What's the differences between DVI and HDMI?

Is there any difference between DVI and HDMI?

DVI stands for Digital Video Interface. HDMI stands for High Definition Multimedia Interface.

Ok, let's discuss what each of these interfaces is and how it works.

Digital Video Interface, or DVI, is actually a predecessor of HDMI. Digital Video Interface was made by the Digital Display Working Group (DDWG). The original design for DVI included conversion of analog signals by converting analog into a digital signal. This was done so that both analog and digital signal monitors could be accommodated by DVI. Data is transmitted by the use of transition minimized differential signaling (TMDS) protocol and provides a digital signal from a PC's graphics subsystem to the display unit.

There is DVI-A and this type of DVI is used for analog signals like VGA. The second type of DVI is DVI-D. This type of DVI is used for digital signals, and this type of signal is the one that all home theater products use and that are intended for consumer home use. DVI-I is the third type of DIV. This type is a combination of DVI-A and DVI-D.

Two levels of performance are supported by DVI-I. These levels are single link and dual link. Currently all home electronics products are designed around the single link standard. A dual link cable, however, is 100 % compatible with a single link cable plus the dual link cable offers the benefit of adaptability in the future for any wide band width applications. DVD-I is a complete, fully digital video transport protocol that is supportive of all digital video formats including 480p, 480i, 540p, 720p,1080p, and 1080i.

High Definition Multimedia Interface is the only uncompressed, all digital audio/video interface that is supported by the industry. Founders of HDMI include manufacturers of leading consumer electronics Panasonic, Phillips, Hitachi, RCA, Sony, Toshiba, and Silicone Image. HDMI is also supported by motion picture producers Universal, Fox, Disney, and Warner Brothers, as well as system operators EchoStar and DirecTV. High Definition Multimedia Interface provides an interface in between any video/audio source, like an A/V receiver, digital television, and DVD player over one cable total, instead of one cable for video and one cable for audio. HDMI will support high definition video, standard video, and / or enhanced video plus multiple channels of digital audio on one single cable. HDMI will also transmit every ATSC HDTV standard and will support eight channel digital audio. HDMI has plenty of band width to spare so any future requirements and enhancements can be accommodated.

HDMI and DVI actually are more alike than they are different. Both of these support the transmission of digital signals. Both DVI and HDMI are based on specifications that are similar, because HDMI specification was derived from the specification for DVI.

There are two important differences between DVI and HDMI. The first difference is that HDMI technology incorporates content security that is called High Definition Content Protection, also known as HDCP. The other huge difference between Digital Video Interface and High Definition Multimedia Interface is that DVI can only support digital video, and HDMI can support audio and video on the same cable.

This leads to another big difference between HDMI and DVI. The number of cables that need to be used and run during installation. With Digital Video Interface at least two cables are needed. One cable is needed to support the video signal, and one cable or cord is needed to support the audio signal, because DVI can only support video, not audio. With HDMI only one cable is needed for the installation. This is because the HDMI can support all formats of digital video plus it can support multiple channels of audio signal as well.

The good news is that despite their differences, a backward compatibility for video exists between HDMI and DVI. Because HDMI evolved from DVI, they are both identical when it comes to video. But remember, DVI can not support digital audio. A good example is an older DVI connection on the source and an HDMI connector to the display. In this case, all that is needed to see the video is an HDMI to DVI cable. However, a separate cable for audio is needed to carry the the digital audio so the sound can be heard.

The best HDMI should look for is Monster Cable. Check it out. Chao.

How can I be sure that my HDMI cables will support higher speeds, deep color, and 1080p?

HDMI cable is capable of providing the highest video resolution that is currently possible. However, an issue that can occur happens because HDMI cable is manufactured of twisted pairs of small-gauge copper conductors, instead of coaxial cable, and this can cause problems when the HDMI cable needs to be run over 50 feet. When an HDMI cable is too long several things may occur. One of these is sparklies, which are where pixels in the images drop out of the picture. Another problem with long cable runs is image degradation to the point that no image is displayed. If the cable is at the length that sparkles or image distortion occurs, then it is too long and an additional device needs to be added to boost or extend the signal. This is because with twisted pair cable it is impossible to keep tight control of any impedance, and without this tight control the signal may reflect along the cable between the signal source and the signal sink, causing interference with the original source bit stream.

Most of the interoperability or image quality issues are not related to the HDMI cable at all, however, but to the software that is used for the device communication and content protection. Quite often, these problems are caused by the HDCP handshaking software. Another common cause is the improper handling of the device capability information that is read through HDMI. It is almost never the HDMI cables that cause the compatibility problems. Non-compliant cables are very rare on the consumer market. The completeness of the HDMI specification has been verified by the fact that there has never been a compliant HDMI cable that is the root cause of HDMI playback issues with compliant devices.

Every HDMI cable is required to support a standard high definition television video signal at the minimum. They have been tested to verify that the cable meets the HDMI specification requirements. This is called a Category one test. HDMI Authorized Testing Centers, also called ATCs, have recently added the equipment to be able to test the cable’s ability to support 1080p, and higher rates, up to the maximum HDMI speeds. Category 2 testing is the name given to the testing done at these higher speeds. Because Deep Color and 1080p are becoming common market requirements, cable manufacturers want their cables verified with this Category 2 high speed test instead of the Category 1 test, so that their cables can be marketed as 1080p verified. Another HDMI testing service is Simplay Labs. They have been performing high speed cable testing for more than a year, and the logo Simplay HD is put on the cables manufactured by cable makers to convey that the cable has this level of quality. This does not mean that a Category 1 tested cable definitely will not support or pass a Category 2 test. A shorter HDMI cable, 3m or less in length, even if it does not have a specific 1080p marking, will probably pass the Category 2 test. The longer that the cable length is, the more demanding the 1080p signal is on the quality of the cable.

The quality of the HDMI receiver chip has a huge effect on the ability of the receiver to cleanly recover and display the HDMI signal. Most, if not all, of the high definition multimedia interface enabled televisions and projectors that support 1080p on the HDMI inputs are created with quality receiver chips that will cleanly recover the 1080p HDMI signal using almost any normal length cable, including those that have only passed the Category 1 test. This cable is not officially guaranteed to support these higher speeds, but in reality these cables usually work fine. This is great for consumers, especially ones who have already purchased HDMI cables before Category 2 testing was easily available. As long as the cables have been Category one tested, they should work just fine for HDMI applications involving 1080p and deep color.

Well I hope you got it.