Hello -
I am on a mac, sequoia 15.7 os, audacity version 3.7.8
I imported a 1.2MB mp3 file into audacity and saved it as an audacity project. The .aup file is almost 35MB.
Is that normal? And, is there any way to reduce the project file size?
Thanks for any suggestions.
The whole audio is stored in the project file. Every time you do something that you can undo, another copy of that audio is added to the project file. When doing a lot of editing of a large audio the size of the project file can build up quickly. Closing the project will remove all those undo buffers (you will see a message on the screen about compacting, and that is what it is doing).
thank you for the response. It is interesting, as i just opened the mp3 in Audacity, and then saved it as a audacity project.. I didn’t do any editing at all. i tried another test just now too, to confirm, and even without doing any editing the .aup file is ~35 MB and the actual MP3 is just 1.2MB.
Could there be anything else going on, or maybe this is just the behavior of Audacity.
Your suspicion is correct. There is more going on.
The MP3 file is compressed and bit rate limited.
The audio data you are working with in Audacity is full uncompressed 32-bit float data.
Audacity converts the imported file into full-range data so you can work with it in as detailed a manner as possible. When Audacity exports it to MP3 again (if that is the format you choose), it will be compressed again.
Yes, but that undo information is discarded when you close the project.
Say you have a 32-bit float Audacity project, with one stereo track of a given length. You can calculate how long a 32-bit stereo WAV file would be. The size of the Audacity project will be almost exactly that.
For example:
Audacity project, one stereo track, 32-bit float, 44100 Hz, 27 min 20 sec: 590.1 MB
Exported WAV, 32-bit float: 582.1 MB
Exported MP3, 256 kbps: 52.8 MB
MP3 files are highly compressed, and while that’s fine when listening to them, Audacity (and I assume many other audio editing programs) cannot edit them as MP3. When you import the file, it converts it to an uncompressed WAV format, and stores that in the project file.
Every time you import and then export again to MP3, the audio will lose quality. If you do it over and over again the quality will become very bad, so if you’re working on an important project, keep the data as uncompressed WAV inside the AUP3 file, and only export to MP3 when you’re completely done.
Thanks to everyone for the replies and information. This helps a lot.