Importing mp4, exporting to wav, corrupts files

Was having issues exporting WAV files, WAV files were corrupted, and the MP4 would get currported, crashing system and audacity.

Using Audacity 2.0.5, Windows 7 Ult 64bit, should have all relevant codecs working properly.

Issue seems to be with a large MP4 ~45 minutes, 300MB recorded with OBS, and making ~200 edits in audacity. tried opening a smaller 35 second file, also recorded with OBS, and was able to edit and save to WAV and orginal MP4 still worked the same.

It also could be w/e was causing the issue had resolved after a reboot or similar system change, as I haven’t tried with another similar OBS file.

Any rate, I have somehow manged to corrupt the original mp4 and both backups I made, but the last export to WAV off the audacity restore (system crashed during export) seems to have worked, though I’m sure if the edits were saved.
Do think there’s anyway to fix the MP4 file now? there’s no windows 7 backup restores of it. and NOTHING seems to recognize it, most programs, including windows 7 will lag for minute when trying to do anything with the file, the size is still the same.

Your description screams Very Unstable Windows install. Do you have room on your system drive C:? When was the last time you did a System Virus Scan, the one where you can’t use the computer for several hours?

MP4 would get currported, crashing system and audacity.

System Crashes can many times be traced back to bad hardware drivers and software. Making a Win7 machine fall over is not that easy.

If you opened a sound file and the original file became corrupted, then you may have a lot more problems than Audacity.

That’s assuming the machine is otherwise in perfect condition. Did you install the memory yourself?


Opening (reading) an MP4 file (or any file) shouldn’t change it in any way. The only way Audacity could possibly corrupt the file is if you save (export over it) with a file of the same name. Files can be changed (or corrupted) when you write, but not when you read.

Any rate, I have somehow manged to corrupt the original mp4 and both backups I made,

So, I’m with Koz… You might have a bad hard drive or bad memory. Were the backups on the same hard drive? If you backups are on a some sort of portable drive, you might try playing the files on a different computer.

It’s also unlikely that Audacity would create a corrupt WAV file. There could be something wrong with the sound in the file, but the file itself should be OK.

AAC audio can be complex to repair ( ) but you could examine the file in “MediaInfo” from . Get the version without installer, because the installer may have malware or adware.

If MediaInfo does not give full information about the file you might be able to rescue the file using SoX from . You have to use it at the command-line, there are no buttons and menus. Something like

sox -r 44100 -t mp4 broken.mp4 fixed.mp4

might possibly work. At least the docs say you could act on headerless MP3 that way.

Of course the file could be all nulls or otherwise corrupted by the problems you’ve been having.


sorry getting back so late, so did a full scan with this, took about 20 hours, with at least 12 hours being over the these corrupted files of <500MB. The only positive was a “special” sony vegas “add on” acquired through a torrent, but these types of files are notorious for false positives and I’ve never any problems with it before and the all the comments reviews were that is was verified negative.

Yes memory installed myself, but funny you mention this, Memory was limit on my responsible overclock, and for about 2 years I left the memory at a fairly high voltage, the largest of any voltage ups. It wouldn’t surprise if at some point there was some minor damage to the RAM. Is that a common culprit for problems like these?

If you overclock you are outside your warranty and you fix problems caused by it yourself. :wink:


Well let’s hold the presses and be reasonable people, Windows Memory Diagnostic just showed no errors, run it about a twice a year, never had an error yet. Personal qualms of OCing aside, we still have no great culprits. I would be interested in checking the OS itself for errors, but not sure the best way to go about. There is a slight chance I’m at higher risk for that since the Windows 7 64 bit ult was installed from a supposed “upgrade” that University of Washington offered free 4 years ago. The idea with the install file I think was to upgrade from XP to 7, requiring you had XP, but it could essentially straight install 7 from a reformat, I believe what I did, I don’t remember there being much if XP verification required.

Even if responsible OCing did damage my RAM it will still behoove open software devs to figure out where the lack resiliency is stemming from. I’ve never had any serious problem such as this on this machine and OS install in 4 years, where all adults here.

You were given a suggestion about recovering the faulty MP4.

For WAV exports, Audacity should warn you if the exported file size does not correlate to the input data.

Audacity or other applications cannot crash the system as I am sure you know. If the system crashes the cause is low level hardware or software issues on your computer. I suggest you look at the memory dump ( ) .

if the system crashes it is expected that files that were being written could be corrupted. Can you replicate Audacity corrupting MP4 exports if the system does not crash? Can you replicate the corruption in WAV exports? In what way was the WAV corrupted? Did you try importing it with File > Import > Raw Data… ?