Android ImageReader.acquireLatestImage returns invalid JPG

Question

I am using Android ImageReader class to receive Bitmaps from MediaProjection.createVirtualDisplay method.

My code so far looks like this:

mProjectio         


        

Answer 1

I encountered exactly your problem. My ImageReader created as so:

ImageReader.newInstance(mCaptureSize.getWidth(), mCaptureSize.getHeight(), ImageFormat.JPEG, 1);

The ImageReader above should only return compressed images, and these need to be decompressed. I acquireLatestImage(), then pass it through the following:

ByteBuffer bBuffer = planes[0].getBuffer;
bBuffer.rewind();
byte[] buffer = new byte[bBuffer.remaining()];
planes[0].getBuffer().get(buffer);
Bitmap bitmap = BitmapFactory.decodeByteArray(buffer, 0, buffer.length);

The key for me was to rewind the ByteBuffer. Your code should work as so:

mProjection.createVirtualDisplay("test", width, height, density, flags, mImageReader.getSurface(), new VirtualDisplayCallback(), mHandler);
            mImageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {
                @Override
                public void onImageAvailable(ImageReader reader) {
                    Image image = null;
                    try {
                        image = mImageReader.acquireLatestImage();
                        final Image.Plane[] planes = image.getPlanes();
                        final ByteBuffer buffer = planes[0].getBuffer();
                        buffer.rewind()
                        final byte[] data = new byte[buffer.capacity()];
                        buffer.get(data);
                        final Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
                        if (bitmap==null)
                            Log.e(TAG, "bitmap is null");

                    } catch (Exception e) {
                        if (image!=null)
                            image.close();
                    }
                }

            }, mHandler);

I don't like having to copy the ByteBuffer through an intermediate byte[], but the internal array is protected.

Tested working on 5.0.1 on an HTC