XCDextractor - CRC-Check, Repairs damaged Sectors, Removes Zeros

[bond]

just stumbled over DeXT's site and found an announcement for this tool, XCDextractor, which really sounds great:

2004/06/02: MarkoZ sent me a new tool called XCDextractor to extract files from a XCD, this time with a built-in CRC check, and an option to repair damaged sectors.why didnt you tell us about this already, DeXT??? :D

grap the tool on DeXT's site (http://webs.ono.com/usr016/de_xt/)


it allows the removal of all tail zeros from the end of the file!

also it allows the creation of so called .xcd files, which carry the filesize and crc inside (hm why is there the need for crc in the .xcd file? isnt it stored on the xcd itself already?)
is this the famous .xcd/.xch file, which is defined in the XCD Specs?

when there are damaged sectors the tool will try to repair or autofill the bad sectors with zeros!
does anyone have any infos on how the repair of damages works? i know that there are CRC values stored on a XCD, but CRC is error detection only. or is it only about being able to get the whole file on the harddisk again?

also what does the CRC-Check in the tool do? does it simply not pass the damaged parts of the XCD when extracting, leading to a correctly working file, but with missing parts, or..?

anyone having a scratched XCD which this can be tested with?

[jkwarras]

Originally posted by bond
anyone having a scratched XCD which this can be tested with?

I think I have 1 XCD with an OGM that hangs at the end of the movie because of a small scratch. I'll try this tool :D

[bond]

if someone is interested, i contacted the author of this nice tool about some more infos about it and here a summary of what he wrote:

- the .xcd files are not compliant to the xcd header files defined in the xcd standard
- the .xcd files contain the filesize (good for removing the tail zeros added to the .dat file during the m2f2 conversion)
- the .xcd files contain the CRC for the whole file, for being able to check whether the extracted file is 100% the same as the one, which was the source for the xcd (for example when using the repair function) if its not equal check the file for errors with virtualdub or a player
- the repair function reads the sector, if it fails it tries it again for 10 times, if it fails than it autofills (it uses mechanical noise of the pickup in the drive so that the reading position is every time slightly different and can produce a successful read (the sector is automatically validated by the drive itself using the CRC stored in the sector frame))
- you can add some text after the lines written by xcdextractor to the .xcd files (maybe nice for movie descriptions). xcdextractor assumes that all data is present exactly in the original position, so dont mess up with this info
- xcdextractor seems to be based on dat2file or extractor

a first test (with a not scratched xcd) showed that it seems to work great :)

Originally posted by jkwarras
I think I have 1 XCD with an OGM that hangs at the end of the movie because of a small scratch. I'll try this tool :D did you try it already? what was the result?

[jkwarras]

Originally posted by bond
did you try it already? what was the result? [/B]

Trying right now...I forgot about that :D

I'll post later.

[jkwarras]

After 8 hours, I had to abort the extraction because it hangs my computer. The XCD hangs at the very end, so the movie at a point wasn't readable at all, the PC hangs after a while. With XCD extractor, when it reaches the bad sectors fo the CD, it goes really very slowly (as I said 8 hours and I had to abort). It repaired 250 sectors. I tried to play the extracted file, ony a few minutes at the end wasn't extracted because I aborted the extraction. The file plays fine and when reaching the point when the XCD hangs and wasn't readable, it's playable :) I mean, there's a lot of blocking appearing at these moments, the picture is horrible but: it doesn't hang the PC.

So my conclusion is that it works fine. But is really slow in recovering errors and if it's really badly scratched then the recovered sectors are far from perfect (lot of blocks).

[jkwarras]

has someone done more tests? :cool: