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:
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:
22.214.171.124 IEC60958 Audio Content may be passed:
126.96.36.199.2 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
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:
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 188.8.131.52.2 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?