(For problems using Repair Kit, see dedicated page.)
First of all, let's differentiate the defects added on purpose by the Repair Kit from the real repair defects:
Defects added by Repair Kit
The Repair Kit needs a password to fully unlock its functionality. If you use the Repair Kit without the password, it will either stop after a certain size (thus not all the corrupt file is repaired), or it will add some defects:
- Video "artifacts" like as colorful blocks usually appear randomly on some frames
- Audio noise of short duration that appears sporadically
- A watermak appearing on top of the movie
- Frames playing in wrong order (shake effect).
Audio and Video defects added by RepairKit are random, so if you run it a second time, the defects will appear at a different time/location.
Real Repair Defects
But real repair defects will always be the same, even if you run the Repair Kit several times.
Each repair technique generates specific types of defects. For example, when reindexing, media data can be incorrectly indexed, due to false negative, false positive, or wrong data length detection.
Defects in Video:
- Missing frame: usually due to lost data or false negative. It will cause gaps in the video and stutters, and also potential audio synchronization issues.
- Defective frame: a completely funny frame, with no visual continuity with previous and next frames, usually due to alien data, or a false positive (audio data interpreted as video, ...)
- Artefacts: A small area of the image is affected, usually due to wrong frame length (too short, or too long)
- Stalled playback, or Crash: Defective data is being sent to the decoder (that should not crash in the first place!)
- Wrong image size, or stretched image: very easy to correct
- Wrong speed: very easy to correct
Defects in Audio:
- Blip: a short noise that is heard every second or at a certain period, usually fixed by fine-tuning of audio scraping
- Noise: during around one second, the audio is replaced by a loud noise.
- Eaten words: every second or so, a bit of word gets eaten. usually fixed by fine-tuning of audio scraping
- Audio out of sync: either by a constant amount, or drifting. usually fixed by fine-tuning of audio scraping
- Stutter in repaired AAC files, that appears progressively after one minute of playback, then becomes silent.
See also the case of long audio files.
When you report a defect, please use those terms for a better undestanding.
