Check the video edition
The resolution of a poster does not establish the resolution of its movie. Inspect the selected viewing offer for HD, Full HD or 4K. Your service, plan and device can affect what is available.
Stable playback matters
If an automatic-quality player keeps changing sharpness, it may be adapting to connection conditions. Try a lower manual setting when offered and give it time to settle. A smooth 1080p session can be preferable to repeated pauses at a higher setting.
Look beyond the number
Sound, captions, compression and the source edition all contribute to the experience. A television capable of 4K cannot create detail that is absent from the selected stream. Compare the edition first, then the player settings.
Controls belong to the player
HTML5 controls, playback speed, keyboard shortcuts and Picture-in-Picture vary by service and browser. Use the controls visible in that viewing session. There is no separate eMovies player setting that changes a video already opened elsewhere.