Forums > MaxMSP

how to repair a damaged aiff file

July 9, 2006 | 7:34 pm

hi,

I was recording live performances on my laptop using sfrecord~ today.

During one performance the power went out. (Agh!!) The laptop was
still running, but obviously the external hard drive I was recording
to went off.

The resulting aiff file shows as 1.9Gb in the Finder (it was a long
performance!), but the programme I’m using to split these files
(Sample Manger) won’t load it.
I had a look with SoundHack,
if I just "open" it, it shows it as a zero length/zero mbs 6 channel
file.
If I use "open any…" it says it’s a headerless file, but then it
says the same with one of the ok files that i tried.

There used to be a little app in OS9 that one could use to fix aiff
files that were wonky due to an attack of recordus interuptus, but
how does one do it in OSX?

thanks

David


July 9, 2006 | 7:49 pm

Hi,

I think you could use ‘Header change’ in Soundhack.

All the best

Alessandro Fogar


July 9, 2006 | 8:56 pm

That’s the first thing I tried. The info in the Header Change
dialogue is exactly the same (except for the length of course) as the
info in the files that are ok. I also tried Apply in header change,
but it hasn’t affected the file.

David


July 10, 2006 | 8:08 am

I found this, http://www.bitcartel.com/irecordmusic/, which has a ‘repair aiff’ function; not sure if it will deal with 6 channel files, but worth a try…
The OS 9 app you were looking for was probably ‘Fix 16bit AIFF’, that came with Thonk, which is at http://www.audioease.com/Pages/Free/FreeMain.html
The Header Change function in SoundHack should work for this sort of thing,though; it’s certainly got me out of a jam in the past,
cheers
Roger


July 10, 2006 | 9:21 am

Tried irecordmusic out, but it doesn’t recognise any of the files
(even the good ones), and Soundhack doesn’t seem to do anything
useful with the damaged file. I think something more than a damaged
header must have happened to it; the power went off to the drive and
the laptop switched to battery; what would that do to a file!
Anyways, I think I’m going to have to let this one go – I’ve still
got about 2 hours of other recordings to work with.

thanks

David


July 10, 2006 | 9:48 am

Did you try DSP Quattro?

http://www.i3net.it/Products/dspQuattro/Asp/Index_EN.asp

I think there is some powerfull "import raw" capability (sorry, I don’t
remember exactly how powerfull it is, especially with mutli tracks
files)

As an ultimate solution, there is HexEdit… Not that difficult but
you’ll need to know the aiff specs quite well.

Good luck


July 10, 2006 | 11:23 am

Interesting. It actually managed to open and play the file. It plays
back as if it was recorded at a much higher sampling rate – ie pitch
too low, speed too slow, and aliasing noise. How strange.
Unfortunately, though, the programme only handles mono/stereo files.
Thanks for the pointer though.

David


July 10, 2006 | 12:26 pm

And as a postscript – much to my surprise, cubase opened the file as
a 5.1 just fine! So I thought I’d try sfplay~, and that too opens it.
What I don’t know is whether something I’ve done with the various
programmes I’ve been trying to fix it with has fixed it, or if cubase
& max would’ve opened it all along. Still, at least I can use sfplay
to get the separate tracks out now.
Hurrah!

Thanks to everyone for help & suggestions.

David


July 12, 2006 | 7:44 pm

David Stevens wrote:
> Interesting. It actually managed to open and play the file. It plays
> back as if it was recorded at a much higher sampling rate – ie pitch
> too low, speed too slow, and aliasing noise. How strange.

Not so strange if you think about it, the header is wrong or missing,
the program does make an assumption on the number of tracks, lets say it
assumes its stereo (not too bad as an assumption nowadays) if the file
is actually 6 channels, it has three times more values per second as the
stereo file…

As Soundhack does only 1, 2 or 4 channels, you could open it with
"openraw" into sfplay and then rerecord it… The help file of sfplay~
explains it all (New Features and subpatcher raw_data_and_force_header).

Stefan


Stefan Tiedje————x——-
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July 12, 2006 | 8:37 pm

hi Stefan

> Not so strange if you think about it, the header is wrong or
> missing, the program does make an assumption on the number of
> tracks, lets say it assumes its stereo (not too bad as an
> assumption nowadays) if the file is actually 6 channels, it has
> three times more values per second as the stereo file…

Oh yeah! That makes sense.

Something I did worked, because Cubase happily opened it as a 5.1
file. (Or maybe doing that is what fixed it). Which made me think of
opening it in sfplay (which I hadn’t thought to do before, assuming
the file was messed up), which also worked (I didn’t even have to
open it as a raw file – unless that happened automatically), thus
allowing me to use sfplay n sfrecord to separate everything out.

Mind you – it took around 14 hours to bounce the 5 tracks in non-
realtime!

thanks

David


July 13, 2006 | 4:45 am

David Stevens wrote:
> Mind you – it took around 14 hours to bounce the 5 tracks in non- realtime!

Any disc access is very, very slow in non-realtime! (There is some
explanation in the archives) It would have been much faster in real time…

Stefan


Stefan Tiedje————x——-
–_____———–|————–
–(_|_ —-|—–|—–()——-
– _|_)—-|—–()————–
———-()——–www.ccmix.com


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