Throughout the years since audio/video devices have become commonly available, there have been a few standards for connecting devices. RCA dominated the 1990s. USB became a game-changer for multi-purpose use.
And then there is HDMI. There are more than 8 billion HDMI-enabled devices in the world currently, making that cable type the most popular by a mile. If you are using a device that transmits audio and video between a receiver/display and a source. That said, there is far more to understand.
What is HDMI?
Look around your home. There is a very good chance that you have a device that uses an HDMI cable. For the most part, modern televisions have several HDMI ports for connecting any type of audio or visual device. HDMI transfers digital audio and video from a source like a computer or cable box into a monitor, projector, or television.
Created in 2002, HDMI was introduced to improve current connectivity standards. The connector became smaller and more versatile while also adding high- resolution video and embedded audio. HDMI officially took over DVI as the primary connector by the end of the 2000s. By the early 2010s, the vast majority of televisions had at least one HDMI port built in.
HDMI Interface
The purpose of the HDMI interface is to transmit high-resolution video, device commands, and theater-quality sound through that connector. These signals go down a single cord, each of which is designed to meet a certain HDMI specification. There are three sizes available: standard, mini, and micro.
You will also find a litany of different HDMI cable types. These are meant to support different data transfer speeds and resolution types. Cable specifications include standard, high speed, premium high speed, and ultra-high speed. If you can’t find a marking of some sort on the cable, it is probably the standard version.
HDMI Features
As mentioned above, there are a plethora of different H DMI cable types. For the most part, they will include the following features:
Consumer Electronic Control (CEC). Using this feature, as many as 15 different HDMI devices can be connected to a single controller. Many streaming devices and televisions support this feature but typically have it turned off by default. CEC can also be brand-specific, so it might be confusing to know what that feature is.
Transition-Minimized Differential Signaling (TMDS). As data is transmitted over a cable, especially over longer distances, it becomes susceptible to signal loss and static noise. TMDS encodes the HDMI signal to protect it from that interference as it moves from source to receiver. The sending device organizes ones and zeros to encode the signal so that it will not degrade.
High-Bandwidth Digital Content Protection (HDCP). This is an authentication protocol that allows both sending and receiving devices to verify each other’s credentials. When verified, they share a key that is then used to both encode and decode the data that gets exchanged between them.
This simple process is known as a handshake and is instantaneous once connected. The connection ensures that any unauthorized device cannot take that data while it travels between those two devices. HDCP is both supported and mandated by the Federal Communications Commission (FCC).
Display Data Channel (DDC). Included in the HDMI interface is DDC, which is a set of protocols that allows the source – a graphics card, for instance – to ask the television or monitor what video and audio formats it is capable of handling. It then automatically adjusts those settings like contrast and brightness. Transmitted through the DDC, this exchanged information is known as Extended Display Information Data (EDID).
Thank you for reading.
