Definitions for "H.261"
Most likely the earliest DCT-based video compression standard. It is an ITU-T standard that assumes CIF or QCIF format and is targeted at ISDN and LAN bandwidths. It has, for the most part, been superceded by the H.263 standard.
ITU-TSS recommendation "Video codec for audiovisual services at p x 64 kbit/s"; Covers the compression and decompression of the video signal in video conference
An early video codec standard which is in heavy use in videoconferencing applications. A precursor to MPEG-1, H.261 is optimized for low data rates and low motion content.