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PC Product Review The Video Blaster is one of the lowest cost ways of entering the world of PC video. Import your PAL or NTSC composite video signal from a camera or VCR, then frame grab and create all sorts of visual effects. VIDEO BLASTER By DARREN YATES W HEN THE ORIGINAL Sound Blaster hit the streets a few years ago, few would have predicted its rise to prominence as the standard for PC audio. The 16-bit ASP model released a year or two later upped the stakes by bringing CD-quality audio to your PC – playing CDs through your PC via a CD-ROM became a reality. Now there’s a system that does for video what the Sound Blaster did for PC audio and, by no surprise, it comes from the same people at Creative Labs in the US. Features Here are some of the features: Supports NTSC and PAL systems; Software selectable video and audio input sources; • 16-bit card; • • 56  Silicon Chip • Supports PCX, TIFF, BMP, GIF and TARGA file formats in 640 x 480 res- olution; • Supports up to 2 million colours; • Live and still image zooming and scaling; • Freeze, save and load images; • Crop and resize images; • Windows® software (Video for Windows from Microsoft). The VB pack also includes manuals for all software packages, as well as instructions on installing both the card and software. For those who are running other equipment such as CDROMs, the I/O addresses, frame buffer base address and software interrupts are all selectable and a test program checks whether your choices are valid. Bundled software As much as the Video Blaster can do, it is remarkably easy to drive with a host of Windows-based software packages to allow you to make the most of its capabilities. Along with Microsoft’s Video for Windows, Tempra Special Edition allows you to edit video images with shapes and paint and supports all the usual file formats. Tempra SHOW is a multi-media presentation package that integrates audio, video, animation and still graphics into high-impact interactive presentations. ACTION from Macromind lets you import graphics from spreadsheet, paint and graphics programs and comes with over 100 templates for your own designs. System requirements • The basic system requirements are: IBM PC-AT or higher system; • • • Full length 16-bit slot; DOS version 3.1 or higher; VGA or multisync monitor running 50-70Hz with a scan rate of about 31.5kHz; • VGA card with a features connector; • Not more than 15Mb of system RAM. This last point may seem a little strange with the latest trends aiming for more and more system RAM but there is a very good reason for this. The VB card has 1Mb of RAM on board which it needs to overlay on to the system. This RAM is used to store the image and to display it as fast as possible to produce real-time video displays. The IBM PC-AT (or 286) has a 24-bit address bus which limits the maximum address RAM to 16Mb. Even on 386 machines, which are capable of addressing 4 gigabytes, the ISA bus limits the effective RAM to 16Mb. It turns out that the most efficient way to display the video image is to map this RAM into the system at the 15-16Mb boundary. However, this causes conflicts with any memory which exists so in order for the system to work correctly, no system RAM can use the 15Mb-16Mb addressing area – hence the 15Mb system restriction. This base address can be lowered for systems which have less than 15Mb of system RAM. Setting the system up This is a little more involved than you might think. To start with, you need a VGA card that has a feature connector on the top of the board. This is an edge connector similar to that found on 5.25-inch floppy drives. An internal-to-the-system cable connects from the VB card to the feature connector on your VGA card. A separate external cable then links the VGA output from your VGA card to the VB card. Your VGA cable then connects to the DB15 output socket on the VB card. What actually happens with the system is that it doesn’t really use the VGA card to produce the on-screen display. It uses a method called chroma-keying and is similar to the effect you often see on the evening news where the weather forecaster is seen standing in front of various meteorological photos and maps. The VGA card produces a blank colour screen which The Video Blaster allows either a PAL or NTSC composite video signal on any one of three inputs to be displayed on a VGA screen. This dialog box allows the user to select the video standard & the polarities of the sync signals. April 1994  57 the VB card uses to key in the video image. You can see this if you try to paste the screen image to the Windows Clipboard. When you go into the Clipboard, all you will see is a pink screen below the top menu. Installing the software Installation of the software is a much simpler affair. The Video Blaster driver software is loaded first under Windows and it automatically loads all the relevant files. You can change the destination drive and directory if you wish. Once the software is installed, you then have to run one of two setup programs to start the software drivers – there’s one for Windows and one for DOS. The Windows version is easier to drive and still allows you maximum flexibility. It automatically selects the correct I/O address and software interrupts. Real time video display After running the Windows setup program, you can then connect up your video source (either VCR or camcorder) to one of the video inputs, select it with the software selector and then click on the VIDEO KIT icon. After maximising the window, you should see the Windows menu routine at the top and whatever signal you have from the video source being displayed on the VGA screen. Tempra Show comes bundled with the Video Blaster software & is designed to incorporate sound & animation into the captured video images. This is the opening screen that appears when the program is loaded. The Video Blaster allows either a PAL or NTSC composite video signal on any one of three inputs to be displayed real time on a VGA screen. This is quite a breakthrough compared to some of the systems we have seen previously which have relied on small screen windows showing just a few frames a second. VB uses the full screen size for a much greater impact. What makes this all possible is a 16-bit nearly full-length card which not only contains stereo input mixing from a CD player or tape and output amplifiers to drive loads down to 4Ω but all the necessary circuitry to convert both NTSC and PAL signals with either negative or positive syncs. At any time while video is being displayed, you can select the freeze option in the main menu in VIDEO KIT, and grab a frame. The grabbed image is then frozen on the screen. To save the image, you just select one of the file formats, whether it be TIFF, BMP, PCX, GIF or TARGA and save it to disc. You can now import that image into either Windows Paintbrush or just about any desktop publishing program. Video for Windows The “slider bars” on this dialog box allow the picture colour to be quickly adjusted, either in continuous mode or in freeze frame mode. 58  Silicon Chip This package from Microsoft is fast becoming the basic standard for PC video and is a great addition to the Video Blaster package. It requires Windows 3.1 and it is capable of some pretty fancy effects. Among its features is the ability to capture real time video and audio using VidCap, however your machine needs to be quite good. The system requirements are: • 33MHz 80386 or better • 4Mb of 32-bit RAM minimum • 100Mb hard drive to hold reasonable amount of video – also must have a write capability of at least 320Kb per second. Video for Windows will handle S-video, RGB and digital video as well if you happen to have another video board capable of capturing these standards. It also comes with a CDROM full of captured video examples which you can look at and edit to your heart’s content. Even if you don’t have a CD-ROM, there’s quite a good little sample file on the distribution discs – at 1Mb, it gives you an idea of just how much space you need to capture a decent length of video! Conclusion Overall, the Video Blaster package is very impressive. The only thing which we feel they could have added is the ability to produce composite video of the edited capture. That would have made it the complete PC video system. Be that as it may, the package represents good value for money at $899. It is available from all Dick Smith SC Electronics stores.