Sync problems with adjust refresh rate turned on (high cpu usage)
#1
Hi,

I just noticed this problem while watching a movie and I couldn't findy any info about it on the forums...

The problem is with the new "adjust refresh rate" feature, which is creating sync issues in MKV videos. By pressing the 'o' key on the keyboard I noticed the CPU usage (dual-core) of my system was above 95% with "adjust refresh rate" turned on and of course, audio and video were unsynchronized. I turned it off, played the same video in the same scene, perfect sync and the CPU was between 50% and 60%, normal.

The video file has a framerate of 23.976fps and as I normally run XBMC with 50Hz, this was how the video played file (correct sync and average cpu usage) but with the "adjust refresh rate" turned on, the frequency was changed to 23.98Hz and the cpu usage was high with sync problems.

How it's 23.98Hz even possible? My TV only supports 23Hz and 24Hz (and of course, others), shouldn't be one of those?

Anyway, if you want a full log with the featured turned on and I try to play the same video file, just let me know...

Any reason for this? Maybe something fixed on more recent builds? I'm running 17890 by the way...
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#2
I have the same problem, except I usually run XBMC in 60hz and the video that's giving me troubles has 23.98 fps.

My CPU is a e5200.
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#3
Forgot about this...

No one has a clue with this happens?
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#4
Your video driver probably busy waits for vsync. Since you're moving to a lower refresh rate the wait time is longer.
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#5
But it shouldn't work like that right?
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#6
Talk to the vendor. I know nvidia thinks it's ok for some dumb reason.
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#7
I was actually talking about XBMC... I fail to see what exactly is the problem to understand what your are talking about lol.
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#8
Right... So the driver doesn't sleep while it's waiting for a vsync flip. Instead it just spins until it happens, eating CPU. Since you're going to a lower refresh rate, the time between flips is longer, so the driver is burning more cpu.
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#9
More info here: http://forum.xbmc.org/showthread.php?tid=41185

This might also tackle the problem: http://forum.xbmc.org/showthread.php?tid=46091
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#10
Louike Wrote:This might also tackle the problem: http://forum.xbmc.org/showthread.php?tid=46091

It seems that it's the same problem as me... I'm going to keep a look on that thread instead of this one.
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Sync problems with adjust refresh rate turned on (high cpu usage)0