CODEWITHSUNDEEP
javaandroid
tomi
tomi

Reputation: 535

onpreviewframe byte[] to int[]

in on previewframe I get the byte[] in ImageFormat.RGB_565. Now I would like to convert this byte[] to int[] so I can do some pixel manipulation.

How could I do that?

ps. thus far I do it like this but it seems very unoptimized:

public void onPreviewFrame(byte[] data, Camera camera) { ...
    ByteBuffer bf = ByteBuffer.wrap(data);

        mBitmap = Bitmap.createBitmap(mWidth, mHeight, Bitmap.Config.RGB_565);
        mBitmap.copyPixelsFromBuffer(bf);

and then I do this do get the pixels in int[]:

        int bitmapArray[] = new int[originalWidth * originalHeight];

    mBitmap.getPixels(bitmapArray, 0, originalWidth, 0, 0,
            originalWidth, originalHeight);
}

Upvotes: 2

Views: 1726

Answers (1)

Stefan Haustein
Stefan Haustein

Reputation: 18803

I think the code to do this manually should look roughly like this: 

for (int i = 0; i < data.length; i += 2) {
  // Reconstruct 16 bit rgb565 value from two bytes
  int rgb565 = (data[i] & 255) | ((data[i + 1] & 255) << 8);

  // Extract raw component values (range 0..31 for g and b, 0..63 for g)  
  int b5 = rgb565 & 0x1f;
  int g6 = (rgb565 >> 5) & 0x3f;
  int r5 = (rgb565 >> 11) & 0x1f;

  // Scale components up to 8 bit: 
  // Shift left and fill empty bits at the end with the highest bits,
  // so 00000 is extended to 000000000 but 11111 is extended to 11111111
  int b = (b5 << 3) | (b5 >> 2);
  int g = (g6 << 2) | (g6 >> 4);
  int r = (r5 << 3) | (r5 >> 2); 

  // The rgb888 value, store in an array or buffer...
  int rgb = (r << 16) | (g << 8) | b;
}

So it may indeed be faster with an intermediate bitmap, unless you need the color components separately later on anyway.

Disclaimer: I did not test this. Some intermediate variables could be avoided, but I wanted to keep this more or less readable.

Upvotes: 1

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