VGA Splitters Explained – Active or Passive?

October 15, 2009 by Victor · Leave a Comment 

What is a VGA Splitter?

A VGA splitter is a device that duplicates a VGA signal. In other words, in accepts one VGA input, and clones it to multiple VGA outputs.

VGA Splitter

VGA Splitters Explained

VGA Splitters and Screen Capture

VGA Splitters are often used in screen capture solutions where a VGA signal needs to be captured. Since a VGA splitter clones a single VGA signal into two or more feeds, this allows the user to retain the use of a standard computer monitor, while at the same time sending the VGA signal to a capture device like a frame grabber.

Connecting frame grabber through a VGA splitter

Connecting frame grabber through a VGA splitter

Active and Passive VGA Splitters

Two different types of VGA splitters exist. Active VGA splitters and passive VGA splitters. Passive VGA splitters, pictured below, are also known as simply Y-splitters or Y-adapters:

Passive VGA Splitter

Passive VGA Splitter

Active VGA splitters, on the other hand, consist of hardware devices that need to be powered to operate and often have more than 2 ports on the output side. A VGA Splitter from Kramer Electronics is shown below:

Kramer VGA Splitter

Kramer VGA Splitter

When to use a Passive Splitter

A passive splitter has only a few advantages over its active counterpart. Firstly, passive splitters are extremely cheap in price, as they can often be found for under $10. Secondly, they are compact and require no power source.

Unfortunately, passive splitters also have some downfalls. They are not compatible with all equipment, as passive splitters don’t let monitors properly identify themselves to the VGA source. Passive splitters support  a maximum of only two outputs and, since there is no amplification of the signal, the outputs are often of inferior quality than if seen without the splitter.

It is suggested to use a passive splitter when you are connecting two of the same model monitor to the splitter’s output, no power source is available, or when picture quality is unimportant to you.


When to use an Active Splitter

Active VGA splitters have countless advantages over passive VGA splitters. Active VGA splitters can clone one VGA port into virtually any number of outputs. Furthermore, an active VGA splitter identifies itself to the computer as a monitor, meaning that there will be no incompatibility issues with the different models of monitors and VGA-based equipment connected to it.

Furthermore, active VGA splitters slightly amplify the signal (not to be confused with VGA amplifiers) which means that the resulting VGA output will be of significantly superior quality when comparing to that of a passive or Y-splitter.

Realistically, the one and only disadvantage of an active splitter is that it requires a power source for it to operate.



If possible, using an active splitter is recommended for all applications. However, since proper active splitters retail for well over the $100 mark, a passive splitter will sometimes suffice.

When choosing an active VGA splitter, always make sure to check its specifications in order to see if it is compatible with the resolution you plan to use it with.

Epiphan Systems Announces New Open Source Frame Grabber

October 14, 2009 by Victor · Leave a Comment 

A first in the market of high resolution video capture hardware, Epiphan Systems has announced a new open source frame grabber – Epiphan Lecture Recorder.

According to the product page, shipping of the Lecture Recorder will start sometime in November. Epiphan Lecture Recorder, or ELR in short, has some promising features that, at the price tag of $2000, are unbeatable by similar offerings.

ELR formats

ELR’s Unique Features

Even though this product seems to be aimed at the educational market, Epiphan Lecture Recorder has some unique features that make it a perfect frame grabber for pretty much any application. Firstly, ELR supports not only DVI and VGA capture, but also has on-board inputs for composite video and stereo audio.

Furthermore, Epiphan Lecture recorder has a very generous 32GB of buffer memory, which is expandable via portable flash sticks, network drives, or external hard disks.

Finally, ELR features 5 USB ports for external devices and peripherals, meaning that you can create software that will allow you to connect external control devices such as IR remotes, CD/DVD writers, wireless modules, an so on.

Open Source

As mentioned earlier, Epiphan Lecture Recorder will be an open source device. What this means for developers is that it is possible to access all features of the frame grabber. And, because the ELR is more of an embedded computer or internet appliance, many interesting applications can be written for it. For example, the ELR, as it has an Ethernet network interface, can function as its own server, as pictured below.

Epiphan Lecture Recorder

In a Nutshell

The Epiphan Lecture Recorder is more of a computer with on-board frame grabber and video and audio capture cards than it is an actual frame grabber. While this might not be the ideal device for the general public, the ELR could be used as a platform for a wide variety of applications.

Click here to view Epiphan Lecture Recorder’s product page on Epiphan Systems’ website.