The Video Standards
H.261:Supports 352x288 (CIF or FCIF) and 176x144 (QCIF). DCT based algorithm tuned for 2B to 6B ISDN communications
H.263: Much improved derivative of H.261, tuned for POTS data rates. Mostly aimed at QCIF and Sub QCIF (128x96 – SQCIF), while providing better video than H.261 on QCIF and CIF.
H.264: Joint collaboration between ITU and ISO. Improved video over H.263 providing similar quality at half the bandwidth