These systems make use of several video resolutions to get the best quality for the user's camera and bandwidth.
Users with PAL camera:
Since the PAL resolution is 704x576, the height of all the resolutions should be an integer fraction of 576 (288 or 144)
QCIF: 176x144
CIF: 352x288
ICIF: 352x288 but encoding both even and odd fields of the video which effectivly get a frame rate of 50fps. The "I" prefix stands for "Interlaced"
4CIF: 704x576 (used only for Data presentations)
Users with NTSC camera:
Since the NTSC resolution is 704x480, the height of all the resolutions should be an integer fraction of 480 (240 or 120)
QCIF: 176x144 (there is no QSIF resolution in use)
SIF: 352x240
ISIF: 352x240 but encoding both even and odd fields of the video which effectivly get a frame rate of 60fps. The "I" prefix stands for "Interlaced"
4CIF: 704x576 (used only for Data presentations using the data utility, so it's not a native NTSC format).
