[MPlayer-users] Playing QHD (3840x2160) material with mplayer

Dean S. Messing deanm at sharplabs.com
Fri Apr 18 16:05:32 CEST 2008

Corey Hickey wrote:
> Dean S. Messing wrote:
> > I am baffled by two things:
> > 
> > 1)    As mplayer sucks the video off of disk the first time around
> >       I would expect to see the glrellm memory meter (Fedora 6) increase,
> >       but I don't.  Once the disk activity drops to zero mplayer speeds up
> >       form 2 or 3 fps to ~14, so it is clearly playing from memory.
> >       The meter shows that I'm using maybe 15% of the memory before
> >       calling mplayer.  The clip is 2.4GB long and i have 4GB of memory
> >       so the meter should move.  But it doesn't.
> Are you just playing from disk a few times and letting the kernel cache
> the file in memory? If so, then gkrellm isn't showing you the memory
> usage of the kernel's cache, which always grows to eat all otherwise
> unused RAM anyway.

Yes, that's exactly what I'm doing.  I didn't realise cache was not
included in memory.  That explains it.  A couple of others have
suggested some cache settings or not playing out of cache at all.  I'm
not sure how that will help since I'm certain it's not coming off of
disk once it's in memory (or, rather, cache) but I intend to try both

> > 2)    It turns out I _can_ play a few frames at 24 fps or faster
> >       using `animate' from ImageMagick.  The problem is that ImageMagick
> >       is a memory pig: a single QHD frame is 24.8MB but it eats more
> >       than 5 times that amount w/in ImageMagick.
> What does "mplayer mf://*.png -mf fps=24" do? If your original source is
> a pile of png files, that will be less I/O load than an uncompressed
> video; I don't know if it would be faster.

It is _much_ slower due to the decoding of the .png.  I'm
not at the lab to test it again, but I've tried it in the past
and it runs at less than 10 fps (I seem to remember 4)  whereas I'm now
getting 14 with -vo x11 on the uncompressed AVI.


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