What does a Capture Card do?


So what do the best Capture Cards do? Capture Card does a lot of different things, however the most popular use of them is to provide gamers with a way to record their game play and upload it to the internet when they want to. A video capture card will capture video signals and convert these video signals to digital data that is compatible with your PC.

Types of Capture Cards

There are two main types, the internal circuit board and external boxes. The internal circuit board you will install inside your computer itself. These will plug into your standard PCI and PCI Express slots on your motherboard. The external box connects via USB or some other interface. Either way, they both work in similar ways in that they capture video, some will only accommodate analog and some only digital and very few will accommodate both. The Capture card will then process all your video input and stream it through either your PCI slot or USB connector.

It differs from a video adapter card as this sends images to your screen and the capture card records the video as data. Capture cards will accept video from various sources, depending on the type of capture card (click for full review) you have, such as a cable TV, DVD players and video cameras and will work in unison with your PC software which is what displays the video and will allow you to save your video in a media file.

How do they Function?

First you have to look at how you will input your data and what features it offers such as tuners. Your capture card take video in from different sources, either digital or analog data.  This means if you have an RCA and S-video jacks they will only process analog video and the HDMI connector will accommodate HD from digital sources. Some capture cards offer tuner circuits that will be able to select channels from either antenna or broadband cable TV signal. If your capture card offers a tuner, you can watch TV and check your emails on your computer simultaneously in different windows.

Next thing to look at when trying to understand what capture cards do is how they convert the video signal. The basics are that the high-speed chip on the capture card will analyse the video signal and then turn it into a stream of digital images. Using different sources will determine what quality you get so if you are taking in analog signal the resolution will be a lot lower than if you are capturing HD signal.

So how does it store the information that it gets from the different sources. These are stores these images into an area called a buffer. The buffer will also help your PC to stay in sync by regulating the amount of data sent through to the PC. The buffer is like a reservoir which keeps the data in storage until ready to be sent to the PC.

Drivers and Editing Software

Every capture card will come with the manufacturer’s software which are called drivers. When you install the capture card on your computer either internally or through USB port the PC will automatically load the drivers which are then integrated into the computer operating system. Without these drivers, your computer will not be able to recognize the card and will not be able to process any information that comes through the card. The capture card will then display the video on your computer and allow you to edit scenes and then save them to your PC’s hard drive.

Things to Remember

Only very few capture cards will be able to record audio signals at the same time as processing video that has been captured. Capture cards can only support audio streaming from one source and not multiple ones. Capture cards are able to process information with standard resolutions or frame rates.