[Mplayer-advusers] Bug? Anomalous CPU usage when playing HDTV clips.

[John Stebbins]

Hey, thanks for the reply.

Do you know of a way to find out what size textures the
graphics card supports?  It appears that the max is 1024x1024
since mplayer reports using 2x1 1024x1024 textures for
the 1280x720 size clip. So you're correct about the white
screen behavior with the gl driver.

Actually, this particular test was run on a desktop with
an integrated intel chipset.  I just re-ran on the laptop
with an ATI Radeon Mobility M9 and 32MB video ram. FYI,
glxgears reports about the same rate on each of these systems,
about 1300fps. Both systems exhibit basically the same behavior.
Both systems appear to have a max texture size of 1024x1024.

To test the memory bandwidth theory, I ran some lower resolution
clips.  One is 1024x576, which requires a 1024x1024 texture.
The other is 720x404 and requires a 1024x512 texture.
Both clips are 30fps.

With gl2 driver:
1024x576 clip runs slow, and does not consume all available CPU.
720x404 clip playback speed is correct.

With gl driver:
Both clips play back at proper speed.

Hope this is useful information for you.  If you would like a
a copy of the 1024x576 clip to run any tests yourself, there's
probably some way we can figure out to make it available.  Its 14M.
(Smaller than some M$ turd documents I've sent via e-mail :-P)

John

On Thu, 2004-04-01 at 11:47, Reimar Döffinger wrote:
> Hi,
> 
> > This led me to try the gl drivers again and take a closer look.
> > They are buggy, so I've been ignoring them until now.
> Well, I'm the maintainer for these, so tell me if you find a bug (but be 
> aware that some of their shortcomings are intentional)
> 
> > Using the vo gl, CPU usage actually looks pretty sane
> > for both 1280x720 and 1024x576 @ 30fps.  mplayer runs 
> > between 20% and 30%, X is negligible. But 1280 has 
> > broken video, nothing but a white display.  Also, higher
> > fps clips do not play at correct speed.
> Don't know about those speed issues, but to play a 1280x720 video your 
> graphics card must support 2048x2048 textures - which many notebook 
> graphics cards probably won't.
> 
> > Using the vo gl2, nothing plays at the correct speed.
> > mplayer CPU usage is high, but below 60%, so its not 
> > due to pegging out the CPU.
> Assuming that your maximum texture size is 1024x1024, vo_gl2 will use 
> _four_ textures of this size. Especially if your graphics card uses 
> system RAM, your memory bus will be simply too slow for this.
> 
> Of course those are just guesses...
> 
> Greetings,
> Reimar Döffinger
> 
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