Summary as posted on the OHF Board list for any possible comments.
-------- Original Message -------- Subject: [OHF Board of Directors] DHCP and HDMI Date: Sun, 18 Feb 2007 13:52:28 -0700 From: James Richard Tyrer <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] So, we have our first issue regarding the Open Graphics Card. :-( The HDCP license rules require that digital *output* of DRM restricted content higher than certain resolutions be encrypted with HDCP. I note that this also applies to DVI digital connections as well. The issue that has been raised in the trade press is whether this requirement also applies to HDCP *input* (and possibly digital DVI) with those resolutions. If this is true, then in the near future all video cards will need to be capable of HDCP encrypted output. I have looked at the license and I don't immediately see that it contains such a requirement. The only requirement appears to be for devices that could be considered to be "repeaters" that if they receive HDCP input that any digital output generated above the stated resolutions be HDCP encrypted. I see nothing that would forbid a device from accepting unencrypted HDMI as input and outputting encrypted HDMI. So, this is an important question and we need to find the answer. The license is very restrictive, but limited to only the output issues. However, it appears to me that the OGC could easily comply with it as long as all that is needed is to provide an DHCP encrypted HDMI output. This could done by using a HDMI transmitter chip that comes with the keys already programed into it and using a micro-controller (soldered to the board) with on chip ROM to control this transmitter chip. This would make it sufficiently difficult to output unencrypted digital content to comply with the license. The source of the MCU code could be published because it would contain no confidential information. Yes, a professional could obtain another MCU, program it, and replace the one supplied, but that is OK because consumers wouldn't be able to do it. A larger issue, and one that is probably something that the the foundation should be more concerned with is the input of HD content to hardware such as the OGC. I have to admit that I don't know how it works if you install an HD-DVD or Blu-Ray drive in your PC and play an HD movie disk on it but I presume that the OS reads the disk data with the disk controller. IIUC, the video content on the disk is MPEG-4. Is this encrypted? IAC, it appears that this is beyond the reach of the HDCP license. If the OGC only has a HDMI transmitter then the HDCP license would start with the transmitter. However, I note that if Open Hardware is going to include an HDMI input this is a much different question. In fact, I wonder if it is even possible for any PC hardware to have an HDMI input that accepts HDCP encrypted input. Currently, the only protection that DRM HD video content has in a PC is that Vista will refuse to output it to an unencrypted digital output. The OS has the 'clear' video data. To get to the question. The issue is whether there is some DRM requirement which would conflict with Open Source Software or Open Hardware. Clearly the approach used by Vista will not work -- there is no way that Linux, OpenSolaris, or BSD being programed to refuse to do this is going to have any effect since the source code is available. If the issue comes down to not being able to release the source or documentation (respectively), then it is a serious issue which the EFF might be able to assist us with. -- JRT _______________________________________________ Board mailing list [EMAIL PROTECTED] http://mail.openhardwarefoundation.org/mailman/listinfo/board_openhardwarefoundation.org _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
