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Revolution Audio Library

Version 1.01

The contents in this document are highly

confidential and should be handled accordingly.

CONFIDENTIAL

RVL-06-0031-001-C

Released: October 22, 2007

Revolution Audio Library

Revolution SDK

Confidential

These coded instructions, statements, and computer programs contain proprietary information of Nintendo

of America Inc. and/or Nintendo Company Ltd. and are protected by Federal copyright law. They may not be

disclosed to third parties or copied or duplicated in any form, in whole or in part, without the prior written

consent of Nintendo.

RVL-06-0031-001-C

Released: October 22, 2007

CONFIDENTIAL

Revolution SDK

Revolution Audio Library

Contents

Revision History .................................................................................................................................. 4

1 Introduction................................................................................................................................... 5

1.1 Terms.................................................................................................................................. 5

2 AX Processing Model ................................................................................................................... 6

2.1 System Components .......................................................................................................... 6

2.1.1 AI............................................................................................................................... 6

2.1.2 DSP........................................................................................................................... 6

2.2 Processing Flow ................................................................................................................. 6

2.3 Voice Processing Pipeline .................................................................................................. 8

2.3.1 Streaming Cache ...................................................................................................... 8

2.3.2 ADPCM Decoder ...................................................................................................... 9

2.3.3 Sample Rate Converter (SRC).................................................................................. 9

2.3.4 Volume Envelope ...................................................................................................... 9

2.3.5 IIR Filter .................................................................................................................... 9

2.3.6 Initial Time Delay (ITD) ............................................................................................. 9

2.3.7 Mixing...................................................................................................................... 10

2.3.8 Controller Speaker Processing ............................................................................... 12

3 Application Notes........................................................................................................................ 13

3.1 Voice Acquisition .............................................................................................................. 13

3.2 Buffer-Addressing ............................................................................................................. 14

3.3 Optimization...................................................................................................................... 14

3.4 Voice Indexing .................................................................................................................. 14

Figures

Figure 2–1 AX Logical Flow ................................................................................................................ 7

Figure 2–2 Voice Processing Flow ..................................................................................................... 8

Figure 2–3 Stereo Mixing.................................................................................................................. 10

Figure 2–4 Surround Mixing.............................................................................................................. 11

Figure 2–5 Dolby Pro Logic 2 Mixing ................................................................................................ 11

Figure 2–6 Controller Speaker Processing ....................................................................................... 12

Tables

Table 1–1 AX Library Terms ............................................................................................................... 5

Table 3–1 Voice Acquisition Priority ................................................................................................. 13

CONFIDENTIAL

RVL-06-0031-001-C

Released: October 22, 2007

Revolution Audio Library

Revolution SDK

Revision History

Version

Version 1.01

Date

Revised

2006/11/24

Item

2.1.2

2.3

2.3.5

2.3.8

3.1

3.5

Version 1.00

2006/03/01

Description

Added controller speaker processing.

Updated Figure 2.

Added a description of the IIR filter.

Added a description of controller speaker processing.

Revised the description of AX_PRIORITY_NDROP.

Deleted the zero buffer.

First release by Nintendo of America Inc.

RVL-06-0031-001-C

Released: October 22, 2007

CONFIDENTIAL

Revolution SDK

Revolution Audio Library

Introduction

The AX library is a thin, low-level interface to the Revolution audio subsystem. The AX library abstracts the

details of managing the audio DSP and associated audio hardware into a convenient library. The AX library

has the following features.

•

Allows user applications to allocate audio voices and provides access to the parameters that describe

each voice.

Automatically generates DSP commands for creating audio as dictated by changes to these voice

parameters.

Manages voice contention and audio system resources.

Provides efficient, low-level control of the audio subsystem so that you can create your own audio

applications without worrying about hardware interfaces.

1.1

Terms

The terms in Table 1–1 are used throughout this document.

Table 1–1 AX Library Terms

Term

Description

Audio Interface. Provides the data path between the major components of the

audio subsystem hardware. Specifically, the AI routes data between the DSP

and the external DAC.

Sample Rate Converter. Interpolates audio data samples to change the sample

rate of specified data.

In this context, a multiplier applied to the samples of an audio signal to modu-

late the signal amplitude.

A fixed change to volume over time.

SRC

volume

volume envelope

CONFIDENTIAL

RVL-06-0031-001-C

Released: October 22, 2007

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