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Please help me salvage recorded MP3 that seems to have been corrupted, [TOS #6: was “Help with file playback issue” in General Audio]
kwdelre
post Jan 6 2013, 01:20
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Hello everyone,

I really need some help here. I recorded a meeting using a MemoQ Pen Recorder MQ-94. It records in MP3 format and has worked in the past. Well, after the meeting I went to download it from the flash drive and the file will not playback on anything. (I've tried all I can on both windos and Mac) The file itself appears to have recorded because it is a 17 mb file, so I know it wrote something. There is clearly an issue with the recorder itself since it used to work fine, but what I need to do is try to recover this file.

When attempting to open the file on a Mac it does nothing. On windows it gives me a general playback error as if it didn't recognize the codec.
The only program I was able to get the file to even open in was Audacity. In Audacity the file appears as a 1.5 sec clip and when I play it, it sounds like the entire hour long meeting in a second.

I tried two programs to repair the file without any luck. (All Media Fixer, and MP3 Repair Tool)

I can't figure out anything else to try at this point to recover this file. Any help would be greatly appreciated.

-Will
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DigitalMan
post Jan 6 2013, 04:59
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You could try using the program Foobar2000. Right click on the file in the playlist view and choose the "verify integrity" and / or "rewrite MP3 data" or "rewrite header" options. Good luck, hope it wasn't too critical of a meeting for you...


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Was that a 1 or a 0?
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splice
post Jan 6 2013, 11:26
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... but remember to make a copy of the file first, in case you accidentally overwrite the original...
Does the memo recorder itself play the file back OK?
Even if the header is corrupt, the individual frames in the file are hopefully OK.
If you have no luck, you could post the first 30 seconds or so of the file (or the first 512KB or so of it) to the uploads section here so the experts can take a look.

This post has been edited by splice: Jan 6 2013, 11:28


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Don Hills
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DonP
post Jan 6 2013, 13:50
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QUOTE (kwdelre @ Jan 5 2013, 19:20) *
. In Audacity the file appears as a 1.5 sec clip and when I play it, it sounds like the entire hour long meeting in a second.


Maybe the sample rate got corrupted? There's some messing you can do with that in Audacity (on a copy).
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kwdelre
post Jan 9 2013, 06:56
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Hi everyone. Thank you very much for the reply.

I tried Foobar and it would not even open the file.
In audacity I tried re-sampling it at various rates and still get nothing.

In the next day or so I will try to post a sample of what this pen is recording, to see if anyone can help me.
Thanks again!
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mjb2006
post Jan 9 2013, 14:01
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Get xvi32 (free binary editor) and open the file in it, maybe stretch the window a bit to show more data, then send us a screenshot so we can see the bytes at the beginning of the file. To get the screenshot in Windows Vista and up, look in the Start Menu for the Snipping Tool, under Accessories (and drag it to your taskbar, as it comes in quite handy). It will let you click-drag a box over what you want to copy, then give you the option to save as a PNG. Upload the PNG to ImageShack or any other image sharing service and link to it here with the "Insert Image" button (looks like shapes in a picture frame).
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kwdelre
post Jan 10 2013, 01:39
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QUOTE (mjb2006 @ Jan 9 2013, 07:01) *
Get xvi32 (free binary editor) and open the file in it, maybe stretch the window a bit to show more data, then send us a screenshot so we can see the bytes at the beginning of the file. To get the screenshot in Windows Vista and up, look in the Start Menu for the Snipping Tool, under Accessories (and drag it to your taskbar, as it comes in quite handy). It will let you click-drag a box over what you want to copy, then give you the option to save as a PNG. Upload the PNG to ImageShack or any other image sharing service and link to it here with the "Insert Image" button (looks like shapes in a picture frame).


Thank you for the detailed suggestion.

This screen shot is of the "fixed" file made from MP3 Repair Tool, as XVi was unable to open the original.
Thanks for the help!





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mjb2006
post Jan 10 2013, 03:04
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xvi32 couldn't open the original? Now that is weird. It doesn't care what the format is. It should open anything. Was something locking the file?

What you did open does not look like MPEG audio to me. Every 288 bytes, the same structure repeats: 00 E3 48 C4 00 (rest varies).

Is this what the whole file looks like?



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kwdelre
post Jan 10 2013, 04:20
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QUOTE (mjb2006 @ Jan 9 2013, 20:04) *
xvi32 couldn't open the original? Now that is weird. It doesn't care what the format is. It should open anything. Was something locking the file?

What you did open does not look like MPEG audio to me. Every 288 bytes, the same structure repeats: 00 E3 48 C4 00 (rest varies).

Is this what the whole file looks like?



Yeah it looks like it does repeat...
This may be the product of running the broken mp3 through the repair software, maybe not the original.
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splice
post Jan 10 2013, 07:15
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QUOTE (kwdelre @ Jan 9 2013, 19:20) *
...
Yeah it looks like it does repeat...
This may be the product of running the broken mp3 through the repair software, maybe not the original.


It does look broken. The repeating pattern makes sense as a frame header if you allow that the first byte should be FF instead of 00. (FF E3 48 C4 instead of 00 E3 48 C4)
The rest of the bits decode as:
MPEG 2.5
Layer III
Not protected
32K Bitrate
8 KHz sampling rate
Mono
Not copyright
Original Media

This would be consistent with a memo recorder designed for best performance at low bitrates. Or it could simply be a coincidence...

We really need to see the original file.

This post has been edited by splice: Jan 10 2013, 07:17


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mjb2006
post Jan 10 2013, 08:49
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In xvi32 you can do a search and replace for that sequence ... might work smile.gif
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kwdelre
post Jan 11 2013, 01:38
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I will get an audio sample ready to post.

Wanted to share the error message from Windows Media Player that may help troubleshoot. When trying to open the original file I get:
"The file you are attempting to play has an extension (.mp3) that does not match the file format. Playing the file may result in unexpected behavior."

Maybe a problem with the extension? It's supposed to have been written as an MP3, and the file extension is such, but it looks like it is not being identified as an MP3 format.
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kwdelre
post Jan 11 2013, 02:00
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I may not have file upload privileges yet. Or, I simply can't find that option. How would I go about that on this forum?
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Aleron Ives
post Jan 11 2013, 02:52
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That error means that although the file has the MP3 extension, it is not an MP3 file. The extension is just text at the end of the filename that makes it easy for Windows to know which program it should launch to open the file when you click it. If you rename the file with the JPG extension, Windows may try to open it with MS Paint, but Paint won't be able to play music. The fact you got that error indicates that the file is not a valid MP3 file. In light of splice's post, you could try changing the extension from MP3 to MP2 and see if the file plays, but as splice also said, the broken frame headers may be the cause of the problem.

As for where to upload the original file, try a file hosting site like File Dropper.
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mjb2006
post Jan 11 2013, 07:55
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nm.

This post has been edited by mjb2006: Jan 11 2013, 07:56
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Dynamic
post Jan 11 2013, 11:10
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QUOTE (kwdelre @ Jan 11 2013, 01:00) *
I may not have file upload privileges yet. Or, I simply can't find that option. How would I go about that on this forum?

For us normal members, these forums allow uploads only in the Uploads forum, not normal forums (unless you have special rights granted to upload files direct to a thread - e.g. to attach latest test version of your encoder), so that's sometimes an easier option than cloud hosting.
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splice
post Jan 11 2013, 13:00
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From looking at the sketchy info online, it looks like my guess about the header format is correct.
The MQ-94 is a 4 GB device with a recording time of 284 hours. That's almost exactly 32K bitrate.
The frame size is 288 bytes for MPEG 2.5 Layer III 32K bitrate 8 KHz sample rate, too.

Will,
Have you successfully played recordings made with this device before?
We really need a piece of the original file - preferably the first 512K bytes or so. You should be able to put it in the uploads thread, I'll leave it for someone else to advise you because I've never done it. There are various free utilities around which allow cutting a section out of a file.

Edit: Try HJSplit (http://www.hjsplit.org)
Specify 512 KB as the split size. It will generate a set of output files ending in .001, .002, .003 etc. Just upload the one ending in .001.

General question for the peanut gallery:
Does WMP support MPEG 2.5? Does Foobar2000?

This post has been edited by splice: Jan 11 2013, 13:46


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Don Hills
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Dynamic
post Jan 11 2013, 14:50
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QUOTE (splice @ Jan 11 2013, 12:00) *
Does WMP support MPEG 2.5? Does Foobar2000?


I'm sure fb2k always has in the past. Not tested it lately or ever tested WMP.


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Dynamic – the artist formerly known as DickD
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kwdelre
post Jan 11 2013, 21:37
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Okay, I was able to upload a sample file from the same time of recording.
Uploaded File

Thank you for taking a look.
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splice
post Jan 12 2013, 00:39
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QUOTE (kwdelre @ Jan 11 2013, 13:37) *
Okay, I was able to upload a sample file from the same time of recording.
Uploaded File

Thank you for taking a look.


Aha... same strange headers.
I wonder if you're supposed to use a utility supplied with the pen to convert these to standard MP3 files?
Some of the adverts imply that it makes 128K bitrate MP3 files,
You still haven't answered the question - have you previously been able to listen to files recorded by this pen?
If so, it implies that it has become defective.

Update: I "fixed" the headers. VLC tries to play it, but it's pretty garbled. There are 2 possibilities:
1. You're supposed to use a utility supplied with the pen to convert these to standard MP3 format.
2. The pen is broken and not correctly writing the files.

This post has been edited by splice: Jan 12 2013, 00:58


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mjb2006
post Jan 12 2013, 01:56
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Turns out the first byte in each frame header varies. It's not always FF. So I opened it in xvi32 and replaced the sequence "__ E3 48 C4 00" with "FF E3 48 C4 00". I posted the result in the same upload thread.

I did not get you saying "testing, testing" ... instead, I got music ... some rap about "I'll take the girl in the front" smile.gif
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kwdelre
post Jan 12 2013, 04:11
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QUOTE (splice @ Jan 11 2013, 17:39) *
Aha... same strange headers.
I wonder if you're supposed to use a utility supplied with the pen to convert these to standard MP3 files?
Some of the adverts imply that it makes 128K bitrate MP3 files,
You still haven't answered the question - have you previously been able to listen to files recorded by this pen?
If so, it implies that it has become defective.

Update: I "fixed" the headers. VLC tries to play it, but it's pretty garbled. There are 2 possibilities:
1. You're supposed to use a utility supplied with the pen to convert these to standard MP3 format.
2. The pen is broken and not correctly writing the files.


Sorry, yes, I have been able to use it in the past, but it has not always worked correctly.


QUOTE (mjb2006 @ Jan 11 2013, 18:56) *
Turns out the first byte in each frame header varies. It's not always FF. So I opened it in xvi32 and replaced the sequence "__ E3 48 C4 00" with "FF E3 48 C4 00". I posted the result in the same upload thread.

I did not get you saying "testing, testing" ... instead, I got music ... some rap about "I'll take the girl in the front" smile.gif

Hahaha....oh yeah, that's right I was playing an Asher Roth song, lol. That is awesome that you were able to hear it!
Now......I will attempt to do what you described...

One thing that is odd about this is that I could not open the original file in XVI until I ran it through the "All Media Fixer." But the short sound byte I uploaded was able to open in XVI without 'fixing'.....

This post has been edited by kwdelre: Jan 12 2013, 04:13
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kwdelre
post Jan 12 2013, 04:52
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I am beyond words right now. I cannot thank you all enough, especially you mjb2006. The file is working now because of your genius.
Man I love the internet!! laugh.gif

This post has been edited by kwdelre: Jan 12 2013, 05:00
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mjb2006
post Jan 12 2013, 11:19
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Still, I think your pen is broken smile.gif
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kwdelre
post Jan 12 2013, 20:37
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QUOTE (mjb2006 @ Jan 12 2013, 04:19) *
Still, I think your pen is broken smile.gif



Oh, most definitely! I already purchased a replacement....USB stick version. Records much better too.
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