Support

Common video and audio formats work, such as MP4, MOV, M4V, MP3, M4A and WAV. Almost anything macOS can open should work. If a file with an unusual codec will not open, tell us the format.

macOS 26 or later on a Mac with Apple silicon (M1 or newer). Intel Macs are not supported.

The speech recognition model is under 1 GB. It downloads once, the first time you use the app, and works offline after that.

The model is large, and putting it inside the app would make the download heavy, so it is fetched on first use. If the download is interrupted it resumes instead of starting over.

Translation uses the on-device translation built into macOS. The first time you translate a given language, the system may ask you to download its language pack. After that, translation runs offline on your Mac.

CapCut: look for an import option such as “Import captions” or “Local captions” in the captions panel (the name and location change between versions), and choose the bilingual file (for example .en-zh.srt, with the target-source language codes in the file name) or the target-only file (for example .en.srt). Final Cut Pro: choose File > Import > Closed Captions and select the .srt file. Keep the subtitle file in the same folder as the video.

Each video is processed up to the first 10 minutes, and live translation is limited to 10 minutes per day; everything else is the same. A one-time purchase removes both limits.

Click “Restore Purchases” in the app and sign in with the same Apple Account. Apple keeps your purchase record.

Write to twinsub@gatheon.com with your macOS version and the rough length and language of the video. You do not need to send the video.