Hi,

I wasn't sure where to post this, as I'm not sure of the root cause. Please be patient with me.

I have a new PRO-151FD, about a week old now. (Actually, a week old today, come to think of it.)

I've been having a problem when watching OTA HD material via a homebuilt HTPC. I'm running Ubuntu Linux 8.10 and MythTV 0.21-fixes. I've got an NVIDIA 9500GT card, and the latest NVIDIA binary driver (180.29). I have it connected via DVI out from computer to an HDMI cable (purchased at monoprice.com) and to an HDMI input on the display.

Whenever I watch full HD content, in full screen (dot by dot mode), anytime there's fast horizontal motion on the screen, about a 1/3 of the way down from the top, I get a "tearing" effect. Like the picture was sliced across, and glued together, slightly off.

This issue does NOT happen w/ Blu Ray. I need to check Comcast. I'm certain about the problem w/ OTA, as that's a lot of what I watch. I'll verify the problem w/ Comcast when I get home.

The way I have it set up, I've run three individual HDMI cables, one from each source (BluRay, Comcast, HTPC), and there is no switching at the pre-pro. Cables go directly from source to display.

When I go into nvidia-settings, I have chosen 1920x1080, and it allows me two sync frequencies, 60Hz and 24Hz. I assume that 60Hz is for 1080i OTA and Comcast, and that 24Hz is for Blu-Ray. So, I have it set for 60Hz.

I assume that Comcast and BluRay will (should?) automatically negotiate the appropriate sync frequency.

So, anyone have any ideas/clues for me?

Other than this one issue, I'm thrilled w/ my purchase.

Sorry if you think this is more appropriate in the HTPC thread. I really wasn't sure which way to go....

AdvThanksance,

-Mark

PS Previously posted in Plasma Display section, was asked to move it here.....

Just thought of something. I'm running 0.21-fixes w/ the VDPAU patch, and VDPAU enabled. Could VDPAU be the culprit?

-Mark

Just thought of something. I'm running 0.21-fixes w/ the VDPAU patch, and VDPAU enabled. Could VDPAU be the culprit?

-Mark

Have you disabled compositing?
sudo nvidia-xconfig --no-composite

EDIT: be sure to restart X after running that command

Aw...so, no Compiz Eye Candy, then?

Ok, I'll sacrifice that, if it solves the problem. This really is primarily an HTPC.

Thanks,

-Mark

Whenever I watch full HD content, in full screen (dot by dot mode), anytime there's fast horizontal motion on the screen, about a 1/3 of the way down from the top, I get a "tearing" effect.
This is a chronic problem with many Linux-based HTPC systems. The "tearing" effect occurs because different parts of the video stack are switching from one frame to the next at different points in time, so what ends up being presented to the display as a "frame" may be the bottom half (or third, or any other fraction) of frame n and the top part of frame n+1. Horizontal pans make the tearing painfully obvious, but it is probably happening all the time without your being able to notice.

Solutions to the problem are generally specific to your video card drivers.

My new mobo has an Intel graphics chipset, and the tearing was horrible until the most recent (still beta) drivers.

Thanks for the info. I'll start w/ disabling compositing, and see if that helps.

-Mark

Point and click method to turn off compositing/Compiz-

System->Preferences->Appearance->Visual Effects->None

Visual Effects are set to "Normal" (which means compositing/Compiz is ON) by default after an Ubuntu install.

Point and click method to turn off compositing/Compiz-

System->Preferences->Appearance->Visual Effects->None

Visual Effects are set to "Normal" (which means compositing/Compiz is ON) by default after an Ubuntu install.

That's exactly what I did, RGB.

Thanks all! The tearing seems to have gone away as soon as compositing was disabled!

So, I guess I'll live without my eye candy... :-)

Thanks again,

-Mark

This is a chronic problem with many Linux-based HTPC systems. The "tearing" effect occurs because different parts of the video stack are switching from one frame to the next at different points in time, so what ends up being presented to the display as a "frame" may be the bottom half (or third, or any other fraction) of frame n and the top part of frame n+1. Horizontal pans make the tearing painfully obvious, but it is probably happening all the time without your being able to notice.

Solutions to the problem are generally specific to your video card drivers.

My new mobo has an Intel graphics chipset, and the tearing was horrible until the most recent (still beta) drivers.

There is actually way to fix this depending on the player you're using. Run xvinfo and see what video ports are available on your intel, then run mplayer using mplayer -vo xv:port=[portnumber goes here] where portnumber is the port base value. Worked like a charm on my system. That + telling mplayer to buffer video a bit made all my video smooth as butta

run mplayer using mplayer -vo xvort=[portnumber goes here]

Hmmm, how would I go about doing that or something like that if I'm watching HD with MythTv (I guess it uses its own internal player right)? I can get rid of tearing if I turn the nvidia VSync on, but then I get high xorg CPU and a slow program guide.

Hmm...got a bit sidetracked, however, just wanted to follow-up here, on one point.

After taking RGB's advice, and doing "System Preferences->Appearance->Visual Effects->None", this disabled the compositing manager, and greatly reduced image tearing, *however*, this didn't entirely solve the problem. I *still* could see image tearing, but at a much lower frequency. Well, it turns out, mythmaster provided the correct solution earlier in the thread. Setting Visual Effects to None only disables the compositing manager, i.e., Compiz. However, support for Compositing is still in the driver.

To disable Compositing completely, you need to do:
'sudo nvidia-xconfig --no-composite'
followed by an X restart (Ctrl-Alt-Backspace)

That will totally disable compositing support in the driver. Since I did that, I have beautiful, rock-solid video!

-Mark

PS One of the NVidia developers over on nvnews.net hinted that the "image tearing w/ compositing turned on" problem should go away "soon"....for whatever that's worth... :-)