SFV Files Explained in Plain English

SFV files contain CRC32 checksums which can be used to determine whether or not the files listed were downloaded correctly. So, after downloading a set of files, you can use a program like SuperNZB to calculate the CRC32 checksums and then compare them to the checksums in the SFV file. If they match, then everything was downloaded perfectly.

If you open an SFV file with Microsoft Word, or any other word processor that can run scripts, it is possible that a virus in the SFV could get you. When downloading text files, it’s always a good idea to open them with a bare-bones text editor like NotePad on Windows and TextEdit on the Mac, both of which come free with your computer.

Here is a sample SFV file:

------------ Begin Sample SFV File Listing ------------
;15000000  08:52.45 2005-07-28 Some.File.avi.part01.rar
;15000000  08:53.06 2005-07-28 Some.File.avi.part02.rar
;15000000  08:53.28 2005-07-28 Some.File.avi.part03.rar
;15000000  08:53.49 2005-07-28 Some.File.avi.part04.rar
;15000000  08:54.12 2005-07-28 Some.File.avi.part05.rar
;15000000  08:54.35 2005-07-28 Some.File.avi.part06.rar
;15000000  08:54.57 2005-07-28 Some.File.avi.part07.rar
;15000000  08:55.19 2005-07-28 Some.File.avi.part08.rar
;15000000  08:55.40 2005-07-28 Some.File.avi.part09.rar
;15000000  08:56.01 2005-07-28 Some.File.avi.part10.rar
;15000000  08:56.23 2005-07-28 Some.File.avi.part11.rar
;15000000  08:56.44 2005-07-28 Some.File.avi.part12.rar
; 2432113  08:56.48 2005-07-28 Some.File.avi.part13.rar
;   13376  08:59.32 2005-07-28 Some.File.avi.par2
;  397444  08:59.32 2005-07-28 Some.File.avi.vol00+01.PAR2
;  794812  08:59.32 2005-07-28 Some.File.avi.vol01+02.PAR2
; 1576248  08:59.32 2005-07-28 Some.File.avi.vol03+04.PAR2
; 3125820  08:59.32 2005-07-28 Some.File.avi.vol07+08.PAR2
; 6211664  08:59.32 2005-07-28 Some.File.avi.vol15+16.PAR2
;11204548  08:59.32 2005-07-28 Some.File.avi.vol31+29.PAR2
;15442596  08:59.32 2005-07-28 Some.File.avi.vol60+40.PAR2
Some.File.avi.part01.rar 5079A617
Some.File.avi.part02.rar 27001333
Some.File.avi.part03.rar C3B6525B
Some.File.avi.part04.rar B8C8C580
Some.File.avi.part05.rar EAFB98CB
Some.File.avi.part06.rar DB963752
Some.File.avi.part07.rar EC26E01A
Some.File.avi.part08.rar 837AE97F
Some.File.avi.part09.rar E580FB75
Some.File.avi.part10.rar 838EFC3C
Some.File.avi.part11.rar A45455D5
Some.File.avi.part12.rar FF34484F
Some.File.avi.part13.rar B963FE25
Some.File.avi.par2 61443265
Some.File.avi.vol00+01.PAR2 25FD04F2
Some.File.avi.vol01+02.PAR2 2C354FD1
Some.File.avi.vol03+04.PAR2 4FDE31A3
Some.File.avi.vol07+08.PAR2 1EEFB660
Some.File.avi.vol15+16.PAR2 FB8481AA
Some.File.avi.vol31+29.PAR2 95A49937
Some.File.avi.vol60+40.PAR2 286279AE
------------ End of Sample SFV File Listing ------------

The files shown above are a typical RAR/PAR set. Any lines of the SFV file that begin with a semicolon are comments and can be ignored. So, the first relevant line is: “Some.File.avi.part01.rar 5079A617.”

“Some.File.avi.part01.rar” is the name of the file, and “5079A617” is the value calculated when the data from the file is run through the CRC32 algorithm. “5079A617” is calculated on the computer of the person who posted the file. If the copy of “Some.File.avi.part01.rar” that you now have yields a value of “5079A617” then you have an exact copy.

Once you have SuperNZB installed, just click the “SFV” button on the main window:

SuperNZB SFV Screenshot

(Note: The screenshot above, and the demo video below were made on Windows, however the program looks identical on the Macintosh.)

Here is a 5 minute demo video:

CRC32 can also be used to find duplicate files on your system. DupeNuker keeps a database of CRC32 “fingerprints” so you can quickly tell if a new file is one you already have, or have already seen before.