VR系列——Oculus Audio sdk文档：一、虚拟现实音频技术简介（1）——概述

导言： 虚拟现实音频技术在虚拟现实内容起到十分重要的作用，很多恐怖类游戏，都需要通过声音的渲染来体现整个的沉浸感，所以我们翻译了Oculus公司官方的该手册，来给从事虚拟现实应用开发的朋友们一些启发。  

这篇博文主要讲解了为什么虚拟现实需要重点关注音频技术 目前音频技术发展缓慢，已经远远落后于视觉技术，想提升VR真实度，不能只注重视觉效果，音效也是关键，好的音效体验，更能让用户认识到虚拟现实空间存在感，像早期的拳皇街机，技能特效音、击打音、角色的对话音等体验都很出色，印象最深刻的就是结束时喊出的ko结束音，这么多年过去，只要想起拳皇街机，首先想到的就是ko结束音，可想而知，音频技术需要做出更多的改变，要赶上时代的发展，机遇和挑战并存。

本文着重介绍开发过程中应注意的关键因素，并以此来阐述虚拟现实（VR）音频开发的基本概念。

This document introduces fundamental concepts in audio development for virtual reality (VR) with an emphasis on key factors that deserve development
attention.

我们想要确立一个理念：音效对于VR体验的真实度提升是至关重要的。由于音效在我们认知感受空间存在的过程中起到关键作用，因此开发团队为此做出任何努力都是值得的，它将大大提升用户的沉浸感。这对中小型企业，甚至大型企业来说都是真理。

We hope to establish that audio is crucial for creating a persuasive VR experience. Because of the key role that audio cues play in our cognitive
perception of existing in space, any effort that development teams devote to getting it right will pay off in spades, as it will contribute powerfully to the user's sense of immersion. This is as true
for small- or mid-sized teams as it is for design houses — perhaps even more so.

从最早的投币式游戏机出现起就充斥着哔哔声、杂音和爆炸声，可以看出音效在游戏体验中扮演着重要的角色。随着时间流逝，电子音频技术稳定提升，从简单的波形信号发生器（SID，1983）到调频合成（AdLib，1987），演化为8位单声道采样（AmigaOCS, 1985; SoundBlaster, 1989）和16位立体声采样（SoundBlaster Pro），并在当今游戏主机的5.1环绕立体声系统中达到顶点（XBox, 2001）。

Audio has been a crucial part of the computer and video gaming experience since the advent of the first coinop games, which filled arcades with bleeps, bloops, and digital
explosions. Over time, the state of computer audio has steadily improved, from simple wave generators (SID, 1983) to FM synthesis (AdLib, 1987), evolving on to 8-bit mono samples (Amiga OCS, 1985; SoundBlaster,
1989) and 16-bit stereo samples (SoundBlaster Pro), culminating in today's 5.1 surround sound systems on modern gaming consoles (XBox, 2001).

从5.1环绕立体声出现后，音频技术就没新的进展了。波形在扬声器中播放的基本原理都是类似的，玩游戏的场所主要仍是客厅或有大屏幕和音响的小房间。
Since the development of 5.1 surround, little has changed. The fundamental technology of playing waveforms over
speakers is the same, and the game playing environment is still primarily the living room or den with a large television and speakers.

然而虚拟现实改变了这一切。虚拟现实通过头戴式显示器（HMD）和耳机，使玩家更近距离体验到游戏，而不再需要巨大的显示器和音响。其中HMD能够追踪用户的头部方向和位置，这将促进音频技术的发展。

Virtual reality, however, is changing all this. Instead of a large environment with speakers, virtual reality brings the experience in close to
the player via a head-mounted display (HMD) and headphones. The ability to track the user's head orientation and position significantly empowers audio technology.

到目前为止，虚拟现实研究的重点都在于视觉方面（分辨率、延时、追踪等），但现在，音频技术该追上视觉技术的发展，以实现更好的体验感。

Until now, the emphasis has typically been placed on the visual aspects of virtual reality (resolution, latency, tracking), but audio must now
catch up in order to provide the greatest sense of presence possible.

本文介绍了VR音频技术相关的挑战、机遇、解决方案，以及传统游戏技术需要针对VR做哪些改变，不深入研究声学、听觉及人类的听觉认知特性，目标受众是对音频和VR感兴趣的读者，包含音效设计、艺术家和程序员。

This document discusses the challenges, opportunities, and solutions related to audio in VR, and how some of the techniques learned in traditional
game development must be revisited and modified for VR. It is not intended to be a rigorous scientific study of the nature of acoustics, hearing and human auditory perception. Its intended audience
includes anyone with an interest in audio and VR, including sound designers, artists, and programmers.

如果你想进行更深入的了解，推荐搜索以下几个关键字：

If you are interested in learning about these details in greater depth, we recommend searching the Web for the following terms:

• Head-Related Impulse Response（头部相关脉冲响应）

• Head-Related Transfer Function（头部相关传递函数）

• Sound Localization（声源定位）