High Definition Multimedia Interface & High Definition Content Protection
While visiting a local aircraft LCD Display manufacturer recently, we blundered into discussion about HDMI/HDCP requirements and specifications and got a lively earful about the technology, the certification and the adopters who have driven the aircraft side of this High Definition video “thing”. We got to thinking and checked with a few industry know-it-all’s and discovered that there is not a lot of common knowledge on the subject. So, undaunted, we thought our readers might find what we discovered interesting.
The HDMI specification in an industry certified standard formed and supported by over 700 companies. It describes an all-digital interface for both video and audio and by doing so, mostly in the consumer electronics world, also sets the stage for aircraft video viewing. HDMI, and its companion video encoding/decoding standard HDCP, provide encoding/ decoding expertise and the simplified cabling and interconnection (video plus audio), which strives to maintain the theatre experience in the air. We asked our hosts about their licensing and Bill Baltra told us; “Aircraft Cabin Systems is an “adopter” of HDMI/HDCP and as such can use the HDMI logo legally. We don’t put it on our monitors; you will see it in our newest Avion ad. You can see which vendors are certified to display the HDMI and HDCP logo’s by checking out the participants in the respective link/web pages at the end of this Hot Topic.
The HDCP part of the licensing delivers encoded, digital video images from players such as Blu-ray disc devices and the HDCP part of the make-up is directed to the encryption/decryption part of the specifications. Because of the High Definition moniker, the higher pixel density supports HD 1080 (progressive and interlaced) images in a 16X9 format, delivering extremely beautiful video up to1920 X 1080 pixel performance. Further, it supports 8 channels of multi-channel digital audio with the video on one cable as noted earlier. The “MI” in the standard – Multimedia Interface – allows PC-based content like high definition movies and multi-channel audio formats. This is significant because the HDMI and DHCP certifications assure the workings of one billion or so devices in the field, and the 200 million or so to be delivered in 2010.
“Compared in the image is the ACS version of their video controller board for their HDMI certified LCD Display (L). Note that the analog Component Video board (R) is approximately the same size of the HDMI/HDCP decoder Video Controller board (L).The digital HDMI board is used on all four of the ACS HDMI LCD models – 32″, 47″, 52″, and 65″ LCD Displays. All these units are shipping today, IFExpress was told.”
As an aside, we note that Closed Captioning (CC) is handled in the player or signal side of the supplying device, embedded or added to the image formation there.
We wont dwell on the HDCP (High Definition Content Protection) part of the specifications but will note that the HDCP licensing adopters can exist without the HDMI certification and after looking at the websites if HDMI and DHCP – links below.
As noted earlier, HDMI is a lossless digital interface; it provides the best because there is no lossy analog-to-digital conversion (as in component or S-video). This difference is especially noticeable at higher resolutions such as 1080p. Digital video is sharper than the other formats, and eliminates the softness with the aforementioned signals. Small, high contrast details like text or fine lines bring this difference out the most. Significantly, HDMI certification is an advantage to users as this level of assurance significantly provides the interface needed for other inputs such as PC’s so that users and installers alike can be assured that the system boxes will talk to one another at 35,000 feet.
Another trap we discovered was sprung by the specification folks (AACS LA). It is the end of component video output (brought about by Blu-ray) which successfully kills the component video output of Blu-ray players) by Dec. 31, 2010. After that date, manufacturers are no longer allowed to introduce new Blu-ray players with component video outputs capable of HD output; they must limit those outputs to SD (480i or 576i). Existing models may continue to be sold until the end of 2013. The reasoning – Blu-ray carries an encryption scheme called Advanced Access Content System, which is a form of DRM to restrict access to and copying of content on Blu-ray video (or HD-DVD in the past). Amazingly, even existing Blu-ray players will be affected after Dec. 31, 2010 as Blu-ray disks will be able to include something called an “image restraint token” which will cripple any HD over the component video channel and limiting it to 480i X 576i resolution. This insures that HD content only runs thru HDMI. Note this if your Inflight Entertainment system is about to upgrade to a Blu-ray player and relies on component video sourcing. Sometimes, specifications are the Holy Grail of interface success and can only be measured in certification assurances.
Also, you may want to read: Analog Sunset Demystified