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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 03:59:12AM +0500, Antonino Daplas wrote:
> If you're seeing half the rate, then the CPU is either too slow, you're
> sleeping too long, or mpeg processing takes a lot of time.

29.97 is not half the rate.  You have to consider that each vsync that
I am counting is a full _frame_ (i.e. two fields) from MPlayer.  We
are only interested in knowing about the vsync that occurs after the
two fields in the frame have been displayed, thus the half-rate.

You will just have to trust me that there is no significant frame
dropping.  Nothing nearly enough to explain the fairly constant judder
I am seeing.

> request flip -> wait for sync1 -> return -> process next field/frame ->
> takes too long, sync2 passed -> request flip -> wait for sync3 -> rinse
> and repeat.

Not quite.  Keep in mind that full frames (two fields at a time) are
being put into the video buffer.

> However, the symptom of a slow cpu is skipped frames, not a repeat of
> the previous frame, because mplayer checks the time stamps (ie if actual
> interval exceeds needed interval, skip this frame).

Right.  Which suggests this is not a case of my processor not being
fast enough to process the MPEG frames.


Brian J. Murrell

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