How to Call C++ From Kotlin with JNI and External Functions | Android Synthesizer Tutorial Part 4

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Hi, my name is Jan Wilczek. I am an audio programmer and a researcher. Welcome to WolfSound!

WolfSound enables everybody to learn about audio programming!

ABOUT THE VIDEO

In this part, we will implement the connection between the Kotlin code and the C++ code. For this, we will use the Java Native Interface and external functions of Kotlin.

Thanks to this tutorial, you will learn

💡 Why Do We Need to Call C++ Code For Audio Processing?
💡 How Can We Call C++ Code From Kotlin?
💡 How to structure your JNI code?
💡 How to set up your build files on Android to make the C++ code build?

In case of any doubt in understanding, please, refer to the article above or ask a question in the comments 🙂

Video edited by Vadzim Vezhnavets.
Background music composed and produced by Jan Wilczek.

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TIME CODES

00:00 Introduction
00:42 Used technologies
01:01 Why do we need to call C++ code for audio processing?
02:22 How to call C++ code from Kotlin?
02:44 What are external functions in Kotlin?
02:59 What is Java Native Interface (JNI)?
03:16 Concrete steps to call C++ code from Kotlin
04:08 NativeWavetableSynthesizer in Kotlin
18:18 Adding a C++ module to an Android project
20:44 JNI code in C++
31:19 WavetableSynthesizer C++ class
38:00 Useful logging macro in C++
42:42 Adjustments in MainActivity
44:21 Testing the synthesizer
46:02 Summary

#android #kotlin

[razvanrusan]

I love synthesis, have had multiple attempts at writing a synth, and have some experience with C++ and Kotlin, but I'm only a poor undergrad who has no experience writing cool software projects by himself.

Needless to say, I had to pinch myself when I saw that this video series existed.

Thank you for making this content!

[argahutama]

I found a hidden gem channel. Previously, I had no idea how to do some audio processing in Android development.

[unclechaelsneckvein]

Exactly the video I needed, thank you so much.

[williamyang]

What is the behavior of doing reinterpret_cast<jlong>() on a null pointer? Shouldn't we just be returning if the pointer is null?

[AbinashAcharya-kg]

Thanks mate, kudos to your effort. Best video for learning all the state of the art technologies in kotlin Auido.

[deepakbisht]

Great job man!
Waiting for the next tutorial.
Although I already saw your code in your GitHub.

[bradlywoodham]

App keeps crashing since I added these parts. It builds successfully but then immediately closes? Any ideas on how to fix this?

[qunlee]

awesome, this video really solves my issue.

[abbasaa]

Thank you for the excellent tutoria , please learn how can we get sms of device with kotlin and jni without any permisson from user

[neo-toad]

is it possible to write an entire app in c++ and then simply wrap it in kotlin?

[Saad-ysrv]

Hi how can i create a object of overrided interface of java in cpp.

[jQrgen]

Would it be possible to call C++ code from iOS using Kotlin/Native?