Technology enhancements in video signal transmission has ensured analogue and digital signals are transmitted using different devices, for instance there are several types of video splitters on the market to select from for video duplication.
The decision must be canvassed thoroughly before buying a VGA or DVI video splitter. Therefore let’s outline what VGA and DVI are, as well as the timeline they were both released.
Video Graphics Adaptor (VGA) technology has been available since 1987 thanks to IBM for development of this analogue video display technology that went onto become a standard used when referring to analogue video display standards.
VGA hardware and the software enable the data processed to become graphical data that can be displayed on a display monitor. The actual resolution for VGA is set at 640 x 480 pixels in display resolution for width and height respectively. However VGA display resolution has been enhanced with higher video resolutions such as SVGA, XGA and UXGA et al. In addition, the majority of manufacturers and resellers still refer to a VGA splitter as ‘VGA Splitter’, even though VGA has higher analogue video resolutions available, such as mentioned early like SVGA, XGA and UXGA.
VGA can carry only analogue video signals thus if you require audio as well, a separate audio connection is required. There are numerous VGA splitters that have audio capabilities built-in to the VGA splitter, for instance several Smart View devices have models available with an audio stereo 3.5mm socket for each video connection.
Digital Visual Interface (DVI) is a newer technology that was released in 1999 by Digital Design Working Group. DVI superseded VGA, and as the name implies, DVI is uncompressed digital video data that is displayed on monitors and projector screens via DVI connectors. There are three main DVI connector types available on the market each with a specific pin arrangement interface, for example DVI-I, DVI-D and DVI-A. Moreover the three DVI connectors support certain video formats, for example:
• DVI-I is integrated video both analogue and digital signal support
• DVI-A is analogue video signal support
• DVI-D is digital video signal support
The key feature about DVI is its compatible with VGA. The two video interfaces work well with one another when an adaptor is utilised.
DVI has two methods available to stream the video signal between devices, which is known as Single link and Dual link. DVI single link maximum resolution is up to 1920 x 1200 (WUXGA) @ 60 Hz, while DVI dual link can produce much higher resolution, but depends on several factors, such as cable copper bandwidth limitations, DVI source limitations, and DVI sync limitations. Additionally DVI supports hot plugging meaning it can be connected and disconnected without powering down the system. However VGA isn’t suitable for hot plugging hence requires the system be shut down first before connection of VGA cables.
In the early days of DVI it was envisaged that DVI would become the recognised standard for digital format. However, DVI was mainly used with computer display monitors and not so much with household TV scenarios.
DVI can stream digital video very well however it can’t transfer audio signals. To enable audio on a DVI splitter you’ll require digital audio capability built-in to the devices with separate audio connections. Furthermore, the release of High-Definition Multimedia Interface (HDMI) technology that can transmit uncompressed digital video and digital audio signals together has ensured HDMI quickly became the popular choice for digital video output to display panels.
The new computer desktops don’t have VGA connections available on most systems. Usually there are DVI or DisplayPort connections instead. The DisplayPort digital interface superseded DVI in 2006 however you still see DVI utilised. Occasionally Information Communication Technology (ICT) hardware staff may be required to mix-and-match connections with adapters, for instance, if a machine has a VGA socket but the display monitor has a DVI connector, an adapter can be utilised since DVI is backward compatible. Note: the signal will still be VGA quality that is transmitted unless a dedicated electrical VGA to DVI converter is used.
When selecting a DVI or VGA splitter ensure you check the specifications for the product, for example resolution supported, frequency rate, the display video type supported, connection types for interface input/output, power adaptor required, switching off/on functions, built-in amplifier booster and whether incorporated with audio socket or not.
The most common video splitter is the type ‘one input video source to two outputs video’ destination. However there are numerous configurations to select from for video input and output setups. Another type of splitter is called a ‘video matrix’ that can have two or more video inputs and two or more video outputs. This can be handy for multiple sources that can be switched on/off to achieve the desired video output display. Each video splitter will suit a particular scenario for video presentation so choose wisely. In addition, several brand video splitters can be cascaded, such as Smart View.
To maintain the integrity of the video signal high quality VGA cables with ferrite filters should be interconnected with the devices. If the installer decides to skimp on the cost of VGA cables for the installation signal degradation can lead to problems such as ghosting and pixelation.
There are DVI splitters and DVI boosters with High-bandwidth Digital Content Protection (HDCP) incorporated into the devices. Authorised digital video content is only allowed to be transmitted and received between HDCP devices while VGA analogue signals aren’t restricted with this security protocol. Some users have reported interconnection issues when using HDCP enabled devices, such as handshaking connection problems and continuity in live video streaming.
If you have the newest high-definition display monitors you should consider HDMI splitters as well. VGA can be problematic when outputting video signals to large panel screens like Plasma TV, LED widescreen TV and OLED TVs. Especially video quality degradation issues and pixelation problems may occur when VGA is the source to high-definition products.
VGA splitters have generally been more popular with computer display monitors over the years than DVI. The cost for a VGA splitter is usually less than its equivalent DVI product. Furthermore with the popularity of the superior HDMI technology integrated into high-definition TVs and notebooks has ensured DVI splitters are less common. With most people selecting a HDMI splitter for their digital video and audio solutions over the less-features of DVI.
Finally, you should consider several pivotal factors for your decision, such as the quality of the video resolution broadcasted you require, and whether it’s digital, or analogue equipment utilised in your setup. Furthermore check the product specifications before purchase, and consider if you require audio as well for the video broadcast? Moreover if you implement a VGA splitter or DVI splitter choose one with a booster built-in to the device. The costs should be secondary to ensure you’re satisfied with your ultimate decision.