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

[Reimar Döffinger]

On Wed, Apr 16, 2008 at 03:33:01PM -0700, Dean S. Messing wrote:
> 
> On Apr 11, 2008, Dominik 'Rathann' Mierzejewski wrote:
> > You could try using -vo gl:yuv=X with various X values or -vo xvidix (see
> > man mplayer), but there are other limiting factors as well.
> 
> and
> 
> On 11 Apr 2008, Reimar Doeffinger wrote:
> > At this resolution, I think at best some really new cards will be able
> > to handle it via -vo gl, probably only -vo gl2 will work. And it
> > certainly should not be that much faster that x11.
> 
> I finally got a few minutes to try both of your suggestions.
> None come close to playing QHD at 24 fps. There were certainly
> speed differences between -vo gl:yuv=X for X==0 compared to the
> other values (which were all faster) but all are slower
> that -vo x11.

None of these results are interesting, the interesting cases with -vo gl
are "-vo gl -dr" with RGB and "-vo gl:yuv=2" when the source is YV12.
Yes, YV12 will introduce small colour artefacts, though those should only be
visible at a viewing distance where any straight line already looks like
a staircase anyway.
In addition, esp. with -vo x11, RGB32/BGR32/RGB24/BGR24 all might have
different speeds.

> 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.

Cache usage does not count as memory usage. You can use large values for
-cache and -cache-min to make MPlayer cache it and that will show up,
but it means an additional memcpy and might actually slow down things.
Better copy the file to a tmpfs and use -nocache.
And both "top" and "free" do show the cache usage (and probably gkrellm
can, too), but it might be quite big before due to all the stuff loaded
during boot.

> 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.
> 
>       Nonetheless, it would seem that since it is able to ship the pixels
>       to the display panel, the system is fundamentally capable of it.

That still leaves open the question where the bottleneck is. E.g.
ImageMagick could have loaded (most of) the images to the graphics card
beforehand.