An HDMI cable delivers uncompressed multi channel audio and video signal simultaneously over a single cable. HDMI has become the standard connection type when connecting high definition equipment. HDMI cables come in different lengths.
It's become the best choice as it does not involve any compression or loss of quality, unlike other cables. So if your source is in 1080p and the screen supports 1080p, it will display it at just that and at nothing less.
High Definition Connection with HDMI Cables
HDMI cables Version 1.3 and above are available in two different categories. Standard HDMI cables (Category One) are suitable for transmitting 720p or 1080i audio video signals. High Speed HDMI cables (Category Two) are suitable for transmitting 720p, 1080i and 1600p audio and video signals.
Selecting the Right HDMI Cable
It is important to choose a quality HDMI cable for your system to avoid the risk of compromising the picture quality. Better HDMI cables are constructed with better materials and plugs. Due to signal loss, it is also important to consider the length of HDMI cable used. If the cable is too long the signal becomes weak and will affect the picture quality. You can use HDMI extenders or repeaters to resolve this issue. The general recommendations for maximum length of HDMI cable is 15m before noticing significant signal loss resulting in picture distortion, pixel drop or no picture at all but sound only.
Most of today's high definition components such as HDTV, HD set-top boxes, Blu-ray players, Playstation 3, HD camcorders, HD digital cameras, etc support HDMI connections for the best possible resolution.
HDMI & TV Interconnects
Many of today's TV's come with an array of audio and video connections. Gone are the days when you had a single connection - a single SCART socket at the back of the TV. Back then connecting the TV to the video was easy - only one cable was needed between the two.
Today's HDTV's are capable of delivering impressive pictures from any of your video sources when connected correctly. But a single incorrect connection can seriously compromise video quality. For best picture quality make sure you use the best available connection between each video source and the TV.
There are many different connections on board today's TVs. Some are there to cater for newer digital video sources where as others are there so that you can have backward compatibility with your older equipment like a VCR.
We have listed below the main connection types found on today's HDTVs, listed them in order of picture quality, going from highest to lowest and stated the maximum resolution available.
High Definition Connections
HDMI (High Definition Media Interface) - Very high bandwidth (up to 5 gigabits per second) digital video and audio connection. HDMI ensures the best video signal is sent to your HDTV by sending uncompressed video and multi channel audio signal via one single cable. HDMI supports HDCP (High Definition Content Protection) copy protection. Because of HDMI's superior capacity and ease of use, it is increasingly becoming the connection of choice in many of today's home cinema equipment. Maximum resolution supported: 1080p. Use to connect: HD Set-top box, Blu-ray DVD, Playstation 3, Home Cinema System.
DVI (Digital Video Interface) - high bandwidth digital video only connection. DVI connections may not use HDCP copy protection. Maximum resolution supported: 1080p. Use to connect: Computers for HD, to receive an HD output, Blu-ray DVD.
Component - analogue video only connection. The three jack (RCA) component video connection carries the picture information in three parts - one brightness signal and two colour signals from which the picture is up. The component video connection delivers an extremely accurate picture and clear colours. Maximum resolution supported: 1080p (note that many sources will only send video up to 1080i via component video output). Use to connect: Any audio/video source that supports Component video output.
VGA - Video only and supports HD. Typical connection between computer and screen.
Standard Definition Connections
S-Video - analogue video only connection. This is a 4-pin connection that carries chrominance (colour) and luminance (brightness) portions of the video signal separately. Maximum Resolution: 576i Use to connect to: VCR, DVD, Set-top box, camcorders and any audio/video equipment that supports S-video output.
SCART - analogue video and audio connection. The SCART is a 21 pin connection and supports stereo audio, composite video, S-video, RGB and some control signals over a single cable. This is probably the most common audio / video equipment connector over the last twenty years. What audio and video signals a SCART cable can carry will depend on the connected equipment. Maximum Resolution: 576i Use to connect to: VCR, DVD, Set-top box, any audio/video equipment that supports SCART output.
Composite - analogue video only connection. This is a single jack (RCA) connection that carries the three basic elements of the video picture - colour, brightness and synchronization data. Maximum Resolution: 576i Use to connect to: VCR, DVD, Set-top box, camcorders and any audio/video equipment that supports composite video output.
High Definition Video Source
It is important to connect your HDTV to an HD (High Definition) video source to get high definition picture quality. Because you have a HDTV does not mean you are watching a high definition picture. How good your HDTV picture looks is limited by the video source resolution. If your HDTV is connected to a lower resolution source, like the VCR or DVD, you will see a lower resolution picture. HDTV cannot transform a low resolution picture to a high definition picture. If you want to see a true high definition picture on your HDTV, ensure that you feed it a high definition source like 720p or 1080i or 1080p.
Optimise Your HD TV's Video Capabilities
If your HDTV and video source have different resolutions, do not worry. Your HDTV will automatically convert or scale the video signal to fit the native resolution of your HDTV. Converting lower resolution signal to fit a higher resolution screen is called 'upconversion' which works well with sources like DVD but not with an analogue antenna signal.
If the incoming signal has more pixels than the screens native resolution, the video signal is 'downconverted'. Downconverted signals lose some detail to fit the image on the screen.
Scaled images may still look great on your HDTV but if it is not at least 720p signal, it is not true high definition.