[dreadlox]

Hi!
In Eden RC1, when I have "Adjust display refresh rate to match video" enabled I get a bit jerky playback... I think this is because the refresh rate is changed to 60 Hz. Normally I have the refresh rate at 50 Hz, and if I disable "Adjust display refresh rate..." the playback is quite a lot smoother.

My graphics card does not seem to be able to output 24 Hz signal - only 50 or 60 Hz, but why is the refresh rate changed to 60 Hz for 24 fps content? Wouldn't it be a lot better to keep 50 Hz and double the frames of the 24 fps video and resample the audio to match 50 Hz instead?? It sure looks a lot better on my system...

I doesn't seem to help to disable Aero or using true fullscreen.

For now I can disable "Adjust refresh rate to match video" and force 50 Hz for smooth playback, but the disadvantage is of course that some content with 29.97 fps or 30 fps is played a lot better with 60 Hz...

Regards,
Tobias, Sweden

[DDDamian]

Doubling frames on 24p and playing back at 50hz would be a 4% resample of audio - not great. Would suggest a better video card with more refresh rate choices.

[dreadlox]

Doubling frames on 24p and playing back at 50hz would be a 4% resample of audio - not great. Would suggest a better video card with more refresh rate choices.

Yes of course, but 4% resample of audio is not a big problem. That has always been the standard way to convert 24 fps movies to DVD PAL (25 fps) and that's considered totally acceptable... (http://en.wikipedia.org/wiki/24p - see "Converting 24p to PAL") Jerky playback, however, is not acceptable :/

My video card is integrated in my HTPC, and I have very little possibility to switch to another card.

[bobo1on1]

The reason that XBMC chooses 60 hertz for 24 fps material is because a lot of tvs can do inverse telecine, also a lot of people use passthrough audio in which case resampling won't work.

If you want to play 24 fps video at 50 hertz then put this in advancedsettings.xml:

Code:

<advancedsettings>
  <video>
    <adjustrefreshrate>
      <override>
        <fpsmin>23.9</fpsmin>
        <fpsmax>24.1</fpsmax>
        <refresh>50</refresh>
      </override>
    </adjustrefreshrate>
  </video>
</advancedsettings>

[dreadlox]

If you want to play 24 fps video at 50 hertz then put this in advancedsettings.xml:

Ahh - thanks, I'll try that!

[dreadlox]

Hmmm - things don't seem to be as simple as I thought regarding this... :/

I have now tested some different movies.
All of them have 23.976 fps (all are mkv-files in 720p from BluRay sources originally), but the strange thing is that some of them plays smoothly with display refresh rate set to 50 Hz and others plays smoother @ 60 Hz!
How can that be?
The fps does not seem to be the only factor here as I thought...
Most movies (say 75% of them) play perfectly smooth @ 50 Hz, but some of them stutter @ 50 Hz and look a lot better @ 60 Hz (however they are not totally perfect).

Maybe it's something wrong with the encoding, but I thought 50 Hz (with 4% resampled audio) would always be as stutter-free as possible for 23.976 fps material.

Could it be that XBMC can't sync the video and resample the audio in some cases?

[DDDamian]

If you used MKVMerge at some point different versions of it seemed to cause issues with exactly that. As mentioned before, upgrading the video card (I recommend the ATI 6450 for Windows) is quite cheap, and you'll be able to use Sync Refresh Rate to Content for much smoother playback.

[bobo1on1]

The 2:3 cadence you get at 60 hertz might mask any stutter present in the video, so it's possible that that video will look worse at 50 hertz.

[dreadlox]

Wohoo - I finally managed to trick my video card to output 24 Hz, and now all movies are perfectly smooth!

For all users with an Intel graphics chipset that doesn't appear to support 24 Hz, check this page out:
http://www.avsforum.com/avs-vb/showthread.php?t=939025

(I almost gave up, but after removing all existing drivers for my card and then reinstalling with a hacked inf-file, 24 Hz suddenly appeared!)