YouTube Dream Track for Shorts: a Lyria soundtrack through an API

How do you get a Lyria soundtrack for a YouTube Short? Inside YouTube, through Dream Track: you enter a topic and it generates a 30-second soundtrack, per Android Police's coverage (read 2026-10-04), and Google DeepMind's page describes Dream Track as an experiment in Shorts built on Lyria. Outside the app, the same family of engines is available through Sume's Music Router, which returns an audio file you can place under any video.

The two are for different jobs. Dream Track is a feature in the Shorts creator flow. The Music Router is for the case where you edit elsewhere, in code or in a pipeline, and want the music as an asset.

What Dream Track is

The DeepMind page describes the partnership between Lyria and Dream Track, and Android Police describes the creator flow. Details such as which regions or which artist voices are available have changed over time, so check YouTube's help pages before relying on any of them.

An API route for the same 30 seconds

Ask for 30 seconds in the prompt. The Music Router rejects duration and duration_seconds, so length is a sentence in the brief, not a field. The Music 1.0 docs show the pattern "a 2-minute track" and section markers like [0:00-0:30] Intro: ....

import os
import requests

r = requests.post(
    "https://api.sume.com/v1/music-router/generate",
    headers={
        "Authorization": "Bearer " + os.environ["SUME_API_KEY"],
        "Idempotency-Key": "dream-track-api-001",
    },
    json={
        "model": "sume/music-auto",
        "prompt": "Upbeat pop-punk bed, 168 BPM, G major. Fast palm-muted guitar, live drums, a shout-along hook at 0:10. A 30-second track. Instrumental, no vocals.",
        "mode": "sync",
        "wait_timeout_seconds": 30,
    },
    timeout=60,
)
print(r.status_code)
print(r.json())

Put it under the Short

Import your clip, then render with the generated file as soundtrack. Timeline 1.0 takes soundtrack as an optional bed with url, gain_db, loop, fade_out_seconds up to 10 and duck_db from 0 to 20; the ducking option needs a real audio spine, not silence.

When to stay in YouTube

If you only post Shorts from your phone, Dream Track is simpler. Use the API when you need many videos, a fixed brief, or a log of which engine ran in job.request.routed_model.