Egads! Three hour recording = 20 second, 4 *gig* file? Halp.

[DowninFront]

Hey folks, been an Audacity user for years, never had a problem quite like this before. We do our podcast recordings in Audacity, and yesterday after a three hour recording session I exported the track to .wav like I usually do, immediately, so it was safe and sound. (So to speak.)

The export looked the same as it always does, and finished just fine, and as is my habit I checked the size of the file on disk before closing Audacity just to make sure it exported right. Yep, 4 gigs, sounds about right. Close Audacity. (Open Audacity later for another thing, so the save-my-life cache is gone.)

Today, I go to listen to the recording and start mixing it, and...it's 22 seconds long. Four gigs, yes - but 22 seconds long. Aside from the rather massive intrigue I find in a dead file that somehow doesn't know it's dead and maintains it's proper filesize, my real problem is I'd love to get that recording back. Anyone have any ideas?

Here's a screencap of my file info, if it helps.

[kozikowski]

WAV has a limit to the size of the show it will hold. It's 4 GB. If you go over the magic limit, the integrity of the file system will go away and/or become unstable. I think we're finding out what happens when you go over.

http://en.wikipedia.org/wiki/WAV

The WAV format is limited to files that are less than 4 GB, because of its use of a 32-bit unsigned integer to record the file size header (some programs limit the file size to 2–4 GB).[14] Although this is equivalent to about 6.8 hours of CD-quality audio (44.1 kHz, 16-bit stereo), it is sometimes necessary to exceed this limit, especially when greater sampling rates or bit resolutions are required.

Normally, Exporting a WAV is the get out of jail card, but in your case, I would probably start Saving a Project as well. Since Projects are billions of little files, they don't run into the Sound Format Limit.

You may also be capturing the show in 32-floating -- the Audacity default -- instead of 16-bit. The file sizes grow a lot when you do that. Reset in Audacity Preferences and restart Audacity after you do.

Koz

[DowninFront]

Huh, interesting stuff.

So it's likely that this one is a goner, yeah? I agree with your suggestions for ways of avoiding this in the future, but boy it'd be nice if I hadn't shot myself so thoroughly in the foot here.

[Gale Andrews]

The only reasonable explanation of the bit rate Finder shows and hence the size is that you either exported as 32-bit WAV with 48000 Hz project rate or 16-bit WAV with 96000 Hz project rate. You really don't need either 96000 Hz or 32-bit if you are podcasting.

Export as 16-bit WAV at 44100 Hz then you have 3 hours 20 minutes for 2 GB (many applications won't play WAV files larger than 2 GB). You still need to export as 16-bit even if you set the Quality Preferences to 16-bit.

For trying to get the recording back, try File > Import > Raw Data in Audacity. You will need to know whether you exported 16-bit/96000 Hz or 32-bit/48000 Hz - I suggest opening the file in QuickTime (Command - I) or iTunes (Control-click > Get Info) to find out.

Since Projects are billions of little files, they don't run into the Sound Format Limit.

Yes but remember that Audacity projects themselves still have the 2^31 samples limit - they will be completely broken if you re-open them having saved them containing more then 2^31 samples. But that's a lot of audio - about 13.5 hours at 44100 Hz


Gale