int[] rgb = new int[previewWidth * previewHeight];
// This method decodes YUV to RGB.
// imageData is byte[] obtained from the Camera.
decodeYUV(rgb, imageData, previewWidth, previewHeight);
Bitmap bm = Bitmap.createBitmap(rgb, previewWidth, previewHeight, Config.RGB_565);
bm.compress(Bitmap.CompressFormat.JPEG, mPreviewQuality, out);However, to produce an app that works across different platform versions, this is not enough. We still want to use the speed of native Jpeg compression done by YuvImage in 2.2+ SDK. With the target SDK version of the app set to 2.1, we need to use reflection in order to use the YuvImage class.
Class<?>[] yuvArgsClass = new Class[] {
byte[].class, int.class, int.class, int.class, int[].class };
Class<?> yuvParamTypes[] = new Class[] { Rect.class, int.class, OutputStream.class};
Class<?> c = Class.forName("android.graphics.YuvImage");
Constructor<?> yuvImageConstructor = c.getConstructor(yuvArgsClass);
Object[] args = new Object[] {
imageData, previewFormat, previewWidth, previewHeight, null};
Object yuvImage = yuvImageConstructor.newInstance(args);
Object params[] = new Object[] {previewRect, mPreviewQuality, out};
Method compress = c.getMethod("compressToJpeg", yuvParamTypes);
compress.invoke(yuvImage, params);In the above code, imageData is the byte[] data obtained from the Camera. previewFormat, previewWidth, and previewHeight are obtained from Camera.getParameters().
previewRect = new Rect(0, 0, previewWidth, previewHeight);
We were unable to get the Java-based YUV -> Bitmap conversion to work on the G1 phones due to OutOfMemory problems. G1 phones have a 16 MB heap which seems to run out pretty quick.
