android视频录制动态添加时间水印

如果要在 Android 视频录制过程中动态添加时间水印，可以使用 Camera2 API 实现。Camera2 API 可以获取到每一帧视频的数据，因此可以在每一帧数据上添加时间水印，并将处理后的数据传递给 MediaRecorder 进行录制。

以下是添加动态时间水印的示例代码：

private CameraDevice mCameraDevice;
private CaptureRequest.Builder mPreviewBuilder;
private ImageReader mImageReader;
private Surface mRecorderSurface;

private void initCamera() {
    CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    String cameraId = CameraCharacteristics.LENS_FACING_BACK + "";
    try {
        manager.openCamera(cameraId, new CameraDevice.StateCallback() {
            @Override
            public void onOpened(@NonNull CameraDevice cameraDevice) {
                mCameraDevice = cameraDevice;
                startPreview();
            }

            @Override
            public void onDisconnected(@NonNull CameraDevice cameraDevice) {
                mCameraDevice.close();
                mCameraDevice = null;
            }

            @Override
            public void onError(@NonNull CameraDevice cameraDevice, int i) {
                mCameraDevice.close();
                mCameraDevice = null;
            }
        }, null);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

private void startPreview() {
    try {
        SurfaceTexture surfaceTexture = new SurfaceTexture(0);
        surfaceTexture.setDefaultBufferSize(640, 480);
        Surface previewSurface = new Surface(surfaceTexture);

        mImageReader = ImageReader.newInstance(640, 480, ImageFormat.YUV_420_888, 2);
        mImageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {
            @Override
            public void onImageAvailable(ImageReader reader) {
                Image image = reader.acquireLatestImage();
                ByteBuffer buffer = image.getPlanes()[0].getBuffer();
                byte[] data = new byte[buffer.remaining()];
                buffer.get(data);
                addTimeWatermark(data, image.getWidth(), image.getHeight());
                image.close();
            }
        }, null);

        mRecorderSurface = mMediaRecorder.getSurface();

        mPreviewBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        mPreviewBuilder.addTarget(previewSurface);
        mPreviewBuilder.addTarget(mImageReader.getSurface());

        mCameraDevice.createCaptureSession(Arrays.asList(previewSurface, mImageReader.getSurface(), mRecorderSurface), new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                try {
                    cameraCaptureSession.setRepeatingRequest(mPreviewBuilder.build(), null, null);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {

            }
        }, null);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

private void addTimeWatermark(byte[] data, int width, int height) {
    YuvImage yuvImage = new YuvImage(data, ImageFormat.NV21, width, height, null);
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    yuvImage.compressToJpeg(new Rect(0, 0, width, height), 100, out);
    byte[] jpegData = out.toByteArray();
    Bitmap bitmap = BitmapFactory.decodeByteArray(jpegData, 0, jpegData.length);

    Canvas canvas = new Canvas(bitmap);
    canvas.drawText(getCurrentTime(), 10, 10, new Paint());
    canvas.save();

    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
    byte[] outputData = outputStream.toByteArray();

    try {
        mRecorderSurface.lockCanvas(null).drawBitmap(bitmap, 0, 0, null);
        mMediaRecorder.writeSampleData(mRecorderSurface, ByteBuffer.wrap(outputData), new MediaCodec.BufferInfo());
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        mRecorderSurface.unlockCanvasAndPost(canvas);
    }
}

需要注意的是，在添加时间水印时，要将视频帧转换为 Bitmap 对象，并在 Bitmap 上绘制时间水印。然后，将处理后的数据传递给 MediaRecorder 进行录制。同时，要在 CameraDevice.close() 方法被调用时，释放资源。