Introduction

Core Audio provides software interfaces for implementing audio features in applications you create for iOS and OS X. Under the hood, it handles all aspects of audio on each of these platforms. In iOS, Core Audio capabilities include recording, playback, sound effects, positioning, format conversion, and file stream parsing, as well as:

• A build-in equalize and mixer that you can use in your applications
• Automatic access to audio input and output hardware
• APIs to let you manage the audio aspects of your application in the context of a device that can take phone calls
• Optimizations to extend battery life without impacting audio quality

核心音频为您在iOS和OS X下创建的应用程序中实现音频功能提供了软件接口，它处理了每个平台上的音频的所有方面。在iOS中，核心音频功能包括录音、回放、音效、定位、格式转换和文件流解析，以及：

• 可以在应用程序中使用的内置均衡器和混频器
• 自动存取音频输入和输出硬件
• api允许您在可以调用电话的设备的上下文中管理应用程序的音频方面。
• 优化延长电池寿命而不影响音频质量

On the Mac, Core Audio encompasses recording, editing, playback, compression and decompression, MIDI, signal processing, file stream parsing, and audio synthesis. You can use it to write standalone applications or modular effects and codec plug-ins that work existing products.

在Mac上，核心音频包括录音、编辑、播放、压缩和解压缩、MIDI、信号处理、文件流解析和音频合成。您可以使用它来编写独立应用程序或模块化的效果和支持现有产品的编解码器插件。

Core Audio combines C and Objective-C programming interfaces with tight system integration, resulting in a flexible programming environment that maintains low latency through the signal chain.

核心音频结合C和Objective-C编程接口紧密的系统集成，从而在一个灵活的编程环境通过信号链保持较低的延迟。

Note:Core Audio does not provide direct support for audio digital rights management (DRM). If you need DRM support for audio files, you must implement it yourself.

注意：核心音频不提供音频数字版权管理（DRM）的直接支持。如果您需要对音频文件的DRM支持，您必须自己实现它。

Core Audio Overview is for all developers interested in creating audio software. Before reading this document you should have basic knowledge of general audio, digital audio, and MIDI terminology. You will also do well to have some familiarity with object-oriented programming concepts and with Apple's development environment, Xcode. If you are developing for iOS-based devices, you should be familiar with Cocoa Touch development as introduced in Start Developing iOS Apps Today.

核心音频概述是为所有有兴趣创建音频软件的开发人员编写的。在阅读本文档之前，您应该具备一般音频、数字音频和MIDI术语的基本知识。你也会做的很好，有一些熟悉面向对象编程概念和苹果的开发环境，Xcode。如果您正在开发基于iOS的设备，您应该熟悉今天开始开发iOS应用程序时引入的“Cocoa Touch”开发。

Organization of This Document

This document is organized into the following chapters:

• What is Core Audio? describes the features of Core Audio and what you can use it for.
• Core Audio Essentials describes the architecture of Core Audio, introduces you to its programming patterns and idioms, and shows you the basic of how to use it in your applications.
• Common Tasks in OS X outlines how you can use Core Audio to accomplish several audio tasks in OS X.

这篇文章的章节：

• 什么是核心音频？描述Core Audio的特性以及可以用来做什么。
• 核心音频要点描述 Core Audio的结构，介绍它的编程模式和风格并且向我们介绍如何在应用中使用它们。
• OS X中常见的任务概述了如何在OS X中使用Core Audio完成多个音频任务。

This document also contains four appendixes:

• Core Audio Frameworks lists the frameworks and headers that define Core Audio.
• Core Audio Services provides an alternate view of Core Audio, listing the services available in iOS, OS X, and on both platforms.
• System-Supplied Audio Units in OS X lists the audio units that ship in OS X v10.5.
• Supported Audio File and Data Formats in OS X lists the audio file and data formats that Core Audio supports in OS X v10.5.

这个文档也包含四个扩展部分：

• Core Audio Frameworks 列出了定义Core Audio的头文件和框架。
• Core Audio Services提供了核心音频的另一种视图，列出了在iOS, OS X以及两个平台上可用的音频服务。
• System-Supplied Audio Units in OS X 列出了OS X v10.5的音频单元。
• Supported Audio File and Data Formats in OS X 列出了在OS X v10.5上Core Audio支持的音频文件和数据格式。

See Also

For more detailed information about audio and Core Audio, see the following resources:

想要了解audio 和 Core Audio, 参阅一下资源：

• AVAudioPlayer Class Reference, which describes a simple Objective-C interface for audio playback in iOS applications.
• Audio Session Programming Guide, which explains how to specify important aspects of audio behavior for iOS applications.
• Audio Queue Services Programming Guide, which explains how to implement recording and playback in your application.
• Core Audio Data Types Reference, which describes the data types used throughout Core Audio.
• Audio File Stream Services Reference, which describes the interfaces you use for working with streamed audio.
• Audio Unit Programming Guide, which contains detailed information about creating audio units for OS X.
• Core Audio Glossary, which defines terms used throughout the Core Audio documentation suite.
• Apple Core Audio Format Specification 1.0, which describes Apple's universal audio container format, the Core Audio File (CAF) format.
• The Core Audio mailing list: http://lists.apple.com/mailman/listinfo/coreaudio-api
• The OS X audio developer sit: http://developer.apple.com/audio/
• The Core Audio SDK (software development kit), available at http://developer.apple.com/sdk/