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VGA2USB

Frequently Asked Questions

Compact pocket sized, external, low cost VGA frame grabber capable of capturing output from virtually any VGA source—such as a Windows PC, a Mac OSX, a Unix machine, an em­bed­ded system, a medical device, scientific or lab equipment, and more.

  1. Will VGA2USB work with USB 1.0 or USB 1.1?
  2. How can I verify whether my system has USB 2.0?
  3. How many frames per second can VGA2USB capture?
  4. Does VGA2USB reduce the resolution of the images it captures in order to transfer it over the USB bus?
  5. Can VGA2USB work on Windows NT, Windows 3.x/95/98/SE/ME?
  6. The video mode that I am using is not listed in the list of supported modes for VGA2USB. Can VGA2USB capture it?
  7. What Linux kernel does VGA2USB support? Is the driver's code open source?
  8. Can VGA2USB save captured signals as a movie?
  9. Which AVI codec works best with VGA2USB?
  10. Images grabbed from some sources appear to be slightly shifted right or left. How this can be fixed?
  11. Can I connect two or more VGA2USB to one computer and capture signals simultaneously? What is the resulting rate of capture for each VGA2USB?
  12. With what software can I interpret the digital signal coming out of the USB port of the VGA2USB device?

1. Will VGA2USB work with USB 1.0 or USB 1.1?

No. VGA2USB transfers substantial amounts of data for each captured frame. As USB 1.x buses are very slow (12Mb/s), they do not provide sufficient bandwidth for VGA2USB. USB 2.0 buses have a much higher transfer rate (480Mb/s), allowing VGA2USB to acquire and transfer several frames per second.

2. How can I verify whether my system has USB 2.0?

Please use this procedure to verify that your system has USB 2.0.

3. How many frames per second can VGA2USB capture?

It depends on the resolution of your screen, the screen refresh rate, your operating system and the speed of the computer that is acquiring the images. Typical results are between 28 and 2 frames per second.

4. Does VGA2USB reduce the resolution of the images it captures in order to transfer it over the USB bus?

No. VGA2USB captures and transfers every pixel of the original VGA frame in 16-bit per-pixel RGB format. In this respect, VGA2USB provides better quality than a VGA-to-video converter paired with a Composite or S-Video grabber. You can see comparisons of screen shots taken with VGA2USB here.

5. Can VGA2USB work on Windows NT, Windows 3.x/95/98/SE/ME?

No. Unfortunately, some of those systems have very poor support or no support at all for the USB 2.0 bus.

6. The video mode that I am using is not listed in the list of supported modes for VGA2USB. Can VGA2USB capture it?

Please contact us. We are always looking for ways to improve our system and may be willing to add support for this mode.

7. What Linux kernel does VGA2USB support? Is the driver's code open source?

Although we provide a Linux SDK (API for driver and examples), we do not provide source code for the driver itself. Please contact us if you need a driver compiled for a specific kernel version or kernel setting.

8. Can VGA2USB save captured signals as a movie?

Yes, the VGA2USB application has the ability to save captured signals as an AVI file.

9. Which AVI codec works best with VGA2USB?

The choice of codec and codec settings depend on the requirements for the quality of the AVI. You may need to try several codecs with different settings to see which codec best fits your task. We suggest using the Indeo 5.10 codec with 50% quality settings for a good compromise between compression rate, image quality and required CPU power.

10. Images grabbed from some sources appear to be slightly shifted right or left. How this can be fixed?

VGA2USB has an automatic algorithm that crops visible images from the VGA frame. The algorithm may make a mistake, however, and be off by a few pixels. Please use the procedure described in this image to correct cropping.

11. Can I connect two or more VGA2USB devices to one computer and capture signals simultaneously? What is the resulting rate of capture for each VGA2USB?

Yes you can connect two or more VGA2USB devices and capture multiple signals simultaneously. You will need to run the VGA2USB application for each VGA2USB device attached. You will, however, notice a significant difference in frame rate for each additional active VGA2USB. The higher the performance of your computer, the better the possible frame rate. Our internal testing on a Dell Dimension 2400 (Celeron 2.4GHz processor, 512mb RAM) at 1024x768 with two VGA2USB devices yielded average frame rates of 7.1 fps and 4 fps. In contrast, a Pentium 4, 3.0Ghz desktop with 512MB of RAM at 1024 x 768 yielded average frame rates of 9.52 fps and 5.85 fps. Please note that you must start the VGA2USB application after connecting each VGA2USB.

12. With what software can I interpret the digital signal coming out of the USB port of the VGA2USB device?

The VGA2USB frame grabber works by emulating a high resolution video camera for Windows. VGA2USB is a DirectShow compatible device, which means that virtually any video capture software designed for Windows is compatible with VGA2USB. For example, VirtualDUB can be used to record .avi files, Microsoft Media Encoder to record .wmv files, and RealProducer to record .rm files.