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6. What are all these other files, then?
What are .SFV files? [Onakra, ed.]
SFV stands for Simple File Validator and is used to check files if they became corrupt after transfer. It does this by doing a CRC (cyclic redundancy check). The poster generates this (text) file with a SFV-generator and the downloader checks it with a SFV-program to see if there are any problems. After the check it displays which files contain CRC-errors and therefore are corrupt.
If a file is corrupt the first thing to do is try to repair it. Since most archives are created with a recovery record you should first try to repair the file yourself. See the RAR recovery records section on how to do this. If this fails you should make a request for a repost by using the guidelines for repost requests. Before you do, however, first check the newsgroups to see if it was reposted already or if there are already outstanding request(s) for it. Don't forget to also check alt.binaries.multimedia.anime.repost (ABMAR) and alt.binaries.multimedia.repost (ABMR) which are other potential repost locations.
The two most used programs for SFV are WinSFV and QuickSFV and are fairly
easy to use. Most SFV's generated can be checked by the other SFV programs.
One exception is WinSFV. The first line for this program must always include:
The only FAQ for WinSFV that exists at the moment is in Dutch. It is supposed to be translated to English, but the page hasn't been updated in a while. It does have a small section in English with the 3 most asked questions. It also offers the latest version (1.1a) for download. It is located at http://members.tripod.lycos.nl/winsfvfaq/
The official page for QuickSFV is http://www.geocities.com/SiliconValley/Mouse/4668/index.html and always has the latest version for download. A nice feature of QuickSFV is that it can generate SFV's compatible with WinSFV. That means it generates the first line that must be included for WinSFV in a SFV-file.
QuickSFV can be downloaded from: http://www.geocities.com/SiliconValley/Mouse/4668/
Other SFV generators/checkers are:
What are .PAR, .P01, .P02...Pnn files? (Parchive files) [Myen, Keikai, ed.]
PAR files (also known as parchive files) are similar to SFV files in that they can check file integrity. Unlike SFV files, parchive files contain the checksum hash in the form of MD5 values instead of CRC-32 values. This greatly decreases the chance of two different files having the same hash and, therefore, makes them less likely to be in error. Furthermore, the parchive files test themselves for corruption.
The primary function of parchive files, however, is that posters will usually also post *.Pnn files (where nn are numbers from 01 to 99) that are slightly bigger than the largest file in the archive set (adds <1K) that can be used to recover bad or missing files on a one-for-one basis. Because the Pnn files contain the information in the .PAR file itself, the .PAR file is not necessary to test or recover files. However, it is highly recommended that the .PAR file be posted anyways, as it is a small and efficient means for testing whether Pnn files should be downloaded, and it has a few advantages over .SFV files.
The PAR client, when run on a PAR file (or any .Pnn file), will report the number of missing or bad files. If there are enough .Pnn files available, it will then recover the missing files.
For more information on the individual clients used both to create parchive files and to recover archive parts using them, go to the individual client websites
(Currently, the most common in AB(M)A)
For the technical details (not required reading), read the file specifications
It is not uncommon to post both a .SFV file and a parchive set. Some people prefer to have a .SFV file as it can be opened in a text editor to verify what files should be in the set.
It is usually preferred that you only include the archive set (RAR files) when creating the parchive set. Including support files (such as .nfo, .txt, .sfv, etc.) can cause problems.
What are .REV files? (RAR Recovery Volumes) [Keikai]
These files are current an inferior and proprietary version of parchive files discussed above. Therefore, one can recover damaged or missing .rar parts using RAR recovery volumes on a one-for-one basis.
Currently, it is strongly urged that posters use parchive files and not WinRAR recovery files. The reasons for this are:
RAR recovery records are a totally different feature and should still be used. They are described in the archive section under RAR recovery method.
Although parchive files are much preferred over WinRAR recovery files, it is still preferable that posters use one of these technologies. Therefore, if parchive files cannot be posted for some reason, please use WinRAR recovery files instead. Inclusion of both is highly unnecessary and is discouraged.
The naming format for these files is:
Where xx is the part number of the last part of the archive set, yy is the total number of recovery volumes created, and zz is the number of this particular recovery volume. The only number that should change throughout the recovery set is zz.
Recovery using RAR recovery volumes requires version 3 or later of WinRAR. More information regarding the use of RAR recovery volumes can be found at http://www.rarsoft.com/.
What are .IDX, .SUB, .IFO files? (VobSub files) [Keikai, Scrippie]
These files will usually be found together in a group of all three, or, more recently, in a group of two (.IDX & .SUB). These vobsub files are produced by a Virtual Dub filter called VobSub. VobSub is used to "rip" the subtitles off of a DVD into the vobsub files. These files can then be used either to create a permanent hardsub on an encoding or used with DirectVobSub to optionally display them when playing the video. Therefore, the former method is "hardsubbing" and the latter method is considered a form of "softsubbing", although, unlike most softsub file formats, the subtitles in these files are in fact timed bitmap graphics.
DirectVobSub (also known as DVobSub) is a DirectShow filter that works with most DirectShow compatible video players. Video players that are known to work with DVobSub are:
While the use of vobsub files is very popular, be aware that unless a person has a system running a Windows or Linux/*NIX OS, they may not be able to play the files. For those people who prefer to watch videos on a non-Windows OS, but have a Windows OS available, they can use the vobsub files to hardsub the video on the Windows OS and then watch it elsewhere. This also, of course, applies to those who do not like "softsubs" or those that reencode AVIs to other formats such as MPEG-1 or MPEG-2.
The homepage for VobSub is http://vobsub.edensrising.com/vobsub.php. Both the encoding filter and DVobSub can be downloaded as one package from there. Inside the package are excellent, if a bit cryptic, resources regarding the use of VobSub and DVobSub.
mplayer for Linux (http://mplayer.sf.net/)
supports the VobSub format as well, therefore making it available on most *nix
For information on creating hardsubbed videos from an unsubbed video and vobsub files, see the appropriate encoding section at http://www.doom9.org/guides.htm.
When watching a video with vobsub softsubs, the subtitles should automatically be displayed if the vobsub files are in the same directory as the video and the file titles are identical to that of the video. The only difference between the files should be the extension. When playing, an icon should appear in the system tray. More options can be found there.
As of version 2.07 of VobSub and DVobSub, the .IFO file is no longer needed. If a post includes only the .IDX and .SUB files, then most likely they were created with a post-2.07 version of VobSub. A post-2.07 version of DVobSub is then necessary to view the subtitles.
What are .SMI, .SSA, .SRT files? (Soft-Subtitles) [Keikai, Onakra, ed.]
These are all different formats for text-format timed soft subtitles (usually called "softsubs"). More information will be included regarding these later.
Installing the DirectShow VobSub plugin (DVobSub) available from http://vobsub.edensrising.com/vobsub.php will allow any DVobSub-compatible media player to display most softsub formats.
A Windows media player that does not support DVobSub but is excellent at manipulating and displaying softsubs is Sasami 2k, freely available at http://www.sasami2k.com/.
Excellent information on other programs that can deal with softsubs can be found at Zen's website: http://www.geocities.com/zenwebpage/
Some softsubs can be displayed directly in Windows Media Players:
What are .NFO, .TXT, .MD5... files? [Keikai]
.MD5 files can be checked with md5summer from http://www.md5summer.org/ [kloug]
User Contributed Notes