HDMI and DVI-D are two digital video standards used in the transmission of high-definition video, and in the case of HDMI, digital audio as well. They are frequently used for various displays in both the computer and home entertainment fields. While the picture quality of both is nearly identical, there are several differences between the two formats.
HDMI stands for High Definition Multimedia Interface. It is an entirely digital standard and seen by many as a replacement to traditional analog standards such as SCART, coaxial cable or composite video. HDMI cables connect to electronic components via a single connector that transmits both audio and video. As the name implies, HDMI can transmit high-definition signals, supporting signals as high as 1080p (progressive scan). They are widely used today, and nearly all HDTVs, Blu-ray players and home console systems support them. Computer monitors with HDMI connectors are becoming more common as well.
DVI-D stands for Digital Visual Interface-Digital Only, and is an all-digital variant of the DVI format. Other DVI formats include DVI-A (analog only), DVI-I (analog and digital) and MI-DA (Digital, analog and USB). Like HDMI, DVI-D supports high-definition digital content, up to 1080p in resolution. DVI-D cables resemble traditional VGA cables in appearance, and require screws be properly attached to displays and other devices. DVI technology is the predecessor to the HDMI standard.
One of the most notable differences between HDMI and DVI-D is only HDMI can support audio. DVI-D is strictly a video format and cannot transmit any kind of audio. If a person is converting an HDMI signal to DVI-D via an adapter, they will need additional cables, such as component audio or TOSLINK. The other major difference between the two is HDMI supports a form of digital copyright protection called High Definition Content Protection (HDCP). This can make copying signals via HDMI impossible. DVI-D does not support any kind of similar copyright control method.
Because HDMI is derived from DVI technology, the two formats have much in common, and are in fact compatible with each other. HDMI/DVI-D adapters are very common, and allow for the conversion of one format to the other with no notable signal degradation. These converters are often used by individuals looking to connect their computer to a large HDTV display that does not have a built-in DVI-D connector. They may also be used to connect video game consoles, which typically only have HDMI support, to monitors with DVI-D connectors.
Usage of HDMI has become incredibly pervasive over the years, and the electronics industry has successfully pushed for it to become the de facto high-definition cable standard. DVI-D cables are still widely used in the computer industry, though, and are more commonly seen as HD connectors for video cards and computer monitors. It is not entirely uncommon to see DVI connectors on HDTVs today, making it possible to connect a computer to a large HDTV instead of an LCD monitor without the use of special HDMI/DVI adapters.