Reaktor Sample Map Generator

What it is

This is a java application for generating sample map files automatically by scanning the file system. Runs on both OSX and Windows.

OSX users should be able to just double-click the .jar file, if you are using windows then you have to have java installed, get it from here.


Java Application : MapFileBuilder.jar

Source Code :

NOTE : This zip contains the original application source code which is written in Ruby. The source code for the current java version is available via SVN from here


1. Choose an output directory for the map files

2. Choose an input directory where your samples are.

The program will recursively scan the directory tree starting at the selected sample directory. It will create a sample map for each directory (or multiple maps if there are more than 128 samples in that directory).

The map file names are created from the 2 directories above the samples, so if your samples are in C:samplesdrumsmachines707 the map will be called

Each sample is mapped to just one key, starting from 0.


1: fix root note to 60.

If its not locked then the roots are set to the same position as the sample (i.e. 0,1,2,3 etc). If it is locked then, well, you guessed it, they are all set to 60.

2: Loop.

If loop is ticked then each map entry will be set to loop for the full length of the sample. Setting this will make the map building a bit slower as it has to open every file and see how many sample frames are in it.

21 thoughts on “Reaktor Sample Map Generator”

  1. Hi !! Thanks for making such an incredibly useful software !
    The only thing missing IMHO, would be the option to save each MAP in it’s respective sample folder,
    that would make browsing and map sorting easier (at least for me, hopefully for others!)

    Do you think that is something easily feasible? That would be so nice !
    Many thanks again !

  2. this is great, although i’ve noticed that if a .wav file is capitalised as .WAV then it cannot be imported… i’ll try modifying source to fix and retest.

    also the ability to save the samples/audio data in the map would be really handy – are you likely to update this fantastic app?

  3. I went through your source code and added a feature that allows a map to be created with each subdirectory mapped to a different velocity. This is useful as large maps can be now be generated (over 16,000 samples!) that would be near impossible to do by hand.

    Thanks for untangling the Reaktor map specification, it’s a shame NI didn’t make this information readily available. You definitely saved me a lot of time!

    I can’t find your contact information, please send me an email. I can send you a copy of what I’ve done.

    Thanks again,


  4. Oh, and as for saving the samples/audio data with the map, it seems simple enough to do that through the Reaktor editor, so coding that functionality would be more effort than it is worth. (At least for me!)

  5. Hi Martin!

    I wanted to take a look into the java source but I couldn’t access it. Why is the original code in Ruby? Have you derived the Java Code from Ruby? To me it would be very interesting how you decoded the map files. Dou you mind putting it online somewhere (the java-src)? I’m pondering to extend it for a better root-key, left-right etc. assignment cause the GUI-editor of REAKTOR is driving me crazy. This would be very cool! Thanks for your efforts! Greetings david

  6. Hi David. I originally coded the tool in Ruby then ported that code to Java. I don’t have any plans to release the java source code as im just finishing up a new version of the tool with a better UI and support for more formats (ableton live, sfz and renoise among others) although im still keeping the focus on generating single key zone maps from samples scanned from file system. I hadn’t considered adding anything for managing the left and right edges of zones or root key management beyond the current ‘same key as zone’ or ‘fixed to one note’. I guess an option to fill the keyboard by expanding zone sizes might be useful if there are less than 64 zones.

    What features were you specifically looking to add?

    The actual job of generating the binary data for reaktor map files is pretty much identical between the ruby and java code as far as I can remember so if i’m not willing to implement the features you want and you’re determined to build your own tool then that will be a good starting point. :)

    1. sorry, I dont understand (Czech right?). Any chance you can ask in English, or I can understand Macedonian and a bit of Serbian :)

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