The Free On-line Dictionary of Computing (30 December 2018):

H.264
Advanced Video Coding
AVC

    (Or Advanced Video Coding, AVC) A low bit
   rate visual communication standard used in video
   conferencing.  H.264 was developed by MPEG and ITU-T
   VCEG to replace H.263.

   Video and image compression resources and research
   (http://www.vcodex.fsnet.co.uk/h264.html).

   (2007-03-16)