What is arkhe-lyric-lock?

Arkhe Lyric Lock is a tool for timing lyrics to a song so they can be used in a lyric video, and its main selling point is that it tells you when it is not confident in its own results instead of quietly guessing. You give it an audio file and a text file of the lyrics, and it works out exactly when each word is sung. The README explains that this is different from typical speech transcription tools, which try to guess what words were sung, a much harder task on singing than on speech, since held notes and dense music mixes trip them up. Instead, this tool already knows the words from your lyric sheet and only has to figure out when each one happens, which the README claims produces much more accurate timing, backed by a small comparison table against a transcription-based approach. Under the hood, it first separates the vocal track from the rest of the song using a tool called Demucs, then aligns the lyrics to that isolated vocal using a technique called forced alignment, then makes a second pass to fix timing on held notes. Every placed word gets a confidence score, and the tool will flag or even stop entirely if it hears singing that is not in your lyric sheet, rather than showing a blank or wrong result. Repeated lines already in the sheet are handled automatically, and unclear ad-libs are left out rather than forced to match text that does not fit. The output includes a timed data file, subtitle files that import into video editors like Premiere or Final Cut, and a plain reference video. A companion repair tool is a webpage you open directly in your browser, with no server needed and nothing sent off your machine, where you can review and manually fix any words the aligner flagged as uncertain. The README is upfront about limits: it needs the lyric text ahead of time since it cannot transcribe singing on its own, very fast rap can still be shaky, and background vocals are intentionally skipped. The project's own code is released under the MIT license, but it depends on a separate speech alignment model whose weights carry a non-commercial license, so the README points to a notice file before anyone considers commercial use.