[Flac-dev] Bug with FLAC raw encoding

Mark Powell M.S.Powell at salford.ac.uk
Mon Feb 5 02:15:26 PST 2001


On Fri, 2 Feb 2001, Josh Coalson wrote:

> this is probably a good point to remind everyone that FLAC is still
> beta so don't delete your originals!  everyone here has been good
> about it but I'm dreading that message from someone who lost all their
> stuff.

You mentioned that one update was to include an md5 signature of the
compressed stream to detect errors? Could you also not store the md5
signature of the original wav data? This would mean it'd be impossible for
flac to extract an invalid .wav file. I know this would not help someone
that had deleted their original wav, but it would at least mean problems
are reported immediately without people then further processing dodgy wav
files? Any possible rot would be stopped early.
  Also, a few more minor points. I don't know what others feel, but I
think the way shorten works is intuitive. i.e. the following compresses a
file:

$ shorten file.wav

this creates file.wav.shn and deletes file.wav. This is the way all UNIX
compressors; compress, gzip, bzip & lame have worked. They simply add on
their own extension without making the mistake of trying to understand and
then munge the existing filename.
  You have the option of specifying this if you want:

$ shorten file.wav file.shn

and in that case the original won't be deleted. But if you don't specify
the destination file then I think the .wav.shn extension is fine as it
allows:

$ shorten -x file.wav.shn

to simply give you back the original file.wav and deletes file.wav.shn. I
know flac is still beta, so the deleting might be left off by default
until v1.0.
  Wav file format is the default, whereas you have to specifiy -fw to
flac.
  It also preserves the modification time of the original file as do all
other UNIX compressors. Unless I'm not paying attention, flac doesn't seem
to do this?
  Cheers.

Mark Powell - UNIX System Administrator - The University of Salford
Academic Information Services, Clifford Whitworth Building,
Salford University, Manchester, M5 4WT, UK.
Tel: +44 161 295 5936  Fax: +44 161 295 5888  www.pgp.com for PGP key





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