MP3 Packer, Rearrange MP3 Data To Save Space

Martin Brinkmann
Jan 5, 2011
Updated • Jan 16, 2013

Common wisdom is that mp3 are already highly compressed which means it does not make sense to compress them further, for instance to zip them before sending them to a friend. But did you know that there is still room for improvement, at least if the encoding settings were not optimal to being with?

MP3 Packer is a free software for Windows and Linux that rearranges data in mp3 files to generate the smallest possible mp3 file but also for other purposes such as turning VBR files into CBR files which can be handy if players are used that do not support VBR.

The application is offered as a command line version and a version with a graphical user interface on Windows. Winmp3packer, that's the name of the gui version, has already been configured to reduce the size of mp3 files loaded into the application.

All it takes to use it is to select a folder or folders with mp3 files before clicking the process button. The application scans all mp3s located in the folders and will process them if they meet certain criteria.

A log is displayed in the end giving information about the processed files and the decrease in size.

mp3 packer

We have run the application on three albums and it managed to decrease the size by about 5 Megabytes or 1.4%.

That may not look like much but it could add up if thousands of songs are stored on a device. The mp3 files need to be encoded with CBR for this to have any effect.

You may have noticed that the program offers additional options in its interface. Users can switch the output type from VBR to CBR, configure a fixed minimum bitrate, strip non-mp3 data from files and set a different output folder to avoid that files are overwritten by the application.

MP3Packer can be a handy program to run once on a mp3 collection to save space on the storage device. The application is available for download at the official website. (via)


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  1. jethro said on March 11, 2011 at 9:20 pm

    So to answer your question: No, it does not

  2. jethro said on March 11, 2011 at 9:11 pm

    Of course it changes bitrate, because mp3 bitrate=size. This tool is lossless however.
    What it does is it re-writes the mp3 file and optimizes the final stage of lossless compression, which all mp3s have in them. Think of it as having a ZIP file, then extracting the contents and then compressing it with something better ie RAR although here it has to be 100% compatible so it’s more like optimized ZIP compression.

  3. BalaC said on January 7, 2011 at 9:46 am


    Just for clarification there are lot of software out there in internet which claim the same thing (i.e.,) decreasing the file size. But actually those software were reducing the bit-rate of the mp3 file thereby degrading the sound quality, Is this one too does the same?

    1. Martin said on January 7, 2011 at 10:37 am

      BalaC, the program is not changing the bitrate as far as I understand it.

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