TS-4900 I2S Audio
The TS-4900 supports an I2S output, but to be usable for most audio applications it must be connected to an audio codec. Our off the shelf baseboards use the Freescale SGTL5000 codec. This provides a standard alsa driver which most Linux applications will support.
For integrating audio into your application, gstreamer is in our default image and provides bindings for most common programming languages.
The Yocto image includes several utilities which can be used to test gstreamer.