Subtitles and Auto-Translate

Nexio keeps the subtitle experience simple first, then adds provider-backed translation when you actually need it.

Baseline recommendation

Start with the built-in subtitle track when the title has one.
Use addon subtitles when the built-in track is missing or poor.
Set your primary subtitle language to the language you want to read most often.
Leave subtitle delay at zero until you have a real sync problem.
Keep your subtitle style consistent so translated subtitles do not feel visually different from normal ones.

Auto-Translate appears in the subtitle dialog after Subtitle Translation is enabled and the provider key is present.
Nexio sends the selected text subtitle to the selected provider, then plays back the translated result as a normal subtitle track or overlay.
Text-based subtitle formats such as SRT, VTT, ASS, and SSA are supported.
ASS/SSA translation preserves styling and drawing markup, but only visible dialogue text is sent to the provider.
Bitmap or image-based built-in subtitles are not supported for translation.
Translated subtitles are cached locally, so the same source and target language do not need to be translated again right away.

Open Settings > Integration > Subtitle Translation.
Choose OpenAI-compatible, Anthropic-compatible, Google Gemini, or Alibaba DashScope (Qwen-MT).
Leave the endpoint alone for the native provider, or set a compatible base URL such as https://openrouter.ai/api/v1.
Set the model. The OpenAI-compatible default is openrouter/free; the Anthropic default is claude-haiku-4-5; the Gemini default is gemini-2.5-flash; the DashScope default is qwen-mt-flash.
Paste the provider API key.
Nexio stores that key through account sync, so you do not have to re-enter it on every device.

Translation is not instant. Expect a short delay while the selected provider processes the subtitle.
Longer subtitle files take longer because Nexio translates them in chunks.
Quality depends on the source subtitle quality and the language pair. It is good enough for practical viewing, but it is still machine translation.
Because this uses an external provider API call, it can count against your provider usage limits or billing plan.

If Auto-Translate fails, keep watching with the original subtitle track and try again later with a cleaner source.

Confirm Subtitle Translation is enabled, the provider API key is present, and the selected provider/model/endpoint are valid before you open the subtitle dialog.
Use a text subtitle track such as SRT, VTT, ASS, or SSA. Bitmap subtitle tracks cannot be translated.
If translation is missing only on one title, try a cleaner subtitle source first.
If the feature should be available but never appears, move to Troubleshooting.