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24 Hz + xv + vsync = fail

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  • 24 Hz + xv + vsync = fail

    Hi, I recently bought a flat panel tv to use as a movie monitor. I currently have an Geforce 7900 series card and I can either get vsync or 24 Hz, using both causes severe, random stuttering in the video where the playback jumps to previous frames, then goes back and the same jumping repeats for some time. Sometimes the video plays nice for quite a long time and sometimes it becomes totally jerky for several seconds. Doing something that affects the video, like switching fullscreen on/off or seeking often aggravates the problem. Seems like some kind of race condition bug to me. This stuttering is accompanied by high cpu usage by the xorg process unless UseEvents="1" is set in xorg.conf. Then there's only the stuttering.

    Can any nvidia user confirm not having this problem? It's important to have working vsync to make it appear (not too easy, unfortunately, especially with compositors and the crappy twinview hack nvidia drivers use). Also, if anyone has had this problem and found a solution, I'd be happy to hear it.

    There's also a thread about it here, although without solutions:

    If there's no way to fix this, how's xv + vsync on the ati side these days?

  • #2
    hi, i have the same problem with nvidia + xv when using PAL/50fps videos and a 50hz modeline, it is much better when using oGL, but not perfect..... for ati radeon cards, there ix an experimental fix in the vdr forum (variable framerate/refrehsrate patch or something like this)

    what you could try to do is using a 48hz or better a 72hz modeline and using oGL, so if the stutter problems appears, it is not soo worse in 72hz than in 24hz


    • #3
      Unfortunately the tv only accepts 24, 50 and 60 Hz. As for opengl, it doesn't work properly at least with 1080p h264 videos. The audio gradually drifts totally out of sync with the video all the time. Seeking will match them again for a few seconds before it's messed up again. This usually happens with a cpu that's too slow, but I'm not even hitting 100%. I've also tried different gl rendering options as suggested in mplayer's documentation without any success.


      • #4
        i had simliar problems with the stable release of mplayer, it seems that this bug was fixed in mplayer svn, try it out!


        • #5
          I also use svn versions of mplayer. It seems to me that distribution packages of media players are always archaic and patent crippled so I find it much easier to just compile it myself. I get the latest decoders and optimizations, too. Anyway, I gave the gl renderer another try on my crt at 85 Hz. It worked just fine. Looks like drifting out of sync is the gl equivalent for messed up matched framerate playback.