song-video-remix-captions 是做什么的？
Polish a phone/live video of someone singing with an instrument — rebalance voice vs. accompaniment (e.g. "the guitar is too loud", "I can't hear the vocal"), burn in timed lyric captions line by line in a chosen font (including Hebrew/Arabic RTL), and verify nothing clips or distorts. Use this whenever the user uploads a video or audio of a song performance and asks to fix the mix, turn the voice up or the guitar/piano down, add lyrics/subtitles/captions to a song, or check a video for distorti