A: Part of the Federal Communications Commission’s (FCC) Caption Quality Best Practices is that closed captioning must be synchronous with the program audio, but must also be on screen long enough to be read completely.
With realtime captioning, captions are usually 5 to 9 seconds behind, as the captioner takes the time to listen and “write” or respeak what they’re hearing (2-3 seconds), captions are transmitted to the networks (1 second), and encoded into the video transmission signal (4-5 seconds.)
Prerecorded captioning shouldn’t have any delay at all, and should appear onscreen synchronously with program audio.
If you’re noticing a significant delay in closed captioning to where it’s hindering your understanding of the program, this could be a transmission issue with your video programming distributor (cable provider, broadcaster, or satellite provider). Per the FCC, programming distributors must pass through captions, and make sure they’re passing through correctly. To report a problem, see “How can I complain about captions?” above.