[kaiseruk]

I'm using openelec 5.0.5 with the Tvheadend HTSP Client. 2 issues 1) live tv is going out of sync after some channel changes and when it is out of sync, changing channel doesnt seem to fix it 2) Randomly, some channels have to buffer before they start. Any cache settings to prevent this? as it doesnt have waf when it happens (i use a network cable not wifi). When it does get to 100%, the channel ends up out of sync.

[wrxtasy]

Try changing your Kodi GUI video output to either 50 from 60.

Kodi > Settings > System > Video Output > Refresh Rate > 50

also Kodi > Settings > Video > Playback > Sync playback to display > enable

If your TV supports refresh rate switching.....

Video > Playback > Adjust display refresh rate to match video > On Start/stop

Buffering for 1-3secs. is normal, even on powerful Kodi hardware.
Overclocking the RPi to Turbo settings will help ever so slightly, if you have a proper power supply.

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If your still having issues then the TvHeadend backend server settings will likely need to be tweaked, suggestion:
(TvHeadend v3.9.2083+)

TvHeadend > Configuration > DVB Inputs > Select each individual Tuner > Advanced Settings > and make sure "Idle Scan" is off for each tuner.
Make sure you SAVE each time.

also Configuration > Networks > Ensure Idle Scan Muxes in NOT selected.

[kaiseruk]

Thanks will check out it out. By the way the buffering does not happen when starting channels with x64 clients.