libskeleton is a library for reading and writing Ogg Skeleton data.

::: About Skeleton

Ogg Skeleton provides structuring information for multitrack Ogg files. 
It is compatible with Ogg Theora and provides extra clues for 
synchronization and content negotiation such as language selection.
Skeleton bitstream version 3.2 or above specifies an indexing
method for Ogg segments. The index headers of the skeleton bitstream
provide an index of periodic keyframes for every content stream in an Ogg segment.

For detailed information
 . ..about Skeleton check :: http://wiki.xiph.org/Ogg_Skeleton
 . ..about Ogg indexing :: http://wiki.xiph.org/Ogg_Index