Karaoke timing tells a video when to show and highlight each part of a lyric. Line timing marks a phrase; word timing adds boundaries inside it. Accurate text and accurate timing are both needed.
Line timing and word timing solve different problems
With line timing, an entire lyric line becomes active when the singer reaches it. With word timing, individual words change color as the performance moves forward. A continuous sweep provides a stronger cue, but it requires more detailed timing. Dividing a line into equal intervals is only an approximation: singers rarely give every word the same duration.
Why songs are harder than ordinary speech
A sung vowel may continue for several beats. Consonants may be brief or partly masked by instruments. Backing vocals can overlap the lead, and a repeated chorus can have a different rhythm the second time. These details affect both transcription and alignment. Automatic processing is a first pass, not a guarantee of exact performance timing.
How this tool highlights captions
The speech model produces words and timestamps. The renderer uses these word spans to animate the highlight. When one recognized token contains several characters, the animation divides that token’s duration between them. This creates a karaoke effect, but it is not a separate phoneme-level alignment system.
What to check when a highlight feels wrong
If every line arrives equally early or late, the whole timeline may have an offset. If the beginning is correct but later lines drift, individual sections need attention. A long note that highlights too quickly may have a short assigned word duration. Preview the result and use a clearer recording when the recognition is poor.
Make the result easier to read
Keep displayed lines short, use clear contrast between inactive and highlighted text, and leave space around the captions. Decorative elements and music visualizers should support the words rather than compete with them.
Common questions
Does a normal LRC file include word timing?
Basic LRC usually marks lyric lines. Word-level timing requires extra information; the extension alone does not guarantee it.
Does accurate transcription mean accurate timing?
No. Transcription identifies the text; alignment places it on the audio timeline.