kuanting / android_uvc_webrtc

Android WebRTC + USB Video Camera

We have created an Android APP, UVCWebRTC, which can stream USB Camera video using WebRTC. The test video below demostrates streaming USB camera through an Android phone to Android Emulator via a node.js singal server.

Our code is based those two awesome repositories:

• Shivam Maindola's AndroidWebRTC
• Jiang Dongguo's AndroidUSBCamera

For the basics of WebRTC, please refer to Shivam Maindola's post: Step by Step Guide to Build WebRTC Native Android App.

Running the code

1. Compile our Android App /UVCWebRTC and install it on two phones.
2. Go to /signal_server and run npm install to install packages.
3. Run the signal server node signal_server.js
4. Open the App on each phone and enter server IP address. You can choose to use UVC or default camera. Click the Connect button. The two Apps will exchange their SDP via signal server and connect to each other automatically!

Combining UVC and WebRTC

The key part of this project is in UvcCapturer.java :

@Override
    public void startCapture(int i, int i1, int i2) {
        if(mUvcStrategy != null) {
            UVC_PREVIEW_WIDTH = i;
            UVC_PREVIEW_HEIGHT = i1;
            UVC_PREVIEW_FPS = i2;
            mUvcStrategy.addPreviewDataCallBack(new IPreviewDataCallBack() {
                @Override
                public void onPreviewData(@Nullable byte[] bytes, @NonNull DataFormat dataFormat) {
                    NV21Buffer nv21Buffer = new NV21Buffer(bytes,UVC_PREVIEW_WIDTH,UVC_PREVIEW_HEIGHT, null);
                    VideoFrame frame = new VideoFrame(nv21Buffer, 0, System.nanoTime());
                    capturerObserver.onFrameCaptured(frame);
                }
            });
            mUvcStrategy.startPreview(getCameraRequest(), svVideoRender.getHolder());
        }
    }

In short, we referred to sutogan4ik's UsbCapturer and replaced UVCCamera with Jiang Dongguo's CameraUvcStrategy.