android - 使用RenderScript进行YUV NV12到RGB的转换

Question

Android has buildin convert function for YUV to RGB, below code works fine for NV21 YUV input but if use NV12 input, it will crash.

public Bitmap YUV_toRGB(byte[] yuvByteArray,int W,int H) {
    RenderScript rs = RenderScript.create(this);
    ScriptIntrinsicYuvToRGB yuvToRgbIntrinsic = ScriptIntrinsicYuvToRGB.create(rs, Element.U8_4(rs));

    Type.Builder yuvType = new Type.Builder(rs, Element.U8(rs)).setX(yuvByteArray.length);
    Allocation in = Allocation.createTyped(rs, yuvType.create(), Allocation.USAGE_SCRIPT);

    Type.Builder rgbaType = new Type.Builder(rs, Element.RGBA_8888(rs)).setX(W).setY(H);
    Allocation out = Allocation.createTyped(rs, rgbaType.create(), Allocation.USAGE_SCRIPT);

    in.copyFrom(yuvByteArray);

    yuvToRgbIntrinsic.setInput(in);
    yuvToRgbIntrinsic.forEach(out);
    Bitmap bmp = Bitmap.createBitmap(W, H, Bitmap.Config.ARGB_8888);
    out.copyTo(bmp);

    yuvToRgbIntrinsic.destroy();
    rs.destroy();
    return bmp;
}

How can I change the code to convert NV12 to RGB? No document say what's the input format supported and how to config it.

Answer 1

The Android documentation on ScriptIntrinsicYuvToRGB clearly states:

The input allocation is supplied in NV21 format as a U8 element type. The output is RGBA, the alpha channel will be set to 255.

If you need a different YUV format, you'll have to write your own RS kernel to do the conversion.