CompuServe Messages

There are two good examples of DOS multimedia products which illustrate the combination of text, graphics, animation, and sound- National Geographics "Mammals: A Multimedia Encyclopedia" and "The Presidents: It All Started With George." Both of these were developed using IBM LinkWay 2.01, using IBM Photomotion for the movies. Mammals uses "Red-book" audio. played directly from the CD through the CD-ROM drive's sound outputs, Presidents uses digitized sound played through a sound card. Both techniques are used on various products. The digitized form has some advantages – for example, digital audio files can be transmitted over a network. Redbook audio requires no sound card, however. The Photomotion movie format requires the transfer of between 80K-120K of data per second typically. Some movies are more compressed than others, but this is typical. Mammals has been on the market for over two years, using an early version of Photomotion which did not allow synchronized sound. Presidents uses sound with the movies. TIME Almanac, and the Groliers MM Encyclopedia and several other products also use IBM PhotoMotion for their movies. I recently did a Photomotion movie of an airplane landing which lasted about 12 seconds – the file size was 89K. This compression is achieved because the frame contents did not change significantly over the 12 seconds time. This would require a CD-ROM drive capable of about 8K/second. I also recently did another movie of about 12 seconds of elk grazing near a running river – taking about 940K to store the movie. With more action and changes in the frame the storage goes up and the data transfer rate required for the playback also goes up. Animations with drawn graphics rather than captured video are typically nuch smaller in file size and data transfer required, so animations such as those done from drawn graphics using Autodesk Animator or other animations are typically smaller in file size and work well of CD. Larry