Screen tearing can occur when presentation timing and display refresh are not coordinated, showing parts of different frames together. Stutter instead appears as uneven movement over time. Similar-looking source artefacts exist, so compare another programme and note whether the split follows a moving horizontal boundary.
Observe the shape of the fault
A tear often looks like a discontinuity across a moving object or camera pan rather than a frozen whole frame. Buffering usually pauses playback, and compression can create blocks without a clean horizontal split. A phone recording can introduce its own timing artefacts, so describe what you see directly.
Check the local presentation path
On a computer, supported graphics-driver and player settings can affect synchronised presentation. Use current manufacturer guidance and a normal supported display mode. Avoid installing unknown performance utilities or changing unrelated network settings when the source plays continuously and the visible problem appears tied to local rendering.
Compare with a reproducible sample
Try the same authorised passage in another supported player and another source in the original player. Record the operating system, graphics device, output timing and whether full screen changes the behaviour. That evidence helps separate a local presentation issue from an artefact already encoded into the stream, without claiming a diagnosis from one screenshot.
