Twinsubs
SmartSub alternative for Mac: bilingual subtitles made on your own Mac
SmartSub is an open-source (MIT) desktop tool for Windows, macOS and Linux, transcribing with local models such as whisper.cpp, and its strengths are batch work, dubbing and automation. Twinsubs is Mac only and focuses on on-device bilingual subtitles plus live translation. For cross-platform use, dubbing or automation, choose SmartSub; for the shortest path on a Mac, choose Twinsubs.
Where they differ
| Item | Twinsubs | SmartSub |
|---|---|---|
| Form | Mac app (on the Mac App Store) | Open-source desktop tool (Windows, macOS, Linux) |
| Where it runs | On your Mac, nothing uploaded | Transcription on your computer (the README says files do not leave the machine); translation can use Bing, Google, Youdao or a large model, so network use depends on the choice |
| Price | Free for the first 10 minutes of each video and 10 minutes of live translation per day; one-time purchase removes the limits | Free and open source (MIT) |
| Bilingual subtitles | Yes, translation above the original (order can be swapped) | Yes |
| Live translation | Yes, the sound playing on your Mac; works offline once the language packs are downloaded | No (not on the page) |
| Export SRT | Yes, a bilingual file and a target-only file | Yes (subtitle files) |
“Not verified” means the official page has no clear statement, or the answer sits in dynamic content we could not read; it does not mean the feature is missing. We did not sign up for any account or try any paid feature.
When to choose SmartSub
- You need more than one operating system. The README says it runs on Windows, macOS and Linux, with several kinds of hardware acceleration.
- You want more than subtitles. The page lists text-to-speech dubbing, voice cloning, subtitle burn-in and downloading online video.
- You want automation. The page mentions MCP and a command line with background jobs.
When to choose Twinsubs
- You only want subtitles and do not want a whole suite. Twinsubs does bilingual subtitles and live translation and little else.
- You want to use the translation built into macOS. Twinsubs calls it directly, so you do not choose a translation provider.
- You want live translation of the sound on your Mac, which the SmartSub page does not mention.
Limits of Twinsubs, stated up front
- System requirement: macOS 26 or later, Apple silicon.
- It outputs SRT only: no subtitle burn-in, no built-in editor, no speaker separation, no ASS, and it cannot import an existing SRT and translate it.
- Machine recognition and translation make mistakes; with heavy accents, loud music or many specialist terms, check the result against the video.
- Which language pairs work depends on Apple's on-device translation; there are 12 source languages and 20 target languages.
Moving from SmartSub
SmartSub writes subtitle files, so videos you have finished stay as they are. To compare on a Mac, run one video through the free version of Twinsubs and pick whichever result you prefer. Twinsubs cannot import an existing SRT and translate it, so keep SmartSub for workflows that need that step.
A few notes
The SmartSub README says transcription runs on local models and files do not leave the machine; it gives no single statement about the translation step, which depends on the provider you choose, so we quote only the transcription claim. The star count (about 5.7k) changes over time.
How to check this yourself
- Read the other product's pricing pagePrices, plans and free allowances change; trust the page on the day you buy.
- Run the same clip through bothPick a clip with an accent and some technical terms; it tells you more than a spec sheet. The free version of Twinsubs covers the first 10 minutes of each video.
- Check the export formatConfirm you can export SRT and that your usual editor imports it without errors.
- Check where the data goesRead the other product's privacy policy to see whether video or audio is uploaded. Ours is the privacy policy.
Sources (verified 2026-10-16)
- SmartSub on GitHub · 2026-10-16
“Not verified” means the official page has no clear statement, or the answer sits in dynamic content we could not read; it does not mean the feature is missing. We did not sign up for any account or try any paid feature.
FAQ
Is SmartSub free?
The software is free and open source under the MIT licence. If you pick a large model for translation you need your own API key, and the provider charges for it.
Does SmartSub use GPU acceleration on a Mac?
The README says it supports hardware acceleration on NVIDIA, AMD, Intel and Apple silicon. Twinsubs also runs only on Macs with Apple silicon.
How reliable is the information on this page?
Every fact carries an official source and a verification date (2026-10-16), and anything we could not find is marked not verified. Prices and features change, so check the other product's own site before you buy; if you spot a mistake, write to twinsub@gatheon.com and we will correct it after checking.
Updated 2026-10-23. Back to the Twinsubs home page