There are two primary types of captions: those that are added to videos after they are recorded (post-production captions), and captions that are used during live events (live captions/transcription). The key to captioning is that quality is important. Bad captions are worse than no captions.
Captions should be:
- Accurate (~99%)
- Synchronized to the audio
- Readable
- Positioned on screen so they do not block important information