H.264 also known as MPEG-4 Part 10 or AVC (Advanced Video Coding) – is a video encoding standard designed for high efficient video streams compression. The first version of the standard was published in May 2003. H.264 was developed by ITU-T Video Coding Experts Group (VCEG) and ISO / IEC Moving Picture Experts Group (MPEG). Some video encoding programs also identify this standard as “AVC1”
H.264 standard contains several video encoding tools for more efficient compression against previous standards:
- Motion compensation for dynamic block sizes from 16×16 to 4×4.
- Out of picture motion vectors
- Qpel interpolation
- Intra prediction modes for intra frames (before only DC coefficient was allowed)
- PAFF and MBAFF modes for combining interlace and progressive encoding
- Discrete Cosine Transform (DCT) algorithms for blocks 4×4 and 8×8
- Deblocking algorithm, sometimes also called “loop filter”
- New entropy coding algorithms
CABAC – Context-adaptive binary arithmetic coding
CAVLC – Context-adaptive variable-length coding - Network Abstraction Level (NAL units)
- Multiframe inter prediction
- Weighted prediction including bidirectional
and many others…
H.264 standard consumed more than a hundred patents held by organizations such as MPEG LA, Microsoft, Fujitsu, Philips, Apple, Samsung, Cisco, Toshiba, Panasonic.
