public class library_name {
  static {
      // if library .so is named 'libname.so'
      System.loadLibrary("name")
  }
  //跟Native註冊interface_name實體的Native function.
  private native registerInterfaceNameNative(interface_name var1);
      
  //假設有一個叫做interface_name的 Interface
  public Interface interface_name {
      void interface_func(byte[]);
  }
  //java的接口，負責把interface_name的實體帶給Native function.
  public void registerInterfaceName(interface_name var1) {
      registerInterfaceNameNative(var1);
  }
}

static JavaVM *gJavaVM;
jobject callback_obj;
jmethodID callback_mid;

JNIEXPORT jint JNICALL Java_com_XXXXX_library_name_somethingInitFunction(JNIEnv* env, jobject obj) {
  (*env)->GetJavaVM(env,&gJavaVM);
}

JNIEXPORT jint JNICALL Java_com_XXXXX_library_name_registerInterfaceNameNative(JNIEnv* env, jobject obj, jobject instance) {
  callback_obj = (*env)->NewGlobalRef(env,instance);
  jclass clz = (*env)->GetObjectClass(env,callback_obj);
  if(clz == NULL) {
      //failed to find class
  }
  callback_mid = (*env)->GetMethodID(env,clz,"interface_func","([B)V");
}

// callback function in C
void cb_function(char* buf) {
  JNIEnv *env;
  if((*gJavaVM)->AttachCurrentThread(gJavaVM, &env, NULL) != JNI_OK)    {
      // attachCurrentThread() failed.
  }
  else
  {
        // create byte[]
        jbyteArray arr = (*env)->NewByteArray(env,len);
        // set buf -> byte[]
        (*env)->SetByteArrayRegion(env,arr,0,len, (jbyte*)buf);
        // call java function, which is implemented by user
        (*env)->CallVoidMethod(env,callback_obj,callback_mid,arr);
  }
}

public class interfaceImpl implements library_name.interface_name {
  @Override
  void interface_func(byte[] a) {
      // show new String(a);
  }
}

 main {
  library_name library = new library_name();
  // call some function to init library
  // ...
  
  //這行最重要，要把implmenet完的實體送下去給Native層知道
  library.registerInterfaceName(new interfaceImpl());

  ...
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.drivequickstart">

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.GET_ACCOUNTS" />
    <uses-permission android:name="android.permission.MANAGE_ACCOUNTS" />
    <uses-permission android:name="android.permission.USE_CREDENTIALS" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="Drive API Android Quickstart"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="Drive API Android Quickstart" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version" />
    </application>
</manifest>

package com.example.drivequickstart;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.api.client.extensions.android.http.AndroidHttp;
import com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.client.util.ExponentialBackOff;


import com.google.api.services.drive.DriveScopes;

import android.accounts.AccountManager;
import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Typeface;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.text.TextUtils;
import android.text.method.ScrollingMovementMethod;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.Arrays;
import java.util.List;

public class MainActivity extends Activity {
    /**
     * A Drive API service object used to access the API.
     * Note: Do not confuse this class with API library's model classes, which
     * represent specific data structures.
     */
    com.google.api.services.drive.Drive mService;

    GoogleAccountCredential credential;
    private TextView mStatusText;
    private TextView mResultsText;
    ProgressDialog mProgress;
    final HttpTransport transport = AndroidHttp.newCompatibleTransport();
    final JsonFactory jsonFactory = GsonFactory.getDefaultInstance();

    static final int REQUEST_ACCOUNT_PICKER = 1000;
    static final int REQUEST_AUTHORIZATION = 1001;
    static final int REQUEST_GOOGLE_PLAY_SERVICES = 1002;
    private static final String PREF_ACCOUNT_NAME = "accountName";
    private static final String[] SCOPES = { DriveScopes.DRIVE_METADATA_READONLY };

    /**
     * Create the main activity.
     * @param savedInstanceState previously saved instance data.
     */
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        LinearLayout activityLayout = new LinearLayout(this);
        LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
                LinearLayout.LayoutParams.MATCH_PARENT,
                LinearLayout.LayoutParams.MATCH_PARENT);
        activityLayout.setLayoutParams(lp);
        activityLayout.setOrientation(LinearLayout.VERTICAL);
        activityLayout.setPadding(16, 16, 16, 16);

        ViewGroup.LayoutParams tlp = new ViewGroup.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT);

        mStatusText = new TextView(this);
        mStatusText.setLayoutParams(tlp);
        mStatusText.setTypeface(null, Typeface.BOLD);
        mStatusText.setText("Retrieving data...");
        activityLayout.addView(mStatusText);

        mResultsText = new TextView(this);
        mResultsText.setLayoutParams(tlp);
        mResultsText.setPadding(16, 16, 16, 16);
        mResultsText.setVerticalScrollBarEnabled(true);
        mResultsText.setMovementMethod(new ScrollingMovementMethod());
        activityLayout.addView(mResultsText);

        mProgress = new ProgressDialog(this);
        mProgress.setMessage("Calling Drive API ...");

        setContentView(activityLayout);

        // Initialize credentials and service object.
        SharedPreferences settings = getPreferences(Context.MODE_PRIVATE);
        credential = GoogleAccountCredential.usingOAuth2(
                getApplicationContext(), Arrays.asList(SCOPES))
                .setBackOff(new ExponentialBackOff())
                .setSelectedAccountName(settings.getString(PREF_ACCOUNT_NAME, null));

        mService = new com.google.api.services.drive.Drive.Builder(
                transport, jsonFactory, credential)
                .setApplicationName("Drive API Android Quickstart")
                .build();
    }


    /**
     * Called whenever this activity is pushed to the foreground, such as after
     * a call to onCreate().
     */
    @Override
    protected void onResume() {
        super.onResume();
        if (isGooglePlayServicesAvailable()) {
            refreshResults();
        } else {
            mStatusText.setText("Google Play Services required: " +
                    "after installing, close and relaunch this app.");
        }
    }

    /**
     * Called when an activity launched here (specifically, AccountPicker
     * and authorization) exits, giving you the requestCode you started it with,
     * the resultCode it returned, and any additional data from it.
     * @param requestCode code indicating which activity result is incoming.
     * @param resultCode code indicating the result of the incoming
     *     activity result.
     * @param data Intent (containing result data) returned by incoming
     *     activity result.
     */
    @Override
    protected void onActivityResult(
            int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch(requestCode) {
            case REQUEST_GOOGLE_PLAY_SERVICES:
                if (resultCode != RESULT_OK) {
                    isGooglePlayServicesAvailable();
                }
                break;
            case REQUEST_ACCOUNT_PICKER:
                if (resultCode == RESULT_OK && data != null &&
                        data.getExtras() != null) {
                    String accountName =
                            data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME);
                    if (accountName != null) {
                        credential.setSelectedAccountName(accountName);
                        SharedPreferences settings =
                                getPreferences(Context.MODE_PRIVATE);
                        SharedPreferences.Editor editor = settings.edit();
                        editor.putString(PREF_ACCOUNT_NAME, accountName);
                        editor.commit();
                    }
                } else if (resultCode == RESULT_CANCELED) {
                    mStatusText.setText("Account unspecified.");
                }
                break;
            case REQUEST_AUTHORIZATION:
                if (resultCode != RESULT_OK) {
                    chooseAccount();
                }
                break;
        }

        super.onActivityResult(requestCode, resultCode, data);
    }

    /**
     * Attempt to get a set of data from the Drive API to display. If the
     * email address isn't known yet, then call chooseAccount() method so the
     * user can pick an account.
     */
    private void refreshResults() {
        if (credential.getSelectedAccountName() == null) {
            chooseAccount();
        } else {
            if (isDeviceOnline()) {
                mProgress.show();
                new ApiAsyncTask(this).execute();
            } else {
                mStatusText.setText("No network connection available.");
            }
        }
    }

    /**
     * Clear any existing Drive API data from the TextView and update
     * the header message; called from background threads and async tasks
     * that need to update the UI (in the UI thread).
     */
    public void clearResultsText() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                mStatusText.setText("Retrieving data…");
                mResultsText.setText("");
            }
        });
    }

    /**
     * Fill the data TextView with the given List of Strings; called from
     * background threads and async tasks that need to update the UI (in the
     * UI thread).
     * @param dataStrings a List of Strings to populate the main TextView with.
     */
    public void updateResultsText(final List<String> dataStrings) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                if (dataStrings == null) {
                    mStatusText.setText("Error retrieving data!");
                } else if (dataStrings.size() == 0) {
                    mStatusText.setText("No data found.");
                } else {
                    mStatusText.setText("Data retrieved using" +
                            " the Drive API:");
                    mResultsText.setText(TextUtils.join("\n\n", dataStrings));
                }
            }
        });
    }

    /**
     * Show a status message in the list header TextView; called from background
     * threads and async tasks that need to update the UI (in the UI thread).
     * @param message a String to display in the UI header TextView.
     */
    public void updateStatus(final String message) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                mStatusText.setText(message);
            }
        });
    }

    /**
     * Starts an activity in Google Play Services so the user can pick an
     * account.
     */
    private void chooseAccount() {
        startActivityForResult(
                credential.newChooseAccountIntent(), REQUEST_ACCOUNT_PICKER);
    }

    /**
     * Checks whether the device currently has a network connection.
     * @return true if the device has a network connection, false otherwise.
     */
    private boolean isDeviceOnline() {
        ConnectivityManager connMgr =
                (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        return (networkInfo != null && networkInfo.isConnected());
    }

    /**
     * Check that Google Play services APK is installed and up to date. Will
     * launch an error dialog for the user to update Google Play Services if
     * possible.
     * @return true if Google Play Services is available and up to
     *     date on this device; false otherwise.
     */
    private boolean isGooglePlayServicesAvailable() {
        final int connectionStatusCode =
                GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
        if (GooglePlayServicesUtil.isUserRecoverableError(connectionStatusCode)) {
            showGooglePlayServicesAvailabilityErrorDialog(connectionStatusCode);
            return false;
        } else if (connectionStatusCode != ConnectionResult.SUCCESS ) {
            return false;
        }
        return true;
    }

    /**
     * Display an error dialog showing that Google Play Services is missing
     * or out of date.
     * @param connectionStatusCode code describing the presence (or lack of)
     *     Google Play Services on this device.
     */
    void showGooglePlayServicesAvailabilityErrorDialog(
            final int connectionStatusCode) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                Dialog dialog = GooglePlayServicesUtil.getErrorDialog(
                        connectionStatusCode,
                        MainActivity.this,
                        REQUEST_GOOGLE_PLAY_SERVICES);
                dialog.show();
            }
        });
    }

}

package com.example.drivequickstart;

/**
 * Created by dell11 on 2015/9/19.
 */

import android.os.AsyncTask;

import com.google.api.client.googleapis.extensions.android.gms.auth.GooglePlayServicesAvailabilityIOException;
import com.google.api.client.googleapis.extensions.android.gms.auth.UserRecoverableAuthIOException;
import com.google.api.services.drive.model.File;
import com.google.api.services.drive.model.FileList;


import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * An asynchronous task that handles the Drive API call.
 * Placing the API calls in their own task ensures the UI stays responsive.
 */
public class ApiAsyncTask extends AsyncTask<Void, Void, Void> {
    private MainActivity mActivity;

    /**
     * Constructor.
     * @param activity MainActivity that spawned this task.
     */
    ApiAsyncTask(MainActivity activity) {
        this.mActivity = activity;
    }

    /**
     * Background task to call Drive API.
     * @param params no parameters needed for this task.
     */
    @Override
    protected Void doInBackground(Void... params) {
        try {
            mActivity.clearResultsText();
            mActivity.updateResultsText(getDataFromApi());

        } catch (final GooglePlayServicesAvailabilityIOException availabilityException) {
            mActivity.showGooglePlayServicesAvailabilityErrorDialog(
                    availabilityException.getConnectionStatusCode());

        } catch (UserRecoverableAuthIOException userRecoverableException) {
            mActivity.startActivityForResult(
                    userRecoverableException.getIntent(),
                    MainActivity.REQUEST_AUTHORIZATION);

        } catch (Exception e) {
            mActivity.updateStatus("The following error occurred:\n" +
                    e.getMessage());
        }
        if (mActivity.mProgress.isShowing()) {
            mActivity.mProgress.dismiss();
        }
        return null;
    }

    /**
     * Fetch a list of up to 10 file names and IDs.
     * @return List of Strings describing files, or an empty list if no files
     *         found.
     * @throws IOException
     */
    private List<String> getDataFromApi() throws IOException {
        // Get a list of up to 10 files.
        List<String> fileInfo = new ArrayList<String>();
        FileList result = mActivity.mService.files().list()
                .setMaxResults(20)
                .execute();
        List<File> files = result.getItems();
        if (files != null) {
            for (File file : files) {
                fileInfo.add(String.format("%s (%s)\n",
                        file.getTitle(), file.getId()));
            }
        }
        return fileInfo;
    }
}

  /**
   * Insert new file.
   *
   * @param service Drive API service instance.
   * @param title Title of the file to insert, including the extension.
   * @param description Description of the file to insert.
   * @param parentId Optional parent folder's ID.
   * @param mimeType MIME type of the file to insert.
   * @param filename Filename of the file to insert.
   * @return Inserted file metadata if successful, {@code null} otherwise.
   */
  private static File insertFile(Drive service, String title, String description,
      String parentId, String mimeType, String filename) {
    // File's metadata.
    File body = new File();
    body.setTitle(title);
    body.setDescription(description);
    body.setMimeType(mimeType);

    // Set the parent folder.
    if (parentId != null && parentId.length() > 0) {
      body.setParents(
          Arrays.asList(new ParentReference().setId(parentId)));
    }

    // File's content.
    java.io.File fileContent = new java.io.File(filename);
    FileContent mediaContent = new FileContent(mimeType, fileContent);
    try {
      File file = service.files().insert(body, mediaContent).execute();

      // Uncomment the following line to print the File ID.
      // System.out.println("File ID: " + file.getId());

      return file;
    } catch (IOException e) {
      System.out.println("An error occured: " + e);
      return null;
    }
  }

private class FileUploadProgressListener implements MediaHttpUploaderProgressListener {

    private String mFileUploadedName;

    public FileUploadProgressListener(String fileName) {
        mFileUploadedName = fileName;
    }

    @Override
    public void progressChanged(MediaHttpUploader mediaHttpUploader) throws IOException {
        if (mediaHttpUploader == null) return;
        switch (mediaHttpUploader.getUploadState()) {
            case INITIATION_STARTED:
            //System.out.println("Initiation has started!");
                break;
            case INITIATION_COMPLETE:
            //System.out.println("Initiation is complete!");
                break;
            case MEDIA_IN_PROGRESS:
                double percent = mediaHttpUploader.getProgress() * 100;
                Log.d(TAG, "Upload to GoogleDrive: " + mFileUploadedName + " - " + String.valueOf(percent) + "%");

                break;
            case MEDIA_COMPLETE:

            //System.out.println("Upload is complete!");
        }
    }
}

mService = new com.google.api.services.drive.Drive.Builder(
                transport, jsonFactory, credential)
                .setApplicationName("Drive API Android Quickstart")
                .build();

private static File insertFile(Drive service, String title, String description,
      String parentId, String mimeType, String filename) {
    // File's metadata.
    File body = new File();
    body.setTitle(title);
    body.setDescription(description);
    body.setMimeType(mimeType);

    // Set the parent folder.
    if (parentId != null && parentId.length() > 0) {
      body.setParents(
          Arrays.asList(new ParentReference().setId(parentId)));
    }

    // File's content.
    java.io.File fileContent = new java.io.File(filename);
    FileContent mediaContent = new FileContent(mimeType, fileContent);
    try {
      Drive.Files.Insert insert = service.files().insert(body, mediaContent)
      MediaHttpUploader uploader = insert.getMediaHttpUploader();
      
    uploader.setChunkSize(1024*1024);
    uploader.setProgressListener(new FileUploadProgressListener(filename));
    com.google.api.services.drive.model.File f = insert.execute();


      // Uncomment the following line to print the File ID.
      // System.out.println("File ID: " + file.getId());

      return file;
    } catch (IOException e) {
      System.out.println("An error occured: " + e);
      return null;
    }
  }

Live555project/jni# tree -d
.
├──BasicUsageEnvironment
│   └── include
├── groupsock
│   └── include
├── liveMedia
│   └── include
├── mediaServer
├── proxyServer
├── testProgs
├── UsageEnvironment
│   └── include
└── WindowsAudioInputDevice

MediaExtractor mExtractor = new MediaExtractor();
ByteBuffer mTransBuffer = ByteBuffer.allocate(1024*1024*2);
private byte[] mTmpBuf = new byte[1024*1024*2];
String path = “video_path/abc.mp4”;
mExtractor.setDataSource(path);
int numTrack = mExtractor.getTrackCount();
int h264Track = -1;
for(int i=0;i<numTrack;++i)
{
    MediaFormat format = mExtractor.getTrackFormat(i);
    String mime = format.getString(MediaFormat.KEY_MIME);
    if(mime.contains(“video”) && mime.contains(“avc”))
    {
        h264Track = i;
    }
}
if(h264Track!=-1)
{
    mExtractor.selectTrack(h264Track);
    while(true)
    {
        int Size = mExtractor.readSampleData(mTransBuffer,0); // read frame to mTransBuffer
        mTransBuffer.get(mTmpBuf);
        mExtractor.advance(); // go next frame
    }
}