Downloadable content, or DLC, is typically a package of audio content added to the game after the main build (the initial game release without any downloadable content).
During the production phase of the game, Wwise produces SoundBanks and streamed files. The File Packager is used with the Default file assignment to have all SoundBanks and streamed files packaged into a single package, although they can be split by language or in streamed files, loose media, and SoundBanks.
When the game is released, however, the content used in the main release stops being packaged using the Default file assignment. All content is manually inserted into the packages:
Main packages are created manually
All content is dragged to the main packages
Those packages, created manually, basically contain all SoundBanks and streamed files that were shipped in the main release. This is the point of reference for identifying newly created content. The File Packager project file is then saved.
All DLC content must be created using the same Wwise Project that was used for the main release. Additionally, the same Wwise version must be used for both releases to ensure compatibility of the SoundBank and package formats.
In the File Packager
For each DLC, a File Packager package is manually created.
The user identifies new content in the File Packager.
The user drags the new content into the manually created package (for DLC):
Then, the content present in the main release can be modified. When an existing SoundBank or streamed file is modified, it must be repackaged into a new package. The game will then load both the main release package(s) and the new (DLC) package(s) by making sure they are loaded in chronological order. In loading different versions of the same object, Wwise gives priority to the most recent one.
SoundBankA was included in the main release and packaged into Package #1.
The content of SoundBankA is modified after the main release. It is repackaged into Package #2, which is new, and becomes part of the DLC.
The game, which has the DLC, loads Package #1 and then loads Package #2.
When the game wants to load SoundBankA, Wwise will load the one found in Package #2 (it has priority over the one found in Package #1).