Face flicker is one of those defects you notice immediately once you have seen it. The eyes pulse, the hairline shifts, or the cheeks change shape between otherwise normal frames. Pausing on a single frame often makes the problem disappear.
That is the clue: each frame may look acceptable in isolation, while the sequence lacks temporal consistency.
Check whether the source already flickers
Look at the original clip for exposure changes, fast cuts, motion blur and sudden shadows. A flickering streetlight or rapid camera flash can confuse the model's idea of consistent facial color. If the source has these issues, ask the model to preserve lighting changes naturally instead of inventing new facial features.
Keep the target recognizable during motion
A high-detail reference with a well-defined hairline and jawline is a better anchor than a heavily filtered portrait. If the source actor repeatedly turns away from camera, accept that the model must infer more geometry. Shorter clips with slower head motion can be a useful test.
You can specify that the uploaded identity must remain stable through profile views and occlusion, but no prompt can guarantee that a model will obey perfectly.
Distinguish flicker from a mapping error
When a face briefly becomes another real character from the scene, that is likely target confusion. When the same face merely changes proportions, it is closer to temporal instability. The remedies differ: clearer character mapping for the first, more reliable reference information and motion-preservation constraints for the second.
Check playback before regenerating
Some browser preview glitches look like visual flicker. Download the video and inspect it locally. A stutter caused by buffering is not the same as a repeated face change in the encoded file.
If the artifact exists in the actual MP4, note the first timestamp where it appears. That makes a provider bug report more useful and helps you compare subsequent versions fairly.
You want consistency, not a pile of sharpening. Higher resolution may expose details, but it is not a reliable fix for unstable identity over time.
