We've just released Steam Audio 4.1.0[valvesoftware.github.io]. This release includes a major update to the Steam Audio Unreal Engine plugin, bringing it up to date with the latest features of the Steam Audio SDK. This is also the first release in which the Unreal Engine plugin is released alongside the other plugins and the core SDK.

The major new features of the Unreal Engine plugin in this release include:

If you are using FMOD Studio as your audio middleware in your Unreal Engine project, the Steam Audio Unreal Engine plugin now works with the Steam Audio FMOD Studio plugin. Events authored in FMOD Studio can use occlusions, reverb, etc. simulated by Steam Audio in Unreal Engine levels.

The Unreal Engine plugin now supports Windows (64-bit Intel), macOS (64-bit Intel), Linux (64-bit Intel), and Android (32-bit ARM, 64-bit ARM, and 32-bit Intel). Note that precompiled macOS binaries are not provided out of the box, but Unreal Engine will automatically compile the plugin for macOS when you open a project that uses the plugin. Precompiled binaries for macOS will be provided in a subsequent patch release.

Geometry can be tagged in any sublevel referenced by a level. Whether the sublevels are loaded automatically along with the main level, or streamed in based on a level streaming volume or any custom logic, Steam Audio will update occlusion, reflections, and reverb automatically.

Any Blueprint class can now be configured to be a Steam Audio dynamic object, and Steam Audio will automatically update occlusion, reflections, and reverb as instances of the Blueprint class move through your levels.

Level geometry (both static and dynamic) as well as baked sound propagation data is now stored in .uasset files that are referenced by Steam Audio components. This simplifies the packaging workflow for your projects.

In addition to the above, this release of the Steam Audio Unreal Engine plugin includes all the latest features of the core Steam Audio SDK, such as pathing, hybrid reverb, and more.

Going forward, updates to the Unreal Engine plugin will continue to be available on GitHub, including source code and pre-built binaries. The version of Steam Audio built into Unreal Engine will be periodically updated, but the latest versions will always be available on GitHub.

For the full release notes for this release, click here[github.com].

We've just released Steam Audio 4.0.0[github.com], which is a major update to Steam Audio. This release includes new features and an updated API that is more flexible than previous releases. Because this is a major update, the version numbering we used so far was no longer sufficient: we have updated from 2.0-beta.20 (the previous release) to 4.0.0 (the next available integer).

This release includes features that were developed or significantly enhanced during the development of Half-Life: Alyx.

The major new features in this release include:

Pathing is a new way of baking sound propagation from a moving source to a moving listener. This involves placing probes in the scene, and calculating shortest paths between each pair of probes. At run-time, this baked data is used to calculate how sound propagates from the moving source to the moving listener, and spatialize the sound accordingly. If a baked shortest path is occluded by dynamic geometry (like a door), Steam Audio can recalculate alternate shortest paths on the fly. Steam Audio also applies a diffraction model to paths that bend around corners or through doorways, etc. This feature is useful for modeling how sound emitted by an occluded source reaches the player through doors or windows instead of directly through walls.

When rendering reflections or reverb, Steam Audio can use convolution reverb (which is defined in terms of an impulse response) or parametric reverb (which is defined in terms of a small set of parameters, like decay time). Convolution reverb results in more accurate reproduction of early reflections and directionality, but requires more CPU. Parametric reverb requires less CPU, but cannot reproduce early reflections as accurately, especially in outdoor spaces. Hybrid reverb is a hybrid of the two: the early reflections are rendered using an impulse response, and the later reverb tail is rendered using parametric reverb. The transition between the two types of reverb is smooth and controllable, as is the length of the reverb tail. This feature is useful for trading off reverb quality and performance.

The Unity plugin now has full support for additive scenes. Multiple scenes can be opened additively in the editor, and exported separately. Scenes can be additively loaded and unloaded freely at run-time, and Steam Audio will automatically update occlusion, reflections, and pathing simulation to account for the changes.

The Steam Audio C API has been significantly redesigned, with the goal of increasing the flexibility available to developers and sound designers. Developers can control when and how often simulations are run, and can perform arbitrary post-processing before using the simulation results for rendering. For example, after simulating reverb, the length of the reverb tail can be increased or decreased based on the game state. Simulation results can also be used outside of spatial audio rendering: for example, the results of pathing simulation can be used to drive enemy AI.

Due to the major changes in the API and plugin design, this release is not backwards-compatible with previous releases. In-place upgrades are not recommended for existing projects, except those in the earliest stages of development.

This release includes updates to the Unity plugin, FMOD Studio plugin, and C API. An update to the Unreal plugin will be released separately.

For the full release notes for this release, click here[github.com].