[MPlayer-users] fb_dev: flickering output

[Reimar Döffinger]

On Wed, Mar 23, 2011 at 01:51:08PM +0100, Alexander Stein wrote:
> On Tuesday 22 March 2011, 21:11:27 Carl Eugen Hoyos wrote:
> > Alexander Stein <alexander.stein <at> systec-electronic.com> writes:
> > > I tried rc4 and noticed a slight flicking in the output. Especially if i
> > > fill the framebuffer using cat /dev/urandom > /dev/fb0.
> > > Using rc2 there is no such flickering. I tried to bisect the problem, but
> > > I have problem building mplayer.
> > 
> > svn co -r {2010-09-27} svn://svn.ffmpeg.org/mplayer/trunk mplayer
> > cd mplayer
> > svn up --ignore-externals -r {2010-09-27} libavutil/ libavformat/
> > libavcodec/ libavcore/ libpostproc/ libdvdread4/ libdvdnav/
> > ./configure && make
> > make distclean
> > svn up --ignore-externals -r {2009-12-31}
> > svn up --ignore-externals -r {2009-12-31} libavutil/ libavformat/
> > libavcodec/ libpostproc/ libdvdread4/ libdvdnav/
> > ./configure && make
> > 
> > Note that libavcore was introduced around 2010-07-21, do not add it to
> > earlier update commands!
> > 
> > I don't know if it is possible to test versions after 2010-09-26.
> 
> Thanks a lot. This helped me tracking down the problem to be caused by double 
> buffering. Disabling it I get nice output, like in rc2.
> Nevertheless I don't know if there problem is my hardware (AT91SAM9263) or the 
> driver atmel_lcdfb but that's an other area.

You didn't give enough information, however there are several things to not
1) disabling double-buffer in my experience results in horrible tearing
2) double-buffering uses two different parts of memory in sequence.
   In "windowed" mode MPlayer on purpose does not clear the screen (so you
   can e.g. have a video playing "on top" of your terminal), so if you fill
   it with random data the background will flip between completely different
   things there. -fs should help, at least for fbdev2.
3) a lot of fbdev drivers seem to be buggy with double-buffering, but if 2)
   does not help you I could look into it.