|This is a video codec. The name to use at the command line is h264.|
H.264, or Advanced Video Coding (AVC) is a video codec described by MPEG-4 Part 10. It can be used in a wide spectrum of applications, ranging from file storage to real-time streaming in video conferencing systems.
Similar codecs are H.263 (its predecessor) and H.265 (its very recent successor).
For a technical description read http://www.dspr.com/www/technology/csvt_overview.pdf