I have this very long recording of a work session (over three hours) that wasn’t saved, and couldn’t save. For some reason, saving was disabled. Using the terminal, I recovered the full content of the temporary files directory, with a huge number (3220) of files with the .au extension, spread in 13 directories (d00 through d0c) inside the temp files directory audacity-user/project1490016467/e00.
I can open any of these .au files with Audacity, but not with a number of other programs I have tried. So it seems these .au files have a proprietary format. A hex editor suggests they all start with a header:
My goal would be to concatenate somehow those 3220 files into a single huge audio file, and to export the result to a more standard audio file format.
Any suggestion on how I can proceed? Is the format of those files documented somewhere? Can I script or import those files by batch?
Moderator note: It is a bad idea to use your e-mail address for your user name. Spam bots will come to the forum and harvest your address. To remove your e-mail address from your user name, I deleted the other unregistered account you have called “jdmuys” and renamed this account as “jdmuys”.
Are you using a USB recording device? You should connect USB devices to a spare USB port on the computer, not share the USB port with other devices. This helps to avoid recording freezes.
Did you try pressing the yellow Stop button? Did you force quit Audacity? If you force quit then if you simply restart Audacity, it should offer to automatically recover the project .
Force quit is the safest choice if a recording has frozen. Even if you choose Audacity > Quit Audacity, then Audacity offers to save changes and you say “Yes”, occasionally the AUP file or even the data may not be saved
Or if you are comfortable installing Python, try this script which tries to recreate the lost AUP file: https://forum.audacityteam.org/t/alternative-recovery-tool/30964/1 . The script forces the project rate, selection position, zoom level and so on but you can edit the script if you want to or resample to the correct project rate if needed when you open the AUP file.
Both solutions suffer from the same issues.
Only unedited recordings will recover with the block files in the correct Timeline position.
You cannot recover stereo recordings in completely correct channel allocation (left channel in the upper track and right channel in the lower track) unless your sort tool and the operating system’s file system have sufficient timestamp granularity to distinguish when the left- and right-channel AU files were written. As far as I know Mac OS X doesn’t have sufficient granularity.