How can I handle the Android framebuffer?

I want to handle android framebuffer. I have a root Galaxy R (SHV-E170K) for testing, on which I run this command:

adb pull /dev/graphics/fb0 fb0

      

        
        
        
      

    

Then I ran the ffmpeg command:

ffmpeg -vcodec rawvideo -f rawvideo -pix_fmt rgb0 -s 540x960 -i fb0 -f image2 -vcodec png frame-%d.png

      

        
        
        
      

    

But I am falling under the wrong images.

How to properly handle the Android framebuffer?

Thank.