If you stop playing a video on a Fifth Generation iPod and then start playing an audiobook, you may hear garbled audio or artifacts from the video over the audiobook's audio. This can happen if you access the audiobook through the Audiobooks menu under Music.
As a workaround, play a music file for a few seconds before you start playing an audiobook or access the audiobook through one of the other menus instead (Playlists, Songs, Artists).
This document will be updated as more information becomes available.