content: package io.agora.api.example.examples.advanced;
  
  import static io.agora.api.example.common.model.Examples.ADVANCED;
  import static io.agora.rtc2.video.VideoCanvas.RENDER_MODE_FIT;
  import static io.agora.rtc2.video.VideoCanvas.RENDER_MODE_HIDDEN;
  import static io.agora.rtc2.video.VideoEncoderConfiguration.STANDARD_BITRATE;
  
  import android.content.Context;
  import android.graphics.Matrix;
  import android.os.Bundle;
  import android.util.Log;
  import android.view.LayoutInflater;
  import android.view.SurfaceView;
  import android.view.TextureView;
  import android.view.View;
  import android.view.ViewGroup;
  import android.widget.Button;
  import android.widget.EditText;
  import android.widget.FrameLayout;
  import android.widget.Spinner;
  import android.widget.Switch;
  
  import androidx.annotation.NonNull;
  import androidx.annotation.Nullable;
  
  import java.nio.ByteBuffer;
  import java.util.concurrent.Callable;
  
  import io.agora.api.example.MainApplication;
  import io.agora.api.example.R;
  import io.agora.api.example.annotation.Example;
  import io.agora.api.example.common.BaseFragment;
  import io.agora.api.example.common.gles.GLThread;
  import io.agora.api.example.common.gles.core.EglCore;
  import io.agora.api.example.examples.advanced.videoRender.YuvFboProgram;
  import io.agora.api.example.utils.CommonUtil;
  import io.agora.api.example.utils.PermissonUtils;
  import io.agora.api.example.utils.TokenUtils;
  import io.agora.api.example.utils.VideoFileReader;
  import io.agora.base.JavaI420Buffer;
  import io.agora.base.NV12Buffer;
  import io.agora.base.NV21Buffer;
  import io.agora.base.TextureBuffer;
  import io.agora.base.TextureBufferHelper;
  import io.agora.base.VideoFrame;
  import io.agora.base.internal.video.YuvHelper;
  import io.agora.rtc2.ChannelMediaOptions;
  import io.agora.rtc2.Constants;
  import io.agora.rtc2.IRtcEngineEventHandler;
  import io.agora.rtc2.RtcEngine;
  import io.agora.rtc2.RtcEngineConfig;
  import io.agora.rtc2.RtcEngineEx;
  import io.agora.rtc2.gl.EglBaseProvider;
  import io.agora.rtc2.proxy.LocalAccessPointConfiguration;
  import io.agora.rtc2.video.VideoCanvas;
  import io.agora.rtc2.video.VideoEncoderConfiguration;
  
  /**
   * The type Push external video yuv.
   */
  @Example(
          index = 7,
          group = ADVANCED,
          name = R.string.item_pushexternal,
          actionId = R.id.action_mainFragment_to_PushExternalVideo,
          tipsId = R.string.pushexternalvideo
  )
  public class PushExternalVideoYUV extends BaseFragment implements View.OnClickListener {
      private static final String TAG = PushExternalVideoYUV.class.getSimpleName();
  
      private FrameLayout fl_local, fl_remote;
      private Button join;
      private Switch switchExEglContext;
      private EditText et_channel;
      private RtcEngineEx engine;
      private Spinner sp_push_buffer_type;
      private int myUid;
      private volatile boolean joined = false;
  
      private VideoFileReader videoFileReader;
  
      private YuvFboProgram yuvFboProgram;
      private TextureBufferHelper textureBufferHelper;
      private EglCore eglCore;
  
      @Nullable
      @Override
      public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
          View view = inflater.inflate(R.layout.fragment_push_externalvideo, container, false);
          return view;
      }
  
      @Override
      public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
          super.onViewCreated(view, savedInstanceState);
          join = view.findViewById(R.id.btn_join);
          et_channel = view.findViewById(R.id.et_channel);
          view.findViewById(R.id.btn_join).setOnClickListener(this);
          fl_local = view.findViewById(R.id.fl_local);
          fl_remote = view.findViewById(R.id.fl_remote);
          sp_push_buffer_type = view.findViewById(R.id.sp_buffer_type);
  
          switchExEglContext = view.findViewById(R.id.switch_ex_context);
          view.findViewById(R.id.btn_confirm).setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  view.findViewById(R.id.fl_container_egl_select).setVisibility(View.GONE);
                  //init egl context option
                  Log.d(TAG, "isChecked =" + switchExEglContext.isChecked());
                  if (switchExEglContext.isChecked()) {
                      if (eglCore == null) {
                          eglCore = new EglCore();
                      }
                      //once set the external egl context, you should use it until engine destroyed
                      int ret = engine.setExternalRemoteEglContext(eglCore.getEGLContext());
                      Log.d(TAG, "setExternalRemoteEglContext:  ret = " + ret);
                  }
              }
          });
      }
  
      @Override
      public void onActivityCreated(@Nullable Bundle savedInstanceState) {
          super.onActivityCreated(savedInstanceState);
          // Check if the context is valid
          Context context = getContext();
          if (context == null) {
              return;
          }
          try {
              RtcEngineConfig config = new RtcEngineConfig();
              /*
               * The context of Android Activity
               */
              config.mContext = context.getApplicationContext();
              /*
               * The App ID issued to you by Agora. See <a href="https://docs.agora.io/en/Agora%20Platform/token#get-an-app-id"> How to get the App ID</a>
               */
              config.mAppId = getString(R.string.agora_app_id);
              /* Sets the channel profile of the Agora RtcEngine.
               CHANNEL_PROFILE_COMMUNICATION(0): (Default) The Communication profile.
               Use this profile in one-on-one calls or group calls, where all users can talk freely.
               CHANNEL_PROFILE_LIVE_BROADCASTING(1): The Live-Broadcast profile. Users in a live-broadcast
               channel have a role as either broadcaster or audience. A broadcaster can both send and receive streams;
               an audience can only receive streams.*/
              config.mChannelProfile = Constants.CHANNEL_PROFILE_LIVE_BROADCASTING;
              /*
               * IRtcEngineEventHandler is an abstract class providing default implementation.
               * The SDK uses this class to report to the app on SDK runtime events.
               */
              config.mEventHandler = iRtcEngineEventHandler;
              config.mAudioScenario = Constants.AudioScenario.getValue(Constants.AudioScenario.DEFAULT);
              config.mAreaCode = ((MainApplication) getActivity().getApplication()).getGlobalSettings().getAreaCode();
              engine = (RtcEngineEx) RtcEngine.create(config);
              /*
               * This parameter is for reporting the usages of APIExample to agora background.
               * Generally, it is not necessary for you to set this parameter.
               */
              engine.setParameters("{"
                      + "\"rtc.report_app_scenario\":"
                      + "{"
                      + "\"appScenario\":" + 100 + ","
                      + "\"serviceType\":" + 11 + ","
                      + "\"appVersion\":\"" + RtcEngine.getSdkVersion() + "\""
                      + "}"
                      + "}");
              /* setting the local access point if the private cloud ip was set, otherwise the config will be invalid.*/
              LocalAccessPointConfiguration localAccessPointConfiguration = ((MainApplication) getActivity().getApplication()).getGlobalSettings().getPrivateCloudConfig();
              if (localAccessPointConfiguration != null) {
                  // This api can only be used in the private media server scenario, otherwise some problems may occur.
                  engine.setLocalAccessPoint(localAccessPointConfiguration);
              }
  
          } catch (Exception e) {
              e.printStackTrace();
              getActivity().onBackPressed();
          }
      }
  
  
      @Override
      public void onDestroy() {
          if (videoFileReader != null) {
              videoFileReader.stop();
          }
          /*leaveChannel and Destroy the RtcEngine instance*/
          if (engine != null) {
              /*After joining a channel, the user must call the leaveChannel method to end the
               * call before joining another channel. This method returns 0 if the user leaves the
               * channel and releases all resources related to the call. This method call is
               * asynchronous, and the user has not exited the channel when the method call returns.
               * Once the user leaves the channel, the SDK triggers the onLeaveChannel callback.
               * A successful leaveChannel method call triggers the following callbacks:
               *      1:The local client: onLeaveChannel.
               *      2:The remote client: onUserOffline, if the user leaving the channel is in the
               *          Communication channel, or is a BROADCASTER in the Live Broadcast profile.
               * @returns 0: Success.
               *          < 0: Failure.
               * PS:
               *      1:If you call the destroy method immediately after calling the leaveChannel
               *          method, the leaveChannel process interrupts, and the SDK does not trigger
               *          the onLeaveChannel callback.
               *      2:If you call the leaveChannel method during CDN live streaming, the SDK
               *          triggers the removeInjectStreamUrl method.*/
              engine.leaveChannel();
              engine.stopPreview();
          }
          releaseTextureBuffer();
          engine = null;
          super.onDestroy();
          handler.post(RtcEngine::destroy);
      }
  
      private void releaseTextureBuffer() {
          if (textureBufferHelper != null) {
              textureBufferHelper.invoke(() -> {
                  if (yuvFboProgram != null) {
                      yuvFboProgram.release();
                      yuvFboProgram = null;
                  }
                  return null;
              });
              textureBufferHelper.dispose();
              textureBufferHelper = null;
          }
      }
  
      @Override
      public void onClick(View v) {
          if (v.getId() == R.id.btn_join) {
              if (!joined) {
                  CommonUtil.hideInputBoard(getActivity(), et_channel);
                  // call when join button hit
                  String channelId = et_channel.getText().toString();
                  // Check permission
                  checkOrRequestPermisson(new PermissonUtils.PermissionResultCallback() {
                      @Override
                      public void onPermissionsResult(boolean allPermissionsGranted, String[] permissions, int[] grantResults) {
                          if (allPermissionsGranted) {
                              // Permissions Granted
                              joinChannel(channelId);
                          }
                      }
                  });
              } else {
                  joined = false;
                  join.setText(getString(R.string.join));
                  if (videoFileReader != null) {
                      videoFileReader.stop();
                  }
                  fl_remote.removeAllViews();
                  fl_local.removeAllViews();
                  engine.leaveChannel();
                  engine.stopPreview();
                  releaseTextureBuffer();
              }
          }
      }
  
      private void joinChannel(String channelId) {
  //        engine.setParameters("{\"rtc.log_filter\":65535}");
          // Check if the context is valid
          Context context = getContext();
          if (context == null) {
              return;
          }
  
          /*Set up to play remote sound with receiver*/
          engine.setDefaultAudioRoutetoSpeakerphone(true);
  
          /*In the demo, the default is to enter as the anchor.*/
          engine.setClientRole(Constants.CLIENT_ROLE_BROADCASTER);
          // Enables the video module.
          engine.enableVideo();
          // Setup video encoding configs
          engine.setVideoEncoderConfiguration(new VideoEncoderConfiguration(
                  ((MainApplication) getActivity().getApplication()).getGlobalSettings().getVideoEncodingDimensionObject(),
                  VideoEncoderConfiguration.FRAME_RATE.valueOf(((MainApplication) getActivity().getApplication()).getGlobalSettings().getVideoEncodingFrameRate()),
                  STANDARD_BITRATE,
                  VideoEncoderConfiguration.ORIENTATION_MODE.valueOf(((MainApplication) getActivity().getApplication()).getGlobalSettings().getVideoEncodingOrientation())
          ));
          /*Configures the external video source.
           * @param enable Sets whether or not to use the external video source:
           *                 true: Use the external video source.
           *                 false: Do not use the external video source.
           * @param useTexture Sets whether or not to use texture as an input:
           *                     true: Use texture as an input.
           *                     false: (Default) Do not use texture as an input.
           * @param pushMode
           *                   VIDEO_FRAME: Use the ENCODED_VIDEO_FRAME.
           *                   ENCODED_VIDEO_FRAME: Use the ENCODED_VIDEO_FRAME*/
          engine.setExternalVideoSource(true, true, Constants.ExternalVideoSourceType.VIDEO_FRAME);
  
          TextureView textureView = new TextureView(getContext());
          VideoCanvas local = new VideoCanvas(textureView, Constants.RENDER_MODE_FIT, 0);
          local.mirrorMode = Constants.VIDEO_MIRROR_MODE_DISABLED;
          local.sourceType = Constants.VIDEO_SOURCE_CUSTOM;
          engine.setupLocalVideo(local);
          // Add to the local container
          fl_local.removeAllViews();
          fl_local.addView(textureView, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                  ViewGroup.LayoutParams.MATCH_PARENT));
          engine.startPreview(Constants.VideoSourceType.VIDEO_SOURCE_CUSTOM);
          /*Please configure accessToken in the string_config file.
           * A temporary token generated in Console. A temporary token is valid for 24 hours. For details, see
           *      https://docs.agora.io/en/Agora%20Platform/token?platform=All%20Platforms#get-a-temporary-token
           * A token generated at the server. This applies to scenarios with high-security requirements. For details, see
           *      https://docs.agora.io/en/cloud-recording/token_server_java?platform=Java*/
          TokenUtils.gen(requireContext(), channelId, 0, accessToken -> {
              /* Allows a user to join a channel.
               if you do not specify the uid, we will generate the uid for you*/
  
              ChannelMediaOptions option = new ChannelMediaOptions();
              option.autoSubscribeAudio = true;
              option.autoSubscribeVideo = true;
              option.publishCustomVideoTrack = true;
              int res = engine.joinChannel(accessToken, channelId, 0, option);
              if (res != 0) {
                  // Usually happens with invalid parameters
                  // Error code description can be found at:
                  // en: https://docs.agora.io/en/Voice/API%20Reference/java/classio_1_1agora_1_1rtc_1_1_i_rtc_engine_event_handler_1_1_error_code.html
                  // cn: https://docs.agora.io/cn/Voice/API%20Reference/java/classio_1_1agora_1_1rtc_1_1_i_rtc_engine_event_handler_1_1_error_code.html
                  showAlert(RtcEngine.getErrorDescription(Math.abs(res)));
                  return;
              }
              // Prevent repeated entry
              join.setEnabled(false);
          });
  
  
      }
  
      /**
       * Push video frame by i420.
       *
       * @param yuv    i420 data
       * @param width  width
       * @param height height
       */
      private void pushVideoFrameByI420(byte[] yuv, int width, int height) {
          JavaI420Buffer i420Buffer = JavaI420Buffer.allocate(width, height);
          i420Buffer.getDataY().put(yuv, 0, i420Buffer.getDataY().limit());
          i420Buffer.getDataU().put(yuv, i420Buffer.getDataY().limit(), i420Buffer.getDataU().limit());
          i420Buffer.getDataV().put(yuv, i420Buffer.getDataY().limit() + i420Buffer.getDataU().limit(), i420Buffer.getDataV().limit());
  
          /*
           * Get monotonic time in ms which can be used by capture time,
           * typical scenario is as follows:
           */
          long currentMonotonicTimeInMs = engine.getCurrentMonotonicTimeInMs();
          /*
           * Create a video frame to push.
           */
          VideoFrame videoFrame = new VideoFrame(i420Buffer, 0, currentMonotonicTimeInMs * 1000000);
  
          /*
           * Pushes the external video frame to the app.
           */
          boolean success = engine.pushExternalVideoFrame(videoFrame);
  
          i420Buffer.release();
  
          if (!success) {
              Log.w(TAG, "pushExternalVideoFrame error");
          }
      }
  
      /**
       * Push video frame by nv21.
       *
       * @param nv21   nv21
       * @param width  width
       * @param height height
       */
      private void pushVideoFrameByNV21(byte[] nv21, int width, int height) {
  
          VideoFrame.Buffer frameBuffer = new NV21Buffer(nv21, width, height, null);
  
          /*
           * Get monotonic time in ms which can be used by capture time,
           * typical scenario is as follows:
           */
          long currentMonotonicTimeInMs = engine.getCurrentMonotonicTimeInMs();
          /*
           * Create a video frame to push.
           */
          VideoFrame videoFrame = new VideoFrame(frameBuffer, 0, currentMonotonicTimeInMs * 1000000);
  
          /*
           * Pushes the external video frame to the app.
           */
          boolean success = engine.pushExternalVideoFrame(videoFrame);
  
          if (!success) {
              Log.w(TAG, "pushExternalVideoFrame error");
          }
      }
  
      /**
       * Push video frame by nv12.
       *
       * @param nv12   nv12 buffer.
       * @param width  width.
       * @param height height.
       */
      private void pushVideoFrameByNV12(ByteBuffer nv12, int width, int height) {
          VideoFrame.Buffer frameBuffer = new NV12Buffer(width, height, width, height, nv12, null);
  
          /*
           * Get monotonic time in ms which can be used by capture time,
           * typical scenario is as follows:
           */
          long currentMonotonicTimeInMs = engine.getCurrentMonotonicTimeInMs();
          /*
           * Create a video frame to push.
           */
          VideoFrame videoFrame = new VideoFrame(frameBuffer, 0, currentMonotonicTimeInMs * 1000000);
  
          /*
           * Pushes the external video frame to the app.
           */
          boolean success = engine.pushExternalVideoFrame(videoFrame);
  
          if (!success) {
              Log.w(TAG, "pushExternalVideoFrame error");
          }
      }
  
      /**
       * Push video frame by texture id.
       *
       * @param textureId   texture id.
       * @param textureType texture type. rgb or oes.
       * @param width       width.
       * @param height      height.
       */
      @GLThread
      private void pushVideoFrameByTexture(int textureId, VideoFrame.TextureBuffer.Type textureType, int width, int height) {
          VideoFrame.Buffer frameBuffer = new TextureBuffer(
                  EglBaseProvider.getCurrentEglContext(),
                  width,
                  height,
                  textureType,
                  textureId,
                  new Matrix(),
                  null,
                  null,
                  null
          );
  
          /*
           * Get monotonic time in ms which can be used by capture time,
           * typical scenario is as follows:
           */
          long currentMonotonicTimeInMs = engine.getCurrentMonotonicTimeInMs();
          /*
           * Create a video frame to push.
           */
          VideoFrame videoFrame = new VideoFrame(frameBuffer, 0, currentMonotonicTimeInMs * 1000000);
  
          /*
           * Pushes the external video frame to the app.
           */
          boolean success = engine.pushExternalVideoFrame(videoFrame);
  
          if (!success) {
              Log.w(TAG, "pushExternalVideoFrame error");
          }
      }
  
  
      /**
       * IRtcEngineEventHandler is an abstract class providing default implementation.
       * The SDK uses this class to report to the app on SDK runtime events.
       */
      private final IRtcEngineEventHandler iRtcEngineEventHandler = new IRtcEngineEventHandler() {
  
          /**Occurs when a user leaves the channel.
           * @param stats With this callback, the application retrieves the channel information,
           *              such as the call duration and statistics.*/
          @Override
          public void onLeaveChannel(RtcStats stats) {
              super.onLeaveChannel(stats);
              Log.i(TAG, String.format("local user %d leaveChannel!", myUid));
              showLongToast(String.format("local user %d leaveChannel!", myUid));
          }
  
          /**Occurs when the local user joins a specified channel.
           * The channel name assignment is based on channelName specified in the joinChannel method.
           * If the uid is not specified when joinChannel is called, the server automatically assigns a uid.
           * @param channel Channel name
           * @param uid User ID
           * @param elapsed Time elapsed (ms) from the user calling joinChannel until this callback is triggered*/
          @Override
          public void onJoinChannelSuccess(String channel, int uid, int elapsed) {
              Log.i(TAG, String.format("onJoinChannelSuccess channel %s uid %d", channel, uid));
              showLongToast(String.format("onJoinChannelSuccess channel %s uid %d", channel, uid));
              myUid = uid;
              joined = true;
              handler.post(new Runnable() {
                  @Override
                  public void run() {
                      join.setEnabled(true);
                      join.setText(getString(R.string.leave));
  
                      if (videoFileReader == null) {
                          /*
                           * VideoFileReader can get nv21 buffer data of sample.yuv file in assets cyclically.
                           */
                          videoFileReader = new VideoFileReader(requireContext(), (yuv, width, height) -> {
                              if (joined && engine != null) {
                                  String selectedItem = (String) sp_push_buffer_type.getSelectedItem();
                                  /*
                                   * Below show how to create different type buffers.
                                   */
                                  if ("NV21".equals(selectedItem)) {
                                      byte[] nv21 = yuv2nv21(yuv, width, height);
                                      pushVideoFrameByNV21(nv21, width, height);
                                  } else if ("NV12".equals(selectedItem)) {
                                      ByteBuffer des = yuv2nv12(yuv, width, height);
                                      pushVideoFrameByNV12(des, width, height);
                                  } else if ("Texture2D".equals(selectedItem)) {
                                      if (textureBufferHelper == null) {
                                          textureBufferHelper = TextureBufferHelper.create("PushExternalVideoYUV", EglBaseProvider.instance().getRootEglBase().getEglBaseContext());
                                      }
                                      textureBufferHelper.invoke((Callable<Void>) () -> {
                                          int textureId = yuv2texture(yuv, width, height);
                                          pushVideoFrameByTexture(textureId, VideoFrame.TextureBuffer.Type.RGB, width, height);
                                          return null;
                                      });
                                  } else {
                                      // I420 type default
                                      pushVideoFrameByI420(yuv, width, height);
                                  }
                              }
                          });
                      }
                      videoFileReader.start();
  
                  }
              });
          }
  
          /**Occurs when a remote user (Communication)/host (Live Broadcast) joins the channel.
           * @param uid ID of the user whose audio state changes.
           * @param elapsed Time delay (ms) from the local user calling joinChannel/setClientRole
           *                until this callback is triggered.*/
          @Override
          public void onUserJoined(int uid, int elapsed) {
              super.onUserJoined(uid, elapsed);
              Log.i(TAG, "onUserJoined->" + uid);
              showLongToast(String.format("user %d joined!", uid));
              /*Check if the context is correct*/
              Context context = getContext();
              if (context == null) {
                  return;
              }
              handler.post(() -> {
                  /*Display remote video stream*/
                  // Create render view by RtcEngine
                  SurfaceView surfaceView = new SurfaceView(context);
                  surfaceView.setZOrderMediaOverlay(true);
                  if (fl_remote.getChildCount() > 0) {
                      fl_remote.removeAllViews();
                  }
                  // Add to the remote container
                  fl_remote.addView(surfaceView, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                          ViewGroup.LayoutParams.MATCH_PARENT));
                  // Setup remote video to render
                  engine.setupRemoteVideo(new VideoCanvas(surfaceView, RENDER_MODE_FIT, uid));
              });
          }
  
          /**Occurs when a remote user (Communication)/host (Live Broadcast) leaves the channel.
           * @param uid ID of the user whose audio state changes.
           * @param reason Reason why the user goes offline:
           *   USER_OFFLINE_QUIT(0): The user left the current channel.
           *   USER_OFFLINE_DROPPED(1): The SDK timed out and the user dropped offline because no data
           *              packet was received within a certain period of time. If a user quits the
           *               call and the message is not passed to the SDK (due to an unreliable channel),
           *               the SDK assumes the user dropped offline.
           *   USER_OFFLINE_BECOME_AUDIENCE(2): (Live broadcast only.) The client role switched from
           *               the host to the audience.*/
          @Override
          public void onUserOffline(int uid, int reason) {
              Log.i(TAG, String.format("user %d offline! reason:%d", uid, reason));
              showLongToast(String.format("user %d offline! reason:%d", uid, reason));
              handler.post(new Runnable() {
                  @Override
                  public void run() {
                      /*Clear render view
                       Note: The video will stay at its last frame, to completely remove it you will need to
                       remove the SurfaceView from its parent*/
                      fl_remote.removeAllViews();
                      engine.setupRemoteVideo(new VideoCanvas(null, RENDER_MODE_HIDDEN, uid));
                  }
              });
          }
      };
  
      /**
       * Yuv 2 texture id.
       * Run on gl thread.
       *
       * @param yuv    yuv
       * @param width  width
       * @param height heigh
       * @return rgba texture id
       */
      @GLThread
      private int yuv2texture(byte[] yuv, int width, int height) {
          if (yuvFboProgram == null) {
              yuvFboProgram = new YuvFboProgram();
          }
          return yuvFboProgram.drawYuv(yuv, width, height);
      }
  
      /**
       * Transform yuv to nv12
       *
       * @param yuv    yuv
       * @param width  width
       * @param height height
       * @return nv12
       */
      @NonNull
      private static ByteBuffer yuv2nv12(byte[] yuv, int width, int height) {
          int srcStrideY = width;
          int srcHeightY = height;
          int srcSizeY = srcStrideY * srcHeightY;
          ByteBuffer srcY = ByteBuffer.allocateDirect(srcSizeY);
          srcY.put(yuv, 0, srcSizeY);
  
          int srcStrideU = width / 2;
          int srcHeightU = height / 2;
          int srcSizeU = srcStrideU * srcHeightU;
          ByteBuffer srcU = ByteBuffer.allocateDirect(srcSizeU);
          srcU.put(yuv, srcSizeY, srcSizeU);
  
          int srcStrideV = width / 2;
          int srcHeightV = height / 2;
          int srcSizeV = srcStrideV * srcHeightV;
          ByteBuffer srcV = ByteBuffer.allocateDirect(srcSizeV);
          srcV.put(yuv, srcSizeY + srcSizeU, srcSizeV);
  
          int desSize = srcSizeY + srcSizeU + srcSizeV;
          ByteBuffer des = ByteBuffer.allocateDirect(desSize);
          YuvHelper.I420ToNV12(srcY, srcStrideY, srcU, srcStrideU, srcV, srcStrideV, des, width, height);
          return des;
      }
  
      /**
       * Transform yuv to nv21.
       *
       * @param yuv    yuv
       * @param width  width
       * @param height height
       * @return nv21
       */
      @NonNull
      private static byte[] yuv2nv21(byte[] yuv, int width, int height) {
          int srcStrideY = width;
          int srcHeightY = height;
          int srcSizeY = srcStrideY * srcHeightY;
          ByteBuffer srcY = ByteBuffer.allocateDirect(srcSizeY);
          srcY.put(yuv, 0, srcSizeY);
  
          int srcStrideU = width / 2;
          int srcHeightU = height / 2;
          int srcSizeU = srcStrideU * srcHeightU;
          ByteBuffer srcU = ByteBuffer.allocateDirect(srcSizeU);
          srcU.put(yuv, srcSizeY, srcSizeU);
  
          int srcStrideV = width / 2;
          int srcHeightV = height / 2;
          int srcSizeV = srcStrideV * srcHeightV;
          ByteBuffer srcV = ByteBuffer.allocateDirect(srcSizeV);
          srcV.put(yuv, srcSizeY + srcSizeU, srcSizeV);
  
          int desSize = srcSizeY + srcSizeU + srcSizeV;
          ByteBuffer des = ByteBuffer.allocateDirect(desSize);
          YuvHelper.I420ToNV12(srcY, srcStrideY, srcV, srcStrideV, srcU, srcStrideU, des, width, height);
  
          byte[] nv21 = new byte[desSize];
          des.position(0);
          des.get(nv21);
          return nv21;
      }
  
  }
  