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TeM

Member

Registered: 2010-06-07

Posts: 8

Very annoying artifacts on videos with a lot of camera motion

Hi guys,

I've been experiencing for quite a long time troubles with video playback. I've lived with it for quite a long time, but I'm really getting tired of the issue and started looking for answers.

Here's what happens : on videos, as soon as there's some action involving the camera moving a lot I get some "lines" on the screen appearing. These lines results for the upper part of the screen beeind out of sync with the lower part during short periods. It creates very annoying artifacts in the video.

Here are some screenshoots that summarizes the effect pretty well :
@VLC (1) http://tem.dev.rezel.net/~tem/screen/Screenshot.png
@VLC (2)  http://tem.dev.rezel.net/~tem/screen/Screenshot-4.png
@Mplayer http://tem.dev.rezel.net/~tem/screen/Screenshot-1.png

I've read what or two things on forum claiming Compiz as the issue, but I get the same result using compiz or metacity.

Did anyone experienced this issue ? Because this is getting really annoying, especially on HD videos.

I'm using an ASUS 21.5'' 1920x1080 monitor and a GeForce 9500 GT based graphic card.

Here's my xorg.conf :

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

Section "Files"
EndSection

Section "InputDevice"

    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"

    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
    Option         "XkbLayout" "fr"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "ACI ASUS VH222"
    HorizSync       30.0 - 85.0
    VertRefresh     55.0 - 75.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce 9500 GT"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "AddARGBGLXVisuals" "True"
    Option         "TwinView" "0"
    Option         "metamodes" "1920x1080_60 +0+0; 1280x1024 +0+0"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Extensions"
    Option         "Composite" "Enable"
EndSection

Last edited by TeM (2010-06-27 19:06:14)

skottish

Forum Fellow

From: Here

Registered: 2006-06-16

Posts: 7,942

Re: Very annoying artifacts on videos with a lot of camera motion

I don't know if this is important, but do you only have one monitor? Your xorg.conf file is for two. And just for fun, I'd remove the Extensions section (composite is on by default), as well as the "addAR..." line (I believe that that is on by default too).

TeM

Member

Registered: 2010-06-07

Posts: 8

Re: Very annoying artifacts on videos with a lot of camera motion

I don't know if this is important, but do you only have one monitor? Your xorg.conf file is for two. And just for fun, I'd remove the Extensions section (composite is on by default), as well as the "addAR..." line (I believe that that is on by default too).

Well I had two for some time, but now It's only one of them.

Fixed this and tried your suggestions, didn't change a thing.

Wintervenom

Member

Registered: 2008-08-20

Posts: 1,011

Re: Very annoying artifacts on videos with a lot of camera motion

Are you using VSync?  Try toggling it and see if that helps.

Last edited by Wintervenom (2010-06-27 20:50:57)

TeM

Member

Registered: 2010-06-07

Posts: 8

Re: Very annoying artifacts on videos with a lot of camera motion

Are you using VSync?  Try toggling it and see if that helps.

I did not find any Vsync option in Xorg, however there appears to be a "Sync to VBlank" checkbox in the nvidia config pannel (and in compiz fusion). I toogled them, reloaded xorg, but the problem is still out there.

Last edited by TeM (2010-06-28 10:01:02)

TeM

Member

Registered: 2010-06-07

Posts: 8

Re: Very annoying artifacts on videos with a lot of camera motion

Well so far, I have not found any permanent solution, however I noticed that when compiz is not running the effect appears to be far less visible (it is still obvious on screenshots, but no longer annoying in practice).

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,801

Re: Very annoying artifacts on videos with a lot of camera motion

Is your video source PAL or NTSC (or, God Forbid, SECAM)?

I assume your computer is non-interlaced.  You should either double buffer the video, -or- ensure that the field rate of the video is the same as the frame rate of your computer.  For PAL ans SECAM, the field rate is 50 Hz.   Unfortunately for color NTSC, the field rate is 59.94 Hz (Monochrome is 60).  You won't be able to set your display rate to 59.94 so you have to settle for 60.  This means you will be off by about one full frame at the end of 30 seconds. 

So, in your case, one of two things is happening.  (1) The frame rates are really different and the line moves all over the place, seemingly at random, or (2) they are really close in rates causing the line to roll through the video every 15 seconds. 

IMHO, for NTSC, the best solution is double buffering and allow it to drop or double frames.

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Milena

Member

Registered: 2010-04-02

Posts: 67

Re: Very annoying artifacts on videos with a lot of camera motion

You have a vdpau capable gpu i would give that a try, there is no tearing with vdpau if you disable compiz or undirect fullscreen windows in ccsm.

for HD videos:

mplayer -vo vdpau -vc ffh264vdpau videofile.mkv

gnome-mplayer and vlc also offers you to use vdpau gpu acceleration if you don't like command line mplayer.

To reduce compiz tearing to a minimum (i have no tearing at all with nvidia + compiz on + watching any videos):

ccsm > general settings: disable detect refresh rate, set the refresh rate manually to twice the amount of your screens refresh rate (120hz for a normal 60hz tft for example) and set sync to vblank in compiz. In nvidia settings set the vblank sync only for XV video but not for opengl.