MioSub

MioSub is an AI subtitle editor for creators and translators working with video or audio. It handles subtitle generation and translation for local files or downloaded media, including podcasts, radio recordings and audiobooks.

• Context-aware translation. Gemini uses the full recording's context to translate dialogue, while a terminology tool extracts names, places and specialist terms to keep translations consistent.
• Transcription and timing. Local Whisper transcribes speech on your machine; automatic speaker labels distinguish dialogue, and built-in forced alignment matches subtitle timing to speech with millisecond precision.
• Live subtitle editing. You can revise captions while previewing their appearance, with bundled NotoSans fonts for Chinese and Japanese text.
• Subtitle and video output. The app imports SRT and ASS files, exports bilingual subtitles and can burn captions into video.

The desktop app is open source under AGPL-3.0. It runs on 64-bit Windows 10/11, macOS 12 or later on Intel and Apple Silicon, and Linux on x64 or arm64. It requires at least 4 GB of available memory and an internet connection.

Whisper transcription can run locally, but Gemini translation uses a cloud API, so the app isn't fully offline. Translation requires an API key that supports Gemini 2.5/3 Flash and Gemini 3 Pro. The interface is available in Chinese, English and Japanese.