Stuttering video at 50Hz

thecapsaicinkid · 08-22-10, 12:53 PM

I'm seeing regular stuttering in PAL video when running at the default 1920x1080 50Hz but not apparent when I use nvidia-settings to switch output to 60Hz. It's most noticeable when the video pans and you can see the video stutter ever half second or so.

Ubuntu 10.04 64bit
Nvidia onboard gpu with driver 195.36.24-0ubuntu1~10.04
Xorg.conf http://pastebin.com/fPvnkGAj
nvidia-settings cleared

Any ideas?

Many thanks

brebs · 08-22-10, 10:54 PM

Follow the procedure at how to report a problem.

thefirstm · 08-23-10, 09:33 AM

You don't need an nvidia bug report to know the cause of this problem. It occurs because the PAL framerate must not be evenly divisible into 50. It apparently is evenly divisible into 60. Why can't you just use 60hz?

Deanjo · 08-24-10, 03:48 PM

Quote:

Originally Posted by thefirstm

You don't need an nvidia bug report to know the cause of this problem. It occurs because the PAL framerate must not be evenly divisible into 50. It apparently is evenly divisible into 60. Why can't you just use 60hz?

PAL is evenly divisible in to 50 Hz. PAL Framrate is 25.0000fps

thefirstm · 08-24-10, 06:13 PM

Still, why not just use 60hz?

poltsy · 08-27-10, 06:59 AM

Disable composite, twinview and gpu scaling. They all make mode setting confusing so what you think is 50Hz might be something completely different in reality.

Looking at the config it seems there isn't really anything that should stop it from working properly. I'm using pretty much the exact same settings and playback is very close to perfection; looking at a news scroller in vdr-xineliboutput it very very rarely pauses for a frame's duration or so.

You could try disabling edid and completely defining the modes yourself, probably won't change a thing but at least then it won't be able to pick the wrong one and lie which one you're seeing.

The driver version is a bit old though, have you tried anything newer?

Perhaps there are settings in your tv that are causing the issue, some "image enhancing" filters or such?

08-22-10, 12:53 PM	#1
thecapsaicinkid Registered User Join Date: Aug 2010 Posts: 47	Stuttering video at 50Hz I'm seeing regular stuttering in PAL video when running at the default 1920x1080 50Hz but not apparent when I use nvidia-settings to switch output to 60Hz. It's most noticeable when the video pans and you can see the video stutter ever half second or so. Ubuntu 10.04 64bit Nvidia onboard gpu with driver 195.36.24-0ubuntu1~10.04 Xorg.conf http://pastebin.com/fPvnkGAj nvidia-settings cleared Any ideas? Many thanks

08-22-10, 10:54 PM	#2
brebs Registered User Join Date: Jul 2007 Posts: 38	Re: Stuttering video at 50Hz Follow the procedure at how to report a problem.

08-23-10, 09:33 AM	#3
thefirstm Registered User Join Date: Feb 2009 Posts: 226	Re: Stuttering video at 50Hz You don't need an nvidia bug report to know the cause of this problem. It occurs because the PAL framerate must not be evenly divisible into 50. It apparently is evenly divisible into 60. Why can't you just use 60hz?

08-24-10, 06:13 PM	#5
thefirstm Registered User Join Date: Feb 2009 Posts: 226	Re: Stuttering video at 50Hz Still, why not just use 60hz?

08-27-10, 06:59 AM	#6
poltsy Registered User Join Date: Jan 2010 Posts: 26	Re: Stuttering video at 50Hz Disable composite, twinview and gpu scaling. They all make mode setting confusing so what you think is 50Hz might be something completely different in reality. Looking at the config it seems there isn't really anything that should stop it from working properly. I'm using pretty much the exact same settings and playback is very close to perfection; looking at a news scroller in vdr-xineliboutput it very very rarely pauses for a frame's duration or so. You could try disabling edid and completely defining the modes yourself, probably won't change a thing but at least then it won't be able to pick the wrong one and lie which one you're seeing. The driver version is a bit old though, have you tried anything newer? Perhaps there are settings in your tv that are causing the issue, some "image enhancing" filters or such? Last edited by poltsy; 08-27-10 at 07:13 AM. Reason: haste is the worst stat of them all