Digital Video Interface, Digital Video Interface
DVI, Digital Video Interface, has come and gone already
DVI stands for Digital Visual Interface and it's one of the new digital connection types that are HDCP-compliant along with HDMI. Digital signals are less prone to compression artifacts and other pitfalls of analogue digital connections. As an alternative to an analogue connection, digital is also safe from interference and degradation. DVI outputs can be found coming from any video source such as a DVD player, digital cable terminal, PVR, Satellite Receiver. Virtually anything that produces a video signal with high bandwidth requirements like those of progressive scan or digital television is a candidate for the use of DVI.
A digital cable box, for instance, that uses a DVI connection to an HDTV doesn't need to rely on its own DACs to uncompress the video portion of the cable network being broadcast to the cable box from the cable company. It can remain in the digital domain as it leaves the cable box through a DVI cable for video and a digital optic or coax audio cable for fully digital audio. The receiver of the video and audio could be a TV (for video) and a home theater receiver (for audio). Remaining in the digital domain means the critical step of conversion to analogue can be performed as close to the presentation of the video as possible. In this instance, the decompression of the video signal takes place in the TV itself.DVI at a glance
- High bandwidth means uncompressed video.
- HDCP-compliant, thumbs up from the industry.
- Can be used to connect your PC to your HDTV.
- Long on the tooth for Home Theater and being replaced by HDMI.
The alternative to digital connection (any HDCP digital connection) is an analogue connection. An analogue video connection to any digital television is accomplished only one way - component video cables. These consist of three video cables, usually red, green and blue, each of which passes an element of the video signal to the TV. The device that is sending video in this manner has already decompressed the video signal and, when it arrives at the digital TV, is likely to be converted back to digital (for the television's processing) and then back to analogue again. This back-and-forth digital-to-analogue conversion is said to degrade the signal. Compression artifacts are the squiggly lines around the borders of high-contrast images caused by over-compression. Be warned, however: using a digital connection is no guarantee you won't see this type of distortion in your video. Compression artifacts in video are common on DVDs and can occur at various steps of the video production. Digital connections like DVI and HDMI can only hope to limit their occurrence.
A lot was made of the improvements in video when DVI first hit the Home Theater market. However, critics and video enthusiasts are a little more guarded about promises of eye-popping results from digital video connections. The benefits to digital video connections might not be noticeable in most equipment. So, if you're considering purchasing new gear just to take advantage of DVI or HDMI don't do so on the basis that it will improve video quality, because there is no guarantee. However, DVI or HDMI are a clear step up from either S-Video or composite, as both are analogue video connections that have limited bandwidth and exist solely in the analogue television realm and weren't designed to present video at resolutions higher than 480i.