The audio class is part of SEGGER’s emUSB-Device USB stack, a high-performance USB stack for embedded applications. The stack is platform independent and allows the creation of multi-class devices through any combination of USB classes. It has classes for Media Transfer Protocol, Mass Storage Device, CDROM, Audio, Human Interface Device, CDC-ACM, IP-over-USB, and printers. It also has a Bulk communication class feature for high-bandwidth peripherals.
Trial packages for SEGGER's emPower board and other readily available boards are available for download.