Audacity is clogging up temp files

[W.Vermeer]

Hi,

I mainly use audacity to convert audiobooks m4b files to mp3 files and split them in smaller chuncks. But when I load an audiobook of about 13 hours, it's clogging up my temp files folder, it takes forever to load and normalize and when it's to full, audacity won't do anything anymore.

What can I do to prevent that?

Thanks,

Katelijntje

[steve]

Audacity is designed for high quality audio processing. It requires uncompressed audio, so when you import an M4B file, Audacity will copy the file into a high quality uncompressed audio format that it is able to use. 13 hours is an enormously large file and when copied to the high quality format required by Audacity it will expand to around 13 GB for a mono track or double that for a stereo track.

Working with such large files is very demanding on the computer, so it is highly recommended that the first thing you do is to split the file into more manageable size chunks. 1 hour sections would probably be a reasonable compromise.

Open the file in Audacity, select a section of about 1 hour, then select "Export Selection" and choose WAV as the file format (this will avoid loosing sound quality).
Delete the section after it has been exported and select the next hour.... continue until the entire track has been Exported.

Close the Audacity Project and start a new Audacity session. All temp files should be automatically deleted when you close the session.
You will now be able to work on the individual sections much more comfortably.

[W.Vermeer]

Hi Steve,

Thanks for the reply, now I understand better why it's clogging up my disc. I have been doing what you suggested, but in mp3 instead of wav. I don't have a lot of knowledge about the different formats, so is wav better than mp3 and why?

Thanks,

Katelijntje

[steve]

MP3 files are a lot smaller than WAV files - that makes them good for MP3 players, or sending by e-mail.
There is a trade-off with the MP3 format - in order to make the file size small, some of the audio data is discarded. This produces the (much) smaller file size, but looses a little bit of sound quality. The loss is not recoverable. If you edit an MP3 and Export it as an MP3, then there are losses times two. Each time the audio is encoded as MP3, there is a little more loss, and the sound quality gets worse.

WAV format does not compress the data, none of it is discarded, so the sound quality is virtually identical to the original.

[Gale Andrews]

Open the file in Audacity, select a section of about 1 hour, then select "Export Selection" and choose WAV as the file format (this will avoid loosing sound quality). Delete the section after it has been exported and select the next hour.... continue until the entire track has been Exported.

Close the Audacity Project and start a new Audacity session. All temp files should be automatically deleted when you close the session. You will now be able to work on the individual sections much more comfortably.

Just to clarify that while deleting sections makes it easier to see "where you are" it doesn't reduce temporary space and in fact will marginally increase it, because Audacity stores changes as extra files so you can undo the changes if you need to.

What you could do to save exporting files and re-importing the smaller ones is to select a section for export, normalize that section, File > Export Selection then clear the Undo History at View > History. Then repeat for each section. This means you need no more than the space to import the whole file then normalize a section. When you clear the Undo History , you will remove the extra files which would have allowed you to undo the normalization, so getting you back to the disk space used for the original import. To clear the history at View > History, click the bottom item in the "Action" list, then click the up arrow to right of "Levels to Discard" until the number is as high as it will go. Then click "Discard".

Another idea - Audacity's default quality of 32-bit float is probably higher than you need for audio books. Click Edit > Preferences: Quality and reduce "Default Sample Format" to 16-bit. That will halve the disk space used.


Gale