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Built by Filmmakers · macOS Native

Professional
Subtitling
for macOS

Built by film-industry professionals. Frame-accurate spotting, on-device AI, and broadcast & cinema delivery — native to macOS, lightweight and fast, on a free, open-core foundation.

Download for macOS Become a Beta Tester
18
Export Formats
100%
Native macOS
Free
Core & Editing
AlphaSUB main window — track list, subtitle table, video preview, waveform and editor
Capabilities

Everything you need for
professional subtitling

From waveform-based spotting to on-device AI transcription, AlphaSUB covers the entire subtitling workflow — frame-accurate and standards-compliant.

Waveform & Spectrogram

Spot to a scrollable waveform and an RX-style spectrogram, with VAD-based speech detection to find dialogue fast.

Multi-Track Workflow

Import and compare multiple subtitle files side by side. Convert between formats, merge translations, and manage tracks for multi-language releases.

Frame-Accurate Editing

SMPTE and drop-frame timecodes, partial italics, vertical & horizontal positioning, and live CPS / CPL / WPM reading-speed thresholds.

On-Device AI, or Bring Your Own

Speech recognition, translation, and speaker diarization run entirely on your Mac — private, fast, and free. Prefer a cloud model? Connect a subscription (OpenAI, Claude, Gemini, Mistral, OpenRouter…), a local server (Ollama, LM Studio, MTPLX), or DeepL with your own account or API key (Pro) — AlphaSUB fetches the available models. Always your choice.

Live Video Preview

Real-time subtitle overlay on video with JKL shuttle control. Preview styling — fonts, colors, borders, and positioning — exactly as it will render.

Quality Control

Pre-delivery conformance checks per format, a native grammar & spelling linter, shot-change detection, and VAD-based resync to your video.

Native, Light & Fast

Written in Swift as a true macOS app — no Electron, no browser engine. It launches instantly, sips memory, and drives 4K playback and waveforms smoothly on Apple Silicon and Intel.

Real-Time Collaboration

Host or join a live session and subtitle together — several editors on one project with conflict-free sync, ideal for teams sharing a reel or reviewing in real time.

Intuitive, Modular Interface

A clean, native macOS layout you shape to your workflow — collapse panels, resize the waveform, detach the video, and arrange the tools the way you work.

A closer look

See it in action

Real screenshots from AlphaSUB. Click any image to enlarge.

Main window
Main window — tracks, table, video, waveform & editor
Video player with subtitle overlay
Live subtitle overlay on video
Waveform timeline
Waveform timeline with subtitle bars
Spectrogram
RX-style spectrogram & speech detection
Subtitle editor
Editor with timecodes & styling controls
Subtitle table
Subtitle table with CPL / CPS validation
AI panel
On-device AI — transcription & translation
Export dialog
Export to 18 subtitle formats
Issues panel
Issues panel — QC & conformance
Compatibility

Every format professionals rely on

Import and export the industry-standard subtitle formats. Everyday and interchange formats are free; broadcast & cinema delivery is unlocked with Pro.

Free — import & export

Free

SRT

SubRip Text — the universal subtitle format

Free

WebVTT

Web Video Text Tracks for HTML5 video

Free

TTML

Timed Text Markup Language (W3C)

Free

DaVinci TTML

TTML tuned for DaVinci Resolve import

Free

ASS / SSA

Advanced SubStation Alpha styled subtitles

Free

FCP XML

Final Cut Pro interchange (import & export)

Free

Premiere XML

Adobe Premiere Pro CC / xmeml round-trip

Free

AVID

Avid Media Composer caption interchange

Free

TXT · DOCX · XLSX

Plain text, Word and Excel for review & hand-off

Free

DCP SMPTE

SMPTE 428-7 digital-cinema subtitles

Free

DCP InterOp

InterOp digital-cinema subtitles

Pro — broadcast & cinema delivery

Pro

EBU STL

EBU Tech 3264 broadcast subtitles

Pro

SCC

CEA-608 / 708 closed captions

Pro

Netflix TTML

Netflix-conformant timed text (IMSC)

Pro

Amazon DFXP

Amazon / Prime Video DFXP delivery

Pro

iTunes TTML

Apple iTunes / TV timed text

Integration

Round-trips with your NLE

Move subtitles in and out of your edit via FCP XML, Premiere CC XML, and Avid DS/MC caption text — keep them synchronized without leaving your timeline.

Final Cut Pro

Import and export FCP XML. Subtitles land in your timeline with frame-accurate timing.

DaVinci Resolve

Hand off via a DaVinci-tuned TTML profile and FCP XML — import subtitle tracks straight into Resolve.

Premiere Pro

CC XML round-trip with Premiere Pro. Edit subtitles in AlphaSUB and bring them back to your sequence.

Avid Media Composer

Import and export Avid DS & Media Composer caption text (.txt) — frame-accurate hand-off to and from Avid.

Final Cut Pro is a registered trademark of Apple Inc. DaVinci Resolve is a registered trademark of Blackmagic Design. Adobe Premiere Pro is a registered trademark of Adobe Inc. Avid and Media Composer are registered trademarks of Avid Technology, Inc. AlphaSUB is not affiliated with, endorsed by, or sponsored by any of these companies.

Intelligence

On-device by default. Cloud when you need it.

AlphaSUB runs speech recognition, translation, and speaker diarization entirely on your Mac — private, offline, and free. Need more power? Connect cloud AI — DeepL or an external model (OpenAI, Anthropic Claude, Google Gemini, Mistral, and more) with your own subscription or API key. Cloud AI is a Pro feature; on-device AI is always free.

  • On-device (free): speech recognition, translation & diarization on your Mac
  • On-device AI runs fully offline — zero data leaves your Mac
  • Cloud (Pro): DeepL or external models — OpenAI, Claude, Gemini, Mistral, OpenRouter, DeepSeek… — with your own key
  • You choose per task — nothing goes to the cloud unless you pick a cloud engine
  • Local servers (free): connect Ollama, LM Studio, LocalAI, AnythingLLM or MTPLX — on your Mac or another on your network
On-device AI
Professional

Pro features for broadcast & cinema

Advanced delivery formats, live output, batch workflows, and collaboration — unlocked with a Pro license.

Broadcast & Cinema Export

EBU STL, SCC (CEA-608/708), Netflix TTML, Amazon DFXP, iTunes TTML, and DCP SMPTE / InterOp — with pre-export conformance checks.

Video Export & Render Queue

Render deliverables with burned-in subtitles — ProRes and DNx masters, H.264/HEVC in MOV, MP4 or MKV — with platform presets, timecode window, watermark and a batch render queue.

Digital cinema subtitle assets

Export ST 428-7 (SMPTE) and InterOp CineCanvas subtitle assets with subsetted fonts, and read the subtitles back out of an existing DCP. Building, playing and delivering the package itself is AlphaDCP.

Blackmagic Live Output

Direct SDI / HDMI output via Blackmagic DeckLink cards. Real-time subtitle burn-in for live broadcast and mastering.

Live Collaboration (Beta channel)

Real-time multi-editor collaboration with conflict-free sync. Host or join a session and edit together, instantly.

Batch Export

Export multiple tracks and multi-language deliverables in one pass — ideal for season and multi-title packages.

Season Bible

Keep names, terms, and translation choices consistent across episodes with a shared bible and consistency checks.

Cloud AI Models

Connect DeepL or an external LLM — OpenAI, Anthropic Claude, Google Gemini, Mistral, OpenRouter, or any OpenAI-compatible endpoint — with your own subscription/API key for higher-quality translation. On-device AI stays free.

Secure Mode (Beta channel)

Air-gap the app for confidential content — block all network egress while you work on embargoed titles.

AlphaDCP
Digital cinema

DCP mastering is now its own application

Building, encrypting, signing, validating and delivering Digital Cinema Packages moved out of AlphaSUB into AlphaDCP, a separate application sold on its own.

AlphaSUB has not lost its cinema work. It still opens a DCP, plays its picture so you can spot against the real image, and exports ST 428-7 (SMPTE) and InterOp subtitle assets with subsetted fonts. What it no longer does is assemble the package.

The two work together: in AlphaDCP, right-click a subtitle track and it opens here with the DCP attached — you correct it against the picture it will run over, and every save lands back in AlphaDCP as you work.

Discover AlphaDCP
Community

Join the AlphaSUB community

Questions, workflow tips, feature ideas — for open-core users and Pro beta testers alike.

GitHub Discussions

The searchable knowledge base: Q&A, ideas, show & tell and release notes. Best for anything worth finding again later.

Discord

Real-time chat with the team and other subtitlers — plus the role-gated #pro-beta lounge for beta testers.

GitHub Repository

Source code, issues and releases of the open-core edition.
Free & Pro

Compatible by design

Every AlphaSUB project is the same file on Free and Pro. Author and QC on Free, then hand it to a Pro finisher for delivery — nothing is lost in between.

Blackmagic DeckLink live output —
Batch & multi-language export —
Season Bible — cross-episode consistency —
Cloud AI models (DeepL + your own subscriptions) —
Live Collaboration & Secure Mode — Beta channel
Price €0 · forever €199 · per year · 2 seats

Pro is €199 per year for two seats, or €12 per month per seat — every update and new feature included for as long as you subscribe. Beta testers get 25% off their first year.

Free → Pro

Start on Free, finish on Pro

Some productions begin on the Free tier — spotting, editing and full QC — then hand the project to a professional with a Pro license for broadcast, streaming or cinema delivery. The .alphasub file is identical at every tier, so quality and QC carry through to the finished product.

Free

Author & edit

Spot, translate on-device, style and time — free, no account.

→
Free · QC

Check quality

Spelling, grammar, breaks & layout and conformance QC run on Free too.

→
Pro

Deliver on Pro

The same project opens on Pro for broadcast/cinema export, DeckLink and batch.

Beta Program

Not for sale yet.
Get in early.

Neither app is for sale yet. Become a beta tester now — each application has its own beta program — and get 25% off your first year at launch.

Beta Tester
Beta access is completely free — no payment now, no card required. Each application has its own beta program.

For reference — the planned prices. Neither app is for sale yet:

AlphaSUB €199/year Subtitling
AlphaDCP €249/year Digital cinema
Alpha Suite €349/year Both apps — save €99

Each plan covers two seats · prices ex-VAT · every update included · cancel anytime

  • All Pro export formats (STL, SCC, DCP, Netflix / Amazon / iTunes TTML)
  • Video export (ProRes / DNx / H.264 / HEVC) with burned-in subtitles
  • Blackmagic DeckLink live output
  • Batch export & Season Bible
  • Cloud AI models & real-time collaboration
  • Every update & new feature, for as long as you subscribe

Join now for free and help shape AlphaSUB. When Pro goes on sale, beta testers get 25% off their first year. We'll email your free beta license once approved.

For schools & universities

Education is €79 per seat per year, or €499 per year as a site license — one license per school that deploys to every workstation, no per-seat activation. Ideal for film schools and media programs.

Ask about Education licensing
Download

Free to download. Free to subtitle.

Two applications: AlphaSUB for subtitling, AlphaDCP for digital cinema mastering. Subtitling is free — import, spot, style, on-device AI and everyday formats are all included. Broadcast & cinema delivery is unlocked with a licence.

Download AlphaSUB Download AlphaDCP All releases

Both are stable releases. The beta channel stays the development channel — new work lands there first.

Requires macOS 14 Sonoma or later · Apple Silicon & Intel · Universal build

AlphaSUB video preview