A Guide to Using Video Capture Cards – The Art of DVI VGA & HD Cap…
So you have been lumbered with the daunting task of video capture. Video capture, especially at high resolutions, can be difficult and expensive, bear this in mind.
Firstly, you need to clarify what kind of signal the source is outputting (Digital, Analog) and secondly you need to clarify what interface the source is outputting on (DVI, VGA, HDMI and so on). Next, clarify what the output resolution and framerate are and decide whether you want to capture in realtime or whether you want to downscale the source. This is crucial as the difference in costs involved in capturing at PAL / NTC at 20 – 25 FPS than capturing at 1920 x 1080 (progressive) are enormous.
Now we need to decide whether we are going to use an external Video Capture Card or an internal Video Capture Card. I would not recommend using an internal Video Capture Card as they are dependent thoroughly on USB bandwidth which as you are probably we aware, is very low. Ever noticed how your USB mouse moves really slow when you are using your webcam? Same issue with USB dongles – You can’t honestly expect to capture 1080p video at 60fps by your USB ports, it just isn’t going to happen. At 1080p 1:1 your looking at around 5fps. Given that, I would definitely recommend using an internal PCI or PCIe Video Capture Card. A PCIe Capture Card uses the PCI-Express slot, something any decent motherboard will have. To put it into context for you – The PCI-Express interface is tailored to run high-end graphics card, allowing ultra-fast data move between the CPU, RAM and card. Makes sense to use this interface huh!
So, lets say we are capturing the following source:
Resolution: 1920×1080 Progressive
Refresh Rate: 60 Hertz
FPS: 60fps as we want to capture in REALTIME (to match the refresh rate)
Output Interface: DVI
We will use the XtremeRGB-Ex2 Video Capture Card as an example, to give you an idea of the specifications you will be aiming for. The specficiations are listed below:
# Dual channel DVI/VGA (PCI-Express)
# Four Lane PCIe bus with a maximum data rate of 480MB/sec
# Maximum analog RGB capture resolution of 2048 x 1536 x 24bit
# Maximum DVI capture resolution of 1920 x 1080 x 24bit
# On card processor for real time mode and sync detection
# sustain for multiple cards allowing up to 32 capture channels. (32 cards)
Once establishing these basics, the physical installation and setup is very easy. Installing an internal Video card is very simple, infact it is almost idential to installing a standard graphics card. Hooking the cabling up is pretty much self explanatory.
So, we’ve made it this far. The next step is installing and configuring the capturing software, configuring the capturing computer and capturing some video:) and this will be coming right up in my next article. I hope this article will be of some help to people facing the task of capturing video for commercial, medical or military use without prior experience.