Importing a large audio MP3 file

[mookien]

I'm trying to import a rather large MP3 file (> 230 MBs - a four-hour radio program that I recorded from my PC) and Audacity seems to get hung-up and won't process/import the file. I'd like to edit this file - removing certain segments. I'm using the stable version. Is there a limit to file size? Should I convert my file to another format or a lesser quality MP3? Any good programs that do this? Thanks!

[steve]

The max file size is about 2GB uncompressed. (This is not a bug, it is a limitation due to 32 bit addressing, and equally applies to the max size of a WAV file).

Use an mp3 splitter to make smaller mp3's so that when uncompressed it is less that 2 GB.

Also make sure that you have LOTS of free disk space - I'd recommend a minimum of 10% of the total disk space + 10x the uncompressed file size (for a 200GB drive and a 1 GB file, that would be a minimum of 20 + 10 = 30GB free space minimum).

Also remember that it will take Audacity some time to import very large files as it has to uncompress them and calculate the wave display before it can proceed.

[alatham]

I have a quick correction.

Steve said:

The max file size is about 2GB uncompressed. (This is not a bug, it is a limitation due to 32 bit addressing, and equally applies to the max size of a WAV file).

This is only true of exported wav files. Audacity can import larger files and export them to a format other than wav. You simply can't export wav files larger than 2GB.

I agree with everything else. Either mookien either doesn't have the available drive space, is working from a network drive, has a corrupt mp3 file, or is simply not waiting long enough. Audacity's "progress bar" when running certain processes doesn't seem to be perfectly accurate so if it stops, walk away for 10 minutes and make a cup of tea, it might still finish.

The tea is important, but others might disagree.

[steve]

This is only true of exported wav files. Audacity can import larger files and export them to a format other than wav. You simply can't export wav files larger than 2GB.

Are you sure about that? I mean, have you tested it?
The reason that I ask is that I remember someone having problems with a project that contained very long tracks and the project crashed as soon as the uncompressed file size got to the 2 GB mark, but only on a 32 bit machine - On 64 bit hardware and OS they did not have the problem (and they had plenty of free disk space on both machines).

(I can't test it myself - not enough free disk space)

[kozikowski]

A 230MB MP3 file at 10:1 compression will expand itself to 2.3GB when it is imported and edited. The import process alone may take enough time for you to go down to the 7-Eleven for a Big Gulp. From that point on, Audacity will have to manage the whole file and two or three UNDO levels, so the whole project can't take any more than about 10GB or so. Invoking the 10% free disk space rule.....you get the idea? This is much too large project for any but the most extreme professional computer.

So yes, you need to break it up into manageable chunks before you do any processing.

As you process, you need to remember what you did so you can apply the same processing to each chunk. Legal Pads and nice Pentel Pens, I think, because not all of the tools will let you save the settings and preferences.

Somebody is forcing you to do this project, right? You didn't volunteer, did you?

Koz