I found [this](https://github.com/VladimirKulyk/SoundTouch-Android) on GitHub which is a wrapper for the great SoundTouch C++ library.

I'm completely new to NDK though, so would any of you kindly explain to me how to set it up correctly?

I downloaded the zip from GitHub and copied the directories into my existing project. Still, it couldn't find the native C++ functions. 

I tried compiling the library using `ndk-build` but I got two errors. This is my terminal log:

```
Android NDK: APP_PLATFORM not set. Defaulting to minimum supported version android-14.    
Android NDK: WARNING:/home/daniele/AndroidStudioProjects/Chords2/app/jni/Android.mk:soundtouch: non-system libraries in linker flags: -lgcc    
Android NDK:     This is likely to result in incorrect builds. Try using LOCAL_STATIC_LIBRARIES    
Android NDK:     or LOCAL_SHARED_LIBRARIES instead to list the library dependencies of the    
Android NDK:     current module    
Android NDK: WARNING:/home/daniele/AndroidStudioProjects/Chords2/app/jni/Android.mk:soundtouch: non-system libraries in linker flags: -lgcc    
Android NDK:     This is likely to result in incorrect builds. Try using LOCAL_STATIC_LIBRARIES    
Android NDK:     or LOCAL_SHARED_LIBRARIES instead to list the library dependencies of the    
Android NDK:     current module    
[armeabi-v7a] Compile++ thumb: soundtouch <= soundtouch-jni.cpp
[armeabi-v7a] Compile++ thumb: soundtouch <= AAFilter.cpp
[armeabi-v7a] Compile++ thumb: soundtouch <= FIFOSampleBuffer.cpp
[armeabi-v7a] Compile++ thumb: soundtouch <= FIRFilter.cpp
[armeabi-v7a] Compile++ thumb: soundtouch <= cpu_detect_x86.cpp
[armeabi-v7a] Compile++ thumb: soundtouch <= RateTransposer.cpp
[armeabi-v7a] Compile++ thumb: soundtouch <= SoundTouch.cpp
[armeabi-v7a] Compile++ thumb: soundtouch <= TDStretch.cpp
[armeabi-v7a] Compile++ thumb: soundtouch <= BPMDetect.cpp
[armeabi-v7a] Compile++ thumb: soundtouch <= PeakFinder.cpp
[armeabi-v7a] SharedLibrary  : libsoundtouch.so
[armeabi-v7a] Install        : libsoundtouch.so => libs/armeabi-v7a/libsoundtouch.so
[armeabi] Compile++ thumb: soundtouch <= soundtouch-jni.cpp
/home/daniele/AndroidStudioProjects/Chords2/app/jni/soundtouch-jni.cpp:133:2: error: 
      no matching function for call to 'convertInput16'
        convertInput16(ar, fBufferIn, BUFF_SIZE);
        ^~~~~~~~~~~~~~
/home/daniele/AndroidStudioProjects/Chords2/app/jni/soundtouch-jni.cpp:58:13: note: 
      candidate function not viable: no known conversion from
      'soundtouch::SAMPLETYPE *' (aka 'short *') to 'float *' for 2nd argument
static void convertInput16(jbyte*, float*, int);
            ^
/home/daniele/AndroidStudioProjects/Chords2/app/jni/soundtouch-jni.cpp:210:16: error: 
      no matching function for call to 'write'
                processed += write(fBufferIn, fBufferOut, nSamples * cha...
                             ^~~~~
/home/daniele/AndroidStudioProjects/Chords2/app/jni/soundtouch-jni.cpp:56:12: note: 
      candidate function not viable: no known conversion from
      'soundtouch::SAMPLETYPE *' (aka 'short *') to 'const float *' for 1st
      argument
static int write(const float*, queue<signed char>*, int, int);
           ^
2 errors generated.
make: *** [/home/daniele/AndroidStudioProjects/Chords2/app/obj/local/armeabi/objs/soundtouch/soundtouch-jni.o] Error 1

```