap. All the capability is here to allow me to use my existing receiver to power my 5.1 system and use my TV to switch the sources, but no it's neutered by a Firmware feature. Now I have to replace my receiver with a HDMI switching model so I don't have to fumble with 3 remotes every time I watch to use a different source.

I just got off the phone with a Samsung level two guy (Charles) who confirmed all of this. He also stated that the law governing this was supposed to change in the next year which would "allow" them to release a new firmware update to unlock the PCM audio restriction.

I don't understand this stupid law. How does this prevent me from copying anything? It doesn't. It just prevents me from being able to enjoy my system legally.
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post #5 of 6 Old 04-07-2008, 12:25 PM - Thread Starter
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Quote:
Originally Posted by EvilBetty View Post

. . .
I just got off the phone with a Samsung level two guy (Charles) who confirmed all of this. He also stated that the law governing this was supposed to change in the next year which would "allow" them to release a new firmware update to unlock the PCM audio restriction.

I don't understand this stupid law. How does this prevent me from copying anything? It doesn't. It just prevents me from being able to enjoy my system legally.

Sorry Betty, but Charles, probably not his real name, lied to you to get you off the phone. There is no law that keeps Samsung from updating their firmware now. You can call Charles back and have him give you the citation to the public law number. With the citation you can go to the Library of Congress Law Library http://www.loc.gov/law/ and read the law for yourself. Of course, he will not be able to give you a public law number but he will provide you with another lie to get you off the phone again.
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post #6 of 6 Old 05-02-2008, 12:29 PM
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I just bought a new Mitsubishi WD-73734 TV, and was planning on using HDMI input from my PC, and letting the TV's coax out go straight to my receiver. The TV's manual says that for whatever source is selected on the TV, it will send a digital stream out the coax, and an analog stereo (downmixed if necessary) out the RCA simultaneously. However, it has a small note:

Quote:


On rare occasions, an HDMI signal may be
copy-restricted and cannot be output from
the TV as a digital signal. To hear these copy-
protected signals through the A/V receiver, use
connections for analog A/V receivers.

This will completely defeat the purpose of my setup, just like you guys are experiencing. I am not interested in doing anything illegal, as I have legit BluRay and HD DVD rentals, a legit PowerDVD licensed copy on my PC, and just want to enjoy my new TV with my receiver.

Does anyone have experience with PowerDVD and the Mits line of DLP's to know if I'm screwed here? It will cost me 2 additional cables and countless time explaining to family how to switch sources if it won't work seamlessly.

-T
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