Introduction

Bilibili provides Danmaku in an XML format that mpv cannot natively render. Furthermore, Bilibili’s AI subtitles often use non-standard language tags (like ai-zh), which can lead to “null” tracks or rendering errors in older mpv kernels (like the one used in IINA).

Thankfully, yt-dlp allows us to extract and download these Danmaku and AI subtitles; danmaku2ass(deveoped by @m13253) provides a brilliant solution to convert XML files to ASS subtitles.