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Author Topic: Recover files after accidental format? (DR-680/user error)  (Read 7333 times)

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Offline lukpac

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Recover files after accidental format? (DR-680/user error)
« on: October 22, 2013, 07:22:50 PM »
So, I pulled a boner the other night and did a format on a card in my 680 before I pulled things off of it. Immediately I tried recovering files, and while various utilities do restore WAV files that seem to be the correct size (and show up as the right length in players/editors), they all play with small bursts of audio, followed by a bunch of static. Sometimes there are small bursts of audio at volume levels that are way too high. I've tried manually importing as RAW in Audacity using various settings, but nothing I've tried gets me any better off than simply opening as WAV.

What's odd/interesting is that I had recorded some MP3s on that card in January with one of my DR-08s (prior to recording several other shows and several formats), and those files play perfectly after recovery. Which makes me think that *maybe* the 680 isn't doing anything to mangle the files when doing a format. But...what's going on?

Any ideas? Has anyone run into this?

Offline it-goes-to-eleven

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #1 on: October 22, 2013, 08:42:25 PM »
How many channels are the files?  How large is the card?

Stating the obvious - don't modify the card or allow anything to card. If there is a write protect switch, enable it.


Offline lukpac

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #2 on: October 22, 2013, 10:38:43 PM »
How many channels are the files?  How large is the card?

Stating the obvious - don't modify the card or allow anything to card. If there is a write protect switch, enable it.

Mono files. 16 GB card. Haven't hit write protect (yet), but haven't written anything to it.

Offline anr

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #3 on: October 23, 2013, 01:39:26 AM »
I have a number of utilities but the consistently best one (IMO) is Card Recovery.  Worth a shot.

Offline lukpac

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #4 on: October 23, 2013, 09:08:37 AM »
I have a number of utilities but the consistently best one (IMO) is Card Recovery.  Worth a shot.

I can't recall if I tried that one or not. I'll see when I get home.

I'm still perplexed that the much older MP3s seemed to get restored perfectly, while the new WAVs have issues.

Offline it-goes-to-eleven

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #5 on: October 23, 2013, 10:39:21 AM »
You always want to do the write protect because it is so easy for an OS, application, toolbar, virus, etc to write to the card (whether you know it or not). The best practice is to not even work with the original media.  You take an image and work on that.

Have you deleted anything from the card since the previous format, before the accident?  I always advise against that in normal workflow, since it can result in fragmentation that makes any subsequent recovery effort far more difficult. Basically, audio samples in the correct order vs. jumbled pieces to an audio puzzle.

If there have been no deletions, your audio should be in contiguous blocks.  The fact that it is mono actually makes it a bit easier to restore.

PCM audio is a series of bits that are assembled to form a sample. Sometimes a sample is two 8 bit bytes, making a 16 bit sample. Other times it is 24 bits.  If one bit, byte or "chunk" is missing, then portions of the subsequent audio often become jumbled noise. From that point forward, the only way to get "aligned" again is to get lucky, or fix it.

It's like if I gave you a list of 10 phone numbers, each 7 digits.  You know that every 7 digits there is a new valid number you could dial. But if one digit was lost in the list, all of the subsequent numbers would be invalid.  If you could find the missing digit and replace it with a number - any number - then the subsequent phone numbers would again be valid.  The one sample would be wrong, but a one sample error is very easy to fix in audio.

If you capture and save a raw image of the card you could revisit this recovery project in the future.

Your audio is likely there and can be recovered via expertise and time.

Offline lukpac

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #6 on: October 23, 2013, 11:25:28 AM »
Have you deleted anything from the card since the previous format, before the accident?  I always advise against that in normal workflow, since it can result in fragmentation that makes any subsequent recovery effort far more difficult. Basically, audio samples in the correct order vs. jumbled pieces to an audio puzzle.

Since hitting format, I haven't touched the card except trying to read from it. To the recorder and Windows, the card is empty except for the basic file/directory structure that gets put there with a format. Prior to that I hadn't deleted any files; I always did a format after downloading from the card. The files I'm trying to recover were the first files on the card after the previous format.

It definitely seems likely that everything is still there, but I'm perplexed why I'm having issues.

Could there be some issue with the fact that I was writing 5 files (4 mono and 1 stereo) at once during recording? I.e., that the recovered files are actually a mix of those 5 files? It just occurred to me that in the case of those (much older) MP3s, only one file was being written at a time.

Offline it-goes-to-eleven

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #7 on: October 23, 2013, 12:29:33 PM »
Could there be some issue with the fact that I was writing 5 files (4 mono and 1 stereo) at once during recording? I.e., that the recovered files are actually a mix of those 5 files? It just occurred to me that in the case of those (much older) MP3s, only one file was being written at a time.

That is surely it.  Those files may be interleaved on the recorder, probably using some blocking factor. Since you have stereo and mono, it could be 4 in one pattern, with an odd duck 5th.

You could do an experiment with another card, reproducing the recording.  If you record each channel with a tone at a very different amplitude, it should reveal how the channels are physically ordered on the card.  You could then write a program to re-assemble the raw blocks.

Offline IowaClint

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #8 on: October 23, 2013, 04:08:24 PM »
Lukpac,  Is this the Mike Mangione and the Union show from the other night?

Offline lukpac

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #9 on: October 23, 2013, 04:09:22 PM »
Lukpac,  Is this the Mike Mangione and the Union show from the other night?

Bingo! Hey!

Offline IowaClint

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #10 on: October 24, 2013, 10:55:28 AM »
If you need copies of what I got let me know.  Nice to meet you as well. 
~Clint

Offline rigpimp

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #11 on: January 13, 2014, 02:22:36 AM »
I had a 1TB external drive freak out on me and I recovered most files with a free utility called Recuva.  It is made by Piriform the same company that makes CCleaner.

http://www.piriform.com/recuva

Good luck.
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Offline lukpac

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #12 on: January 13, 2014, 08:39:29 AM »
I had a 1TB external drive freak out on me and I recovered most files with a free utility called Recuva.  It is made by Piriform the same company that makes CCleaner.

http://www.piriform.com/recuva

Good luck.

Thanks, I'll take a look.

I've been meaning to recreate this to try and see if I can write a utility to put the files back together, but I haven't gotten around to it yet.

Offline starscape182

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #13 on: September 12, 2014, 10:35:28 AM »
Hello, new user here  :) I know this is quite an old thread but I was curious to see if there was anyone else who has experienced this same issue. Lukpac, did you end up finding out what was wrong with the files? and in doing so, end up fixing them?

I too am having trouble recovering a deleted audio file from my dr-680. While I have no trouble finding the file using dedicated recovery software, each one results with the same static bursts of audio.

If you did end up writing something to rebuild the audio files, I would love to know if anything was able to come of it.

Hoping this message gets out there!!

Thanks   ;D

Offline lukpac

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Re: Recover files after accidental format? (DR-680/user error)
« Reply #14 on: September 15, 2014, 07:32:27 PM »
Still a pending project for me, but I haven't tried anything yet...

 

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