[mythtv-users] xorg high cpu usage while playing video in mythtv

Raphael Pooser rpooser at gmail.com
Wed Nov 16 12:42:54 EST 2005

Nick wrote:

>On 12/11/05, Raphael Pooser <rpooser at gmail.com> wrote:
>>I've noticed relatively high processor usage by xorg when playing back
>>previously recorded video.  To play back a 480x480 resolution rtjpeg
>>recording, xorg take 40% processor time.  To play back a 384x480 video
>>it takes about 33%.  This is on top of the normal usage by
>>mythfrontend.  Mythfrontend takes about 13% to play back the recording.
>>Mythbackend takes about 35-30% to record a 480x480 stream.  It seems to
>>me, it should take a lot more power to record something using software
>>encoding like I am than to actually play it back.  I must be missing
>>hardware acceleration for the video playback, I'm guessing.  I'm using a
>>radeon9600pro with the vga hooked directly up to the vga input of an lcd
>>TV.  So the TV is acting like a monitor.  Thing is, I have the
>>proprietary ATI fglrz drivers installed.  But since I'm not really using
>>any of the functions of this driver, like opengl or TVout, maybe there
>>is a better driver I could install that could accelerate this 2D
>>video.... Anyone know what a normal amount for xorg to be using during
>>playback is, and if mine is abnormally high what are some methods I can
>>use to get that back down to a manageable 10-15%?
>I use the fglrx drivers on my frontend system (2GHz Celeron, Radeon
>9100IGP) and when just testing, got 3-4% X usage and 13% mythfrontend
>usage whilst playing back a 720x576 MPEG2 recording.
>First thing is to make sure you have xv working (type 'xvinfo' at the
>prompt and check the output). The MPEG4 codecs require more CPU power
>to decode than MPEG2 which is how they offer better compression
>mythtv-users mailing list
>mythtv-users at mythtv.org
Hey I got XV working by basically recompiling the kernel module from 
fglrx.  Not sure why it didn't work last time, now suddenly the kernel 
module is working and gives me 3D acceleration, and as I suspected it 
can also use XV at the same time (don't know why it couldn't, I guess 
because the kernel module wasn't loading properly).  Anyway, now that 
that is solved, I get about 1% cpu usage in X when playing a 480x480 
stream.  So far so good.  Only problem, now my overscan settings in 
mythtv won't work properly.  I normally set it to overscan the vertical 
by 2, to get rid of some ugly noise on the top of all my cable channels 
coming in (normally you wouldn't see on a tube TV).  Now, when I use the 
overscan, my video window which used to have black strips of about two 
pixels above and below the image are now filled with garbage.  It seems 
to be whatever would be in the video frame buffer before the overscan 
was applied to make those strips black.  It is annoying because the 
overscan gets rid of the cable TV noise inherent in the signal but now 
causes the graphics card to add it's own noise.  Has anyone seen this / 
have a solution?  It's a radeon 9600 pro using fglrx drivers.  Hmm, 
maybe I could try recording the video in a different resolution and see 
if the problem is related to the actual screen resolution as video plays 
I also had the picture offset too far to the right in the x direction 
but was able to fix that somehow using a combination of horizontal 
overscan and scan placement.  The horizontal overscan actually doesn't 
work, but has to be set to particular values to get the horizontal scan 
placement to work!  Anyway, that's fixed, leaving me with only the 
vertical overscan problems.

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