Audacity temp files

[MDOC]

My computer froze when I ran one too many write-to-disk processes. While doing that, I was recording my tapes through audacity. I recovered from the crash, restarted audacity, and this message popped up:



How can I recover my temp files, and can I recover my recordings (there were three in the same project) after a system crash?

[steve]

Crash recovery is notoriously difficult - it's like trying o reassemble thousands of tiny fragments from a shattered mirror. However if you want to have a go, see here: http://audacityteam.org/wiki/index.php? ... shRecovery

[MDOC]

I have successfully recovered the audio files using aud_recover. However, when played in Audacity, the audio sound is fast-talking gibberish. I halved the data rate and the audio is back to normal. But the audio has to be played back at half the data rate I recorded at (22050 from 44100). Looks like a bug in aud_recover.

[steve]

That's not a bug, that's a miracle
As I said, crash recovery is notoriously difficult, so it's great that you managed to get something back.

My guess is the double speed thing is that it recovered half the data (one channel of a stereo recording) but knowing that it should be stereo , split the data between the two tracks, thus halving the length (doubling the speed). Was the original recording stereo? Is it still stereo, or 2 channel mono?

Backing up data for important projects is very important, and in particular, keeping wav file backups of original recordings.
I generally Export my original recording as a WAV file as soon as I have made it, then make backups of the project at various stages as I go, using "Save Project As" and appending a number to the file name. I then end up with a series of projects (project001, project002, project003...) and I also have my original recording (for very important stuff, I make a couple of CD copies of the WAV file as well as the copy on my hard drive). This uses a lot of disk space, but provides a lot of safety.

[MDOC]

That's not a bug, that's a miracle
As I said, crash recovery is notoriously difficult, so it's great that you managed to get something back.

Heh, well, it was much easier with aud_recover since I had 4,729 files to put together 2.5 hours of recording. It was either that or start over, which wasn't really a problem, because it's only 2.5 hours; but I wanted to see what's available in terms of recovery.

My guess is the double speed thing is that it recovered half the data (one channel of a stereo recording) but knowing that it should be stereo , split the data between the two tracks, thus halving the length (doubling the speed). Was the original recording stereo? Is it still stereo, or 2 channel mono?

The original was stereo, 44100Hz, 32bit float. Here's a sample MP3 after recovering one file of one channel (attached). (it's in mono, since it's a file from either the left or right channel of stereo).
And no, both channels were recovered automatically if you specify 2 as the number of channels, one file for left channel, one right.

But one curious observation: running aud_recover again and specifying the same params except for the number of channels (I used the stereo parameter, this time I tried mono), I compiled one selected small sample file (named b000004.au). Importing the resulting sample file into Audacity resulted not only in doubling the length of the track, but repeated the same audio as the file compiled with 2 ch (stereo) parameter from the same b000004.au file. So I was hearing the same 6-second audio twice in a 12-second file! And yet gibberish, too.

Backing up data for important projects is very important, and in particular, keeping wav file backups of original recordings.

If you have lots of HD space!

[waxcylinder]

Backing up data for important projects is very important, and in particular, keeping wav file backups of original recordings.

If you have lots of HD space!

No need to clog up your PC with backups of Audacity data and WAV files - just buy one (or better two, for a redundancy copy) external USB disc drive - they are very cheap these days.

WC

[steve]

Or a box of CDR's

I've recently bought an 8 GB USB memory stick which was quite cheap - handy for keeping temporary backups with smaller projects.

You need to be a bit careful backing up projects onto external devices - if path names change, then the .aup project file can loose track of the data fragments. No problem such with backing up WAV files though.

[MDOC]

OK, might get a 500GB external USB drive for $140.

EDIT: changed my mind. An internal drive, 500GB, is more than 6 times faster. Same price.

[kozikowski]

Have you ever opened up your AUP file in a text editor and read it?

http://kozco.com/tech/audacity/aup1.jpg

Channel 0 is left and Channel 1 is right. Audacity does things split like that which is why recovering from a crash is almost impossible. Actually, since you failed too, is impossible. Nobody to my knowledge has ever recovered a show from a pile of rubble.

Koz

[MDOC]

Have you ever opened up your AUP file in a text editor and read it?

http://kozco.com/tech/audacity/aup1.jpg

Yes, I've seen it. But that's not the type file I recovered from. I recovered from the raw data in my temp directory.

Channel 0 is left and Channel 1 is right. Audacity does things split like that which is why recovering from a crash is almost impossible. Actually, since you failed too, is impossible. Nobody to my knowledge has ever recovered a show from a pile of rubble.

I did not fail to recover my data, although the data rate had to be halved. I encountered no errors. I suspect the reason I was successful was because I knew I had all the files necessary to recompile into one file.