Custom Video Source and Renderer

Introduction

Generally, Agora SDKs use default video modules for capturing and rendering in real-time communications.

However, these default modules might not meet your development requirements, such as in the following scenarios:

Your app has its own video module.
You want to use a non-camera source, such as recorded screen data.
You need to process the captured video with a pre-processing library for functions such as image enhancement.
You need flexible device resource allocation to avoid conflicts with other services.

Agora provides a solution to enable a custom video source and/or renderer in the above scenarios. This article describes how to do so using the Agora Native SDK.

Before proceeding, ensure that you have implemented the basic real-time communication functions in your project. For details, see Start a Video Call or Start Live Interactive Video Streaming.

Sample project

Agora provides the following open-source sample projects on GitHub:

You can view the source code on Github or download the project to try it out.

Custom video source

The Agora Native SDK provides the following two modes for customizing the video source:

Push mode: In this mode, call the setExternalVideoSource method to specify the custom video source. After implementing video capture using the custom video source, call the pushVideoFrame method to send the captured video frames to the SDK.

Video frames captured in Push mode cannot be rendered by the SDK. If you capture video frames in Push mode and need to enable local preview, you must use a custom video renderer.
Switching in the channel from custom video capture by Push to SDK capture is not supported. To switch the video source directly, you must use the custom video capture by MediaIO. See How can I switch from custom video capture to SDK capture.

MediaIO mode: In this mode, call the setVideoSource method to specify the custom video source. Then call the consumeByteBufferFrame, consumeByteArrayFrame, or consumeTextureFrame method to retrieve the captured video frames and send them to the SDK.

Push mode

Refer to the following steps to customize the video source in your project:

Before calling joinChannel, call setExternalVideoSource to specify the custom video source.
Implement video capture and processing yourself using methods from outside the SDK. According to your app scenario, you can call AgoraVideoFrame before sending the captured video frames to the SDK. For example, you can set rotation as 180 to rotate the video frames by 180 degrees clockwise.
Call pushExternalVideoFrame to send the video frames to the SDK for later use.

API call sequence

Refer to the following diagram to implement the custom video source.

If you are not sure whether your custom video source supports Texture encoding, call isTextureEncodeSupported to find out. Then use the returned result to set the useTexture parameter in the setExternalVideoSource method.

Video data transfer

The following diagram shows how the video data is transferred when you customize the video source in Push mode:

1607670382235

You need to implement the capture module yourself using methods from outside the SDK.
Captured video frames are sent to the SDK via the pushExternalVideoFrame method.

Code samples

The following code samples use the camera as the custom video source.

Before joining a channel, call setExternalVideoSource to specify the custom video source.

// Creates TextureView
TextureView textureView = new TextureView(getContext());
// Adds SurfaceTextureListener, which triggers the onSurfaceTextureAvailable callback if SurfaceTexture in TextureView is available
textureView.setSurfaceTextureListener(this);
// Adds TextureView to local video layout
fl_local.addView(textureView, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.MATCH_PARENT));
// Specifies the custom video source
engine.setExternalVideoSource(true, true, true);
// Joins the channel
int res = engine.joinChannel(accessToken, channelId, "Extra Optional Data", 0);

Configure the video capture module, and implement your custom video source. The code sample uses the camera as the custom video source.

// Triggers this callback if SurfaceTexture in TextureView is available
public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
        Log.i(TAG, "onSurfaceTextureAvailable");
        mTextureDestroyed = false;
        mSurfaceWidth = width;
        mSurfaceHeight = height;
        mEglCore = new EglCore();
        mDummySurface = mEglCore.createOffscreenSurface(1, 1);
        mEglCore.makeCurrent(mDummySurface);
        mPreviewTexture = GlUtil.createTextureObject(GLES11Ext.GL_TEXTURE_EXTERNAL_OES);
        // Creates a SurfaceTexture object for camera preview
        mPreviewSurfaceTexture = new SurfaceTexture(mPreviewTexture);
        // Creates OnFrameAvailableListener using the Android API setOnFrameAvailableListener, which triggers the onFrameAvailable callback if there are new video frames for SurfaceTexture
        mPreviewSurfaceTexture.setOnFrameAvailableListener(this);
        mDrawSurface = mEglCore.createWindowSurface(surface);
        mProgram = new ProgramTextureOES();
        if (mCamera != null || mPreviewing) {
            Log.e(TAG, "Camera preview has been started");
            return;
        }
        try {
            // Enables the camera (the code sample uses Android's Camera class)
            mCamera = Camera.open(mFacing);
            // Sets the most suitable resolution for your app scenario
            Camera.Parameters parameters = mCamera.getParameters();
            parameters.setPreviewSize(DEFAULT_CAPTURE_WIDTH, DEFAULT_CAPTURE_HEIGHT);
            mCamera.setParameters(parameters);
            // Sets mPreviewSurfaceTexture as the SurfaceTexture object for camera preview
            mCamera.setPreviewTexture(mPreviewSurfaceTexture);
            // Enables the portrait mode for camera preview. To ensure that camera preview stays in the portrait mode, rotate the preview image by 90 degrees clockwise
            mCamera.setDisplayOrientation(90);
            // The camera starts capturing video frames and rendering them to the specified SurfaceView
            mCamera.startPreview();
            mPreviewing = true;
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }

The onFrameAvailable callback (Android's method, see Android's help document) is triggered when new video frames appear in TextureView. The callback implements the following operations:

Renders the captured video frames using the custom renderer for later use in local view.
Calls pushExternalVideoFrame to send the captured video frames to the SDK.

// The onFrameAvailable callback gets new video frames captured by SurfaceTexture
// Renders the video frames using EGL for later use in local view
// Calls pushExternalVideoFrame to send the video frames to the SDK
public void onFrameAvailable(SurfaceTexture surfaceTexture) {
        if (mTextureDestroyed) {
            return;
        }
        if (!mEglCore.isCurrent(mDrawSurface)) {
            mEglCore.makeCurrent(mDrawSurface);
        }
        // Calls updateTexImage() to update data to the OpenGL ES texture object
        // Calls getTransformMatrix() to transform the texture's matrix
        try {
            mPreviewSurfaceTexture.updateTexImage();
            mPreviewSurfaceTexture.getTransformMatrix(mTransform);
        }
        catch (Exception e) {
            e.printStackTrace();
        }
        // Configures MVP matrix
        if (!mMVPMatrixInit) {
            // This code sample defines activity as the portrait mode. Since the captured video frames are rotated by 90 degrees, you need to switch the width and height data when calculating the frame ratio.
            float frameRatio = DEFAULT_CAPTURE_HEIGHT / (float) DEFAULT_CAPTURE_WIDTH;
            float surfaceRatio = mSurfaceWidth / (float) mSurfaceHeight;
            Matrix.setIdentityM(mMVPMatrix, 0);
            if (frameRatio >= surfaceRatio) {
                float w = DEFAULT_CAPTURE_WIDTH * surfaceRatio;
                float scaleW = DEFAULT_CAPTURE_HEIGHT / w;
                Matrix.scaleM(mMVPMatrix, 0, scaleW, 1, 1);
            } else {
                float h = DEFAULT_CAPTURE_HEIGHT / surfaceRatio;
                float scaleH = DEFAULT_CAPTURE_WIDTH / h;
                Matrix.scaleM(mMVPMatrix, 0, 1, scaleH, 1);
            }
            mMVPMatrixInit = true;
        }
        // Sets the size of the video view
        GLES20.glViewport(0, 0, mSurfaceWidth, mSurfaceHeight);
        // Draws video frames
        mProgram.drawFrame(mPreviewTexture, mTransform, mMVPMatrix);
        // Sends the buffer of EGL image to EGL Surface for local playback and preview. mDrawSurface is an object of the EGLSurface class.
        mEglCore.swapBuffers(mDrawSurface);
        // If the user has joined the channel, configures the external video frames and sends them to the SDK.
        if (joined) {
            // Configures external video frames
            AgoraVideoFrame frame = new AgoraVideoFrame();
            frame.textureID = mPreviewTexture;
            frame.format = AgoraVideoFrame.FORMAT_TEXTURE_OES;
            frame.transform = mTransform;
            frame.stride = DEFAULT_CAPTURE_HEIGHT;
            frame.height = DEFAULT_CAPTURE_WIDTH;
            frame.eglContext14 = mEglCore.getEGLContext();
            frame.timeStamp = System.currentTimeMillis();
            // Sends external video frames to the SDK
            boolean a = engine.pushExternalVideoFrame(frame);
            Log.e(TAG, "pushExternalVideoFrame:" + a);
        }
    }

API reference

MediaIO mode

In MediaIO mode, the Agora SDK provides the IVideoSource interface and the IVideoFrameConsumer class to configure the format of captured video frames and control the process of video capturing.

Refer to the following steps to customize the video source in your project:

Implement the IVideoSource interface, which configures the format of captured video frames and controls the process of video capturing through a set of callbacks:
- After receiving the getBufferType callback, specify the format of the captured video frames in the return value.
- After receiving the onInitialize callback, save the IVideoFrameConsumer object, which sends and receives video frames captured by a custom source.
- After receiving the onStart callback, start sending the captured video frames to the SDK by calling the consumeByteBufferFrame, consumeByteArrayFrame, or consumeTextureFrame method in the IVideoFrameConsumer object. Before sending the video frames, you can modify the video frame parameters in IVideoFrameConsumer, such as rotation, according to your app scenario.
- After receiving the onStop callback, stop the IVideoFrameConsumer object from sending video frames to the SDK.
- After receiving the onDispose callback, release the IVideoFrameConsumer object.
Inherit the IVideoSource class implemented in step 1, and construct an object for the custom video source.
Call the setVideoSource method to assign the custom video source object to RtcEngine.
According to your app scenario, call the startPreview or joinChannel method to preview or publish the captured video frames.

API call sequence

Refer to the following diagram to implement the custom video source:

1607670515750

Video data transfer

The following diagram shows how the video data is transferred when you customize the video source in MediaIO mode:

1607670413195

You need to implement the capture module yourself using methods from outside the SDK.
Captured video frames are sent to the SDK via the consumeByteBufferFrame, consumeByteArrayFrame, or consumeTextureFrame method.

Code samples

The following code samples use a local video file as the custom video source.

Implement the IVideoSource interface and the IVideoFrameConsumer class, and rewrite the callbacks in the IVideoSource interface.

// Implements the IVideoSource interface
public class ExternalVideoInputManager implements IVideoSource {
...
    // Gets the IVideoFrameConsumer object from this callback when initializing the video source
    @Override
    public boolean onInitialize(IVideoFrameConsumer consumer) {
        mConsumer = consumer;
        return true;
    }
    @Override
    public boolean onStart() {
        return true;
    }
    @Override
    public void onStop() {
    }
    // Sets the IVideoFrameConsumer object as null when media engine releases IVideoFrameConsumer
    @Override
    public void onDispose() {
        Log.e(TAG, "SwitchExternalVideo-onDispose");
        mConsumer = null;
    }
    @Override
    public int getBufferType() {
        return TEXTURE.intValue();
    }
    @Override
    public int getCaptureType() {
        return CAMERA;
    }
    @Override
    public int getContentHint() {
        return MediaIO.ContentHint.NONE.intValue();
    }
 ...
}

// Implements the IVideoFrameConsumer class
private volatile IVideoFrameConsumer mConsumer;

Specify the custom video source before joining a channel.

// Specifies the custom video source
ENGINE.setVideoSource(ExternalVideoInputManager.this);

Configure external video input.

// Creates an intent for local video input, sets video frame parameters, and sets external video input
// Calls setExternalVideoInput to create a new LocalVideoInput object which retrieves the location of the local video file
// The setExternalVideoInput method also sets a Surface Texture monitor for  TextureView
// Adds TextureView to subviews in relative layout for local preview
Intent intent = new Intent();
setVideoConfig(ExternalVideoInputManager.TYPE_LOCAL_VIDEO, LOCAL_VIDEO_WIDTH, LOCAL_VIDEO_HEIGHT);
intent.putExtra(ExternalVideoInputManager.FLAG_VIDEO_PATH, mLocalVideoPath);
if (mService.setExternalVideoInput(ExternalVideoInputManager.TYPE_LOCAL_VIDEO, intent)) {
       // Deletes all subviews in relative layout
       fl_local.removeAllViews();
       // Adds TextureView as a subview
       fl_local.addView(TEXTUREVIEW,
              RelativeLayout.LayoutParams.MATCH_PARENT,
              RelativeLayout.LayoutParams.MATCH_PARENT);
      }

Refer to the following code sample to implement the setExternalVideoInput method:

// Implements the setExternalVideoInput method
boolean setExternalVideoInput(int type, Intent intent) {
        if (mCurInputType == type && mCurVideoInput != null
                && mCurVideoInput.isRunning()) {
            return false;
        }
        // Creates a new LocalVideoInput object which retrieves the location of the local video file
        IExternalVideoInput input;
        switch (type) {
            case TYPE_LOCAL_VIDEO:
                input = new LocalVideoInput(intent.getStringExtra(FLAG_VIDEO_PATH));
                // If TextureView is not null, sets a Surface Texture monitor for this TextureView
                if (TEXTUREVIEW != null) {
                    TEXTUREVIEW.setSurfaceTextureListener((LocalVideoInput) input);
                }
                break;
           ...
        }
        // Sets the created LocalVideoInput object as the video source
        setExternalVideoInput(input);
        mCurInputType = type;
        return true;
    }

Implement the local video thread, and decode the local video file. The decoded video frames are rendered to Surface.

// Decodes the local video file and renders it to Surface
LocalVideoThread(String filePath, Surface surface) {
    initMedia(filePath);
    mSurface = surface;
}

After the local user joins the channel, the capture module consumes the video frames through the consumeTextureFrame method in ExternalVideoInputThread and sends the frames to the SDK.

public void run() {
                ...
                // Calls updateTexImage() to update data to the OpenGL ES texture object
                // Calls getTransformMatrix() to transform the texture's matrix
                 try {
                 mSurfaceTexture.updateTexImage();
                 mSurfaceTexture.getTransformMatrix(mTransform);
                      }
                 catch (Exception e) {
                 e.printStackTrace();
                 }
                // Gets the captured video frames through the onFrameAvailable callback. This callback is rewritten in the LocalVideoInput class based on Android's corresponding API.
                // The onFrameAvailable callback creates EGL Surface through the SurfaceTexture for local preview and uses its context as the current context. You can use this callback to render video frames locally, get Texture ID and transform information, and send the video frames to the SDK.
                if (mCurVideoInput != null) {
                    mCurVideoInput.onFrameAvailable(mThreadContext, mTextureId, mTransform);
                }
                // Links EGLSurface
                mEglCore.makeCurrent(mEglSurface);
                // Sets the EGL video view
                GLES20.glViewport(0, 0, mVideoWidth, mVideoHeight);
                if (mConsumer != null) {
                    Log.e(TAG, "Width and Height ->width:" + mVideoWidth + ",height:" + mVideoHeight);
                    // Calls consumeTextureFrame to consume the video frames and send them to the SDK
                    mConsumer.consumeTextureFrame(mTextureId,
                            TEXTURE_OES.intValue(),
                            mVideoWidth, mVideoHeight, 0,
                            System.currentTimeMillis(), mTransform);
                }
                // Waiting for the next frame
                waitForNextFrame();
                ...
        }

API reference

Custom video renderer

The Agora SDK provides the IVideoSink interface to customize the video renderer in your project.

Refer to the following steps to implement the video renderer:

Implement the IVideoSink interface, which configures the format of captured video frames and controls the process of video rendering through a set of callbacks:
- After receiving the getBufferType and getPixelFormat callbacks, specify the format of the rendered video frames in the return value.
- After receiving the onInitialize, onStart, onStop, onDispose, and getEglContextHandle callbacks, perform the corresponding operations.
- Implement the IVideoFrameConsumer class for the rendered video frames' format to retrieve the video frames.
Inherit the IVideoSource class implemented in step 1, and create a video capture module for the custom renderer.
Call the setLocalVideoRenderer or setRemoteVideoRenderer method to render the video of the local user or remote user.
According to your app scenario, call the startPreview or joinChannel method to preview or publish the rendered video frames.

API call sequence

Refer to the following diagram to implement the custom video renderer in MediaIO mode:

Video data transfer

The following diagram shows how the video data is transferred when you customize the video renderer in MediaIO mode:

1607670404631

You need to implement the rendering module yourself using methods from outside the SDK.
Captured video frames are sent to the capture module via the consumeByteBufferFrame, consumeByteArrayFrame, or consumeTextureFrame method.

Code samples

The code samples provide two options for implementing the custom video renderer in your project.

Option 1: Use components provided by Agora

The Agora SDK provides classes and code samples that are designed to help you easily integrate and create a custom video renderer. You can use these components directly, or you can create a custom renderer based on these components. See Customize the Video Sink with the Agora Component.

After the local user joins the channel, import and implement the AgoraSurfaceView class, then set the remote video renderer. The AgoraSurfaceView class inherits the SurfaceView class and implements the IVideoSink class. AgoraSurfaceView also embeds a BaseVideoRenderer object that serves as the rendering module, which means you do not need to implement the IVideoSink class and customize the rendering module yourself. The BaseVideoRenderer object uses OpenGL as the renderer and creates EGLContext, and it shares the Handle of EGLContext with Media Engine. For more information about how to implement the AgoraSurfaceView class, see the demo project.

@Override
       public void onUserJoined(int uid, int elapsed) {
           super.onUserJoined(uid, elapsed);
           Log.i(TAG, "onUserJoined->" + uid);
           showLongToast(String.format("user %d joined!", uid));
           Context context = getContext();
           if (context == null) {
               return;
           }
           handler.post(() ->
           {
               // Implements the AgoraSurfaceView class
               AgoraSurfaceView surfaceView = new AgoraSurfaceView(getContext());
               surfaceView.init(null);
               surfaceView.setZOrderMediaOverlay(true);
               // Calls the setBufferType and setPixelFormat methods in the embedded BaseVideoRenderer object to set the type and format of the video frames
             surfaceView.setBufferType(MediaIO.BufferType.BYTE_BUFFER);
               surfaceView.setPixelFormat(MediaIO.PixelFormat.I420);
               if (fl_remote.getChildCount() > 0) {
                   fl_remote.removeAllViews();
               }
               fl_remote.addView(surfaceView);
               // Sets the remote video renderer
               engine.setRemoteVideoRenderer(uid, surfaceView);
           });
       }

Option 2: Use the `IVideoSink` interface

You can implement the IVideoSink class and inherit it to construct a rendering module for the custom renderer.

// Creates an instance to implement the IVideoSink interface
IVideoSink sink = new IVideoSink() {
    @Override
    // Initializes the renderer either in this method or beforehand. Sets the return value as true to indicate that the renderer has initialized
    public boolean onInitialize () {
        return true;
    }
    @Override
    // Starts the renderer
    public boolean onStart() {
        return true;
    }
    @Override
    // Stops the renderer
    public void onStop() {
    }
    @Override
    // Releases the renderer
    public void onDispose() {
    }
    @Override
    public long getEGLContextHandle() {
        // Constructs your Egl context
        // If the return value is 0, no Egl context has been created in the renderer
        return 0;
    }
    // Returns the Buffer type the renderer requires
    // If you want to switch to a different VideoSink type, you must create another instance
    // There are three Buffer types: BYTE_BUFFER(1), BYTE_ARRAY(2), and TEXTURE(3)
    @Override
    public int getBufferType() {
        return BufferType.BYTE_ARRAY;
    }
    // Returns the Pixel format the renderer requires
    @Override
    public int getPixelFormat() {
        return PixelFormat.NV21;
    }
   // SDK calls this method to send the captured video frames to the renderer
   // Use the corresponding callback for the format of the captured video frames
   @Override
   public void consumeByteArrayFrame(byte[] data, int format, int width, int height, int rotation, long timestamp) {
   // The renderer is working
   }
   public void consumeByteBufferFrame(ByteBuffer buffer, int format, int width, int height, int rotation, long timestamp) {
   // The renderer is working
   }
   public void consumeTextureFrame(int textureId, int format, int width, int height, int rotation, long timestamp, float[] matrix) {
   // The renderer is working
   }
}
rtcEngine.setLocalVideoRenderer(sink);

API reference

Considerations

Performing the following operations requires you to use methods from outside the Agora SDK:
- Manage the capture and processing of video frames when using a custom video source.
- Manage the processing and display of video frames when using a custom video renderer.
When using a custom video renderer, if the consumeByteArrayFrame, consumeByteBufferFrame, or consumeTextureFrame callback reports that rotation is not 0, the rendered video frames are rotated by a certain degree. This may be caused by the capture settings of the SDK or your custom video source. You need to modify rotation according to your application scenario.
If the format of the custom captured video is Texture and the remote user sees anomalies (such as flickering and distortion) in the local custom captured video, Agora recommends that you make a copy of the video data before sending the custom video data back to the SDK, and then send both the original video data and the copied video data back to the SDK. This eliminates the anomalies during the internal data encoding.

Agora Developer Center

Custom Video Source and Renderer

Introduction

Sample project

Custom video source

Push mode

API call sequence

Video data transfer

Code samples

API reference

MediaIO mode

API call sequence

Video data transfer

Code samples

API reference

See also

Custom video renderer

API call sequence

Video data transfer

Code samples

Option 1: Use components provided by Agora

Option 2: Use the `IVideoSink` interface

API reference

Considerations

See also