Pre-Cursor to Installment 028 – EDID Management

This blog post provides background material on Enhanced Display Identification Data (EDID Management), the topic of Installment 028.  I thought it would be useful to publish the information ahead of time because it is difficult to describe byte-code level data structures verbally and seeing it visually ahead of time makes it easier to grasp the concepts we will be discussing.

EDID handshaking is an integral part of the HDMI initialization process.  It is how the Source understands the capabilities of the Sink(s) to which it is sending both video and audio streams.  As we have discussed several times throughout our different Installments, having the appropriate EDID information presented to a Source when incorporating HDMI Switchers as part of a distributed HDMI infrastructure is key to a successful implementation.

Exposing EDID-based capabilities is easy when there is a single display connected to a single source, but what happens when you start throwing multiple displays with different capabilities into the mix?  How does the Source know what formats it can send out successfully?  That is where EDID management comes into play.  There is a whole new set of skills required to pull off EDID Management when working with complex HDMI topologies and infrastructures and it is imperative that any integration firm have someone on staff who understands the complexities of making it all work properly.  We will be drilling down into that as our main topic for our next Installment, but I thought it would be good to get the information out ahead of time in preparation for it.

I think the following diagrams depict the basics of EDID structures well.  They are taken from an HDMI Overview presentation from LIGHTWARE (http://www.lightware.eu/siteE0.htm), a manufacturer of HDMI Switchers, Extenders, and Diagnostic Tools and Components out of Hungary.  They provide a wide range of EDID (and HDCP) Management tools for their broad set of HDMI Switcher offerings.  I thought it easiest to use their examples because they depict the breakdown of the EDID data blocks visually.

We will dive into the relevance of this information in Installment 028 and hopefully shed some light on how EDID structures fit into a well engineered HDMI infrastructure – and especially its relevance to 3-D capabilities and structures.  Be sure to keep an eye out for when we publish the associated Podcast.

  =D-