Image processing with Android Camera

Question

I want to use the onPreviewFrame to post-process the image before displaying it to the user (i.e. apply a color tint, sepia, etc). As I understand, the byte[] data returned to the callback is encoded in YUV420sp. Have people been decoding this to RGB in Java or using NDK (native code)? Does anyone have an example of a function that decodes this to RGB and how the RGB values are used afterwards?

Thanks.

Community · Accepted Answer · 2012-10-30 21:51:41Z

7

I found a sample application that translates the YUV420 into RGB and displays (sort of) real time histograms over the preview image.

http://www.stanford.edu/class/ee368/Android/index.html

edited Oct 30, 2012 at 21:51

CommunityBot

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answered Feb 6, 2011 at 0:13

anelson

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2 Comments

Robert Over a year ago

Nice link, thanks. I'm running it in a Android virtual target, however the YUV420->RGB decoding is REALLY slow, despite it being just simple additions/multiplications/clamping. Is this something that would be expected in my debugging environment ?? (I'm a complete noob! :)

anelson Over a year ago

Yes, the implementation in that code is not optimized at all. If I were doing that sort of thing in a real app I would implement the bit-twiddling in native code.

bmkay · Accepted Answer · 2013-04-02 09:19:32Z

This helps?

Parameters params = mCamera.getParameters(); param.setPreviewFormat(ImageFormat.RGB_565); mCamera.setParameters(param);

First check if rgb is supported

http://developer.android.com/reference/android/hardware/Camera.Parameters.html#getPreviewFormat%28%29

and then set preview format to rgb

http://developer.android.com/reference/android/hardware/Camera.Parameters.html#setPreviewFormat%28int%29

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