DVI Image and Video Capture – The Basics

Almost all computer equipment sold these days supports DVI. This can range from modern computers and  projectors to game consoles like the Microsoft X-Box. Of course, this means that high end hardware solutions for DVI capture are now becoming readily available.

The first thing that you must determine is whether your DVI signal is a true digital video signal or a traditional analog source. The easiest way to tell if a digital or analog signal is running through your DVI port is to look at he connector that you are using and match it with the diagram of the DVI connector below.

If either your DVI plug or connector are DVI-D (DVI-Digital), this means that a 100% digital signal is being used. For this kind of signal, you absolutely need to use a DVI frame grabber.

If the connector or plug is of the DVI-A (DVI-Analog) flavor, then you’d be able to use a DVI to VGA adapter and a VGA frame grabber. DVI-A supports analog signals only is and is identical to VGA but with a different pin placement.

If the plug is DVI-I (DVI-Integrated), this means that it is capable of running both an analog and digital signal along the cable. Thus, unless you know if the signal is analog or digital, you would need a DVI-capable frame grabber to capture the signal.

 

As stated earlier, a VGA frame grabber would do the job for DVI-A and analog-only DVI-I signals.  Before a VGA grabber can be used, the DVI signal needs to be converted to a VGA one using a DVI-to-VGA adapter, which costs roughly $10 (pictured below).

You can now follow the same procedure as you would when recording a VGA signal with your VGA frame grabber.

 

Digital Signals (DVI-D and DVI-I)

If you have determined that you have a digital DVI signal that needs to be captured, a DVI-specific frame grabber must be used. Before choosing a suitable frame grabber, you must determine if the DVI signal is single link or dual link.

A single link DVI signal can support, at a refresh rate of 60 Hz, a maximum resolution of 1915 x 1436. If your DVI cable supports a higher resolution at a refresh rate of 60 Hz, then you are running a dual link signal. Dual link DVI is used primarily on large LCD monitors, such as the Apple monitor or the 25″+ Dell monitors.

If you need to capture a dual link DVI signal, then your choice of frame grabber is limited to one model, the Epiphan Systems DVI2USB Duo (pictured below), which captures single and dual link digital DVI signals only.

Unfortunately, the DVI2USB Duo is a very specific high-end frame grabber that does not have the ability to capture an analog or VGA video signal. However,  the DVI2USB Duo is a blessing for those with dual link DVI capture requirements. You can see how the DVI2USB Duo stacks up against its competition in this table.

If, however, you need to capture a single link DVI signal, then your choices are much greater. If you are looking for a PCI-based card, then you have a choice of the EMS Imaging Xtreme RGB, NCast DCC 3.1 or the Unigraf UFG-03. If you are into external USB-based solutions, then Epiphan Systems offers the DVI2USB, which is an external dual-mode VGA and DVI frame grabber or the DVI2USB Solo, which can capture a single link DVI signal only.

There is no one ideal frame grabber that does everything. Your choice of a DVI capturing device should depend on your needs, as outlined above. If you wish to find the specifications of each frame grabber featured in this article, then this would be a good place to start.

 

Feature comparison table for the world’s best VGA and DVI frame grabbers

The niche market for VGA and DVI frame grabbers is full of different products, each with its own advantages and disadvantages. Since there are no defined standards in the field of high-resolution frame grabbers, it is often very difficult to choose among the various offerings. Analyzing each frame grabber and then comparing it to others in the industry can be a very tedious task, which is why we’ve compiled a side-by-side comparison table to ease the selection process, making it easy to compare these cutting edge products side by side.

This table was made using specifications supplied via each manufacturer’s website and data sheets. Some manufacturers do not provide complete specifications for their products, in which case “Not specified” is written in the table cell. For actual real-life tests and results, consult the “Reviews” section of this website.

Please note that all specifications supplied by the manufacturer are included in this table, making this the most comprehensive frame grabber comparison on the internet. After the table you will find short descriptions for what each specification means and how it impacts the capture process.

Brand/Product	EMS Imaging Xtreme RGB	Epiphan Systems VGA2Ethernet	Epiphan Systems DVI2USB Duo	Epiphan Systems VGA2USB Pro	Foresight Imaging I-RGB 200	Ncast DCC 3.1
Product Image
Interface	PCI (internal)	Gigabit Ethernet (external)	USB 2.0 (external)	USB 1.1 and 2.0 (external)	PCI (internal)	PCI (internal)
Board Format	3/4 Size PCI Card, 105mm x 170mm; PCI Bus Master with scatter/gather DMA providing up to 1GB/sec peak, 500MB/sec sustained	External device, 7.95″×4.13″×1.38″, 202×105×35 mm; Gigabit Ethernet Bus	External device, 5″ x 3.2″ x 1.2″; 126 mm x 81 mm x 30 mm; USB Bus providing with up to 480 Mbit/s	External device, 80 mm x 54 mm x 23 mm; 3.15″ x 2.125″ x 0.91″; USB Bus providing with up to 480 Mbit/s	3/4 Size PCI Card; 120+ MB/sec sustained to system memory via PCI bus master; Real-time transfer to VGA memory	Full size PCI card; PCI 33MhZ, 32Bit BUS
Connectors	2 DVI-I Type connectors	Two VGA D type connectors Two Ethernet RJ45 connectors One USB type A connector One 5V DC power supply connector or Power-Over-Ethernet	DVI dual-link; USB mini B type connetor	VGA D type connector; USB mini B type connector; 5V DC 1.3mm power supply connector	15 pin D-shell connector (VGA type)	RGB on DB15; DVI-D; S-Video; Composite
Input	VGA, DVI (single link)	VGA	DVI (single link and dual link)	VGA	VGA, DVI-A (analog only)	VGA, DVI (single link), composite, S-Video
Input Mode Detection	Automatic	Automatic	Automatic	Automatic	Automatic	Automatic
EDID Support	Programmable EDID	Programmable EDID	Programmable EDID	Programmable EDID	Not specified	Not specified
Video Format	R,G,B plus separate HSYNC and VSYNC signals; R,G,B plus CSYNC signal; R,G,B with Sync-on-Green synchronization. TDMS Single Link	R,G,B plus separate HSYNC and VSYNC signals; R,G,B plus CSYNC signal; R,G,B with Sync-on-Green synchronization.	TMDS Dual Link; HDCP ready	R,G,B plus separate HSYNC and VSYNC signals; R,G,B plus CSYNC signal; R,G,B with Sync-on-Green synchronization.	R,G,B plus separate HSYNC and VSYNC signals	R, G, B plus separate HSYNC and VSYNC signals; TDMS Single Link
Maximum Resolution	2048 x 1536 (VGA) 1920 x 1080 (DVI)	2048 x 2048 2560 x 1600 (wide)	2048 x 2048 2560 x 1600 (wide)	2048 x 2048	1600 x 1200	1920 x 1200
Update Rate	User defined, typically up to 60 frames per second, limited by available PCI bandwidth. Multi-buffered to eliminate tearing artifacts	Up to 120 frames per second, depending on resolution and amount of change in frames	Up to 52 frames per second, depending on amount of change in frames	Up to 62 frames per second, depending on amount of change in frames	Not specified	YUV mode: 24 60 fps RGB mode: 15 30 fps
Capture Rate at 1280 x 1024	60 fps	20-100 fps	10.0-52 fps	10.0-62 fps	Not specified	28-56 fps
Color Resolution	16 bits per pixel, 5:6:5 format; 24 bits per pixel, 8:8:8 format. 16 bits per pixel, YUV(422) Chroma packed YUYV format.	24 bits per pixel, RGB 8:8:8 format; 16 bits per pixel, RGB 5:6:5 format ; 8 bits per pixel, RGB 3:3:2, 3:2:3, 2:3:3; 8 bits per pixel, 256-grey scale format ; 16 bits per pixel, YUY2(422), UYVY;	24 bits per pixel, RGB 8:8:8 format; 16 bits per pixel, RGB 5:6:5 format ; 8 bits per pixel, RGB 3:3:2, 3:2:3, 2:3:3; 8 bits per pixel, 256-grey scale format ; 16 bits per pixel, YUY2(422), UYVY;	24 bits per pixel, RGB 8:8:8 format; 16 bits per pixel, RGB 5:6:5 format ; 8 bits per pixel, RGB 3:3:2, 3:2:3, 2:3:3; 8 bits per pixel, 256-grey scale format ; 16 bits per pixel, YUY2(422), UYVY;	24 bits per pixel, RGB 8:8:8 format; RGB 8:8:8; RGB 5:5:5, YUV 4:2:2, Y-only	RGB 8:8:8 format; YUV 4:2:0 format
Transfer Rate	330 Megapixels per second	270 MPixel/s and 532MPixel/s for two consequent frame interlaced grab	330 Megapixels per second	270 Megapixels per second	200 Megapixels per second	165 Megapixels per second
On-board memory	32MB	32MB	32MB	32MB	12MB
Multiple devices supported	Up to 32	Yes, limited by network bandwidth	Limited by number of USB ports present on computer	Limited by number of USB ports present on computer	Not specified	Not specified
Operating System	Windows 2000, Windows XP, Windows Vista	Linux (x86, amd64), Windows 2000, Windows XP, Windows Vista (x86, amd64), Mac OS X 10.3.x and up.	Linux (x86, amd64), Windows 2000, Windows XP, Windows Vista (x86, amd64), Mac OS X 10.3.x and up.	Linux (x86, amd64), Windows 2000, Windows XP, Windows Vista (x86, amd64), Mac OS X 10.3.x and up.	Windows XP Professional	Windows 2000, Windows XP, Linux
SDK, API	Windows: EMS SDK included. WDM streaming drivers included.	Windows: DirectShow API, Proprietary API (C/C++, VB 6, C#, Delphi) Linux: Video4Linux API, Proprietary API (C/C++) Mac OS X: Quicktime API, Proprietary API (C/C++)	Windows: DirectShow API, Proprietary API (C/C++, VB 6, C#, Delphi) Linux: Video4Linux API, Proprietary API (C/C++) Mac OS X: Quicktime API, Proprietary API (C/C++)	Windows: DirectShow API, Proprietary API (C/C++, VB 6, C#, Delphi) Linux: Video4Linux API, Proprietary API (C/C++) Mac OS X: Quicktime API, Proprietary API (C/C++)	Auto-SYNC automatic configuration software; Example application programs (source code included); Real-time video streaming with AVI file creation; IDEA software development kit; ActiveX controls; Common Vision Blox, Image-Pro Plus, and TWAIN drivers	SDK available: Ncast Screen capture software application, Ncast Control Program for settings
Power Requirements	Max current at +3.3V – 1A Max current at +5V – 1A Max power – 8 Watts	5V DC external adapter or Power-Over-Ethernet	5V DC external adapter	5V DC external adapter	Not specified	Input RGB analog 1600×1200 (capture set to 18fps): 3.3V @ 1.20A = 3.96W; 5V @ 0.55A = 2.75W; Total= 6.71W typical
Operating Temperature	0 to 35 ?C	Not specified	Not specified	Not specified	Not specified	0 to 35 ?C
Storage Temperature	-20 to 70 ?C	Not specified	Not specified	Not specified	Not specified	Not Specified
Relative Humidity	5% to 90% non-condensing	Not specified	Not specified	Not specified	Not specified	5% to 90% non-condensing
Other Features / Specifications	Update rates when used with the EMS Vigilant-X graphics card are: 1 channel at 1280 x 1024 = 75Hz. 1 channel at 1024 x 768 = 75Hz.	LEDs to indicate operational status (power, source, capturing)	LEDs to indicate operational status (power, source, capturing)	LEDs to indicate operational status (power, source, capturing)	Pixel jitter: 0.5 ns S/N ratio: 47 dB Dedicated trigger input Camera power: +12 V DC @ 1.0 A Camera integration Dedicated high current digital output	Simultaneous capture of two synchronized input streams; Picture-in-Picture capability
Common Applications	Capturing VGA and DVI signals using a stationary source	Capturing a VGA signal over a distance;	Capturing high-resolution imagery from dual-link DVI signals. High speed and high precision military, medical, and industrial applications.	Capturing ultrasound, radar and other industrial diagnostic-quality images. Broadcasting VGA output to web.	Capturing VGA and DVI signals using a stationary source. Monitor, display testing. Supports camera integration.	Capturing camera output, archiving HD video.
Price	Not specified	$1 600.00	$2 000.00	$2 000.00	Not specified	$ 1 995.00

This table was made using specifications supplied via each manufacturer’s website and data sheets. Some manufacturers do not provide complete specifications for their products, in which case “Not specified” is written in the table cell. For actual real-life tests and results, consult the “Reviews” section of this website.

Brand/Product	PixelSmart VGA-Master	Unigraf UFG-03A Hidef
Product Image
Interface	PCI (internal)	PCI (internal)
Board Format	Full size PCI card; 32 bit 33 MHZ 5 Volt BUS	3/4 Size PCI card; 175mm length; PCI bus master; bursts up to 133 MBytes/sec; Compatible with both 5 V and 3.3 V bus logic voltages
Connectors	DB15 VGA	RGB on DB15; DVI-D; optional composite video
Input	VGA	VGA, DVI (single-link)
Input Mode Detection	Not specified	Automatic
EDID Support	Not specified	Not specified
Video Format	R, G, B plus separate HSYNC and VSYNC signals	R,G,B plus separate HSYNC and VSYNC signals; R,G,B plus CSYNC signal; R,G,B with Sync-on-Green synchronization.
Maximum Resolution	1280 x 1024	1600 x 1200
Update Rate	Not specified	Not specified; Progressive and interlaced scan modes.
Capture Rate at 1280 x 1024	Not specified	Not specified
Color Resolution	Not specified	16, 24, 32 bits per pixel
Transfer Rate	Not specified	133 Megabytes per second (~300 MP/s)
On-board memory	Not Specified
Multiple devices supported	Up to 4	Up to 10
Operating System	DOS, Windows 98, Windows 2000, Windows NT, Windows XP	Windows 2000, Windows XP, Linux
SDK, API	Victor SDK by Catenary Systems; ImageJ processing software.	Video for Windows, UFG-03 Extended Driver Interface, SDK with examples, DLL library, C++, Visual Basic, LabView code included
Power Requirements	Not specified	7.5 watts maximum
Operating Temperature	Not specified	Not specified
Storage Temperature	Not specified	Not specified
Relative Humidity	Not specified	Not specified
Other Features / Specifications	None	Picture-in-Picture mode allows for up to 10 capture images displayed on one screen; Hardware image scaling from half of imput image size to 1600 x 1200
Common Applications	Presentation recording, low-quality image capture	Webcasting, testing and measurement (LabView)
Price	$349.00	Not specified

*Manufacturers specification sheets were used to compose the table above. In cases where the manufacturer did not indicate a specification, not specified is written in the table cell.

Analysis

Interface

All manufacturers except for Epiphan Systems, which makes external USB-based devices, produce internal PCI cards.

Input

Frame grabbers from Epiphan Systems and PixelSmart only have one input for a single VGA or DVI stream. However, Epiphan Systems DVI2USB Duo is the only frame grabber on the market that is able to capture dual link DVI signals with a maximum resolution of 2048×2048. Ncasts DCC 3.1 gives the user the most choice in terms of signal inputs as it has on-board VGA, DVI, composite, and S-Video inputs.

Capture Rate

Out of the two manufacturers that specified capture rates in their specification tables, Epiphan Systems has the highest possible capture rate at 62 frames per second, while Ncast has a higher lowest frame rate at 1280 x 1024. Capture rate depends highly on the nature of the image that is being captured. The user will notice lower capture rates in applications where there is a lot of movement in the VGA or DVI source.

Color Resolution

Compared to other manufacturers, Epiphan Systems VGA2USB and DVI2USB have the widest range of support for different video formats, whereas Unigrafs UFG-03A is the only frame grabber with support for a color resolution of 32 bits per pixel.

Transfer Rate

The maximum transfer rate determines how much data can be moved between the frame grabber and the computer. While it doesnt directly affect the picture quality, a higher transfer rate means that the frame grabber can handle more pixel changes from frame to frame.

Multiple Devices Supported

Many times, the user needs to record output from multiple sources onto one device simultaneously. Basically, this number indicates the maximum number of devices all functioning at the same time, while connected to a single computer.

Operating System

All manufacturers have Windows XP support. Epiphan Systems is the only manufacturer to support MAC OS X while PixelSmart is the only company to have support for the ancient command line-based DOS and Windows 98 operating systems. Epiphan Systems, Ncast, and Unigraf are the only companies to support Linux.

SDK/API

All manufacturers provide the user with an SDK and sample code. Epiphan Systems and Unigraf are the only two companies which produce Video for Windows capable frame grabbers which have the capability to appear as high-resolution cameras in Windows.

Price

All high-resolution and high quality frame grabbers are generally priced around $2 000 USD. PixelSmarts VGA-Master is priced at only $349 because it is not capable of grabbing high resolution signals, meaning that the picture quality will be poor compared to the other frame grabbers in this review.

*Note

Be wary of manufacturers that omit important specifications such as capture rate in their specification sheets. Specifications are usually not included if the product is unable to achieve steady performance.