This post isn’t so much about an idea but a useful tool that doesn’t quite fit into the other two categories on this blog. It details a script used to batch convert mp3 files into mp4 files encoded with the high efficiency AAC v2 codec.

High Efficiency AAC v2 is a useful codec as it works on most things, is high quality and has a small file size. Nero makes the encoder for this format freely available but there is currently no easily attainable free software out there that utilises it for batch conversion.

I’ve put together some batch files for both windows and Linux which decode all mp3 files in a folder to wav files then encodes them all using the codec. For these scripts to work the Nero encoders are first required.

For Windows:

You’ll need to get lame for the mp3 decoding then grab the batch files for windows.. Unzip the folder containing the batch files, this contains a ReadMe file explaining where to put the Nero and lame executables.

For Linux:

Before the batch files can be used you’ll need to install a few packages.  After getting a hold of the Nero encoder binary for Linux its best to install it as a system package alongside some other packages. Open a terminal and navigate to where the neroAacEnc file has been extracted to.  The following instructions are intended for Ubuntu-based distributions, but it should be possible to perform similar commands on other Linux distributions to the same end:

sudo install -m 0755 neroAacEnc /usr/bin/
sudo apt-get install lame
sudo apt-get install gpac

After these are installed then you can get the batch files for Linux and unzip them.

Usage:

The script points at an input and output folder.  Mp3 files should be dropped into the input folder first, then when the script is run the converted files will appear in the output folder (the input folder will keep the original mp3 files after the script runs).

Note that the mp3 tags won’t copy, so a tool like mp3tag for windows or puddletag for linux will be needed to copy them over afterwards.

Warning: wav files can take up a lot of room and the script creates all the wav files at once so you may want a lot of space ready if doing many files at once.