How do I convert ByteArray from ImageMetaData() to Bitmap? - arcore

Question

I have this code:
Frame frame = mSession.update();
Camera camera = frame.getCamera();
...
bytes=frame.getImageMetadata().getByteArray(0);
System.out.println("Byte Array "+frame.getImageMetadata().getByteArray(0));
Bitmap bmp = BitmapFactory.decodeByteArray(bytes,0,bytes.length);
System.out.println(bmp);
When I print Bitmap, I get a null object. I'm trying to get the image from the camera, that's the reason I'm trying to convert byteArray to Bitmap. If there's an alternative way, it would also be helpful.
Thank You.

Answer 1

The ImageMetaData describes the background image, but does not actually contain the image itself.
If you want to capture the background image as a Bitmap, you should look at the computervision sample which uses a FrameBufferObject to copy the image to a byte array.

Answer 2

I've tried something similar. It works. But I don't recommend anyone to try this way. It takes time because of nested loops.
CameraImageBuffer inputImage;
final Bitmap bmp = Bitmap.createBitmap(inputImage.width, inputImage.height, Bitmap.Config.ARGB_8888);
int width = inputImage.width;
int height = inputImage.height;
int frameSize = width*height;
// Write Bytebuffer to byte[]
byte[] imageBuffer= new byte[inputImage.buffer.remaining()];
inputImage.buffer.get(imageBuffer);
int[] rgba = new int[frameSize];
for (int i = 0; i < height; i++){
for (int j = 0; j < width; j++) {
int r =imageBuffer[(i * width + j)*4 + 0];
int g =imageBuffer[(i * width + j)*4 + 1];
int b =imageBuffer[(i * width + j)*4 + 2];
rgba[i * width + j] = 0xff000000 + (b << 16) + (g << 8) + r;
}
}
bmp.setPixels(rgba, 0, width , 0, 0, width, height);
Bytebuffer is converted to rgba buffer, and is written to Bitmap. CameraImageBuffer is the class provided in computervision sample app.

Answer 3

You may not able to get bitmap using image metadata. Use below approach.Use onDrawFrame override method of surface view render.
#Override public void onDrawFrame(GL10 gl) {
int w = 1080;
int h = 1080;
int b[] = new int[w * (0 + h)];
int bt[] = new int[w * h];
IntBuffer ib = IntBuffer.wrap(b);
ib.position(0);
GLES20.glReadPixels(0, 0, w, h, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, ib);
for (int i = 0, k = 0; i < h; i++, k++) {
for (int j = 0; j < w; j++) {
int pix = b[i * w + j];
int pb = (pix >> 16) & 0xff;
int pr = (pix << 16) & 0x00ff0000;
int pix1 = (pix & 0xff00ff00) | pr | pb;
bt[(h - k - 1) * w + j] = pix1;
}
}
Bitmap mBitmap = Bitmap.createBitmap(bt, w, h, Bitmap.Config.ARGB_8888);
runOnUiThread(new Runnable() {
#Override public void run() {
image_test.setImageBitmap(resizedBitmap);
}
});
}