ILW's Software Page

Programs Available Here

MP3 Checker: Rapidly scan lots of MP3 for RIAA corruption, the so called "Screechy MP3's" syndrome

MP3 Autoscanner: automatically scans MP3's for screeching on completion and moves them to a quarantine folder

KChecker: Scans a file and highlights the chunks which are corrupt for redownload

KSigMod: Modified version of KSig, offers all the features KSig does, but also generates CRC information (for KChecker)

KPadder: Pad or truncate a file to any size (useful with KChecker)

Whats the point in these programs

As you may well be aware the fasttrack network and its main client kazaa are very poorly maintained and as such there is no corruption handling on the network. Corruption comes in 2 main types on the network; there is random corruption which occurs because bit errors occur in transmission between computers, and there is intentional corruption added to music files on the network by the RIAA (Recording Industry Association of America). In order to purposefully add corruption to the network the RIAA have taken advantage of the fasttrack networks quick and dirty method of file hashing, which leaves the vast majority of a file unprotected from tampering.
I've written programs to try and combat both types and they can naturally be split between the 2 categories; the MP3 checkers and the Random-Corruption Stoppers.

MP3 Checkers

The two programs fulfill different requirements, MP3 checker is designed to check all your existing MP3's and remove any screechers from your existing collection and the autoscanner is designed to stop any more screechers getting into your collection (and thereby helping to remove them from the fasttrack network).

MP3 Checker is a GUI based program which can scan MP3's for the tell-tale signs of RIAA added screeching. It can scan around 800 MP3s at a time and can do a full scan in under a minute.

MP3 Autoscanner, is a command line program designed to work with the KLExtension's file organiser so that MP3's are scanned and if bad are quarantined as soon as they are downloaded.

Random-Corruption Stoppers

These programs are based on the same principle as the Intelligent Corruption Handling available in better maintained p2p networks such as the edonkey network. The idea is to calculate CRC (Cyclic Redundancy Check) information for chunks of a file, this means that each chunk has been given a unique identifier based on the data contained in it. Any errors or changes to this data gives a different CRC value and so chunks can be easily checked for corruption. The way I hoped this would turn out was that lots of people (especially those who often contribute verifieds) would convert to KSig mod and use it to generate the modified quicklinks which contain the CRC hashes. Then anyone downloading one of these verified files can CRC check their finished files CRC data and if there is any corruption then Kchecker will see it and redownload that part of the file(2% resolution).

If a verified file you downloaded is corrupt then you have 3 choices

1) To ask someone who has a good version of the file to crc hash it with one of my programs
2) If you know where in the file the error is (eg if its a video file the errors are visible and rough file position can be estimated) then you can use DrSpud's KCF (see link on left menu) and use that to redownload the bad parts of the file.
3) Junk the file and redownload it all.

A couple of things to note

The corruption fixing programs' main focus should probably be software, games etc. ie places where corruption really matters. I'm not 100% how necessary it is for movies & music because corruption is not so critical and people are therefore more likely to keep slightly corrupted versions of these files. (software slightly corrupted won't work). The fact that people don't delete minor movies and music for minor imperfections could mean that you spend a significant amount of time trying to download perfect copies of movies. At the moment there is no way of telling sources with perfect copies of the file from people with non-perfect copies.
Also note that if using these programs to post verifieds make sure the files are in good - perfect condition because any errors in your copy may 'lock in' those errors for that file. Preferably post verifieds of software that works or files that have come from reliable networks with corruption handling, eg Bittorrent, Emule, Shareaza etc.