--- Harry Sack <tranzedude@gmail.com> wrote:> 2007/7/25, Josh Coalson <xflac@yahoo.com>: > > > > --- Harry Sack <tranzedude@gmail.com> wrote: > > > 2007/7/25, Harry Sack <tranzedude@gmail.com>: > > > > > > > > Hi > > > > > > > > I have downloaded a FLAC file somewhere and when trying to > decode > > > it to > > > > WAV it gives the error message: ERROR, MD5 signature mismatch > > > > So my question is now: are FLAC files that give the error > message > > > above > > > > still decodable to WAV (and how can you do this, because > flac.exe > > > doesn't > > > > want to decode the file), even if there is a MD5 signature > > > mismatch, or is > > > > this not possible at all? > > > > if that is the only error given even when decoded with -F, then > > it got all the samples back. they are also highly likely to be > > the same samples that were encoded. most likely they were encoded > > on a machine with bad hardware (bad ram, aggressive overclocking), > > less likely is that the file was corrupted or tampered with. > > But how is it possible then the FLAC encoder allows files which have > a bad > resulting MD5 to be encoded? Is it because of the bad ram, ... this > incorrect MD5 is not detected during encoding?it happens like this, x.wav gets encoded with flac.exe on a machine with bad ram. flac.exe reads some audio data from x.wav into memory and encodes it. samples are buffered to md5 checksummer which writes intermediate checksum to bad memory. md5 is corrupted but samples were encoded ok. the user will not know unless the --verify option was used during encoding.> Can you also give me an example of an error message that would occur > when the file is corrupted?you would get errors about lost sync, frame crc mismatch, bad header, or unparseable stream. Josh ____________________________________________________________________________________ Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user panel and lay it on us. http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7
2007/7/27, Josh Coalson <xflac@yahoo.com>:> > > > But how is it possible then the FLAC encoder allows files which have > > a bad > > resulting MD5 to be encoded? Is it because of the bad ram, ... this > > incorrect MD5 is not detected during encoding? > > it happens like this, x.wav gets encoded with flac.exe on a machine > with bad ram. flac.exe reads some audio data from x.wav into memory > and encodes it. samples are buffered to md5 checksummer which writes > intermediate checksum to bad memory. md5 is corrupted but samples > were encoded ok. the user will not know unless the --verify option > was used during encoding.Is it also possible the samples themself get corrupted, because they are too (just like the md5) written to the memory for encoding them? -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/flac/attachments/20070727/2d0ca2b7/attachment.htm
--- Harry Sack <tranzedude@gmail.com> wrote:> 2007/7/27, Josh Coalson <xflac@yahoo.com>: > > > > > > > But how is it possible then the FLAC encoder allows files which > have > > > a bad > > > resulting MD5 to be encoded? Is it because of the bad ram, ... > this > > > incorrect MD5 is not detected during encoding? > > > > it happens like this, x.wav gets encoded with flac.exe on a machine > > with bad ram. flac.exe reads some audio data from x.wav into > memory > > and encodes it. samples are buffered to md5 checksummer which > writes > > intermediate checksum to bad memory. md5 is corrupted but samples > > were encoded ok. the user will not know unless the --verify option > > was used during encoding. > > > Is it also possible the samples themself get corrupted, because they > are too (just like the md5) written to the memory for encoding them?yes, but in that case when you decode it you won't get an md5 error. from flac's point of view everything went fine because it can't know the samples coming in were wrong to begin with. ____________________________________________________________________________________ Yahoo! oneSearch: Finally, mobile search that gives answers, not web links. http://mobile.yahoo.com/mobileweb/onesearch?refer=1ONXIC