Topic: MT2496 - CD-Wave msg re WAV header; FLAC msg re sub-chunk

[it-goes-to-eleven]

The other questionable thing that happened that I haven't seen reported is that CDWave reported that the file size reported in the .way header differed from the actual file size.  Easy enough to fix but I'm not sure what that was all about.

That can be a VERY serious problem.  It shouldn't be but often is..  FLAC, for example, has serious trouble with it.  If the header says 20 bytes and the file is 1 Gig, FLAC will only save 20 bytes.  I've reported it to the flac team and it will get fixed.. But they've put a very low priority on it (which I don't agree with at all).  Other programs may have similar problems, so watch out for that one.

[Brian Skalinder]

The other questionable thing that happened that I haven't seen reported is that CDWave reported that the file size reported in the .way header differed from the actual file size.  Easy enough to fix but I'm not sure what that was all about.

That can be a VERY serious problem.  It shouldn't be but often is..  FLAC, for example, has serious trouble with it.  If the header says 20 bytes and the file is 1 Gig, FLAC will only save 20 bytes.  I've reported it to the flac team and it will get fixed.. But they've put a very low priority on it (which I don't agree with at all).  Other programs may have similar problems, so watch out for that one.

The JB3 had a similar problem.  My notes from the JB3 FAQ based on my testing:

[380] Opening JB3-recorded WAV:  "File header reports a size that is different than the system reports..."?!?

When opening JB3-recorded WAVs in CD-Wave, what's with the message:  "File header reports a size that is different than the system reports.  Do you want to adjust the size?  (Yes to override header, No to trust header, Cancel to abort)"

The JB3 appears to add 8 bytes of "junk" at the end of some WAV files recorded onto the JB3.  At any rate, if prompted with this message by CD-Wave, it doesn't matter whether you select Yes or No, CD-Wave strips the "junk" 8 bytes out of the file in either case.  All other commonly used taper programs - Cool Edit, Wavelab, Soundforge, etc. - seem to strip the junk bytes out but don't present a message to the user.  Bottom line:  don't sweat it!

Anyone have a MT file that generates the same message in CD-Wave and able to test whether it's the same issue?  If so, it's really a non-issue, IMO.  But if it's a different issue, then...maybe worth addressing assertively with MT / FLAC.

[rodeen]

The JB3 had a similar problem.  My notes from the JB3 FAQ based on my testing:

Anyone have a MT file that generates the same message in CD-Wave and able to test whether it's the same issue?  If so, it's really a non-issue, IMO.  But if it's a different issue, then...maybe worth addressing assertively with MT / FLAC.

I've got the original file on compact flash.  I'll check it out when I get home tonight.

Thanks!

[JasonSobel]

Anyone have a MT file that generates the same message in CD-Wave and able to test whether it's the same issue?  If so, it's really a non-issue, IMO.  But if it's a different issue, then...maybe worth addressing assertively with MT / FLAC.

yes, actually, every file that I have recorded with the MicroTrack has reported that same thing.  I didn't think it was a big deal, so I guess I never mentioned it.  WaveLab opens up all files just fine.  CD Wave will also open up the files just fine.  and, as a matter of fact, when putting an "original" file from the MicroTrack through FLAC frontend, it gives some message about the header, but then continues with the compression as normal.  FLAC definitely compresses the whole file.  So although I've seen it, it has never been a problem for me, in any way.

got to run out now for a show tonight, I'll catch up with this thread tomorrow

[Brian Skalinder]

Alright, so I've done a bit of digging.  If you're interested, you may want to review this good primer on the Microsoft WAVE format.  It appears as though the MT2496 - like the JB3 - adds some useless sub-chunk data to the WAV file.  The MT2496, in writing the WAV header, does not appear to take into account this extra sub-chunk it adds to the file.  So we're left with a WAV header file size descriptor that does not match the actual file size (i.e. the WAV header file size descriptor is always smaller than the actual file size).  Hence, CD-Wave (and perhaps other apps) warn that the file size as reported by the WAV header differs from the actual file size.

The message FLAC presents (please note the contents of the sub-chunk data may differ from one file to the next):

WARNING: skipping unknown sub-chunk '⌠5☺;'

The specific message CD-Wave presents:

File header reports a size that is different than the system reports.  Do you want to adjust the size?  (Yes to override header, No to trust header, Cancel to abort)

What I've found is it doesn't matter how you answer, Yes (override header) or No (trust header) - CD-Wave strips the sub-chunk data regardless.  Likewise, CEP strips the sub-chunk data.  So does FLAC.  Haven't tested Wavelab, but I suspect it strips the data, too.  And one may also strip it manually with  hex editor.  Basically, I think this is not something about which anyone should worry.

But..."Ack!!", you might say, "what happens if my app trusts the WAV header file size descriptor and therefore doesn't handle any data beyond the file size as designated in the WAV header?"  I think that since the MT adds the sub-chunk data at the END of the file, the only thing that will happen is the app will not handle this useless sub-chunk data.  In other words, nothing happens, other than the useless sub-chunk data is stripped from the file.

[F.O.Bean]

ive never seen this message in cd wave or flac frontend using the latest versions of each FWIW

[Brian Skalinder]

ive never seen this message in cd wave or flac frontend using the latest versions of each FWIW

What versions, specifically, Bean?  Mine...

CD-Wave 1.94.5
FLAC FrontEnd 1.7.1

If you open and save the files in another app first (e.g. Wavelab), the other app will usually strip the sub-chunk data.  Try opening a WAV direct from JB3 sometimes, without using another app and see if it happens.

[F.O.Bean]

ive never seen this message in cd wave or flac frontend using the latest versions of each FWIW

What versions, specifically, Bean?  Mine...

CD-Wave 1.94.5
FLAC FrontEnd 1.7.1

If you open and save the files in another app first (e.g. Wavelab), the other app will usually strip the sub-chunk data.  Try opening a WAV direct from JB3 sometimes, without using another app and see if it happens.

dang, maybe i DONT have the newest versions, I have:

CD Wave 1.93.3
FLAC Frontend 1.1.2a

I used to get that error when opening jb3 stuff, but that was about 2 years ago and I havent had one problem since around that time period strangely enuf, thats the only reason I said anything!

[keepongoin]

FWIW, i get the "Warning: skipping unknown subchunck" in FLAC whenever I compress files generated with soundforge6/7/8 or wavelab 5.0/5.1.

probably because those programs have some sort of header info in their that designates the files as generated with that software... I have never worried about seeing that message, and have never uncompressed the FLAC to find anything was different in the file.

[JasonSobel]

FWIW, i get the "Warning: skipping unknown subchunck" in FLAC whenever I compress files generated with soundforge6/7/8 or wavelab 5.0/5.1.

probably because those programs have some sort of header info in their that designates the files as generated with that software... I have never worried about seeing that message, and have never uncompressed the FLAC to find anything was different in the file.

at least in WaveLab, there is an option that says "create optimized headers" (not sure if that is the exact phrase, but something very similar if not that).  If you uncheck that option, WaveLab will then create "standard" headers, and you won't ever see that message again.

[keepongoin]

FWIW, i get the "Warning: skipping unknown subchunck" in FLAC whenever I compress files generated with soundforge6/7/8 or wavelab 5.0/5.1.

probably because those programs have some sort of header info in their that designates the files as generated with that software... I have never worried about seeing that message, and have never uncompressed the FLAC to find anything was different in the file.

at least in WaveLab, there is an option that says "create optimized headers" (not sure if that is the exact phrase, but something very similar if not that).  If you uncheck that option, WaveLab will then create "standard" headers, and you won't ever see that message again.

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