Setup in Wwise

In the Wwise project settings, navigate to the External Sources tab. The Output Path needs to point to the Unreal project Sound Data Path, in a sub-folder named ExternalSources. Using the default integration settings, the path should be ../Content/WwiseAudio/ExternalSources. Each platform must be placed in an individual sub-folder.

If external source conversion is invoked manually, care must be taken to ensure that the files are output to the appropriate location. This allows the External Source Importer in Unreal to catch the converted WEM files and package them into Unreal Assets.

Here is an example of settings

How to use External Sources in Blueprint

To use external sources in Blueprint, use the Post Event node and expand it to reveal the External Sources input pin:

Use the External Sources input pin to make an array.

Use input pin 0 to make an AkExternalSourceInfo instance. Make sure to expand to get all available parameters.

The available parameters are:

• External Src Name: The name of the external source in the Wwise project, also known as the cookie, it is used to identify the media internally.
• Codec ID: The audio codec used to decode this external source.
• File Name: The file name of the external source without the file extension. This file is loaded by the I/O Hook. When referring to an external source by file name, the file is always streamed, regardless of the Is Streamed value.
• External Source Asset: Instead of specifying the file name by hand, you can refer to the External Source asset directly.
• Is Streamed: Only works when using the external source asset input pin. When set to false, the external source is loaded in memory and doesn't use the I/O hook and streaming.

How External Sources are imported and played

External sources need to be converted in a specific folder (<soundbank path>/ExternalSources), so an Unreal Factory can find them. You should use the Unreal Platform Name as the folder name for each platform. When new WEM files are found by the Content Browser in the ExternalSources folder, the Unreal Editor prompts you to import new assets. It is mandatory to accept the import. A factory then converts the WEM data from all platforms to a UAkExternalSourceMediaAsset.

You can reference the asset directly in blueprint when creating an AkExternalSourceInfo instance, instead of typing the file name. The external source can be either loaded to memory or streamed from disk. The Is Streamed parameter only works when referencing the asset (it is ignored when specifying the name). When using the file name parameter, the external source is always streamed from disk.