Jerky playback at 50Hz
#1
I'm using Kodi 18.2-3 on Arch Linux with GNOME on X11. It outputs to a 1080p TV over HDMI.

I noticed a problem trying to play F1 motor racing footage that I'd recorded from Channel 4 HD in the UK with tvheadend. It's 1080i at 25 frames/s (50 fields/s). When I let Kodi adjust the display refresh rate to 50Hz the playback is jerky. With VAAPI enabled and Motion Adaptive deinterlacing there's a slight stutter at regular intervals, which seem to be slightly more than twice per second. It's very unpleasant to watch. I tried all the deinterlacing settings, including off, and felt maybe some of them changed the regularity of the stutter, but none of them fixed it. I tried with Kodi's vsync option on and off, with and without a GNOME extension that fixes fullscreen tearing, it made no difference. Software rendering has the same problem. I used the TV's OSD to verify that it really is 50Hz.

When I disabled Kodi's refresh rate setting, so the display stayed at 60Hz, with vsync off, I got smooth playback. That's an acceptable solution, because tearing doesn't seem to be a problem with this configuration, I suppose it's only noticeable if the tear occurs at about the same vertical position every frame, but there are other advantages to letting Kodi adjust the refresh rate, so I'd like to find a fix for this.

I also tried playing the same video in mpv with VAAPI and the display set to 50Hz manually with xrandr. That played smoothly, so it seems like the problem is with Kodi, not something else like VAAPI.
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#2
(2019-05-13, 14:59)realh Wrote: I got smooth playback. That's an acceptable solution
Thanks for that tip, at least it usable.
(2019-05-13, 14:59)realh Wrote: mpv with VAAPI and the display set to 50Hz manually with xrandr. That played smoothly
Another great discovery would be using it as an external player within Kodi External players (wiki)
(2019-05-13, 14:59)realh Wrote: I'd like to find a fix for this.
Put something into the bug tracker and link this thread to it, but be patient there is a lot of irons in the fire atm.
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