Why I Hate HDMI

Alright! I don’t completely hate HDMI. Loathe is a better word. My home theater is integrated using HDMI and it works great but that is what it was intended for. If you are new to video, HDMI is a format that caries digital video and up to 8 channels of audio over a consumer friendly cable that attaches as securely as an S-video connection (this is an insult not a praise). Any commercial project intending on using HDMI as its main format should increase their budget to cover several correction devices, HDMI over CAT5 convertors, very expensive CAT5 with individually shielded pairs and a common group shield, and Tylenol for all the headaches. Also budget for the extra time you will waste trouble shooting why the farthest display is working great but the one only 25’ away, using all the same components, is not.

Here are some reasons for my dislike of HDMI:

First, the connection is a lousy one. Unlike DVI, VGA or BNC which securely fastens to the components, the HDMI plug is held in by friction which requires multiple micro pins to maintain perfect contact.

Second, the HDMI signal is inconsistent from device to device. This is due more to cost cutting measures by manufactures than the HDMI signal itself. One of our preferred manufactures of scalers and video tools tested five exact LCD displays with the same variables and components using their HDMI over CAT5 convertors. Three worked just fine, one had intermittent problems and the fifth one did not work at all. There was nothing wrong with the HDMI ports on these TV’s but they reacted differently to the same HDMI signals. Springtree Media Group just recently completed work for the U.S. Army that consisted of ten 42” LCD TV’s (all the same brand and model) and one LCD projector. The signal came from eleven DirecTV HD receivers. Five of the TV’s were close enough to run HDMI cables direct. The other five TV’s and projector required HDMI over CAT5 due their distance from the receivers. Two TV’s did not like the signal even though they were not the longest runs. We tested the HDMI ports to be sure they were not defective and could not find any problems with them. After replacing the CAT5 cables, and the convertors several times with no luck, we ran super long HDMI cables (not recommended) and they worked. All we could surmise was that on the particular day that those two TV’s were assembled, an inferior resistor or part or whatever was used and that made the difference on how it handled the HDMI signal. We have recently been awarded another installation for the military in which we stipulated that we would be allowed to run Component HD instead of HDMI. What a relief!

Third (for the sake of brevity but not last), HDMI is an all or nothing delivery system. If the packets of digital information are not delivered at the required specs then you get nothing. Also the handshake (the process where HDMI component sync up with another one) can take up to 13 seconds. This makes it cumbersome for live presentations in worship and corporate environments where this kind of delay is unacceptable.

HDMI has been adopted by manufacturers because of pressure from movie studios which like the HDCP protection which prevents the copying of movies and other encrypted videos over the HDMI connection. So far this has not been a major issue since BluRay players include a Component HD output (HD content over analog). This ends at the beginning of next year. You didn’t think the movie studios were going to let you get away with it, did you?

There are many solutions and formats that we recommend for churches and corporate environments where HDMI may be problematic. I will cover these in the next newsletter. If you are in the middle of a project now, please call anyone of our associates for recommendations and assistance. We will do our very best so save you time, money and reduce the chance of headaches!

Peter Vaque