AllSubConverter
Privacy-first subtitle workspace
About AllSubConverter
AllSubConverter is a privacy-first subtitle processing workspace that pulls the whole subtitle lifecycle - converting, editing, syncing, translating, cleaning, and quality-checking - into one browser-based toolkit. Anyone who has worked with captions knows the usual mess: a format converter on one site, a timing fixer on another, a cleaner somewhere else, and a subtitle file bounced between half a dozen services that each want an upload and an account. AllSubConverter collapses that into a single workspace where you bring a file in once and chain the tools you need, with the file carrying through every step. Its defining choice is that standard tools run entirely in your browser - the subtitle file never leaves your device for the convert, edit, sync, clean and QA operations - which matters for anyone handling unreleased video, client material, or anything they would rather not hand to a server.
The catalogue is deliberately broad: 117+ tools covering 40+ conversion routes across 11 core formats (SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI and TXT) plus YouTube JSON3 input. Where AI genuinely helps - translation, rewriting, and furigana/pinyin/ruby annotation - AllSubConverter uses a bring-your-own-key model rather than reselling credits. You plug in your own OpenAI, DeepSeek or Claude key and the cue text goes directly from your browser to that provider, so you pay provider wholesale rates with no markup and the tool never becomes a metered middleman. The result is a workspace that treats subtitles as real work with real privacy constraints rather than a one-off conversion gimmick.
You start by dragging a subtitle file into the workspace or clicking to browse; each file can be up to 50 MB, and batches handle up to 200 files or 1 GB. The file loads into a live workspace with a timeline preview and cue list, and from there you move through a recommended workflow - Convert, Clean, Sync, Translate, Merge, Export - applying only the stages you need. Standard operations run against your device's own compute, so conversion and edits are instant and work even offline. When you reach for an AI tool, you supply your API key and the relevant cue text is dispatched straight to your chosen provider; the original file is not uploaded. Finished subtitles export in whichever of the 11 formats you need, with options like WEBVTT headers and line-ending control. Because the file persists across tools, a single pass can convert a format, fix timing, strip SDH tags, balance line breaks, translate, and run a QA report without ever leaving the page.
- •117+ Subtitle Tools In One Workspace - Convert, edit, clean, sync, split, merge, QA and export are all present in a single place, so a full subtitle job runs end to end without switching services
- •Local-First Processing - Standard convert/edit/sync/clean/QA tools run in the browser sandbox; the subtitle file stays on your device, with no server upload step and no transfer wait
- •Broad Format Coverage - 40+ conversion routes across 11 core formats (SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI, TXT) plus YouTube JSON3 input
- •Bring-Your-Own-Key AI - AI translation into 19 target languages, rewriting, and furigana/pinyin/ruby annotation route cue text directly to your own OpenAI, DeepSeek or Claude key with no resold credits and no markup
- •Workflow Chaining - Upload once and carry the same file through Convert, Clean, Sync, Translate, Merge and Export, with a live timeline preview at every step
- •QA And Analysis - Reading-speed checks, timing and overlap detection, statistics, diffing and auto-fix catch the subtitle problems that break playback or fail delivery
AllSubConverter fits anyone who treats subtitles as a working format rather than an afterthought. Subtitle creators and editors get a single place to convert, retime and clean captions without juggling tools. Translators and localization teams get format-stable conversion plus BYOK AI translation into 19 languages and bilingual merging for multilingual deliverables. Developers and media engineers who move between SRT, VTT, ASS and TTML - or ingest YouTube JSON3 - get reliable programmatic routes and batch processing up to 200 files. Language learners lean on the annotation tools for furigana, pinyin and ruby text. And because standard processing is local and requires no account, it is a natural choice for anyone handling unreleased footage, client work, or sensitive material who cannot or will not upload subtitle files to a third-party server. The free, no-signup workspace means the barrier to trying it is essentially zero.
