[Flac-dev] MD5 Signature Mismatch

Brian Willoughby brianw at sounds.wa.com
Wed Jun 1 13:15:19 PDT 2011

On Jun 1, 2011, at 05:12, Scott C. Brown 02 wrote:
> He sent me a link to the files here:
> http://www.archive.org/details/wolf2011-05-29.cleantone
There are no uncompressed files here, so it's difficult to discover  
what you need to know.

> I just grabbed the first track (only 2.7 MB), and metaflac gave me  
> an MD5, but
> the file failed testing and won't decode.
At least you've determined that there is an MD5.  I should test one  
of my files with a missing MD5 to see if it's possible to tell the  
difference between a bad MD5 and a missing MD5.

> md5 in flac file: 8cefa4d345df955912a2ca94178f072d
> correct md5 according to shntool: ce67ad906f81db0d914104bea08b0825
I could be wrong, but I don't think that it is possible to calculate  
the "correct" MD5 without the original file.  FLAC does not calculate  
the MD5 of the compressed data, but instead calculates the MD5 of the  
uncompressed data.  You need the original, uncompressed data before  
you can know the correct MD5.  Otherwise, the uncompressed data that  
comes from the decoded FLAC could be wrong, and would thus give a  
different MD5, possibly even a third value.

> So it looks like his machine is creating bad md5s.  I just don't  
> know enough about
> why this could be the case or what else I should be looking at...

This could be an uploading problem.  There are still too many  
variables at this point to know for sure.  Is he using the flac  
command line tool, or some third-party front-end for FLAC?


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