What is H.263?

H.263 is a successor of H.26x video codec standards. H.263 is a hybrid of interframe compression and intraframe transform coding. In comparison with previous codecs H.263 allows high compression ratio.

What is H.263 designed for?

It was initially made to serve H.324 based low-bitrate internet communication systems (videoconferencing and telephony), but as new extensions were added to the further versions, H.263 found use in other applications.

What are H.263 special features?

• supports five resolutions(CIF (Common Interchange Format), QCIF (Quarter Common Interchange Format), SQCIF, 4CIF and 16CIF)
• has motion compensation capability, allowing optional incorporation of this technique in the coder
• uses spatial redundancy as a compression advantage
• enhanced robustness against data loss in the transmission channel

What are H.263 advantages?

• may be used for bidirectional or unidirectional visual communication
• supports flexible customized picture formats and custom picture clock frequencies
• uses variable length coding to be transmit symbols
• supports international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits
• can be encoded and decoded freely with programs of the ffmpeg project

Where it can be applied?

Despite the fact that now H.264 is more extended, H.263 is still widely employed by internet applications such as Flash Video content (as used on sites such as YouTube, Google Video, MySpace, etc.), desktop video conferencing, video telephony, surveillance and monitoring, 3GPP files for playback on mobile phones. It is also required for IP Multimedia Subsystem (IMS) and Multimedia Messaging Service (MMS).