Batch-Translating a Full Season: A Subtitle Workflow That Scales

Using SubFly · 5 min read · Updated 21 October 2026

How to plan and run the translation of a whole season of subtitles: organise files, lock style and glossary, pilot one episode, batch the rest, review fast.

Translating one episode is a task. Translating a whole season is a project - twelve, twenty-four or fifty files that all need the same names, the same tone and the same quality, produced on some kind of schedule. The techniques that work for a single file break down at that scale. This guide lays out a workflow for season-sized subtitle translation, from organising the files to the final review.

Phase 1: organise before you translate

Gather and name the source files

Collect every episode's subtitles in one place and name them consistently: show-name_s01e01.ass, show-name_s01e02.ass and so on. Consistent names make it obvious when an episode is missing and keep downloads in order.

Check that all files come from the same release (the same encoding group, the same video version). Mixing sources means mixing timing and styling conventions.

Check timing once, at the start

Spot-check a few episodes against the video. If the timing is off, it's usually off in the same way for every episode of a release, so fix it consistently before translating. See how to fix subtitle timing and sync drift.

Group the files

Keep a season together. In SubFly, create a project for the show or season and upload all the episode files into it. Projects keep each episode's original, its translations and their status in one place, so you can see at a glance what's done.

Phase 2: lock the decisions that must stay the same

This is the most important phase, and it happens before a single line is translated.

Build the glossary

Go through the first two or three episodes and list every recurring name, technique, place, organisation and title. Decide each one's translation - or mark it "keep as-is". Add the main characters' genders if your target language needs them. Our guide on building a subtitle glossary has the full method.

Write the style

Decide honorifics, tone, profanity, how to handle cultural references, and readability limits. Turn it into a short set of instructions. In SubFly, pick a style preset or save your own in the prompt library so it's applied identically to every episode. The fansub style guide lists the decisions worth making.

Choose the model

Faster models are cheaper and quicker; more capable models handle subtle dialogue better. For a long season, it's worth translating one episode with each and comparing a few scenes before committing.

Phase 3: pilot one episode

Translate a single episode end to end with your glossary and style, then review it carefully against the video. This pilot almost always reveals something: a term missing from the glossary, a tone instruction that's too vague, a character whose voice isn't right. Fix the setup now, while it's cheap. Every later episode benefits.

Phase 4: translate the rest in batches

Once the pilot is good, translate the remaining episodes. A few habits keep a large batch healthy:

Translate in order. Earlier episodes introduce names and terms that later ones use. Translating in order lets you add new terms to the glossary as they appear, before the episodes that need them.

Send several episodes at once, but not all blindly. Starting a few episodes together is efficient; reviewing between groups catches problems before they're repeated twenty times.

Spread the load across API keys. If you translate on your own Gemini keys, rate limits apply per key and per project. SubFly can rotate across several keys automatically, so a busy season doesn't stall on one key's limit.

Let failures resume. Long jobs sometimes fail midway - a rate limit, a timeout, a provider hiccup. SubFly saves each finished batch as it completes; retrying a failed job picks up from the last completed batch, so you never lose or pay twice for lines that were already translated. You can also stop a running job if you need to change something, and keep the lines done so far.

Phase 5: review efficiently

Reviewing a whole season is the slowest part, so make it focused.

Review with the video, at normal speed

Watch each episode with the translated subtitles. Note problems by timestamp rather than stopping constantly; fix them in a single pass afterwards.

Use side-by-side review for the fixes

Seeing the original and translated line next to each other makes it fast to judge whether a translation is right. SubFly's review view shows both, with find and replace across a file - ideal for fixing a term that slipped in a few places.

Search for known problems

Some errors are easy to find mechanically: an old spelling of a name, a term you changed mid-season, an honorific that crept back in. Search for them across the files rather than hoping to spot them.

Feed fixes back into the glossary

Every recurring fix belongs in the glossary or the style instructions. If you correct the same thing three times, it's a setup problem, not a review problem.

Phase 6: export and release

Export each episode in the format you're releasing: ASS for styled fansubs, SRT for maximum compatibility, VTT for web players. Use consistent filenames, and spot-check the first and last episode in the player your audience uses.

A season at a glance

Common mistakes to avoid

• Skipping the pilot. Problems found in episode 1 are cheap; found in episode 20, they're expensive.
• Changing the glossary mid-season without going back. If a term changes, search earlier episodes for the old version.
• Translating out of order. New names appear before the glossary knows them.
• Reviewing without the video. Many errors only show up in context.

A season-long project rewards preparation more than speed. Lock the decisions first, pilot once, then let the batches run. If you'd like the batching, retries, glossary and consistency handled for you, create a SubFly account and start with a single project.