Print Article: Epiphan DVI2USB Review



		Epiphan DVI2USB Review June 02, 2006 Alan /.effect Dang

Summary: At FiringSquad, we're passionate about our scientific testing methods. From CPUs to GPUs and even our LCD monitor colorimetry, we're always looking for new technologies that help us deliver the best information to our readers. For the last few months, I've been using the $999 Epiphan DVI2USB. This is the upgraded version of the VGA2USB that we reviewed several months ago, with several considerable improvements.

Overview Page:: ( 1 / 2 )

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At FiringSquad, we're passionate about our scientific testing methods. From CPUs to GPUs and even our LCD monitor colorimetry, we're always looking for new technologies that help us deliver the best information to our readers. For the last few months, I've been using the Epiphan DVI2USB. This is the upgraded version of the VGA2USB that we reviewed several months ago, with several considerable improvements.

Whereas the VGA2USB does exactly what you expect it to do, the DVI2USB is actually special. Not only is it a USB 2.0 device that can capture a DVI signal, but it is also a device that can capture an analog RGB signal. The DVI2USB also captures images at the full 24-bit color. More importantly, the DVI2USB has an integrated memory buffer that fixes the problem of motion artifacts during the capture stream.

This means that while the DVI2USB still has a limited sampling rate (29 fps at 640x480, 4.3 fps at 1920x1200), the device will still produce perfect images every time. Although development is taking longer than expected, Epiphan believes they can reach capture rates of 1280x1024 at 30 fps with future driver releases. This is because the technology inside the DVI2USB is fully reprogrammable as opposed to the fixed function design of the VGA2USB.

When Epiphan achieves 30fps capture at resolutions such as 720p, they may have a budget way to capture HD-SDI and SDI video (when you have an SDI to DVI adapter).

Resolution	DVI2USB (Current Driver see note below)	DVI2USB (Target see note below)	VGA2USB
640 x 480	29.0	30.0	28.0
800 x 600	21	30.0	20.6
1024 x 768	15	30.0	10
1280 x 1024	10	30.0	5.6
1600 x 1200	6.7	10.0	4.3
1920 x 1200	4.3	5.0	3.1

*Specifications table as published by Epiphan

Videos Page:: ( 2 / 2 )
For still image captures using an analog VGA connection, image quality with the DVI2USB was superb, even better than the VGA2USB. This comes as no surprise since Epiphan designs their hardware for commercial, military, and medical imaging use – meaning that image quality is exceptional. The DVI2USB samples at a full 24-bit color instead of the 16-bit color of the VGA2USB. Obviously, when it comes to DVI frame grabbing, the DVI2USB provides a perfect capture.

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Buffered Capture

The real strength of the DVI2USB is the ability to buffer its capture. While the framerates are lower with higher resolutions, the individual frames are perfectly clear. This makes the DVI2USB a very useful tool for screenshots from NVIDIA and ATI graphics cards as well as from consoles such as the Xbox 360. Videos can say a lot more than words, so please take a look at these videos from the Lost Planet E3 demo for the Xbox 360:

640x480 capture:
DVI2USB 640
VGA2USB 640

1280x1024 capture:
DVI2USB 1280
VGA2USB 1280

The DVI2USB again provides a monopoly on the niche market of low-cost, high-quality DVI frame grabbing technology. While the $1000 price tag means it's too expensive for enthusiasts, it's a relative bargain for anyone needing precision DVI frame capture. For example, with this instrument, we'll now be able to get even better shots comparing the picture quality of NVIDIA vs. ATI video processing, clearer Xbox 360 and PS3 screenshots, and so on. If Epiphan can truly reach 30 fps capture rates at 1280x720, it could be a interesting alternative to HD-SDI capture tools (provided you had an HD-SDI to DVI convertor).

While the DVI2USB has a maximum supported resolution of 1600x1200 (it didn't sync properly at 1920x1200 for us), the VGA2USB can sync to a 2048x1536 display. That is, while we toyed with the idea of using the $200 VGA2USB as a debugging/diagonstic tool, we cannot say the same thing for the $1000 DVI2USB. It's more expensive, and doesn't support the same range of resolutions.

In the end, Epiphan has developed two very interesting niche products, the VGA2USB and DVI2USB. Both provide exceptional performance with superb value. Bottom line? If you need low-cost, USB 2.0 based DVI frame grabber, there's really nothing available that's better than the DVI2USB. Most of you don't need a DVI frame grabber… but rest assured that this product will help us improve the quality of our future reviews.

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