A $20 VGA to USB Capture System (and more!)

If you ever had the necessity to capture HDMI to USB, you’ll know that nowadays there are cheap HDMI to USB capture dongles available in Amazon, Aliexpress or Ebay, that allow to record your HDMI stream to your PC, using OBS or even VLC. Be aware that most of these dongles are advertised as USB 3.0, but instead they are USB 2.0 only, so forget about 1080p @60Hz. Still, USB 2.0 is enough for some applications. These cards are sold under 15$, so, despite they are USB 2.0, they are worth a try.

Fig. 1. A low cost HDMI to USB capture device.

However, if you need to capture a VGA signal (like we did, to capture uSVC images), the situation is completely different. There are some VGA to USB dongles, or other VGA capture cards, but these are overly expensive, well above 100$ (sometimes above 200$) and some of them have a noticeable lag between input and output.

This article is different from the ones we used to write: in this hack, we won’t create anything from scratch, but instead, we will show a simple trick that allows you to reduce the cost of your VGA acquisition system by a factor 5 at least. Furthermore, you’ll get a more versatile equipment.

A very simple hack

We already wrote that you can find cheap HDMI to USB capture cards (note! HDMI -> USB, not the opposite, which is useless for this hack!). The trick is simple: buy one of these adapters, and also buy a VGA to HDMI adapter (note: VGA -> HDMI, not the opposite, which is useless for this hack!). You’ll also need to get an HDMI cable too (of whatever length) if you don’t have one spare.

There are many VGA to HDMI adapters, but if you can afford some 8$ extra, we recommend buying one that also has an additional VGA output. It is always useful to see in an actual monitor what you are recording, without having to check the recording software window on the PC screen.

Fig. 2. A VGA to HDMI + VGA converter. The additional VGA output might be useful in several cases.

Therefore, instead of having to purchase a VGA capture device (which can only do just that job), you need to buy:

Connecting everything

Then, just make the connection:
VGA OUTPUT to be recorded -> VGA TO HDMI CONVERTER -> HDMI CAPTURE CARD -> USB of your PC/MAC and you’re set.

This is our setup to capture the VGA output of our DIY VGA console. Yes, it is quite a mess of cables, but it does the job quite nicely!

Fig. 3. Our rudimentary VGA capture setup! From the top, we get uSVC VGA and audio signals, which are converted to HDMI (the adapter in the center of the photo), which feeds through the HDMI cable the HDMI to USB capture dongle, which is connected to the PC. Simple, right ?

Configuring OBS to Capture the Video

To capture the actual video data:

  • Download and install OBS
  • Connect everything as written above
  • Launch OBS
  • Under “Sources”, click on “+”
  • On the menu, find and select “Video capture device”

Fig. 4. Select Video Capture Device.

  • On the “Create/Select Source” window, click on “create new”, and press OK.

Fig. 5. Select Create new, give a name and press OK.
  • Choose the device from the drop down list. In our case it was named “USB Video”. Also choose the resolution and FPS type. Once the parameters are configured correctly, you should already see the preview.

Fig 6. Setting example, showing the VGA video capture (main menu of the Tetris clone on uSVC)

Final Words…

You should spend no more than 20-28$ (including shipping) for not only a system that allows you to capture a VGA signal, but also:

  1. Has also an HDMI capture device.
  2. Has also a VGA to HDMI converter.
  3. (if you purchase the VGA->HDMI converter with an additional VGA output) It allows to show the same image in two monitors (one VGA and one HDMI).

And what about lag? 20ms!

Not bad for 20$, isn’t it?

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