Hardware-accelerated subtitle sync and translation from the command line
Subtitles out of sync, in the wrong language, or just missing. Anchor fixes all three - using Whisper for audio-based timing and NLLB for context-aware translation.
Runs on NVIDIA, Apple Silicon, AMD, and CPU. Drop it in wherever you process video.
The name comes from the core sync algorithm. When re-timing a subtitle, Anchor transcribes the audio and looks for points where it can match subtitle lines to the transcript with very high confidence. Only those high-confidence matches become anchors - everything uncertain gets rejected as an outlier. The timeline is then reconstructed from those anchors alone. Because the algorithm never commits to a shaky match, it works reliably on any subtitle, no matter how drifted, recut, or badly timed the original is.
Features
Everything subtitle-related, in one tool
From fixing timing to generating subtitles from scratch, Anchor handles the full workflow.
🔊 Audio Sync
Re-times subtitles by transcribing the audio with Whisper and aligning phonemes. Works even when the subtitle was made for a different cut - and even when the subtitle is in a different language than the audio.
📌 Point Sync
Syncs using a reference subtitle as the source of truth. Handles cross-language pairs - sync a PT subtitle using an EN reference without needing audio.
🌐 Translation
Context-aware translation via NLLB into 200+ languages. Choose between small, medium, or large models depending on the quality vs. speed tradeoff you need.
📝 Generation
Generate subtitles from scratch by transcribing audio with Whisper when no subtitle file exists at all.
📦 Extract, Embed, Burn
Extract subtitle tracks from video containers, embed .srt or .ass files back in, strip them out entirely, or burn them hard into the video stream.
🛠️ Repair and Convert
Repair malformed subtitle files, clean up formatting artifacts, and convert between .srt and .ass formats.
⬇️ Auto-download
Search and download subtitles automatically from SubDL, OpenSubtitles, Addic7ed, and Podnapisi before processing.
🔌 API Mode
Expose Anchor as a local API server. Compatible with the Subtitle Edit external tool interface for GUI workflows.
Hardware-accelerated. Runs fast on whatever you have.
GPU acceleration cuts sync time drastically. Anchor auto-detects your hardware and configures itself.