powerbook and dvd playback

Posted:
in Current Mac Hardware edited January 2014
There seems to be these horizontal splits in video playback where the image above the split will be updated more quickly than the image below the split (or vice versa- I really can't tell). I think this might be called "tearing" and its really annoying. Does anyone know what could be causing this problem and how to fix it? I have an LCD monitor and these splits don't seem visible when i'm outputting the video to a tv so I'm thinking it might have something to do with the LCD.

Comments

  • Reply 1 of 13
    I don't know the answer to your problem, but it may help others to know what hardware & system you are using. Is this an Apple LCD or third party?



    Have you tried to play your DVDs with something like VLC to see if it happens with other software than Apples DVD Player (which I assume you are using)?
  • Reply 2 of 13
    Tearing is cause by not having v-sync on (vertical synchronisation) I dont have a mac so I dont know where that setting would be, on a pc its in your display settings.



    Is the TV your outputting to 100Hz by any chance?



    If so thats why it doensnt 'tear'



    If the video/whatever (for example) is running at say 80 frames per second but your screen is only refreshing at 60Hz (60fps) then that extra 20 frames per second causes the tearing you see.... v-sync forces the video/whatever to refresh at the same rate as your screen.



    If your telly was 100Hz it woulnt tear as its capable of 100fps.



    Theres nothing wrong with your LCD



    HTH
  • Reply 3 of 13
    Ok thanks. I don't know how to enable vertical sync. There is no option for it in the sysprefs. I googled it but I'm having trouble finding it. Does anyone know how to enable vsync in OSX?
  • Reply 4 of 13
    it should be where you control the anti-aliasing, your graphics card settings.... is there a thing for that in osx ?
  • Reply 5 of 13
    neutrino23neutrino23 Posts: 1,546member
    You don't say but I think you only see this from time to time, mostly when the camera is panning across a scene or there is other motion. I see this on my PB as well.



    I don't know the exact cause but I suspect it has to do with the inability of the overall system (DVD drive, CPU, GPU) to deal with the data rates required to render a smooth movie under some conditions.



    Do others see this on other Macs (iMacs, G5s)?



    Does anyone see this on standard DVD players?
  • Reply 6 of 13
    The powerbook is a fast computer. Do you really think it has trouble rendering a movie? I hope that is not the case, but I'm starting to worry.
  • Reply 7 of 13
    I have 2 powerbooks, a 667 Titanium & a 1.5 gig 17". Never had a problem like this with either, and I've been using OSX since version 10.1



    How much Ram do you have?
  • Reply 8 of 13
    Quote:

    Originally posted by Bulky Cranium

    I have 2 powerbooks, a 667 Titanium & a 1.5 gig 17". Never had a problem like this with either, and I've been using OSX since version 10.1



    How much Ram do you have?




    512MB. It is possible that you have the problem but haven't noticed it.
  • Reply 9 of 13
    Quote:

    Originally posted by neutrino23

    You don't say but I think you only see this from time to time, mostly when the camera is panning across a scene or there is other motion. I see this on my PB as well.



    I don't know the exact cause but I suspect it has to do with the inability of the overall system (DVD drive, CPU, GPU) to deal with the data rates required to render a smooth movie under some conditions.



    Do others see this on other Macs (iMacs, G5s)?



    Does anyone see this on standard DVD players?




    It isn't the DVD drive because I get the same problem with movies from my hard drive.
  • Reply 10 of 13
    Quote:

    512MB. It is possible that you have the problem but haven't noticed it.



    I don't think so. I would find that pretty annoying, as I am sure that you do.



    Have you tried booting up in OS 9 an running DVDs from there, or trying a program like VLC?



    If you computer is under warranty I would advise taking it back to Apple. Or at least phoning Apple.
  • Reply 11 of 13
    Quote:

    Originally posted by Bulky Cranium

    I don't think so. I would find that pretty annoying, as I am sure that you do.



    Have you tried booting up in OS 9 an running DVDs from there, or trying a program like VLC?



    If you computer is under warranty I would advise taking it back to Apple. Or at least phoning Apple.




    other things like vlc have the same problem. This happens more when there are a lot more other applications open, so i think it has something to do with the computer performance. It might be that quartz is very processor intensive. The lines happen from time to time even when i have no other apps open, however. Anyone else notice the problem? I don't think it has to do with the hardware itself since other people are seeing the same problem and this doesn't really look like a typical hardware issue, at least in my experience.
  • Reply 12 of 13
    I think this has something to do with image tearing. I don't know how to fix the problem and I'm getting quite annoyed.
  • Reply 13 of 13
    Quote:

    Originally posted by alexplank

    Ok thanks. I don't know how to enable vertical sync. There is no option for it in the sysprefs. I googled it but I'm having trouble finding it. Does anyone know how to enable vsync in OSX?



    I think what they were referring to was vertical sync on a television (assuming you had the PB connected to a TV for viewing DVDs).



    One thought just came to me. In system preferences/energy saver try selecting Highest Performance under Optimize Energy Settings. I've found that selecting this makes a substantial difference in X-bench scores.



    If you have an Apple store in your area you might check with the genius and get his opinion.



    I don't know how DVDs are decoded. I was under the impression that a lot of the work is done by the graphics chip. I'm still suspicious that somehow the various pathways the data has to flow through are not up to the task under peak load.



    I think panning puts the heaviest strain on the system. Normally the system can look for similarity between frames. So if you have a fixed background and one actor moving about that requires less data in the stream. If the camera is panning then almost every frame is different from the previous frame meaning the system has to work really hard.



    Just my speculation.



    If you see that happening in a scene try backing up and replaying it to see if it happens in the same location. That would indicate that it was data dependent as opposed to some random timing event.
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