SubEnvoy focuses on a niche but common problem: local videos with subtitles you can’t understand. Unlike typical subtitle tools, it works directly with local files (MKV, MP4, SRT), extracts or generates subtitles, and translates them with AI while preserving timing and context. No video upload is required — your media stays on your device. It also handles large subtitle files efficiently, making it practical for full-length movies and series.