Spatial audio — bringing realistic sound to 360 video

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Hans Fugal
14 min readintermediate
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Overview

The article discusses advancements in spatial audio technology that enhance the realism of sound in 360 video experiences. It details the development of a hybrid higher-order ambisonics system and the Spatial Workstation tool, which allows creators to produce high-quality spatial audio for large-scale consumption.

What You'll Learn

1

How to use the Spatial Workstation for designing spatial audio in 360 videos

2

Why hybrid higher-order ambisonics is beneficial for spatial audio quality

3

How to implement real-time spatial audio rendering with low latency

Prerequisites & Requirements

  • Understanding of audio encoding and rendering concepts
  • Familiarity with audio editing software(optional)

Key Questions Answered

What is hybrid higher-order ambisonics and how does it improve audio quality?
Hybrid higher-order ambisonics is an 8-channel audio system that combines the benefits of higher-order ambisonics with fewer channels, optimizing sound quality while saving bandwidth. This technology allows for more accurate spatial audio rendering in 360 video, enhancing the immersive experience for users.
How does the Spatial Workstation enhance the audio production workflow?
The Spatial Workstation provides a suite of tools for sound designers to position audio in 3D space while previewing it in VR. This end-to-end workflow ensures high-quality audio from content creation to publication, allowing creators to effectively manage spatial audio for 360 video.
What are the challenges in encoding spatial audio for Facebook?
Encoding spatial audio for Facebook involves constraints such as the need to use MP4 with H.264 video and AAC audio, which limits channel configurations. The solution includes using a three-track audio format to maintain quality while ensuring compatibility with Facebook's delivery systems.
What is the audio latency of the spatial audio renderer?
The spatial audio renderer achieves less than half a millisecond of latency, which is significantly lower than most renderers. This low latency is crucial for real-time experiences, ensuring that audio reacts instantaneously to head movements in 360 video.

Key Statistics & Figures

Audio latency
less than half a millisecond
This low latency is essential for real-time spatial audio experiences.
Channel configuration
8 channels
The hybrid higher-order ambisonics system uses 8 channels to optimize audio quality.

Technologies & Tools

Software
Spatial Workstation
A tool suite for designing spatial audio for 360 video.
Audio Engine
Audio360
Engine that spatializes hybrid higher-order ambisonic and head-locked audio streams.
Audio Codec
Opus
Used for transcoding spatial audio in WebM format.

Key Actionable Insights

1
Utilize the Spatial Workstation to create immersive audio experiences for your 360 videos.
By leveraging the Spatial Workstation's capabilities, sound designers can enhance the realism of audio in virtual environments, making the experience more engaging for viewers.
2
Implement hybrid higher-order ambisonics to optimize audio quality while reducing bandwidth usage.
This approach allows for high-fidelity sound reproduction without overwhelming network resources, which is essential for large-scale video distribution.
3
Focus on minimizing latency in audio rendering to improve user experience in real-time applications.
Achieving low latency is critical for applications like VR, where audio must align perfectly with visual cues to maintain immersion.

Common Pitfalls

1
Failing to account for the limitations of AAC when encoding spatial audio.
AAC's handling of multiple channels can lead to quality loss, especially when using aggressive low-pass filtering. Understanding these limitations is crucial for maintaining audio fidelity.

Related Concepts

Spatial Audio Rendering Techniques
Ambisonics And Object-based Audio
Real-time Audio Processing In VR