<br><br><div><span class="gmail_quote">2007/10/15, David W. Tamkin <<a href="mailto:dattier@panix.com">dattier@panix.com</a>>:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Harry,<br><br>> so i was wondering what advantages it could give me to make a ffp<br>> file, because there is already a internally stored md5 checksum on the<br>> decoded audio data inside the flac file?<br><br>Testing the .flac file against its internally stored fingerprint lets
<br>you know that you have a properly encoded .flac file of *something*. If<br>you also certify that internally stored fingerprint against a list of<br>correct fingerprints in another file, then you know you have a properly
<br>encoded .flac file of the *right* audio, and that the person who sent<br>you the .flac files didn't accidentally provide a wrong file instead.<br><br>Yes, a miscreant who would intentionally switch .flac files on you would
<br>also alter the .ffp file to show the fingerprint of the wrong file<br>instead of the right one, but that could not happen by accident.<br>Sending a set of .flac files with an .ffp file says, "I wouldn't<br>deliberately deceive you"; sending a set of .flac files with no
<br>checksums at all says "I never make mistakes." There are people whom<br>I'd trust not to deceive me deliberately but nobody from whom I'd accept<br>a claim of infallibility.<br><br>Moreover, if a set of .flac files is being shared, a copy of the
<br>fingerprints can be kept at a URL distributed with them, so that<br>everyone receiving them can make sure that the fingerprints of the files<br>(s)he gets match those of the original set.</blockquote><div><br><br>yes, I all understand that, but I mean advantages when you don't send those files over the internet. So just encode them and burn them to a cd. Or is a ffp file only useful when you want to upload those files?
<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">> i was also wondering how files encoded by using the new<br>> --keep-existing-metadata option are verified when using -verify. Is
<br>> there a separate internally stored md5 for metadata next to the md5<br>> for decoded audio data or how is everything verified?<br><br>Until we hear from someone who knows, I'd venture to say that --verify<br>
does just what it always did, and it has nothing to do with existing<br>metadata in the uncompressed input. As it encodes each segment of the<br>audio, it re-decodes it and compare the result to the original input.</blockquote>
<div><br><br>but how can you verify the metadata of the input files then if there is no check for this?<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
> Is making a ffp file for such files also possible for the non-audio<br>> data (so all metadata)?<br><br>No, fingerprints are defined only for audio.</blockquote><div><br><br>same question as above <br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
> i was also wondering if there exists a GUI program for win32 to verify<br>> flac files using a ffp file (so not md5check.exe)<br><br>Yes: Trader's Little Helper at <a href="http://thor.prohosting.com/roh0205/">
http://thor.prohosting.com/roh0205/</a>.</blockquote><div><br><br>thx, it's exactly what i'm looking for! unfortunately the file is offline, can you maybe email the file to me if you still have it? <br></div><br></div>
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