Defect of image with ScriptIntrinsicBlur from support library

Question

I am trying to blur an image with ScriptIntrinsicBlur from the RenderScript support library. I am using gradle and I have used this approach to use the Support Library version of RenderScript.

On my Nexus 4, everything works fine and is really fast, but when I try it on my Samsung Galaxy S with Android 2.3.3, the picture that I get looks like this:

I am using Roman Nurik's tip for having the bitmap width as a multiple of 4, but I don't think that this is the cause of my problem. My blurring code looks exactly like in this post. Thanks for any advice.

Here's my code:

Getting Bitmap of the View and rescaling the Bitmap:

public static Bitmap loadBitmapFromView(View v) {
        v.setDrawingCacheEnabled(false);
        v.setDrawingCacheQuality(View.DRAWING_CACHE_QUALITY_LOW);
        v.setDrawingCacheEnabled(true);
        Bitmap b = v.getDrawingCache();
        return b;
    }

public static Bitmap scaledBitmap(Bitmap dest, float scale) {
        int scaledWidth = (int) (scale * dest.getWidth());
        if (scaledWidth % 4 != 0) { //workaround for bug explained here https://plus.google.com/+RomanNurik/posts/TLkVQC3M6jW
            scaledWidth = (scaledWidth / 4) * 4;
        }
        return Bitmap.createScaledBitmap(dest, scaledWidth, (int) (scale * dest.getHeight()), true);
    }

Renderscript code:

Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);

final RenderScript rs = RenderScript.create(context);
final Allocation input = Allocation.createFromBitmap(rs, sentBitmap, Allocation.MipmapControl.MIPMAP_NONE, Allocation.USAGE_SCRIPT);
final Allocation output = Allocation.createTyped(rs, input.getType());
final ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
script.setRadius(radius);
script.setInput(input);
script.forEach(output);
output.copyTo(bitmap);
return bitmap;

I have noticed this error in the logcat output:

E/RenderScript_jni﹕ No GC methods

After that my application is frozen.

Answer 1

I was getting a very similar image from the ScriptInstinsicBlur in my application. It took a while to figure this out but it turns out that the MediaMetadataRetiever getFrameAt methods return a Bitmap config that is RGB_565. Applying the blur in renderscript gives you the funky results because it apparently doesn't work on 565 pixels.

Converting my Bitmap to a ARGB_8888 and then handing it to the renderscript gave me the blur I was looking for.

Hopefully this helps someone else.

This is the method I found to convert it. (It's from a SO post I don't have bookmarked)

 private Bitmap RGB565toARGB888(Bitmap img) {
    int numPixels = img.getWidth()* img.getHeight();
    int[] pixels = new int[numPixels];

    //Get JPEG pixels.  Each int is the color values for one pixel.
    img.getPixels(pixels, 0, img.getWidth(), 0, 0, img.getWidth(), img.getHeight());

    //Create a Bitmap of the appropriate format.
    Bitmap result = Bitmap.createBitmap(img.getWidth(), img.getHeight(), Bitmap.Config.ARGB_8888);

    //Set RGB pixels.
    result.setPixels(pixels, 0, result.getWidth(), 0, 0, result.getWidth(), result.getHeight());
    return result;
}