Im having same issue on uk hd channels only. Ive tried changing settings as in post they sometimes help but overall problem still exists.
I have submitted logs
Issue Judder / staccato playback / missing frames
App Channels dvr
Ap Version 5.1.1
Device apple tv a1625
Device Software version 15.1.1
Server Windows 10 Pro
Version 20H2
Channels server version 2021.10.25.1801
Tuner HD home run quattro
Model HDHR5-4DT
Firmware 20210624
Other This is also happening on playback in other apps: Plex and HDHR. Also similar issue on iPad and screen goes blue. Apple tv 4k problem exists but not as obvious. similar to an issue I had previously on Nvidia shield cube
Other This seems to be a recent issue
Other No issue on sd version of same channel
Other Problem exaggerated when first starting channel and transitioning from pip.
Screenshot of dropped frame count is about 5-10mins of watching