What is H.264?

H.264 is an industry standard for video compression, the process of converting digital video into a format that takes up less capacity when it is stored or transmitted. Video compression (or video coding) is an essential technology for applications such as digital television, DVD-Video, mobile TV, videoconferencing and internet video streaming. Standardising video compression makes it possible for products from different manufacturers (e.g. encoders, decoders and storage media) to inter-operate. An encoder converts video into a compressed format and a decoder converts compressed video back into an uncompressed format.

Recommendation H.264: Advanced Video Coding is a document published by the international standards bodies ITU-T (International Telecommunication Union) and ISO/IEC (International Organisation for Standardisation / International Electrotechnical Commission). It defines a format or syntax for compressed video and a method for decoding this syntax to produce a displayable video sequence. The standard document does not actually specify how to encode (compress) digital video – this is left to the manufacturer of a video encoder – but in practice the encoder is likely to mirror the steps of the decoding process.  

H.264 tutorials and resources

An Overview of H.264 Advanced Video Coding.

H.264/AVC Inter Prediction - Methods of predicting inter-coded macroblocks in P-slices in an H.264 video compression codec.

H.264/AVC Intra Prediction - Methods of predicting intra-coded macroblocks in an H.264 video compression codec.

H.264/AVC Context Adaptive Binary Arithmetic Coding (CABAC) - Short introduction to CABAC. Familiarity with the concept of Arithmetic Coding is assumed.

H.264/AVC Context Adaptive Variable Length Coding - The Variable-Length Coding scheme is described in this document.

H.264/AVC Loop Filter - Methods of filtering reconstructed blocks in an H.264 video compression codec.

H.264 Picture Management - Introduction to the parameters and processes involved in managing coded frames within the H.264/AVC standard.

H.264 Transform and Quantization - A derivation of the forward and inverse transform and quantization processes applied to 4x4 blocks of luma and chroma samples in an H.264 codec.


Visit our resources page to find out more about H.264, HEVC and other video compression topics.