Libavcodec contains more than 100 codecs, most of which do not just store uncompressed data. Most codecs that compress information could be claimed by patent holders. Such claims may be enforceable in countries like the United States which have implemented
software patents, but are considered unenforceable or void in countries that have not implemented software patents. Furthermore, many of these codecs are only released under terms that forbid reverse engineering, even for purposes of interoperability. These terms of use are forbidden in certain countries. For example, some
European Union nations have not implemented software patents and have laws expressly allowing
reverse engineering for purposes of interoperability. ==Libraries that depend on libavcodec==