如何在 Android Studio 中使用 ffmpeg 构建库？

Question

I have build ffmpeg libs for Android using tutorial provided by https://medium.com/@karthikcodes1999/cross-compiling-ffmpeg-4-0-for-android-b988326f16f2

But I don't know how to use the libraries in my Android project.

Everything done according to above mentioned example getting error when trying to build project/gradle

Cmakelists.txt file:

UPDATE: new error message while building saying:

Build command failed.
Error while executing process /root/Android/Sdk/cmake/3.6.4111459/bin/cmake with arguments {-H/home/mrx/tester/app -B/home/mrx/tester/app/.externalNativeBuild/cmake/debug/armeabi -DANDROID_ABI=armeabi -DANDROID_PLATFORM=android-15 -DCMAKE_LIBRARY_OUTPUT_DIRECTORY=/home/mrx/tester/app/build/intermediates/cmake/debug/obj/armeabi -DCMAKE_BUILD_TYPE=Debug -DANDROID_NDK=/root/Android/Sdk/ndk-bundle -DCMAKE_CXX_FLAGS= -DCMAKE_TOOLCHAIN_FILE=/root/Android/Sdk/ndk-bundle/build/cmake/android.toolchain.cmake -DCMAKE_MAKE_PROGRAM=/root/Android/Sdk/cmake/3.6.4111459/bin/ninja -GAndroid Gradle - Ninja}
CMake Error at CMakeLists.txt:56 (set_target_properties):
  set_target_properties Can not find target to add properties to: swscale-5


-- Configuring incomplete, errors occurred!
See also "/home/mrx/tester/app/.externalNativeBuild/cmake/debug/armeabi/CMakeFiles/CMakeOutput.log".

Update: everything working fine but only error i am getting is

org.gradle.internal.UncheckedException: Build command failed.

Error while executing process /root/Android/Sdk/cmake/3.6.4111459/bin/cmake with arguments {--build /home/mrx/tester/app/.externalNativeBuild/cmake/debug/armeabi --target native-lib} ninja: error: '../../../../src/main/jniLibs/armeabi/libavcodec-58.so', needed by '../../../../build/intermediates/cmake/debug/obj/armeabi/libnative-lib.so', missing and no known rule to make it

at org.gradle.internal.UncheckedException.throwAsUncheckedException(UncheckedException.java:63)
at org.gradle.internal.UncheckedException.throwAsUncheckedException(UncheckedException.java:40)
at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:76)
at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:46)
at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:39)
at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:26)
at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:788)
at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:755)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:124)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:113)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:95)
at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:73)
at org.gradle.api.internal.tasks.execution.OutputDirectoryCreatingTaskExecuter.execute(OutputDirectoryCreatingTaskExecuter.java:51)
at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:59)
at org.gradle.api.internal.tasks.execution.ResolveTaskOutputCachingStateExecuter.execute(ResolveTaskOutputCachingStateExecuter.java:54)
at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:59)
at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:101)
at org.gradle.api.internal.tasks.execution.FinalizeInputFilePropertiesTaskExecuter.execute(FinalizeInputFilePropertiesTaskExecuter.java:44)
at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:91)
at org.gradle.api.internal.tasks.execution.ResolveTaskArtifactStateTaskExecuter.execute(ResolveTaskArtifactStateTaskExecuter.java:62)
at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:59)
at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:54)
at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:34)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker$1.run(DefaultTaskGraphExecuter.java:256)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:336)
at org.gradle.internal.progress.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:328)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:199)
at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:110)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:249)
at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:238)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.processTask(DefaultTaskPlanExecutor.java:123)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.access$200(DefaultTaskPlanExecutor.java:79)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:104)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker$1.execute(DefaultTaskPlanExecutor.java:98)
at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.execute(DefaultTaskExecutionPlan.java:663)
at org.gradle.execution.taskgraph.DefaultTaskExecutionPlan.executeWithTask(DefaultTaskExecutionPlan.java:597)
at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor$TaskExecutorWorker.run(DefaultTaskPlanExecutor.java:98)
at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
at java.lang.Thread.run(Thread.java:745)

Caused by: Build command failed. Error while executing process /root/Android/Sdk/cmake/3.6.4111459/bin/cmake with arguments {--build /home/mrx/tester/app/.externalNativeBuild/cmake/debug/armeabi --target native-lib} ninja: error: '../../../../src/main/jniLibs/armeabi/libavcodec-58.so', needed by '../../../../build/intermediates/cmake/debug/obj/armeabi/libnative-lib.so', missing and no known rule to make it

at com.android.build.gradle.tasks.ExternalNativeBuildTaskUtils.executeBuildProcessAndLogError(ExternalNativeBuildTaskUtils.java:245)
at com.android.build.gradle.tasks.ExternalNativeBuildTask.executeProcessBatch(ExternalNativeBuildTask.java:307)
at com.android.build.gradle.tasks.ExternalNativeBuildTask.build(ExternalNativeBuildTask.java:185)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
... 45 more

Answer 1

Here is a good example for using ffmpeg in android studio

Find MainActivity.java file in the project, you will see this:

public class MainActivity extends AppCompatActivity {

    // Used to load the 'native-lib' library on application startup.
    static {
        System.loadLibrary("native-lib");
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Example of a call to a native method
        TextView tv = (TextView) findViewById(R.id.sample_text);
        tv.setText(stringFromJNI());
        Log.i("hh","java.library.path:"+System.getProperty("java.library.path"));
    }

    /**
     * A native method that is implemented by the 'native-lib' native library,
     * which is packaged with this application.
     */
    public native String stringFromJNI();
}

Notice cpp and jinLibs folders, copy them and paste into same location of your project.

Edited: its build.gradle file should also be read carefully