Type of format	Lossless video format
First published	August 17 2004
Developer	ITU-T Study Group 16, VCEG, MPEG
Filename extension	.264
Open Format?	Yes
Free Format?	Depends of implementation
Magic Number	00 00 00 01 09 10 00 00 00 01 67 64 00 29 AC

 Advanced Video Coding ( AVC) (also called H.264 or MPEG-4 Part 10 Main Profile@4.1/High Profile@4.1), jointly created in 2004 by Video Coding Experts Group (VCEG) and Moving Picture Experts Group (MPEG), is the most widely used video codec for BD movies. It is considered the best for its better compression without losing picture quality. It can hold 5-6 hours of video in a single 50GB disc in high quality^[1]. The codec features Interlaced coding (PicAFF, MBAFF), multiple reference frames, in-loop deblocking filter, 4:0:0 (Monochrome), 8×8 vs. 4×4 transform adaptivity, Quantization scaling matrices, and Separate CB and CR QP control.

Two forms of entropy encoding are used for lossless compression, CAVLC and CABAC. However, most studios use CABAC because it provides much better compression than competing video codecs.

AVC includes three basic types of coded splices: intra-coded splices (I-splice), predictive-coded splices (P-splice), and bidirectionally-predictive-coded splices (B-splice). A slice is a spatially distinct region of a frame that is encoded separately from any other region in the same frame.

Due to the expiration of some of its older patents, the codec is now more accessible to the public without payment of royalties. One famous open implementation of the AVC codec is x264.

It is under the  .264 extension name in the M2TS container. 

Footnotes

• [1]  Fanny and Alexander - 2011, The Stand - 2019.

Specs

• H.264 official specification page

Open Software

• x264
• OpenH264

References

• H.264-MPEG-4 Wikipedia entry
• Cisco open-sources H-264 codec
• Mozilla to use H.264 codec from Cisco
• MultimediaWiki: H.264

Links

• Wikipedia page
  
• Archive Team's Page

Author(s) : Æ Firestone