Why it happens
- Auto-generated subtitles weren't proofread; homophones, names and numbers are the usual errors.
- The video model was asked to render on-screen text directly, which it handles unreliably.
- The voice file and the final subtitle script are different versions.
How to fix it
Proofread auto subtitles against the script, checking every name, number and proper noun.
Leave screens blank or blurred at the keyframe stage and overlay accurate text in post.
Write “no readable text on screen” in the prompt and add garbled text to the negative prompt.
Treat the locked script as the source of truth for subtitles; if the voice changes, update the script too.
Before and after
Fails
The phone screen clearly shows the message: “Sis, don't look back.”
Works
The old phone screen lights up white with unreadable, blurred content; in the edit, overlay “Sis, don't look back.” and track it to the screen.
Prevent it next time：Add any text that must be read in post, and proofread every subtitle before export.
Worked examples