YUV420ToNV21.java

/**
 * Converts the YUV420_888 Image into a packed NV21 of a single byte array,
 * suitable for JPEG compression by the method convertNv21toJpeg. Creates a
 * memory block with the y component at the head and interleaves the u,v
 * components following the y component. Caller is responsible to allocate a
 * large enough buffer for results.
 *
 * @param img image to be converted
 * @param dataCopy buffer to write NV21 packed image
 * @return byte array of NV21 packed image
 */
private byte[] convertYUV420ImageToPackedNV21(ImageProxy img, byte[] dataCopy) {
    // Get all the relevant information and then release the image.
    final int w = img.getWidth();
    final int h = img.getHeight();
    final ImageProxy.PlaneProxy[] planeList = img.getPlanes();
    ByteBuffer y_buffer = planeList[0].getBuffer();
    ByteBuffer u_buffer = planeList[1].getBuffer();
    ByteBuffer v_buffer = planeList[2].getBuffer();
    final int color_pixel_stride = planeList[1].getPixelStride();

    Log.d(TAG, "Size of Y buffer: " +String.valueOf(y_buffer.capacity()));
    Log.d(TAG, "Size of U buffer: " +String.valueOf(u_buffer.capacity()));
    Log.d(TAG, "Size of V buffer: " +String.valueOf(v_buffer.capacity()));
    Log.d(TAG, "Color Pixel Stride: " +String.valueOf(color_pixel_stride));

    final int y_size = y_buffer.capacity();
    final int u_size = u_buffer.capacity();
    final int data_offset = w * h;
    for (int i = 0; i < y_size; i++) {
        dataCopy[i] = (byte) (y_buffer.get(i) & 255);
    }
    for (int i = 0; i < u_size / color_pixel_stride; i++) {
        dataCopy[data_offset + 2 * i] = v_buffer.get(i * color_pixel_stride);
        dataCopy[data_offset + 2 * i + 1] = u_buffer.get(i * color_pixel_stride);
    }
    return dataCopy;
}