|
Amigas have developed a special niche in the market as the best tool to develop desk top videos. The future of the Amiga in the fast growing interactive videodisc market is assured if the virtues of the machine are understood. Currently and surprisingly this market is the territory of IBM and its clones, in spite of the fact it takes a lot of special hardware to make them perform half as well as the Amiga.
My brief from the Western Australian Department of Conservation and Land Management (CALM) was to develop an interactive system for the solar powered Milyering Visitor Centre located in the Cape Range National Park, in the Pilbara region of Western Australia.
I have worked with interactive videodisc systems since 1982 and put together my first Amiga genlock system when someone lent me a Rendale genlock in 1987. At that time there was little software for interactive video, although this has changed recently. It was the arrival of the Ariadne Interactive AAAE Microtext authoring system just at the time the Ningaloo project was taking shape which encouraged me to look again at the Amiga as a viable professional option for a public access videodisc. The Amiga offered better price performance than the "Big Blue" (IBM) options and the graphics packages were easier to use. The new Rendale 8806 genlock, which delivers RGB PAL and PAL composite at the same time, makes it easy to run projection televisions and drone monitors off the system. That is important for this installation.
AAAE Microtext is a special version of the Microtext Authoring language developed by the National Physical Laboratory in England. It is an interpreted language that can be extended to meet new requirements and to my knowledge an Arexx interface, multiple input devices and a Superbase patch are in the works and may well be available as I write. The AAAE version supports many of the Amiga features plus it has a program called AAAE video player device that supports videodisc players and some video recorders with a common interface in a similar way to their own code.
In this application I combined an Amiga 2000 with a 44 Mb hard disk, the Rendale genlock, a Pioneer disc player, a touchscreen and the Amiox multiport serial card to complete the basic system.
The Ningaloo disc is named after the Marine Park that borders the Cape Range National Park where the system is installed. This park has a fabulous coral reef only 100 to 300 metres off shore and is fast becoming a popular tourist destination in the winter months from April to November. The videodisc contains nineteen video segments and about five hundred slides of plants, fish, molluscs and corals. The program has over forty segments as it uses Amiga graphics and sound for some additional segments to deliver volatile information that can easily be changed. On site updates of pages was an important design feature of the system. Currently the system can be used with touchscreen input by the public and a special hidden menu allows staff to transfer control to the theatre in the building, where they can present information from the disc on the projection TV, using a trackball controller.
Major worries for the system were dust, power and heat. Currently the system operates in a sealed kiosk with filtered air and two extractor fans. The solar power is also filtered as the output from the solar system inverters is 240 V 50 Hz square wave. An isolation transformer cleans up the waveform very well and makes a big difference to the stability of the genlocked image. Heat has not so far been a problem as the building is of a passive solar design and stays cool below 40 degreesCelsius even in the height of summer.
Power usage by the system is about 440 watts, including the requirements of a 29 inch drone monitor. This amount was of some concern as the centre is open seven days a week from 10 am to 4 pm. To cut down on power requirements a simple sound activated switch connected to the right hand audio channel of the Amiga was added. It is controlled by the attract loop and activated by the Amiga's say command in the program. A viewer coming near the system is spotted by a security infra red device which in turn emulates a mouse button press and starts the program. The Amiga then says the letter A and closes a solenoid switch, switching on the drone TV monitor with a remote infrared hand control. When the system is no longer surrounded by viewers the program goes to sleep and switches off the big monitor again, thus saving valuable energy.
The videodisc in this system is a PAL disc, cut on the special Optical Disc Corporation's glass disc machine in England. This machine produces a disc that will play on standard players but at reduced cost and acceptable quality.
The Amiga 2000 has performed well during the development of this project. The multitasking features of the machine are an advantage, as in interactive video lots of different things can be going on at once; disc players searching frames, graphics loading, timeout timers timing and disc players status reporting, etc. However, if Amigas are to lead in this field there needs to be some standardisation. Software controls of genlocks need to be standardised. The new genlock features announced for the Advanced chipset and Workbench 2.0 are a golden opportunity for the Amiga interactive video industry to get it right. Genlocks for interactive video need to be software controlled and not hardware controlled.
Multistandard disc players will soon become the norm in the industry as people want to see the best that the USA and Europe can offer in videodiscs. Amiga custom chips will support both PAL and NTSC I am told, but where are the multistandard genlocks that we need to stay competitive as most PC clone interactive video systems already support PAL and NTSC? The future I hope will provide us with these tools but for now the system I am using has served me well and I can recommend it as an ideal tool to develop and deliver PAL interactive videodisc presentations.
From the outset of the Ningaloo project we wanted colour flexibility, plus easy composite genlocked output in PAL and genlocked RGBA going to the 1084S touchscreen system. The Amiga seemed the only choice at a reasonable price, as VGA and EGA based systems require multisync monitors, an added expense. My graphics artist, George Borzyskowski, and I have used Amigas on a day to day basis for over two years and we felt that the machine was right for the task.
Nearly all the videodisc material had been produced, although not assembled when we were brought in on the project. This meant that I had to take responsibility for this disc project and bring it to completion without being able to do any reshooting or significantly changing its video content. Fortunately my video producer, David Moore, was able to maximise the use of the material provided and we ended up with nineteen short segments of about 1.5 min each.
No graphic menus were put on the videodisc and we relied on the Amiga graphics for all the menus. Graphics artist, George, looked for ways of using graphics colours as sign posts to the various parts of the program. We settled on a 16 colour palette in 640x256 resolution to use for menus, graphic information pages and maps. This avoided having a palette library to remember and by choosing the colours carefully, we were able to insure that a digitised 16 colour picture could on occasion be used as a menu if required.
After the Paintbox graphics I was used to on other disc systems, this was somewhat of a compromise, but with "dithering" techniques we found over 195 colours could be produced from our 16 colour palette. AAAE Microtext does support HAM 4096 colour images. We have not used any in the presentation yet although we may do so in the future.
Public access video and computer systems benefit from a consistent interface and we developed a visual and oral syntax for the program. Blue text pages give marine information about the Ningaloo Marine Park and green text pages give land information about the Cape Range National Park that borders the Marine Park. Yellow targets on digitised colour pages lead into video segments with full motion colour videos and sound.
There are three custom feedback sounds when the screen is touched. One indicates a successful choice of a menu, the second indicates that there is a failure to touch a specific target and the third indicates the program is returning to the main menu due to a timeout or as a result of the user touching the logo in the right hand top of the screen. Verbal sound prompts were also added, using digitised voice files. The system made use of sound prompts using the say command when starting up the program, to indicate to staff that all was well. The digitised voice files were sampled at 1200 samples per second and that seems to be about the limit without quantising distortion.
Among the segments using sound was one where the calendar is touched and the system speaks the tide chart for the day from the hard disk. All the files are there to make up tide charts until 1992.
The text pages use digitised backgrounds depicting marine or land scenes which have been reduced to two or three colours. We felt that this was a great improvement over plain colour backgrounds and we further enhanced the pages with drop shadow text to keep the pages legible. We digitised these pages with Digiview, using our standard palette and then reducing the colours with Butcher II software.
The decision to use raised touch buttons rather than hypermedia style touch areas, was made because of the age groups the system has to cater for (10 to 70 or more years). We also made the maps that specified the touch areas oversized to allow for any touchscreen calibration errors, thus reducing the need for recalibration. The system records the time at which each segment is viewed by the public and stamps this time and date on the files. Users will also quickly discover that they can jump to any segment within about four moves from the main menu.
AAAE Microtext, the authoring language that drives the whole system, is an interpreted language, developed by the National Physical Laboratory in the UK some years ago. In its core form it runs on many different computer platforms and the Amiga version has many enhancements. The software is a collection of packages which multitask together to make the system. Ariadne Interactive UK Ltd, who developed this product, have put in a lot of time into making it a truly professional interactive video solutions package. Most PAL and NTSC disc players are supported, and U-matic and VHS decks as well.
Choosing a disc player is made from a menu of preferences, in a similar way to choosing a printer. Touchscreens are handled in the same way and when more genlocks with software control are supported, no doubt a similar interface will be added. The system used the Amiox serial/parallel port board for the touchscreen and the main serial port for the player.
The videodisc or computer based training project is authored in simple ASCII text files. The syntax is very much like English and there are extensive debugging tools, to keep your code on the straight and narrow, with a profusion of help menus at every turn. The script files can be made up on a word processing package which delivers ASCII code or a text editor such as Memacs. The inbuilt editor is more use when tracing faults during the often short debugging process. Macros can be written to control the videodisc if there are a lot of commands to send to a player at one time.
Although the Ningaloo system is a custom program, the disc has been designed to allow it to be reused (repurposed) with different graphics and text information to suit the needs of other parties who might like to purchase it. Much of this is due to the flexibility of the Amiga and the use of computer based text, graphics and sound prompts. As mentioned earlier, serial port adaptors are now available for some U-matic and VHS video tape recorders giving the new user a chance to experiment with interactive video without the cost of disc mastering.
The hard disk on the system is partitioned into three sections with a floppy disk as the start up disk. The first partition (Dh0:) has the operating system on it. The second partition (Dh1:) has the application programs for editing the graphics and sound. The third partition (Dh2:) has the authoring system plus all scripts, graphics and sound necessary for the program. At start up a recoverable RAM disc (rad) is created which holds 1.1 Mb of graphics and sound. Audits of system usages are recorded on Dh1:, so that the startup partition and authoring system are not corrupted if there is a power failure during an audit summary write sequence.
The idea is for the system to be self supporting, because it is located so far from Perth. It can be extended easily to meet new needs in the parks. Future on site enhancements may include a sound digitiser, a Canon Zapshot still video camera with underwater housing, plus a PAL RGB splitter and Digiview. This would allow pictures shot on the reef or in the park in the morning to be presented in the afternoon. Also a window keypad would allow use of the system after hours.
The Amiga is so often underrated even though for interactive communications it is a very cost effective and powerful tool which needs more universal acceptance.
Winfield, Cliff, & Temple, Anthony. (1989). Hooking 'em on the reef. The Australian Ranger Bulletin, 5(3).
| Author: Anthony Temple is currently working on a DEET sponsored Japanese Language disc for WADEC and on the Surrogate Laboratory Project disc also sponsored by DEET (refer Docherty and Edgar in this volume). He is also completing a touchscreen based interactive game on drilling for oil, for Scitech, sponsored by Woodside Petroleum. Anthony may be contacted at Temple Interactive Media, PO Box 762, Perth Western Australia 6005.
Please cite as: Temple, A. (1990). The Ningaloo Videodisc Project. In R. Atkinson and C. McBeath (Eds.), Open Learning and New Technology: Conference proceedings, 299-304. Perth: Australian Society for Educational Technology WA Chapter. http://www.aset.org.au/confs/olnt90/temple.html |