In this autumn's major upgrade of Windows 11 (24H2), one of the less pleasant updates is the removal of built-in support for Dolby Digital audio. If you have files utilizing the AC-3 codec, such as those in question, they will no longer be playable in Windows Media Player or other associated apps.
Microsoft clarifies in a support document that this change solely affects new installations. Current system updates will not eliminate Dolby Digital support.
However, this change isn't a deal-breaker. Users can still utilize third-party applications like the versatile VLC to play Dolby Digital files if desired. Unfortunately, this contrasts with the fate of some other disappearing features in Windows 11.