Mitsuko
Mitsuko · Writing
Mitsuko is an AI subtitle translator that turns SRT, VTT, and ASS files into 100+ languages using frontier models, with context extraction, audio transcription, and batch jobs.
About Mitsuko
What Is Mitsuko
Mitsuko is a browser-based subtitle translation tool built for people who move videos between languages. You drop in an SRT, VTT, or ASS file, pick a model, and get subtitles back in the target language. What separates it from a plain translator is the context layer: you feed it episode summaries, character notes, or prior subtitles, and it keeps names, tone, and terminology steady across a whole season.
The tool covers three jobs in one place. Subtitle translation handles the script you already have. Audio transcription turns a video or audio file into timed subtitles. Context extraction reads your subtitles, audio, or notes and pulls out characters, settings, and plot so later translations stay consistent. Actors, indie studios, and localization freelancers are the people most likely to care, since they usually work episode by episode and hate re-fixing the same name ten times.
Pricing runs on credits rather than a subscription. You buy a pack, spend credits on translation, transcription, or context work, and the balance lasts a year. Credits burn at different rates depending on the model, so a cheap model like Gemini 3 Flash stretches much further than Claude Opus. That means the real cost depends on your model habits more than on a fixed monthly fee.
The limits are worth knowing up front. There's no free tier beyond free models, transcription is labeled experimental, and long audio jobs run on the server in the background rather than finishing instantly. The translation quality also leans on the context you supply, so skipping that step gives you flatter output.
Getting Started
- Sign in at mitsuko.app with an account, then buy a credit pack if you plan to use paid models.
- Upload an SRT, VTT, or ASS file, or drop in audio if you need subtitles transcribed from scratch.
- Choose a model. Start with a cheaper one like Gemini 3 Flash, then move up to a larger model if the result needs more nuance.
- Add context if you have it. Paste character notes, a plot summary, or earlier subtitles so names and tone stay consistent.
- Run the translation, review the timing and phrasing, then export the file for editing and QA.
Product Information
A quick look at Mitsuko's pricing, supported platforms, and performance.
Best for
The users, tasks, and scenarios where this tool fits best.
Users
- Anime and drama fansubbers
- Indie filmmakers and YouTubers
- Localization freelancers
- Content teams at small studios
Tasks
- Subtitle translation
- Audio transcription
- Context extraction
- Batch translation
- Project backup and transfer
Scenarios
- A fansub group finishes a 12-episode season and wants every episode to use the same character names.
- A YouTuber with a back catalog in one language wants English subtitles added across twenty older videos.
- A freelance translator gets raw audio from a client and needs a first-pass timed subtitle file before editing.
- A small studio translates a pilot, then reuses the character sheet for the whole series.
Key features
Subtitle translator with frontier models
The core tool translates SRT, VTT, and ASS files using models from Gemini, Claude, Grok, and OpenAI. You pick the model per project, so you can trade cost against nuance. Translation keeps formatting and timing in the file rather than dumping plain text, which saves you a clean-up pass before editing.
Audio transcriber
Drop in an audio or video file and Mitsuko produces timed subtitles, handling the spotting and segmentation so lines land where the speech happens. You can add custom instructions before it runs, which helps with names or terms the audio alone wouldn't clarify. It supports large files and can process them in the background.
Context extractor
This is the feature that sets Mitsuko apart from a plain subtitle translator. You feed it subtitles, audio, or text and it pulls out characters, settings, plot, and relationships. Reusing that context across episodes keeps a translator from renaming the same character in every file, and it lifts the overall quality of later passes.
Context-aware translation
Beyond raw context, Mitsuko prioritizes meaning over word-for-word rendering. It aligns tone with how characters speak, adapts idioms and cultural references, and lets you steer the output with custom instructions. An angry line reads angry in the target language instead of coming out stiff and literal.
Batch translation
You can translate several subtitle files at once instead of queuing them one by one. For anyone working through a season or a back catalog, that turns a repetitive chore into a single run. It pairs naturally with the shared context so every file in the batch follows the same names and tone.
Project management and backup
Mitsuko stores your projects, subtitles, and related assets in one place, with backup and transfer built in. That matters when more than one person touches a project, since you hand off a clean bundle instead of scattered files. It also keeps earlier versions around when you need to compare a revision.
Model choice and credit control
Every model on the platform is available, from cheap options like Gemini 3 Flash and GPT-5 nano to premium ones like Claude Opus and GPT-5.6 Sol. Because credits burn at model-specific rates, you control spending by matching the model to the job. Free models are offered at no credit cost for basic work.
Pros and cons
Pros
- Context extraction keeps names, tone, and terminology consistent across a full season, which is the hardest part of subtitle work.
- One credit balance covers translation, transcription, and context jobs, so you don't juggle separate subscriptions.
- You choose the model per project, letting a cheap model stretch credits on rough drafts and a premium one handle final passes.
- Batch translation and project backup fit series-scale work instead of single-file translation.
- Supports 100+ languages and the three common subtitle formats, SRT, VTT, and ASS.
Cons
- There's no subscription and no meaningful free tier, so regular use means buying credit packs, and credits still expire after a year.
- Transcription is labeled experimental, so anyone relying on audio-to-subtitle output for critical work should expect to verify timing.
- Output quality depends on the context you supply, which adds a setup step that casual users may skip and then find the results flat.
- The pricing page lists no public developer API, so teams wanting to automate translation inside their own tools can't count on one.
Frequently asked questions
Mitsuko translates subtitle files and transcribes audio into timed subtitles. You use it to move an SRT, VTT, or ASS script into another language, to turn a raw audio track into subtitles, and to keep character names and tone consistent across episodes with context extraction.
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