CIF vs SIF

In this article I will explain the differences between CIF & SIF. In keeping with our sanity & to continuing with the theme of keeping it simple I will try to make use of as few techno jargons as feasible. CIF & SIF are most notably used to document video resolution & are used heavily to specify CCTV camera equipment resolution.

So you say, what is the difference? & why the double spellings like double spelled words? Which is better? I will answer these questions but first small history of the word. CIF & SIF are surprisingly not double spelled word like "aeroplane & airplane" a British or American spelling difference. CIF & SIF actually are letter acronyms that do the same thing. Depending on the spelling you may be purchasing inferior product or a highly adaptable robust product.

OK, speaking in codes. Let's first take the word CIF & break this down to a much simpler term. C.I.F is not a letter acronym meaning "California Interscholastic Federation", CIF is a resolution format meaning Common Intermediate Format. Keep in mind they are speaking about resolution format. In case you are using hardware that specifies the resolution as CIF & spelled with a "C" you are using know-how that has a resolution of 352x288 pixels. In case you require knowing the H-dot number CIF is often associated with is H.261/H.263.

So what is SIF, you ask. SIF is a letter acronym meaning Source Input Format. SIF is most often associated with MPEG video format & to confuse you more I have seen it spelled as CIF. Depending what side of the world you are on you are either using PAL for the European standard or NTSC the North & South American standard. PAL SIF resolution is 352x288. NTSC SIF resolution is 352x240. Doesn't appear like much of an advantage over elderly regular CIF resolution.

Here is what I haven't told you. If your hardware says it makes use of CIF resolution (spelled with a C or 2CIF or 4CIF) you are using an elderly H.261/263 codec. If your Hardware specifies it is using SIF resolution (spelled with an S) then it can take advantage of MPEG-4 & H.264 compression format. I will have another "Keep It Simple" article to speak about MPEG & H.264 compression standards.

So which one's right? They are both right. CIF is still being used for video conferencing solutions or applications. SIF on other hand has evolved & is predominantly being used as the codec of choice for IP cameras & encoders. What you require to know is how to speak the lingo & that what to write on your RFP is the correct resolution you are looking for.

 One last thing, SIF & CIF are used interchangeably which is where most of the confusion is. To write this article I read several resource materials. Each used both SIF & CIF to document 325x240 which is SIF. So how did I pick which SIF/CIF they were referring to? Here is small tip. If the CIF is followed by 352x240 (NTSC) then they are referring to SIF. In case you see CIF followed by 352x288 then they mean CIF. Another tell, tell sign is if the encoder, transmitter, coded is H.264 compatible or MPEG-4 compatible then there is a lovely chance they are speaking about SIF.