MP3Gain Express for Mac OS X

Version 1.2
Based on MP3Gain 1.5.2

ScreenshotMP3Gain Express is a basic port of MP3Gain to Mac OS X. It allows you to analyze or apply track gain to a list of MP3 files. Anyone who has used the Windows UI for MP3Gain should find this one familiar, as it was designed to look similar to that version.

It's easy to use. Simply select the files you want to increase or decrease the volume of, enter the desired loudness, and click Apply Gain to update your files.

Disclaimer: If you are using this program for the first time, please remember to back up your files before trying to modify them with MP3Gain. While the application should work fine for most users, differences between machines could result in problems that only affect a small number of people.

Download: mp3gain_mac12.zip (897 KB)
Requires OS X 10.7 Lion or later. (Pictured running under Yosemite 10.10)

Last updated on November 9th 2014:
Added the ability to drag and drop files or folders into the file list.

Version History

Questions and Answers (Also found in the included Readme file)

What is MP3Gain?
MP3Gain is a tool to increase or decrease the volume of MP3 files without re-encoding them. This is useful when you have a lot of music at different volumes, you can use this tool to make everything the same volume so that you don't need to adjust the volume on your MP3 player when listening to your music on shuffle.

What does MP3Gain Express do?
This version of MP3Gain only does three things. It can:
  1. Analyze MP3 files and write the volume information to a tag without changing the audio data itself. This is useful if you have a player that supports "ReplayGain" tags. (Not iTunes or iPods, so mostly useless on Mac OS X)
  2. Apply Gain to MP3 files. This updates the audio data in the files to apply the new volume directly to them. This is done without re-encoding the file, so there usually is no loss in audio quality compared to original data. (I assume that if you make the file loud enough to start "clipping" that this would count as quality loss. The loudness of digital audio can be represented within a range of values, and once you go above the maximum any points above the maximum can only be represented as the maximum itself. If the "Clipping" column shows Yes then this situation is occurring. In some cases, depending on how loud you go, you may not notice it. You can click the "Prevent Clipping" checkbox to automatically use a lower value if clipping would occur.)
  3. Undo changes applied to MP3 files, returning them to their original volume. This will only work if the file has previously had gain applied to it, and undo has not been performed on the file. The undo feature cannot remove file corruption in files that were accidentally damaged by the program.
What does MP3Gain Express not do?
MP3Gain Express omits several features of the original MP3Gain, hence "Express" tacked onto the name.
  1. Album gain is not supported. (All tracks have their volume adjusted individually, you can't adjust tracks as a group)
  2. MP3Gain Express does not back up your files for you. As with any application, there is a chance something could go wrong. If you've never used the tool before, I suggest backing up your files first to make sure it works as you intended.
  3. Versions of Mac OS X older than 10.6 are not supported. If you want an alternative, try Bery Rinaldo's port which is old and has more features: http://homepage.mac.com/beryrinaldo/AudioTron/MacMP3Gain/
Why port MP3Gain to Mac again, even though a port already existed?
This port was made to fulfill one need that I had. I wanted to increase the volume of a few tracks I had that were too quiet. I didn't need any of the other features of the program, so they aren't available in this port. I started this port a few weeks before Mac OS X 10.7 Lion was released, and Bery Rinaldo's port had not been updated in over 3 years so I assumed it was dead. It also wasn't compatible with Snow Leopard at the time.

I decided to do my own port for two reasons:
  1. The existing port was a front-end written in AppleScript. Anyone familiar with my previous work (MultiPatch for example) might be aware that I prefer to call code natively and not use an external tool to do the work. I felt that this could benefit from the increased flexibility of a native application.
  2. The existing port was bundled with PPC binary at that time, which would not work on Mac OS X Lion. My intention was to release the port around the time Lion came out in order to fill that gap.
After I reached the point where it was partially working, it sat untouched for a few months. By the time I eventually came back to it, Bery had updated his version with Lion support. I guess the only advantages of this version are that it would be slightly faster due to the native MP3Gain integration, and the UI is a bit more modern since it was designed on Snow Leopard and Lion. Disclaimer: I have not actually used his port, so my comparisons are based on the information on his website.

Is there a build of the command-line version of MP3Gain available on OS X for power users?
Yes. I am now providing a command-line build of MP3Gain with AACGain support. This is the command-line version of AACGain 1.9 built for OS X 10.6 or later. It is based on the 1.9 code from MP3Gain's SVN repository with no changes made. You can download it here.

Will this port be actively maintained and updated?
Probably not. MP3Gain itself isn't updated often anymore (Why would it be? It already does what it was intended to do) and I primarily wrote it for myself to use once every few years. I listen to my music on shuffle, so I didn't need Album Gain. If this program ever breaks in a future version of OS X, I will probably update it just so that there's always a working port available.

What is the license?
MP3Gain is LGPL. This port is also LGPL. You can probably find more information about that license on Wikipedia.

Where can I get the source code, report bugs, or request features?
There is a project on GitHub for MP3Gain Express where you can check out the current development code for the application, submit your own changes, bug reports, or feature requests. You can find it at https://github.com/Sappharad/mp3gainOSX/.

I can be contacted via e-mail at sappharad @ [same thing as before the @ symbol] .com.