What is called HDMI
新建网页 1




The digital interface HDMI is one advancement of the popular DVI standard and is heavily focused on entertainment device and industry requirements. It transmits video and audio data and offers, like DVI-D, a digital copy protection system, better know as "HDCP" (High-bandwidth Digital Content Protection), developed by Intel back in 2003.

Key features of HDMI

Superior image quality like with DVI

The high data rate of up to 8.16 GBit/s enables the HDMI interface to transmit data uncompressed to suppot FullHD resolution for HDTV displays.

While using HDMI as a transport standard in home entertainment is usually a good choice, be carefull to inspect your devices capabilities first as there are several revisions of the HDMI standard providing a large range of capabilities and limitations as well. The table below will show you the revisions and their key features. Each device coupling is bound to it´s lowest HDMI partners revision.

Supports audio and video feeds

HDMI is image and audio interface in one piece of equipment. Transmission of one video and up to 8 audio channels is possible at the same time, like when hooking a game console up to a TV.

Installation and operation

HDMI has several advantages when it comes to long cables. Even distances of 20m are no problem due to enhanced susceptibility in regard to electro-magnetic noise (EM interference). It also supports "CEC" and "AV.Link" for easier operation of the devices. You may use the same remote control to communicate with several, linked by HDMI devices.

Compatibility to DVI and DisplayPort

Compatibility to DVI

HDMI is more recent than DVI and backward compatible to SingleLink DVI-D  - with one major limitation: Most first-gen DVI devices are not compatible with the HDCP feature, even though it has been added to the DVI feature list as well. If they do not support HDCP over DVI and the source requires it to do so, the device may not be used with a HDMI to DVI adapters.

Compatibility to DisplayPort

For the owners of Apple Macs featuring a Mini-DisplayPort InLine offers high quality HDMI adapters.

Revisions and features table

HDMI_UebersichtThe most recently deployed HDMI versions are 3D capable since Rev 1.3 while 1.4 also supports ARC (Audio Return Channel) nd 4K2K resolutions. The return channel for audio (ARC) feature renders the S/PDIF cables useless.
4K2K is the advancement of the common 720p and 1080i/p displays. By provising about 4 times the FullHD 1080 resolution it is developed to be used not only for home entertainment systems but also for educational and medical installations.

HDMI Ethernet Channel (HEC)

Since Rev. 1.4 the HDMI Ethernet Channel (HEC) has been integrated. The name already tells the story: The HEC provides an ethernet channel within a HDMI cable. You may use the ethernet channel to link ethernet ready devices to enable them exchanging data. Like connecting a media server to your receiver and displays to stream the the recorded data over the internet.
Only one device has to be connected by a regular ethernet or WiFi link to the router. HEC offers data rates of up to 100 Mbit/s in both directions and supports all rev. 1.4 capable devices like TVs, game consoles, media players.

Distribution of HDMI-Signals

Distribution of HDMI can be devided in four major categories. 

  1. HDMI Splitter are routing one source to multiple receivers. They support lossless operation. HDMI Splitters are most commonly used for large enternainment events to show a movie on multiple screens at the same time.
  2. A HDMI Switch more than one source is connected. The user selects the source to be displayed without having to physically change any cables. A switch will allow you to connect many devices like a game console, a set-top box and a Blu-ray player to you TV using only one HDMI port at the TV. With the push of a button the source can be switched as needed.
  3. The HDMI Switch/Splitter will connect multiple sources and will multiply the selected source to multiple displays. It combines the features of splitter and switch. The device offers significant easement of conference setups or educational scenarios.
  4. The HDMI Matrix extends the features of the Switch/Splitter even more by giving the user complete freedom in regard to source and output selections. Different sources are available to different devices at the same time. This way the LED display may show a Blu-ray while at the same time the game console routes it´s signal to the projector.

Special cabling

Special tasks require special cables. InLine offers angled plugs and cables with active amplification / signal boost to transport HDMI signals over long distances in confined spaces at the best possible quality.
With the high quality InLine cable extensions even 30 meters @ HDTV resolution are no problem.

Wireless HDMI

Wireless HDMI (WHDMI) provides a wireless extension to the HDMI standard. It will transmit high resolution video data @ 1080p and may also be used with WiFi, UWB and 60 Ghz point-to-point links.

Plug types

The HDMI standard supports different plug types: A, B, C, D and E, while E is only used by car manufacturers.

Type A

The most common HDMI plug, supported since the very first HDMI revision.

Type B

Advancement of the A type plug featuring double transmission capacity, most commonly used in professional application scenarios.

Type C

Small HDMI plug featuring a locking mechanism. Technically most like the A type this plug is best for connecting small devices like a digital camcorder.

Type D

Designed to be used with mobile devices like digital cameras, camcorders, smartphones and multimedia players. It is the first mobile plug yet to support the HDMI 1.4 revision in all reagards.