This article relates to the Cisco TelePresence MCU 4203, Cisco TelePresence MCU MSE 8420, Cisco TelePresence IP VCR 2210, Cisco TelePresence VCR MSE 8220, Cisco TelePresence ISDN GW 3241, Cisco TelePresence ISDN GW MSE 8321, Cisco TelePresence IP GW 3510, Cisco TelePresence MCU 4505, Cisco TelePresence MCU MSE 8510 and Cisco TelePresence Advanced Media Gateway 3610 products.
Q. What's the difference between SIF and CIF?
A. CIF and SIF are acronyms that describe video resolutions and have come to video conferencing the from broadcast industry.
CIF stands for Common Interchange Format and represents a resolution of 288 x 352. This is the resolution used by PAL (European) television systems. Related resolutions are QCIF (Quarter CIF) and 4CIF which are 144 x 176 and 576 x 704 respectively.
SIF stands for Standard Interchange Format and represents a resolution of 240 x 352. This is the resolution used by NTSC (North American) television systems. Related resolutions are QSIF (Quarter SIF) and 4SIF which are 120 x 176 and 480 x 704 respectively.
Both CIF and SIF are fullscreen (4:3) resolutions; the resolution 288 x 512 is sometimes referred to as WCIF (Wide CIF) but is more commonly known as w288p.
Some endpoints are available with a choice of PAL or NTSC cameras: a PAL camera operates at 25fps and an NTSC camera at 30fps. Due to the larger frame size of PAL (CIF) over NTSC (SIF), they both generate the same amount of information.
If H.264 level 2.1 is used unmodified, 4SIF will be possible at 15fps and 4CIF at 12.5fps.