These tools allow information about (ogminfo) or extraction
from (ogmdemux) or creation of (ogmmerge) OGG media streams.
Note that I'll use OGM for "OGG media streams".
These tools replace 'oggmerge' and 'ogmdemux' that could be found here.
MKVToolNix: Matroska is aiming to become the new standard media container format. These tools can work with Matroska files: mkvmerge creates Matroska files and mkvinfo lists information about them. They are for Matroska what the ogmtools are for OGM files.
librmff: A RealMedia file format access library.
AVIextract, a small utility to extract the raw video and audio streams from an AVI. Can be used to easily extract the MP3 audio track.