From: Donald Richard Tillery Jr Organization: The Amiga Online Review Column - ed. Jason L. Tibbitts III Subject: REVIEW: ColorBurst Keywords: hardware, graphics, 24 bit Path: menudo.uh.edu Distribution: world Newsgroups: comp.sys.amiga.reviews Followup-To: comp.sys.amiga.graphics Reply-To: Donald Richard Tillery Jr Much maligned, and often doubted, M.A.S.T. (Memory And Storage Technology) has delivered what appears to be a solid leader in the 24 bit display device race. This device will connect to ANY Amiga model, and display a rock steady, video compatible, 24 bit image in any of the standard Amiga resolutions. ColorBurst 24-Bit Display Device for the Amiga Computer My Story I've been waiting since last November when I read a M.A.S.T. advertisement in Amiga World about the ColorBurst 24 bit display device. Armed with an inordinate amount of blind faith, I have been in constant contact with M.A.S.T. since then. I was the first person on their domestic list of interested parties, and all the patience, understanding, and assistance I could muster is beginning to pay off. The completed PAL ColorBursts (the European video standard) have been shipping for a couple of months now. The NTSC (American standard) units have one large obstacle to overcome that the PAL units do not -> the F.C.C. (Federal Communications Commission). All American electronics devices must be tested to be sure that they do not interfere with other devices. Like all dealings with the federal government, this often takes much more time than seems reasonable. Currently ColorBurst has passed FCC Class A (this took 6 months), which allows its distribution on a commercial level and to developers. FCC Class B (which will allow sales to private individuals) will surely follow, but who knows how long (complain to the FCC, not MAST). On Monday July 15, 1991, the UPS man delivered one of three NTSC units available for developers (more units go into production at the end of August). After paying the COD, I unpacked the unit, which includes the ColorBurst itself (approximately 5" x 2" x 8", with power and active indicators on the front panel), a 16 V AC adapter power supply, video cable, 65 page notebook style manual (nice for future updates), and two 3.5" disks of software. I carefully hooked up the device to my Amiga 2000 (with extras) in accordance to the short but adequate installation instructions (although they really should be closer to the beginning of the manual). I then ran the test/alignment programs on the included disk, and failed. The software seemed to be functioning, but the unit's active light never lit, and no 24 bit images showed on my screen. On the way to deliver the unit to UPS for return to M.A.S.T., I opted to test the unit on my girlfriend's A500. I was dumbfounded when the unit performed flawlessly! The ColorBurst unit uses the digital signals present on the video port to receive the 24 bits of digital data (this is similar to the way the HAM-E and DCTV devices function). However, in the ultimate turn of irony, my particular Amiga was missing these digital signals and did not work with the ColorBurst (I had never tried the HAM-E or DCTV on my machine, but they don't work with it either). I was eventually able to swap mother boards with a friend (for a nominal fee - he doesn't plan on using an external 24 bit device ;-), and I have been able to test the unit since then. Hardware The hardware of the ColorBurst is a high quality piece of workmanship that includes an internal fan for cooling. The video cable is a bit of a mess with 4 external wires as well as the shielded cable. M.A.S.T. assures me that they are working on a source for better cables, but they didn't want to hold up shipping ColorBurst while a contract is solidified. ColorBurst will work with ANY Amiga model from the A1000 to the A3000. It plugs into the 23 pin video port and you plug your monitor into it. When not displaying 24 bit images, it passes through the normal Amiga video. Those functions that I can attribute to the hardware itself indicate it is a fine piece of work. When displaying a 24 bit image as a backdrop for Amiga screens, it effortlessly switches between non-interlace and interlace as the Amiga screen changes. Output of the ColorBurst is RGB analog and is comparable to the standard Amiga video signal (sorry, no de-interlaced version here). It will display up to 24 bitplanes and has provisions for a 24 bit image with a 24 bit overlay (the purported 48 bit mode). The actual image produced by the ColorBurst unit is a very clean (albeit brighter than standard Amiga video - hand on the brightness knob) and fantastic picture as viewed on 1084 and 1950 monitors. I have not had the opportunity to dump the image to video tape as of yet (I don't have that kind of hardware), but I can safely assume that it would record as well as the Amiga signal it emulates. The unit is compatible with my Commodore de-interlacer and M.A.S.T. says the Microway Flicker-Fixer is compatible as well. The manual mentions that the NewTek Video Toaster and ColorBurst have problems and mention a board level modification for the Toaster to allow compatibility. Some internal genlocks also evidently have problems (according to the manual), but the remedy will most likely have to be on a model by model basis. Software The software definitely could use some improvement. In its current version, it all works well, but it has some inherent flaws. All programs will load standard IFF files (including IFF 24, but excluding HAM and Extra Half-Brite) as well as the ColorBurst fast-load format (a non-compressed format). My system consists of an A2000 with GVP A3001 at 30Mhz (that's a 68030 & 68882) with 4 Megs of RAM, a HardFrame 2000 and a Quantum 210 hard drive. The conversion of a 768 x 480 image from the hard drive to viewing takes about 18 seconds, while the ColorBurst format file takes less than 4 seconds to show. Accompanying programs include Show24 - shows images until left mouse key pressed, Convert24 - converts IFF to ColorBurst fast-load format while viewing the process, BackDrop24 (This program was mentioned in the manual, but was not included on the actual distribution disks I received. It is, however available from the M.A.S.T. support BBS for the cost of the long distance call to download it.) - "genlocks" a 24 bit image behind the standard Amiga screen, Kill24 - turns off any currently displayed image, SlideShow24 - utilizes a script file to sequentially view images, Color_Cycle - demonstrates the 24 bit color cycling ability of the ColorBurst, Sound_Cycle - color cycles in sync with audio provided through a parallel port audio digitizer, Scroll24 - allows real-time scrolling of an image using the mouse, Mouse24 - functionally the same as Scroll24, and CBPaint - the real-time 24 bit paint program (integer and floating point versions included). Chip memory is a limiting factor for all of these programs. A 512 K chip RAM machine tested was able to display about the first 380 lines of a 768x480x24 image. My 1 Meg chip RAM machine had no problem with any display size except within the paint program (see below). The source is freely available (with the exception of the paint program, source code is included with the package), and I am working on re-writing some of the routines before a promised shared library is released. Each program opens the ColorBurst screen before checking the image file's validity or even whether the user just wants the program's usage. Many of the subroutines make blanket assumptions about the image, the computer and the system configuration, and at least the Show24 program hits the hardware directly while looking for a mouse click. Other examples: one of the test routines malfunctions with an interlaced workbench; the Color_Cycle demo assumes that the unit is a PAL unit; and all of the programs have hardwired assumptions about the size of the images which correspond to the usual Amiga resolutions. CBPaint The paint program is a plain, but adequate implementation that utilizes an Amiga screen overlay for menus. Its gadgets are displayed at the bottom of the screen with generic text labels. The opening menu allows a choice of standard Amiga resolutions ranging from 320x200 to 736x480. Unfortunately, as of the newest version, virtual memory has not been implemented yet. This means that 2 megabytes of chip memory are required to paint in resolutions higher than 368x480 or 736x240 (640x400 seems to be too large also). A 512 K chip RAM machine is limited to 368x240. The program will actually open up the screen in any requested resolution, but painting can only be done from the top of the screen to the area where chip RAM runs out. M.A.S.T. promises virtual memory (fast RAM used for chip, and hard drive space used for both) in future releases of all the software. The paint program will load in images in a variety of formats including the ColorBurst fast-load format, IFF 24, Impulse's file format, TIFF, Caligari format, and IFF format (excluding HAM and EHB). Tools include airbrush (similar to Deluxe Paint's spotty version), polygon fill, polygon cut, draw fill, rectangle fill, draw, dots, lines, cut, paste, curve, circle, ellipse, scale and flood. [Mr. Tillery also informed me that there exists a much extended spray paint tool which goes far beyond Deluxe Paint's 'spotty' airbrush. -JLT3] The modes menu allows solid, gradient, transparent, texture, addition, subtraction, conversion to grey (de-Turnerizing ;-), blending, smoothing (very nice), and tinting among others. The color requester allows choice of colors for draw color, gradient color, transparent color and others with RGB or HSV sliders. It also allows setting 24 bit dithering to give the appearance of texture. Extras include a spare screen, magnification, 90 degree and any angle rotation, grid setting, and horizontal and vertical flipping of brushes. Overall the program is adequate for most touch-up work and some original creativity, but it could easily be improved. Feedback on an A500 and my accelerated A2000 is very quick. Operations are comparable to those of Deluxe Paint in speed. There are a few quirks left in the program (none fatal), but the version I have now was an update available three days after I first received my unit. This would indicate that updates will be forthcoming at regular intervals. Technical Info For anyone interested, the following is as much info as I have at my disposal about the operation of the ColorBurst 24 bit device. Whether you know it or not, the 23 pin video port on the back of your Amiga has quite a few more signals on it than just red, green and blue analog outputs. Among other signals, there are 4 digital pins for use with a digital TTY monitor. Normally, these pins are 1 bit each of red, green and blue as well as an intensity bit. The most significant bits of the red, green and blue data values are present on the appropriate digital pins. The intensity bit is tied (for a reason I fail to fathom) to the least significant bit of the blue data. What results is a _very_ rough approximation of the colors of the analog screen as represented by the 16 colors (red, green, blue, yellow, cyan, magenta, white, black and intense versions of each) that can be displayed by a digital monitor. You probably don't know anyone who uses such a monitor with the Amiga, but those lines aren't a complete waste. The HAM-E device, DCTV, and now the ColorBurst make use of this high speed potential data (which is, of course, what my original mother board was missing, and why it didn't work). For each pixel generated during a single frame, there are 4 bits being output through the video port. This represents about 5.5 Megabytes per second of data. I won't go into the operation of the HAM-E and DCTV devices, but the ColorBurst utilizes this data to fill its own 1.5 Megs of memory and to receive commands from the Amiga. The data from the Amiga is sent in chunks the size of high resolution screens (which is what you'll see without it attached, or if your machine's digital lines are faulty :-), 4 bitplanes at a time. The ColorBurst memory is in two "banks" that are responsible for the even and odd pixels in a scanline. The first 12 bits go to the first bank, 4 bits into the red, green and blue sections respectively, and the next 12 bits fill the second bank in a like manner (this information is easily gleaned from observation of the Convert24 program's operation). This means that a high resolution interlace 24 bit image takes 6 full frames (or 1/5 of a second) to be sent to the computer. A low resolution non-interlace 24 bit image can be updated 4 times that often, leading to the 20 fps animation capability of the ColorBurst. With fewer bitplanes, even faster animation is possible. The difficulties in data manipulation and transfer become apparent when it is realized that the data being dumped out of the video port must come from chip RAM (hence the limitation on screen size even in 1 Meg Agnus machines). It will require full implementation of virtual memory (and more specifically virtual CHIP memory) before the limitations can be lifted and before animation can be accomplished (the software doesn't exist yet). Most hard drives can only deliver 1 Meg per second, so animation will most likely have to come from memory. This obviously limits the size of such animations. I hope to get more specific information in the next few weeks. Armed with such knowledge, I feel confident that I can speed up the loader and the converter, and put out a version that will deal with HAMs, EHB images, and possibly even GIFs. [Ed. Note: In conversations we've had, Mr. Tillery gave me some additional words to pass on, mostly on minor points which were left out of the original review. I include them here. Also note that the wording is partially mine. -JLT3] Here are the displayable resolutions of the ColorBurst: NTSC: 320x200, 384x240, 320x400, 384x480 (Low resolution, interlaced or non-interlaced, with or without overscan) 1-7, 8, 12, 15, 18, 24, 48 bits per pixel. Note that the 48 bpp mode is the mode which uses two overlaid 24 bit screens. This is not a 281 trillion color mode! 640x200, 768x240, 640x400, 768x480 (High resolution, interlaced or non-interlaced, with or without overscan) 1-7, 8, 12, 15, 18, 24 bits per pixel. It really looks like the software (I looked at and analyzed the code quite a bit) makes the decision on the mode. Here are some brief comments on the quality of the provided manual: I don't particularly like the order of all the info (the Installation is on page 11 after all the technical info, copyright, some software excuses and a 24 bit description) But it does have a decent, if brief, description of the software that comes with it including the test programs and then the last 55-60% of the manual is for the paint program. There are a few pictures, but no color ones. About one every fourth page or so. Actually, the pictures are not even full screenshots; they just cover the paint program's control panel overlay which is about 40 lines or so on a non-laced screen. ColorBurst 24-Bit Display Device $699 (list according to August Amiga World) Memory And Storage Technology 1395 Greg Street Suite 106 Sparks NV, 89431 (702)359-0444 Rick Tillery (drtiller@uokmax.ecn.uoknor.edu)