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TVCoder: the sequel to Video Blaster! As good as the Video Blaster is, it does not have the ability to deliver output from your PC to your VCR or TV monitor. Now there is the TVCoder. It will output VGA graphics to NTSC & PAL video monitors & VCRs, & will also perform as a stand-alone unit. Review by DARREN YATES W HEN WE REVIEWED the Video Blaster from Creative Labs earlier in the year, our impressions were that it was a great product with one important feature missing – you could bring video into your PC but you couldn’t take it back out again. Creative Labs obviously thought the same and have completed the package with the TVCoder which will export video in either NTSC or PAL format to your TV or VCR. It supports both composite video and S-video compatible TVs and VCRs in any one of the following video standards: • NTSC (4.43) 50Hz; • NTSC (4.43) 60Hz; • NTSC-M 60Hz; • PAL (B/G) 50Hz; • PAL-M 60Hz; and • PAL-N 50Hz. It will also run both your TV monitor and your VGA display at the same time, which is something that most of the current generation PC-TV converters can’t do. System requirements In order for TVCoder to work on your PC, it must have at least the following: 80  Silicon Chip • • • • • • • 286 processor or higher; 1Mb of RAM minimum; 1Mb of hard disc space; VGA monitor and card; One 8-bit slot; DOS 3.3 or later; Microsoft Windows 3.1 or later. Obviously, if you only have 16-bit slots in your PC, then one of these will do equally as well. Note that you don’t have to have the Video Blaster package for the TVCoder to work. The package The TVCoder package is more hardware than software. There’s only a thin manual and one floppy disc. The rest of the box is taken up with external cables and the card itself. I don’t know about you but whenever I look at or buy one of these packages, I always like to have a squiz at the board and see what makes it tick. In the case of the TVCoder, there’s one monster 84-pin Philips SAA 7199B chip which I would hazard to guess does most of the TV standards conversion. However, it would seem that there is a combined effort in this card with devices also coming from NEC and Sony. A couple of Creative Lab’s own proprietary chips are also thrown in for good measure. The only components which are not surface-mounted devices (SMDs) are a few electroly­tic capacitors, the crystal and a couple of 7805 regulators. The card mounting bracket has two VGA DB-15H female sock­ets, one RCA socket and one S-video output socket. One thing which is great to see is that the card mounting bracket has labels for each connector stamped into it. How many times have you come across a card with three or four connectors and then had to go searching for the manuals to find out which connector plugs into which socket! As noted above, the card is only an 8-bit type which is great if you’re running a 386 with a Sound Blaster ASP16, Video Blaster and a memory card and you’ve only got an 8-bit expansion slot left. The only thing you need to be careful of is that the cable which connects the VGA card to the TVCoder card is quite short but this shouldn’t cause any problems. Software Before running the installation program and setting up the software you need to first install the card, otherwise when the installation program goes looking for it, you’ll be forced to quit out and start again later. The manual that comes with the TVCoder is quite good in this respect and shows that you can run the TVCoder card with or without the Video Blaster option. More importantly, it shows how to connect up the TVCoder, your VGA card and the TV set using the external cables. As mentioned before, the TVCoder comes with only one disc which suggests that most of the hard work is done by the card with the PC only acting like a “traffic controller”. With the software running under Windows, this reinforces the theory. As with all Creative Lab’s products, the installation of the software is basically automatic as it unzips the program files from the archive by itself. While it was running through this, one point worthy of interest was the fact that the package was written using Visual BASIC Version 2 which was evident by the appearance of the VBRUN 200. DLL run-time dynamic-linked library. Once the installation is completed, you’re then asked to reboot your machine so that the settings can be put into place. If you live in the US or anywhere where NTSC is the television standard, then setting up the package is easy. However, there’s a bit of work for us “poor” PAL users to do! The initial TV standard upon start up is one of the NTSC standards. Now although you will still get a picture on your PAL TV (I used a Samsung 34cm with external video input for the test), you won’t see any colour. Unfortunately, this NTSC default is not explained anywhere in the manual. To make the change you need to go to the TVCODER directory and run a little utility called TVSET. To select the correct PAL standard, you need to run the following command: TVSET VIDEO PAL-BG This will switch the card into our PAL mode and you should see colour appear on your screen if you’re running with a co­loured DOS prompt but you should definitely see it when you go back to the DOS shell. If you don’t, then you may have to switch the colour on, on the card. You also do this with TVSET by entering the following command: TVSET COLOR ON If you need to get at the settings of the TVCoder in a hurry, then you A spare 8-bit slot in your computer is all that’s need to mount the TVCoder card. The large 84-pin Philips chip at top centre apparently does most of the TV standards conversion. might as well run the TVAdjust terminate-and-stay-resident (TSR) program in the background. By holding the CRTL key down and pressing “5” on the numeric key­board, a panel with all of the controls appears on the screen. Here you can change the video standard, turn the colour on or off, and adjust the alignment, etc. If you’re not likely to want to change things in a hurry then you should stick with the TVSet program and save your memory space. TVTEST utility Once you have the TVCoder up and running, you can run the TVTEST utility. This will carry out the following: check the the port address for the card; perform a register check on the card to ensure that they are functioning correctly; and perform a colour output test which will produce colour bars on the screen and go through the video standards test. Initially, when I ran this, the video standards test only went through the NTSC standards which made me twig to the fact that the software is initially set up for NTSC standard. Finally, a fairly coarse graphic picture file is displayed on the screen. At this time, you should be seeing the display on both your VGA screen and the TV set. And this is where you’ll notice something else. Your VGA picture won’t look quite as good as it did before. As I write this, I’m looking at a Philips 14-inch SVGA monitor and the colours do appear to be a little washed out, the image is not as sharp and the screen seems to be suffering from a little “colour-run”. I have seen a few of This is the screen that appears as soon as you load the TVCoder Control Panel from within Windows. It allows you to select any one of three PAL or NTSC input signals, to switch colour on or off, & to position the display on both the VGA monitor & TV screen via the vertical & horizontal alignment bars. July 1994  81 got caught out) and have Windows running in Super-VGA (800 x 600) mode, then you’ll have to switch it back down. If you don’t, the result is a scrambled VGA display and a mess of flickering from your TV screen. Windows TVPanel This Colour Lookup Table shows the default settings of the software. As it stands, the TVCoder will process VGA colours & display them as they are on the TV screen. The input colour luminance is displayed on the horizontal axis and the output luminance is on the vertical. There are three graphs, one each for red, green & blue, each of which is selectable for on-screen display. Editing of the Colour Lookup Table is possible using a unique point & click method. By selecting one of the 14 grab points, the Lookup Table can be reprogrammed so that various shades of a given VGA colour appear on the TV screen as any colour you desire. Although all three colours are displayed on the same graph, you can only edit one at a time. these PC-TV encoders but this would still be the best out of all of them with regards to the lack of degradation to the VGA screen. So what does the TV picture look like? Well, it doesn’t look too bad at all. There is no obvious screen flicker which a number of other converters suffer from and the picture stability is quite good. The image isn’t as sharp as you would get on your VGA screen but if you choose 12-point Arial type from Windows Write and write a few 82  Silicon Chip lines you can easily read it on the TV screen. This reminds me of another possible trap. Don’t forget to switch your Windows video standard back to 640 x 480 VGA mode before you next run Windows. You can do this quite easily by going into your WINDOWS directory and running the DOS version of SETUP. You simply select to change the display adaptor and switch it to standard VGA. If you’re like most people (including yours truly, who The Windows software consists of only one program – TVCoder Control Panel – but it is an extremely versatile little tool. Firstly, when you run it, you’re given the option of set­ting the video standard to any one of the six listed above. When you make the changes, the results are instantly translated to the screen so you can quickly work out which standard suits the TV you’re using. If you’re already running Windows in standard VGA mode then you can come straight into Windows and select the correct video standard from here rather than using the DOS utili­ty if you prefer. Other parameters which you can change include the horizontal and vertical positions of the picture on both your TV and VGA displays. The “Vertical Align­ment” control is used to stop screen rolling if it is occurring. Horizontal alignment does likewise in the X direction. The Horizontal and Vertical pan allow you to shift the image around on the VGA display without affecting the TV screen. One of the reasons I would hazard to say this feature was includ­ed is that the VGA display shifts quite a bit when you toggle the TV screen output off and on. This option allows you to shift it back into place again. You can also switch the colour off if you wish to record black and white images on your VCR. Colour lookup table Instead of just feeding the same colours used by your programs straight out to the TV screen, the TVCoder uses a Colour Lookup Table. The great thing about this is that they’ve made it such that you can reprogram the three primary video colours – red, green and blue – and produce your own colour display. One of the screen shots of the Windows control panel shows what fun you can have with this tool. The way the Lookup Table works is as follows. Each of the three video colours has an 8-bit register which can have a count anywhere between 0 and SILICON CHIP SOFTWARE Now available: the complete index to all SILICON CHIP articles since the first issue in November 1987. The Floppy Index comes with a handy file viewer that lets you look at the index line by line or page by page for quick browsing, or you can use the search function. All commands are listed on the screen, so you’ll always know what to do next. Notes & Errata also now available: this file lets you quickly check out the Notes & Errata (if any) for all articles published in SILICON CHIP. Not an index but a complete copy of all Notes & Errata text (diagrams not included). The file viewer is included in the price, so that you can quickly locate the item of interest. The Floppy Index and Notes & Errata files are supplied in ASCII format on a 3.5-inch or 5.25-inch floppy disc to suit PC-compatible computers. Note: the File Viewer requires MSDOS 3.3 or above. ORDER FORM PRICE ❏ Floppy Index (incl. file viewer): $A7 ❏ Notes & Errata (incl. file viewer): $A7 ❏ Alphanumeric LCD Demo Board Software (May 1993): $A7 ❏ Stepper Motor Controller Software (January 1994): $A7 ❏ Gamesbvm.bas /obj /exe (Nicad Battery Monitor, June 1994): $A7 ❏ Diskinfo.exe (Identifies IDE Hard Disc Parameters, August 1995): $A7 ❏ Computer Controlled Power Supply Software (Jan/Feb. 1997): $A7 ❏ Spacewri.exe & Spacewri.bas (for Spacewriter, May 1997): $A7 ❏ I/O Card (July 1997) + Stepper Motor Software (1997 series): $A7 POSTAGE & PACKING: Aust. & NZ add $A3 per order; elsewhere $A5 Disc size required:    ❏ 3.5-inch disc   ❏ 5.25-inch disc TOTAL $A Enclosed is my cheque/money order for $­A__________ or please debit my ❏ Bankcard   ❏ Visa Card   ❏ MasterCard Card No. Signature­­­­­­­­­­­­_______________________________ Card expiry date______/______ Name ___________________________________________________________ PLEASE PRINT Street ___________________________________________________________ Suburb/town ________________________________ Postcode______________ Send your order to: SILICON CHIP, PO Box 139, Collaroy, NSW 2097; or fax your order to (02) 9979 6503; or ring (02) 9979 5644 and quote your credit card number (Bankcard, Visa Card or MasterCard). ✂ 255; 0 for no luminance and 255 for full luminance. In the default mode, the TVCoder maps the lumi­ nance values used by your VGA card from these registers, through the video chip and out to your TV. If you look at the default graph, the output luminance values are on the vertical axis and the input values on the horizontal axis. You can see here that an input value of 0 corresponds with an output value of 0, 128 corresponds with 128 and 255 with 255. So white on your VGA screen appears as white on the TV screen, red as red and so on. If we load in one of the other colour bar options, say GAMMA_1.2, the graph then matches the pre-programmed table but as you can see from the next screen shot, there are a number of pick-up points along the plot. You can reprogram the colour Lookup Table by picking one of these points and dragging it around the graph with your mouse. By doing this, we could program out the colour red, for example. To do this, we just select the red line option from the panel and then pull all of the pick up points down to the hori­zontal axis. What this tells the TVCoder is that for any red input luminance value, we want each corresponding output level to be zero, so no matter what the input luminance for red is, the output for red will always be zero and hence there will be no red on the TV display. Make sure you remember to click on the enable button to see these changes on the screen. You can save any lookup tables you create to disc as well, so that you can easily set up the options you want just by load­ing in the correct file name. Also available is reverse colour. Not only does this turn blacks into whites and whites into blacks but it also turns blues to yellows, greens to red, etc. Using this reverse video mode, text is much easier to read on the TV screen as well. There’s also a comprehensive help manual within Windows so that if you get stuck, there should be a solution. Overall, the TVCoder is the best PCTV converter we have seen but there is still some room for improvement in the overall picture quality. The ability to change the Colour Lookup Table is a great feature which gives the TVCoder a lot of ver­satility. And the price? – $379 from all Dick Smith SC Electronics stores. July 1994  83