Matlab audioread/audioplay into C/C++ through Coder

Question

I am working on a matlab project where I add effects to audio files (mp3, wav). Therefore, I load the files into arrays using the matlab function audioread(..).

Now, I want to export this to Android. I read that the best way is to use the Matlab Coder to export the matlab code to C/C++ (or Java) and then export it into android (more or less).

However, the function call audioplayer (and play) are Unsupported (that's what the code generation readiness issues says).

What can I do ? One idea was to play the sounds directly using c++ code (so after the code generation). But how to play sounds from arrays using c++ ?

Or if you guys have others ideas without touching c++ codes (so fixing the problem directly in matlab), I would be glad to hear it !

Thanks and have a good day !

Answer 1

Typically what I recommend in cases like this is to factor your code in two pieces:

1. The part that does the audio file I/O and audio playing (namely the OS-specific part)
2. The computational kernel for which you will generate code using MATLAB Coder. This piece usually takes numeric arrays representing the image or audio data as arguments.

I've used this approach to leverage MATLAB Coder generated code to do image filtering on Android.

To do part (1), as Navan says, you'll need to use Android APIs to read in audio files, write data back to files, and to play them as desired. Note, I haven't done extensive Android development, so doing these tasks may take some research or be difficult.

Once you have the data in a format suitable for the function(s) in (2), likely a numeric array, then you can call your generated code using JNI to add the desired effects. The generated code would return the data back to the Java code and you can then encode it, play it, or do as you please with it using the Android APIs.

Answer 2

Playing audio normally uses platform dependent libraries. In DSP System toolbox, there is an audio player object called dsp.AudioPlayer which supports C code generation. But I believe this uses platform dependent libraries in the generated code and it will not be straight forward to make it work in Android. You will be better off finding an audio player library for Android and hooking that in manually after generating code.