Dropped frames
Also known as: frame drops, skipped frames
Frames a camera failed to write, leaving a recording that is technically valid and briefly jumps where the missing moments should be.
Updated
What it means
Dropped frames are gaps rather than damage. The camera could not write fast enough, so some frames were never recorded, and the file is perfectly well formed with less in it than it should have.
The symptom is a small jump in motion rather than a visible fault. Nothing looks broken, which is why it is often noticed only when a cut lands oddly or a landing appears to teleport.
The usual cause is the card rather than the camera. A card below the required SD card speed class cannot absorb a high bit rate, and the camera discards what it cannot store.
How it works in practice
Matching the card to the recording specification is the fix, and it has to be the real specification rather than the number printed on the label of a suspect card.
Formatting in the camera before every session reduces the chance measurably, which is one of the main reasons Card formatting is worth doing as a habit rather than when something goes wrong.
Checking a sample clip for duration against its frame count reveals drops arithmetically, which is faster and far more reliable than hunting for them by eye at normal playback speed.
What to watch out for
Variable frame rate recordings hide drops completely, because the file declares an irregular rate and nothing looks inconsistent, which makes Variable frame rate (VFR) footage harder to diagnose.
Drops also break sync progressively. Picture missing frames while audio runs continuously is a route to Audio drift in a clip whose clock was never wrong.
The highest quality modes are where it appears first, so a camera that seems fine at a moderate setting can drop steadily at the one somebody actually wanted. Testing at the intended Bitrate rather than a convenient one is the only meaningful check.
How RawClip handles it
Clips are checked for duration against their declared frame rate, so a recording that quietly lost frames is identified rather than scored as if it were complete. Sync is handled per clip, which keeps a dropped stretch from shifting everything after it.