jzsub

jzsub takes a video link and hands back a finished MP4: highest quality available, cover art, and bilingual subtitles burned in, translated by GPT. It works across YouTube, Bilibili, TikTok, Vimeo, and anything else yt-dlp can reach. MIT licensed and free; you bring your own LLM key for the translation step.

The setup is the tax. Python 3.10+, yt-dlp, Deno, and an FFmpeg build compiled with libass for subtitle rendering, plus a specific font. That FFmpeg requirement is what trips people up. The docs are Chinese-first, so English speakers are translating as they go.

Use it if you archive or localize video with dual-language captions and want one command instead of a four-tool pipeline. For plain downloads, yt-dlp alone is simpler. For transcription without the download step, Whisper-based tools do the job.

The catch: this is one maintainer's pipeline, tuned to their workflow. If your FFmpeg build or font doesn't match, you're debugging the plumbing yourself.