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Strange effect if RAR has CRC-Errors

PostPosted: Wed Feb 09, 2011 8:32 am
by billynews
Hi,

I've downloaded a RAR-Archive with two videos in it - let's say CD1.avi and CD2.avi
Download was complete, no repair needed, but the Archive is damaged and I'm getting
CRC-Errors for CD2.avi if I test the archive with WinRAR.

Newsbin did the following:

After download it starts to unrar, gets an error but keeps CD1.avi in the download folder.
It downloads then the last PAR-File and tries to extract again, gets an error again,
and leaves another copy of CD1.avi in the download folder
Now it downloads next PAR-File, tries to extract and creates the next copy
of CD1.avi
This goes on till last PAR-File was downloaded and I'm ending with as many copies
of CD1.avi as this post has PAR-Files :wink:

@Quade: I will send you the subject per PN

Best regards,

billy

Re: Strange effect if RAR has CRC-Errors

PostPosted: Wed Feb 09, 2011 11:40 am
by Quade
Typically this means the RAR set is damaged and nothing can fix it. That it was damaged before they generated the PAR files and that what Autopar does when it repairs it is simply repairs it back into bad RAR files. What you feed into quickpar is what you get back out.

Newsbin is assuming it can eventually get enough pars to fix it but, it never happens. So, I understand what it's doing.

You can verify this by running Quickpar to make sure the rars are all good then use Winrar to unrar and see if the unrar works,

If Quickpar says every thing is good but, winrar fails, then you know it's bad RAR files.

If Quickpar and WinRAR both work and the files are still bad, then they were bad before they were rared.

Re: Strange effect if RAR has CRC-Errors

PostPosted: Wed Feb 09, 2011 12:14 pm
by billynews
then this is a change from 5.5 to 6.
In 5.5 you never tried to repair (AutoPAR) an archive for which only unrar failed.
And you never tried to extract more than one time - that's new to me.

Re: Strange effect if RAR has CRC-Errors

PostPosted: Wed Feb 09, 2011 12:31 pm
by Quade
Yeah it's different. The only thing I see wrong is that the failed unrars leave bad AVI's behind. They should be deleted after the unrar fails. I'm probably telling unrar to keep the bad files.

Re: Strange effect if RAR has CRC-Errors

PostPosted: Wed Feb 09, 2011 9:57 pm
by billynews
Quade wrote:Yeah it's different. The only thing I see wrong is that the failed unrars leave bad AVI's behind. They should be deleted after the unrar fails. I'm probably telling unrar to keep the bad files.


you don't keep the broken avi from the archive - only the good one. :wink:
But you're creating x copies of it - as many as par files exists.

If it's a big upload with 30 GB and 10 Par-Files you will try to extract 10 times
and you will create 10 copies of every good file in the archive - scary :roll:

Re: Strange effect if RAR has CRC-Errors

PostPosted: Wed Feb 09, 2011 11:26 pm
by Quade
Yeah that's why I said

The only thing I see wrong is that the failed unrars leave bad AVI's behind.

Re: Strange effect if RAR has CRC-Errors

PostPosted: Fri Feb 11, 2011 10:37 pm
by billynews
just a short note - same happens for password protected archives.
Newsbin downloads all Pars and tries to extract. Not a big problem,
but not necessary.