Tuesday, April 7, 2020

Video Ghost review: screenshots of the unscreenshotable?

Another day, another blog. As many of us vintage enthusiasts are collectors and we want to proudly show off our restorations, with many of our old machines some of the most interesting pictures are the screenshots during bootup before any operating system services are available. (And, of course, on some machines no screenshot facility is available at all.) Similarly, there are many converters that will additionally take composite video and turn it into VGA, useful for 8-bit and 16-bit systems, if only you could just get a grab of the VGA. In my case, since I use Linux on ppc64le, I wanted a device that could grab VGA frames and make them available over USB without special drivers or OS support. The device I settled on to try first was a Keelog VideoGhost VGA Pro, which on each press of its button grabs a frame and stores it to its built-in flash. Theoretically, you can then simply connect the flash like any other USB mass storage unit and copy off the frames. Will it blend? Let's find out.

The VideoGhost comes in three main forms: the basic VideoGhost and the midrange Pro, here in the VGA version with a USB control connection, and the topspec Max that has the video connector, the USB connector and a separate hardware serial port (DE-9). Both the Pro and the Max can be controlled by a serial connection (either a "virtual" COM port over the USB connector or the Max's actual DE-9 serial port) and allow images on demand. Since I wanted images on demand but found the concept of having to have the serial connected to an additional system technically disgusting and not worth the price differential, I went with the Pro. It cost about US$160 shipped.

The "guts" are in the video port dongle. With the cover off we see an Atmel ARM microcontroller which is the brains of the operation. There isn't much space in the dongle, so the exposed leads from the HD-15 VGA are covered in Kapton tape. Flash memory is on the underside of the board.

Also visible on the underside of the mainboard is this lithium battery for the real-time clock. However, the manual says nothing about it being field-replaceable.

In normal operation the VideoGhost works as a passthrough, even if the USB is not plugged in (necessary to power the microcontroller). I won't talk about the potential for spying here because that's not my intended application, but it does make it easier to use with workstations where you just connect it in-line (and possibly with the USB to a regular USB charger if the machine in question doesn't have any available USB ports). However, the Video Ghost only works if a signal is actually being sent through it. This can sometimes be difficult to determine, and usually means you need a monitor hooked up on the other end which is a little inconvenient with laptops.

Configuration and access to the flash is done by putting the Ghost into USB Mass Storage Device mode; the button on the side of the video dongle is held in while the USB is connected. A text file on the flash memory can be edited to set system options or the clock, and the JPEG images on the flash may be read.

I tested this first with my Tadpole M1400 SunRay2 device, which usually emits a 1024x768 VGA image to its external output. For this first run I connected the Ghost to its VGA out and used the M1400's built-in USB for power. The Ghost captured what looked like a 1070x800-ish image with overscan apparently from the vertical blanking interval. It took it several seconds after pushing the button to register and encode the image even with minimal compression, but the image was generally sharp and appeared accurate. (However, there's a reason I'm not showing this image; hang tight.)

I then decided to see how it did with sync-on-green VGA connectors by hooking it up to my NeXTSTEP 3.3 SAIC Galaxy 1100, which is essentially a Hewlett-Packard PA-RISC "Gecko" 9000/712 in a MIL-SPEC portable chassis. I connected this with using a known-good Apple iPhone charger (no USB onboard, natch) and pressed the button. Nothing showed up on the flash, so I connected it again. After a minute or two, however, I started to smell that all-too-familiar odour of burning electronics and after some sniffing around realized with horror it was coming from the Video Ghost. I disconnected everything and plugged it into my workstation to see if it was dead. It was, taking the image from the M1400 along with it. Barely a couple hours of usage!

In fairness this is not what it was sold for, and I don't know if I had simply a defective device, but I will say that the slowness to acquire and the awkwardness of the setup pretty much erase any utility for this specific purpose. I'm sure it's much better in covert environments as befits its design, but as a generic frame grabber after this brief and sorrowful experience I'm forced to conclude that the Video Ghost doesn't cut the mustard and certainly not at its price.

To be continued with something else.

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See more of my general vintage computing projects,
mostly microcomputers, 6502, PalmOS, 68K/Power Mac
and Unix workstations, but that's not all. Be kind, REWIND and PLAY.

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Old VCR is advertisement- and donation-funded, and what I get
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Thanks for reading. -- Cameron Kaiser