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Subject: Re: Sync problems in grayscale lib?
From: Matthias Wientapper (
Date: 2004-05-23

Tobi wrote:
> Hello,
> I have an Archos Recorder with USB 2.0. All applications, that uses the
> grayscale lib have some sort of a display error. It seems like a problem
> with the lcd timing. A gray bar goes all along from the top of the
> display to the bottom. It looks like you film a television. Is this a
> common problem?

Hi Tobi,

this is because of a missing v-sync scheme of the display. Jukebox clock
and display refresh rate are not synced. Grayscale refresh rate is
somewhat really close to the display's framerate and tends to drift due
to temperature effects/tolerances of the LCD timing oscillator. That
drift causes bars/artefacts wandering along your screen. Your assumtion
with an lcd timing issue is right.


For every complex problem, there is a solution that is simple, neat, and 
H.L. Mencken (1880-1956)

Page was last modified "Jan 10 2012" The Rockbox Crew