Can I extract captions/subtitles if they're burned into the video?

No. TokScript extracts the transcript that's embedded in the video's metadata by the platform — it doesn't do optical character recognition (OCR) on text that's visually burned into the video.

If a video has hardcoded text overlays or burned-in subtitles but no embedded transcript, TokScript won't be able to extract that text. This is relatively rare on major platforms, since TikTok, Instagram, and YouTube typically generate their own embedded transcripts for videos with speech.

If you're consistently seeing "Failed" on videos that have visible subtitles, it's likely that those subtitles are burned in (part of the video image) rather than embedded as metadata.