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[directfb-dev] Re: Seeing "tearing" using mplayer dfbmga
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[directfb-dev] Re: Seeing "tearing" using mplayer dfbmga



On Sun, Dec 08, 2002 at 03:53:48PM +0500, Antonino Daplas wrote:
> 
> In effect, the backend (in this case, DirectFB) has nothing to do but
> display the frame, and to make it pleasurable for the viewer, do the
> flips during the sync pulse. Since Mplayer already guarantees that each
> frame is delivered at the correct time, waiting for vsync is needed only
> for hardware incapable of synchronous flips.

Consider the following:

1. Flip() is called sometime during one frame
2. Next frame is being decoded into the new back buffer
3. vsync happens and the flip actually happens

In step 2 we've been decoding into the buffer that was still displayed.
The result is tearing.

To avoid this you need to use triple buffering or make sure the flip has
actually happened before you touch the new back buffer.

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/


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