IRIS Indigo Audio and Graphics Programming Environment A Case Study using Csouncl and Scrub

Multimedia is coming of age, and 16 bit, 44.1kHz audio will soon be as common as the mouse. The IRIS Indigo represents the first Advanced Computing Environment (ACE) compatible workstation (ACE consortium members at last count was greater than forty). There are still many issues to be resolved, like standard file format:;, libraries, and synchronization, etc.. However the tools exist, and the open systems environment permits the industry to leverage technology through combined efforts. This paper presents one such environment. Outline IRIS Indigo architecture, followed by brief descriptions of the Audio and Graphics libraries, concluding with two audio applications presented as a case study in software development Csoundm and Scrub. Hardware The IRIS Indigo is a MIPS R3000/R3010 based, 56001 coprocessor, graphics/audio workstation (biendiari). The audio subsystem consists of a 56001, 32K x 24 bits SRAM, 16-bit stereo 64x oversampling delta-sigma ADC, ‘18-bit stereo 8x oversampled DAC, third-order filtering, MDAC attenuator software controlled, and IEC958/AES3 digital I/O. Supported sampling rates are 29.4, 32, 44.1, 48kHz, and any of these divided by integers 2 through 8. Audio Library 1.0 The basic construct implemented in release 1.0 of the Audio Library are audio ports. Programmers open ports to listen or generate sounds. These ports have intermediate buffers to relax real-time O/S and program requirements. Audio ports may be configured to different buffer sizes, sample widths, number of channels (1,2) and two configuration management calls. Hardware state parameters control the ports sampling rate, gain and input source. The audio library is currently designed around goals similar to our early implementations of the Graphics Library. Simplicity So the programmer can quickly learn how to use it. Completeness If the hardware can do it,. the library should let you. Efficiency Close enough to the metal to be optimum, yet not stifle hardware evolution. Graphics Library 4.0 The Graphics Library has evolved over the past ten years, at least eight graphics architectures (known to the author), and a CISC to RISC migration, with major efforts placed on minimizing obsolete Csound is a trademark of MIT functions. There are currently over 300 functions ranging from drawing primitives, text, modeling transformations, and performing raster operations, to the more esoteric functions like alpha-blending, fog and haze, lighting, NURBS, stencil planes, overlays, underlays, accumulation buffer, and zbuffer support.