Ultimate Smart Subs (USS) is a free, multilingual subtitle addon for Stremio movies and series, currently in public beta. Basic subtitle searches require no API key.
Ultimate Smart Subs (USS): Ranked Subtitles with Timing Adjustments and AI Translation
USS ranks multilingual subtitles for movies and series, adjusts timing when reliable, and offers optional translation using your Gemini or DeepL key.
- movies
- subtitles
- tv shows
Subtitle matching and bilingual viewing
- Ranked results: Weighs release compatibility, timing evidence and available human/AI metadata while keeping alternatives selectable.
- Selective timing adjustments: Changes timing only when reliable evidence is available; perfect synchronization is not guaranteed.
- Episode matching: Supports individual episodes and season packs, with regional-language or English fallbacks where available.
- Bilingual subtitles: Can display a second language beneath each line.
Sources include OpenSubtitles V3, SubDL and SubSource, alongside dedicated Turkish and Romanian sources. OpenSubtitles V3 requires no key but has limited coverage; optional sources have their own access requirements.
Translation when subtitles fall short
If no usable subtitle is found, USS can translate one with your own Gemini or DeepL API key. Provider limits apply, but USS charges no per-translation fee.
- Shared translations: Reuses compatible translations when available to reduce waiting and repeated API usage.
- Experimental AI review: Optionally checks meaning and wording using your provider allowance, though mistakes can remain.
Beta limitations
Free hosting and provider limits can cause delays or interruptions. Subtitle availability and quality vary by release, and USS cannot make Stremio prioritize its tracks over embedded subtitles or other addons.