LRC is the lyrics format music players read for a synced, line-by-line display - a timestamp in brackets, then the line. It has starts but no ends, so a converter has to infer each line's duration from where the next one begins.
Every conversion below runs in this page, on your own machine. Nothing is uploaded, there is no queue, and there is no account to make. Pick a target format, or just drop a LRC file above and choose afterwards.