Rombo Vidi-ZX

Sinclair User

DIGITAL NEWS Product: VIDI video digitiser. Supplier: ROMBO, [redacted]. Price: £34.95 It's not often we look at new bits of hardware for the Spectrum for the jolly good reason that there are few new ones appearing. Even this goodie, the Rombo VIDI video digitiser, isn't strictly speaking NEW as such, but the operating software has been extensively revised and upgraded, by an enthusiastic owner of the original version, so if worth a second eyeball. The function of a video digitiser is to fake a picture signal from a video recorder or camera, and shove it into your computer's memory in such a way that the image can be displayed and manipulated on screen. In the case of the VIDI, the connections are simple; plug the little black box into the user port of the Spectrum (any Spectrum), and a lead from the VIDEO OUT of your recorder or camera into the VIOI's phone IN socket. Then load the VIDI software, which can be transferred if you wish to backup tape, microdrive, Plus 3 or Disciple disc. A menu bar appears at the top of the Spectrum display screen, and the rest of the screen is filled by a digitised image of whatever signal is being output by your video recorder or camera. If magic! The image is in black and white, of course, since only very expensive digitisers can create a colour display. However, you can select any other combination of paper, ink and border colours if you prefer. Also, by pressing the spacebar you can switch on a SHADE option which introduces a more graduated toning. You can also adjust a signal level knob on the side of the VIDI, which controls the overall brightness/contrast. The spacebar and enter key are used to flip through a series of menus on the control bar, and select the required function. If all dead easy to use, and to my amazement I had the whole thing up and going in about three minutes. The digitiser can grab either single frames, or a sequence at a rate of about twelve per second, which is slower than real-time but which gives a fairly "live" feel. You don't need a still frame to digitise, which is good since not all video recorders have good still-frame facilities. You can save single pictures or sequences to any medium, verify them and reload later. Sequences allow you to create animations of up to six frames (the most the Spectrum can manage, since each frame occupies 8K of memory). The sequence can be shown either forward, backwards, or in a continuous loop. Both the digitising and the animation rate can be set to slow, medium or fast, which allows you to create some interesting slow and fast-motion effects. A complete sequence with animation parameters can be saved as a single file. These files contain a small machine code routine which allows you to incorporate the animations in your own programs, and alter the speed and direction settings from Basic. Experienced machine-code programmers should be able to write their own VIDI applications using the technical data given in the brief photocopied manual. Since VIDI saves pictures in conventional Spectrum SCREEN$ format, you can print them out directly from the program, or load them into most graphics packages for further editing, colouring and manipulation. For the price of four full-price games VIDI should give you hours of enjoyment. Owners of the original version can upgrade their software for £1.99.

Your Sinclair

Phil South

RAGE HARD! Introducing the new YS hardware page, featuring Technical Ed Phil Snout on oscilloscope and magic screwdriver. This month he takes apart a pair of video digitisers, the Rombo VIDI-ZX and the Dataskip Videoface. Video frame grabbing used to be the province of more sophisticated computers, with the interfaces costing from £90 to around £500 for some of the biggies. But even on the Spectrum it's possible to grab frames from video and manipulate them, and indeed use them in your own program as you would any other SCREEN$ file. There are currently two brands of digitiser on the market at the moment, and both of them are relatively inexpensive. Although we are comparing these two devices head-to-head, it would be unfair to compare them too closely. As in anything, it's what you prefer on a personal basis and whether or not it fits your needs, which in the end will dictate what you'll buy. I prefer to tell you the merits of both and let you make up your own mind. But as comparisons must be drawn, for what it's worth. I'll give you my verdict at the end. Okay, let's plug in the video and see what develops. DATASKIP VIDEOFACE Readers will no doubt be familiar with the name Dataskip Videoface, as they've been advertising for some months under their own name. But now they're doing a deal with Romantic Robot, and the Videoface has been re-launched in a new box. The device comes with a software cassette and a manual; or more accurately a sheet of paper, explaining how to use it. One of the main features that struck me about this device, 'cos I saw it first in prototype about a year ago, is that as well as being stuck in a new box, the software that goes with it has been re-written, adding a couple of new features. The device scans the TV picture at six frames a second, and stores the preceding six after you press the frame grab button. So, main additions are the facility to save from one to six frames at once, and animate them at any speed. This can be very handy for making videos, giving you access to Max Headroom style digital effects, and enabling you to set up sequences which repeat over and over again. To use the unit, you plug one end of a lead into the BNC plug marked 'video out' on the back of a domestic video player, and the other end into the photo or RCA plughole on the digitiser. Then you load the software, and the picture from the video comes out on your monitor, via the Speccy. When you spot a piccy you like on the screen, you slap the SPACE bar and the image is frozen or 'grabbed,' and prepared for animation or saving to tape/disk. You can step through the six screens in the frame buffer to select the best one, before saving one or more of them. I must admit, I found the manual a bit insubstantial and a trifle difficult to understand, but as it was, I presume, written by the Dutch bloke who designed the machine, I s'pose we can't be too harsh. It does raise a few interesting questions, though. Like, nowhere does it say what the red LED does, and this was a bit of a problem at one point as the red light was on and no picture was forthcoming on the Speccy screen. Hmm. Still, this had stopped by the time I booted it the next day, so your guess is as good as mine as to what was going on there. On the plus side, the animation is pretty smooth, flipping those six screens without very much flicker at all. It would have been better to see more instructions about how to use those six screens in your own programs though. There isn't a grey tone as such, but the machine cheats it in the way it bleeds out in areas which offer neither black nor white. The effect is a bit erratic, but as you can see in our piccy of Spock, it can be quite effective. A bit of judicious gain twiddling usually manages to get a good balance for most source screens. The best results apparently, are to be had from colour video signals, but it says in the manual that you can use black and white as well... although quite where you'll get a black and white video source anyway, I wouldn't like to say. The Videoface is a nicely put together bit of kit, and all the additions to the software work well. VIDI-ZX This is a really new device which has a nice home-built look to it, being housed in what looks like an electronics project box, with a Rombo sticker on the top. The edge connector and the PCB sticks out of the bottom of the box, but although it looks as though it might be a bit wobbly when plugged in, it actually seats itself quite firmly. Once you're all connected up, the free cassette of software is then loaded and you're presented with the fast 10 frames per second display. On the top edge of the screen is a menu with (G)rab, (S)hades On, (V)iew, and (M)enu written on it. When you see a frame that you like, just press G, then the screen is frozen ready to be saved. Grab then changes to (R)un, so if you don't like the screen you've grabbed, you can start again by pressing R. You shift menus with M and are presented with one that says (L)oad, (S)ave, (C)opy, (M)enu, and their use is obvious. View is an option for turning off the menu so you can see the whole screen. By far the most interesting thing about this interface, apart from its nippy 10fps speed, is the Shade option. This turns on a proper grey tone, a sort of stipple effect, which gives you a flat grey tone as well as black and white on the output screens. This is a very pleasing effect, and so fast! It's the speed of grabbing and the stipple effect that makes the VIDI-ZX such an interesting proposition. The manual is still not very big, but this one is well written, and told me at some points, more than I really wanted to know about the machine. There's also a useful troubleshooting section, and telephone number to call for technical support. Oh yes, on the back of the unit there's a little orange plastic link pushed onto the top two of three small pins which protrude from the PCB. This link reconfigures the machine for use with the DISCiple, and the DISCiple uses address line 6, which is also used by the VIDI-ZX. Moving the link from the top two pins to the bottom two, will change the VIDIs control to address line 4, allowing use of the DISCiple. An additional program, called VIDI4, is featured on the software cassette to run the machine from address line four. Full details of the driver software are given in the manual, so that anyone can use the VIDI with their own programs along with full details of the machine code. Plus, all the appropriate addresses in memory are labelled and annotated so you can design your own software if necessary. No operational problems or bugs showed themselves whilst the unit was being tested. In fact the few things that did go wrong were well error trapped. When I put in a filename too long for the string handler for example, the program broke out of Basic to tell me 'Invalid filename'. On a badly worked out program, this would have been the end of civilisation as we know it. But not only didn't the machine reset my Speccy, but the picture I'd grabbed stayed in memory for some minutes while I sorted myself out. All I did was to press RUN and ENTER, and I was back where I started again. The VIDI-ZX is a first class bit of kit, and seems reliable and well set out. Highly recommended. (Snouty Star Trek Note: THe veteran Trekkers among you will recognise the episode of ST I used for this experiment. It was of couse 'Obsession'. What a corker that was!)

CONTACT BOX Rombo Productions [redacted] Romantic Robot [redacted]

FEATURES VIDI-ZX Frames per second: 10 Shading: Yes Animation: No Multiframe Save: No Copy Protected Software: No Variable Video Gain: Yes Scroll Picture Area: No Saves To Tape/Disk/MD/Opus: Yes* Through Port: No Cable Included: No Price: £29.95 *saves to any medium if the basic program is altered to do so. VIDEOFACE Frames per second: 6 Shading: No Animation: Yes Multiframe Save: Yes Copy Protected Software: No Variable Video Gain: Yes Scroll Picture Area: Yes Saves To Tape/Disk/MD/Opus: Yes Through Port: Yes Cable Included: No Price: £44.00

SUMMING UP Well, there you have it and... what? You want me to tell you which one I like best? Well, I don't really think it's fair to favour one over the other, as they both do slightly different jobs. But, if you really twisted my arm, I'd prefer the Rombo at a pinch. And that's just on the grounds of speed and the shading option. And the fact that it's a fraction cheaper. There, I've committed myself. Hope you're satisfied.