For specs see at: -http://www.itscj.ipsj.or.jp/sc29/ -http://www.chiariglione.org/mpeg/ -ftp://standards.polycom.com/ -http://ftp3.itu.ch/av-arch/ -http://www.neuron2.org/library/library.html an other ISO Base File Format based Standards with heavy MPEG4 relationship is the .3gp from 3GPP http://www.3gpp.org/specs/specs.htm Robert Vincenz