File saved incorrectly on a flash card

H

hairylarry

New member
Hi,

I use a Zoom H4 for field recording and I have a problem. Maybe someone here has had to deal with this situation and can help me out.

I was recording the Hoggard Brothers at a KASU Blue Monday show. I recorded the first set fine. Then after the second set was done but before I stopped the recording there was and accident and the power went off on my recorder. The file for set two is there all right but it shows as zero bytes.

If I look in a hex editor I can find the file header and look at the wav file data. I just can't listen to it or copy it to another drive.

I just did post on the first set and it sounds fantastic. So this makes me want to recover the second set even more.

Does anyone know how to recover wav data like this. It's on the flash card ok. It's just not part of the FAT file system because of the inadvertant power off before the file was closed.

Thanks,

Hairy Larry
 
This is why the Edirol R-09HR is so good - it has a built-in facility to recover files in cases like this.

As for your problem - sorry, it's never happened to me - I hope someone else can help you.

Or maybe THIS will help ???
 
Since you say you can't copy it, I would think that the directory entry is corrupt, so a utility like the one suggested above may be able to rebuild the directory entry and make the file accessible. Then, editing the header to reflect the true size of the file may make what audio data there is accessible.
 
John Willett said:
Not if you have an Edirol R-09HR (that has a recovery feature) or a pro recorder that saves as it goes along. ;)

Though, in this instance, I suspect this is the case and it's lost - unfortunately. :(
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Which is why I was wondering about the batteries too. Pull the plug on the R44 and it keeps going.
 
Good feature

John Willett said:
This is why the Edirol R-09HR is so good - it has a built-in facility to recover files in cases like this.

As for your problem - sorry, it's never happened to me - I hope someone else can help you.

Or maybe THIS will help ???
Click to expand...

That's a good feature indeed. I will contact Samson tech support to see if they have a similar utility.

The problem with searching for data recovery software is they all undelete files. This is really a separate problem. The file is there but the header says 0 bytes. The data is there. I can see it in a sector editor.

But how can I turn it into a file or play it?

Anyone who does a lot of field recording knows it's a crap shoot every time. Usually I get great recordings but not always.

Thanks,

Hairy Larry
 
It was running on batteries

mixsit said:
Just curious.. With the batteries in, when you 'pull the plug doesn't it cover you? :confused:
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And a good feature of the H4 is if your batteries get low it auto saves before it shuts down.

There was an accident. Before I hit stop the tripod it was on was knocked over and the machine reset.

The H4 is fine. The data is fine. I just don't know how to get it.

Thanks,

Hairy Larry
 
It's a FAT32 or DOS file system

Hi,

Thanks for the suggestions so far. I appreciate everyone's help.

The FAT32 file system is well understood. I have used sector editors to recover text.

If the FBI needed the audio their forensics experts could recover it.

I just ain't no forensics expert.

In other words I know it's possible. I know I could hire it done. I just can't afford it. I'm looking for a software or expertise solution.

Thanks,

Hairy Larry
 
Is it possible to clone the card to another card and then try various recovery programs on the copy rather than the original?

Then, if it doesn't work, you have not done anything with the original.

Just a suggestion.
 
Something Like That

John Willett said:
Is it possible to clone the card to another card and then try various recovery programs on the copy rather than the original?

Then, if it doesn't work, you have not done anything with the original.

Just a suggestion.
Click to expand...

John,

I only have two 4 gig cards and I'm using the other one for now while I still have hopes of recovering the missing set. I did clone a backup onto my hard drive.

If I ever get a break I might try cloning it to my other card. Tomorrow I'm recording Blues Traveler. Saturday, Hairy Larry and Geroge with The Swing Band Project. Sunday, Higher Ground and The Mudcats at the Craighead Forest Bandshell. It's good to be busy.

Thanks,

Hairy Larry
 
Who said anything about a job?

John Willett said:
Then you could try IsoBuster on the hard drive copy...


And I envy you - recording jobs are a bit quiet round here at the mo. :(
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John,

Thanks. I will try isobuster and we'll see.

I'm retired. I mostly tape for my own label or to upload to the Live Music Archive. Then I use the recordings on my Something Blue radio show and podcast.

I also run Delta Boogie and the Delta Boogie Network. In business to make music.

Thanks,

Hairy Larry
 
Recovery is probably pretty simple, assuming you were recording WAV and not some unholy compressed format. Copy the entire flash drive to a file (an ISO image or whatever), truncate the first part of the file up to the start of the WAV header, and open it in an audio editing app. In the worst case, you might have to splice out hunks of other audio data in the middle, but unless you regularly record and then delete lots of short audio recordings, 99% of the time, an audio file will be mostly or completely contiguous on disk.

Oh, yeah, and you might have to tweak the WAV header with a hex editor if it contains length data (I don't remember).

If you really want to get fancy, write a script that lists the block numbers of all the other files on the disk, then take all the blocks that aren't allocated to anything else, and copy them in order to a file. Even with a heavily fragmented flash volume, that's likely to be correct up until the end of the audio data (beyond which you'll likely get high volume garbage, so don't listen to it until you trim it). :)

Note: before you record anything else on this flash card, copy the whole thing block-by-block to a disk image. That way, you won't overwrite the data. [Edit: I see you already did that. Good job.]
 
dgatwood said:
Recovery is probably pretty simple, assuming you were recording WAV and not some unholy compressed format. Copy the entire flash drive to a file (an ISO image or whatever), truncate the first part of the file up to the start of the WAV header, and open it in an audio editing app. In the worst case, you might have to splice out hunks of other audio data in the middle, but unless you regularly record and then delete lots of short audio recordings, 99% of the time, an audio file will be mostly or completely contiguous on disk.
Click to expand...

What software can I use to truncate the file? It's a 4 gig flash card so the image file is rather large.

I always completely delete the files on my cards after I back them up so I am hoping the audio will be contiguous.

Thanks,

Hairy Larry
 
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