H.264 is a video codec standardized by the ITU that operates over IP networks. H.264 was designed to support real-time transfer of both audio and video data over packet networks like IP. The standard, like most standards, is agreed upon and governed by the International Telecommunication Union (ITU). H.264 is the most widely used video codec today, and it is the video codec of choice for optical discs (Blu-Ray) and streaming video (YouTube, iTunes, Vimeo). H.264 is also the is the most common standard used when estimating how much bandwidth an enterprise will require for video over a given length of time.
As a video codec, H.264 can be incorporated into multiple container formats. Some of the most common formats to see H.264 are MPEG-4 (.MP4), Quicktime (.MOV), and Flash (.F4V). Most, but not all, of the time, h.264 video uses encoded audio in the AAC format, which is the same audio codec favored by iTunes.
H.264 was designed to use half the bitrate of many competing formats, such as the popular H.323, without being overly complex or expensive to implement. The earliest version of H.264 was created in 2003. Over time, more features were added to make it scalable (SVC), then later to make it possible to see multiple angles (MVC) from the same stream. H.264 is so versatile that it can cover low bitrate videos and high definition television. Many high definition still and video cameras use some version of H.264.
H.264 is sometimes called AVC, for “Advanced Video Coding.” It is one of the most advanced video codecs, and makes it possible to have high definition video conferencing at a reasonable cost.