Unable to start activity - java.lang.NullPointerException when trying to load ffmpeg with ProcessBuilder

[publioelon]

Greetings, I've been trying to use this library's ffmpeg resources but it seems to be crashing. I am using a default activity to attempt to stream a randomly generated image, for the sake of testing I tried to simply call ffmpeg using an echo command. If I do something like: ProcessBuilder pb = new ProcessBuilder("echo", "Hello World!"); it will work without any issues. However, if I attempt to pass ffmpeg by doing: ProcessBuilder pb = new ProcessBuilder(ffmpeg, "Hello World!"); it gives me NullPointerException error, or whatever command I attempt to use with ffmpeg after I load it, it'll give me the same error. For instance, I tried converting some video by using this command: ProcessBuilder pb = new ProcessBuilder(ffmpeg, "-i", "/storage/emulated/0/DCIM/20220617_220627.mp4", "-c:v", "libx264", "-crf 19", "destinationfile.flv"); The same error happened. So, I suspect there is something wrong with my FFMPEG version, perhaps? I tried installing it following this link: #1117 (comment)

this is the snippet that I am using:

package com.example.myapplication;

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;

import org.bytedeco.javacpp.Loader;

import android.os.Build;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {
    static final String ffmpeg = Loader.load(org.bytedeco.ffmpeg.ffmpeg.class);
    @RequiresApi(api = Build.VERSION_CODES.O)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ProcessBuilder pb = new ProcessBuilder(ffmpeg, "Hello World!");
        pb.redirectErrorStream(true);
        System.out.println("Run echo command");
        Process process = null;
        try {
            process = pb.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
        int errCode = 0;
        try {
            errCode = process.waitFor();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("Echo command executed, any errors? " + (errCode == 0 ? "No" : "Yes"));
        try {
            System.out.println("Echo Output:\n" + output(process.getInputStream()));
            BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            OutputStream writer = process.getOutputStream();
        } catch (IOException e) {
            e.printStackTrace();
        }
        Log.e("TAG", "void OnCreate called successfully!");

    }

    private static String output(InputStream inputStream) throws IOException {
        StringBuilder sb = new StringBuilder();
        BufferedReader br = null;
        try {
            br = new BufferedReader(new InputStreamReader(inputStream));
            String line = null;
            while ((line = br.readLine()) != null) {
                sb.append(line + System.getProperty("line.separator"));
            }
        } finally {
            br.close();
        }
        return sb.toString();
    }

}

My build.gradle:

plugins {
    id 'com.android.application'
}

android {
    compileSdk 31

    defaultConfig {
        applicationId "com.example.myapplication"
        minSdk 23
        targetSdk 31
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}
configurations {
    javacpp
}
task javacppExtract(type: Copy) {
    dependsOn configurations.javacpp

      from { configurations.javacpp.collect { zipTree(it) } }
    include "lib/**"
    into "$buildDir/javacpp/"
    android.sourceSets.main.jniLibs.srcDirs += ["$buildDir/javacpp/lib/"]

    tasks.getByName('preBuild').dependsOn javacppExtract
}

dependencies {

    implementation 'androidx.appcompat:appcompat:1.4.1'
    implementation 'com.google.android.material:material:1.5.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    implementation group: 'org.bytedeco', name: 'javacv', version: '1.5.6'
    javacpp group: 'org.bytedeco', name: 'openblas-platform', version: '0.3.17-1.5.6'
    javacpp group: 'org.bytedeco', name: 'opencv-platform', version: '4.5.3-1.5.6'
    javacpp group: 'org.bytedeco', name: 'ffmpeg-platform', version: '4.4-1.5.6'
}

It gives me the following error constantly:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.myapplication, PID: 18328
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapplication/com.example.myapplication.MainActivity}: java.lang.NullPointerException
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:4035)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4201)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2438)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loopOnce(Looper.java:226)
        at android.os.Looper.loop(Looper.java:313)
        at android.app.ActivityThread.main(ActivityThread.java:8663)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:567)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1135)
     Caused by: java.lang.NullPointerException
        at java.lang.ProcessBuilder.start(ProcessBuilder.java:1012)
        at com.example.myapplication.MainActivity.onCreate(MainActivity.java:36)
        at android.app.Activity.performCreate(Activity.java:8290)
        at android.app.Activity.performCreate(Activity.java:8270)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1329)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:4009)

[saudet]

Android won't let you start new processes when using API 29 or newer, that's normal, see issue #1127 (comment).

[saudet]

Duplicate of #1127