About This Guide

The Audio Drivers guide tells you how to use the Audio Driver Development Kit (DDK) to write your own audio driver that's compatible with the QNX Audio Architecture.

In this preface, you'll find:

Supported features
Assumptions

If you want to:	Go to:
Estimate how much time it will take to develop an audio driver for your card	Evaluating Your Card
Understand how the audio driver fits into the QNX architecture	Organization of a driver
Write an analog mixer	Handling Analog Audio Data
Use a standard mixer DLL	Handling Analog Audio Data
Code a Pulse Code Modulation (PCM) device	Handling PCM Audio Data
Get details about the API functions	API Reference
Read about the codecs supported by QNX	Supported Codecs
Explore the code of a sample mixer	Sample Mixer Source
Understand the terms used in this guide	Glossary

For general information about working with the DDK source code, see About Driver Development Kits.

For information about other audio drivers, see "Audio drivers (deva-*)" in the summary chapter of the QNX Utilities Reference.

Supported features

Currently supported features include:

digital audio (PCM) playback and capture
analog mixing controls
routing of Digital Audio Data (AC3) through S/PDIF.

This DDK doesn't support:

MIDI
3D audio
game ports

Assumptions

To use this guide, you need to have:

a basic familiarity with audio cards, terminology (e.g. DMA transfer, codec, analog signal, and interrupts), and basic audio operations
sufficient hardware documentation for your audio chip in order to be able to program all the registers
a working knowledge of the C programming language.

You might also need to refer to the QNX Audio Developer's Guide.