Video file repair
Also known as: file recovery, clip repair
Rebuilding a damaged or unfinalised recording so a player can open it, which recovers most clips that appear to be lost.
Updated
What it means
Video file repair addresses structure rather than picture. Most unplayable clips contain perfectly good footage with a broken or missing index, so repair means rebuilding the table of contents rather than reconstructing frames.
That is why the success rate is high. A recording interrupted by a flat battery leaves a Camera crash file whose data is intact, and rebuilding the index makes the whole thing playable again.
Genuine data damage is a different and much worse case. Frames corrupted on the way to the card cannot be recovered, only cut around, which is what Corrupted frames describes.
How it works in practice
Powering the camera on with the card still in it is the first thing to try, since many bodies detect an unfinalised recording and repair it themselves without any tools involved.
Where that fails, rebuilding the container is the next step, and doing it by Remuxing rather than re-encoding keeps the original quality rather than taking a generation off it.
Working on a copy is the rule that prevents regret, because some tools write to the source and a second attempt on an altered file is worse than the first.
What to watch out for
Repaired clips sometimes carry a wrong duration, which produces apparent sync problems in a recording whose clock was never actually wrong.
The final seconds are usually unrecoverable, and that is frequently the part that mattered, since a power loss tends to coincide with the moment somebody was actually filming something. Nothing recovers data that was never written.
Formatting the card to get the camera working again destroys exactly what repair needed, so Card formatting after a failure is the one irreversible mistake available here. Copy the card first and attempt repair on the copy.
How RawClip handles it
Files that cannot be opened are reported rather than silently skipped, so an upload containing a damaged recording is not quietly short. A repaired clip with a valid index and duration is then treated exactly like any other in the upload, and a stretch of damaged frames inside it is simply weighted down.