Use this to create an AI music track (full songs with vocals, or instrumentals). Three models: music-3.0 (default, 200 credits — songs from a prompt and/or lyrics, lyrics optimizer on by default so a prompt alone works), mureka-v9 (60 credits — sings the user's EXACT lyrics verbatim, or instrumental/BGM), and lyria-3 (100 credits — high-fidelity from a rich prompt, can condition on up to 10 reference images), and sonilo-music (instrumental/background music of an EXACT length via duration, 5–360 s — priced PER SECOND at 4 credits/s with a 10-second minimum, no vocals). VIDEO-TO-MUSIC: pass a `video` URL (upload_media first for local files) and sonilo-video-music composes a licensed soundtrack for the clip's content, pacing and mood — priced per second of the video's measured length (15 credits/s, 10 s minimum, ≤360 s). Flat price per track (per second for the Sonilo models), charged on success only; the user's plan discounts apply automatically. Submits an async job and returns a numeric job_id — music takes a minute or three: poll check_generation_status with the job_id AND type "music" every 15–30 seconds, then share the finished track's listen/download link with the user (chat can't embed audio players).