Tech review intro music: a 20-second sting and bed

For a tech review channel intro, ask for a 20-second clean synth bed with a hit at 0:03 for the title card and a stop at 0:20. Generate it once and reuse the file in every video. On Sume that is one generation at $0.125, and, if you render the intro as its own clip, a one-minute render at $0.10, so $0.225.

An intro is a signature, so it should be short, clean and distinctive. It is not a one-off asset: because it repeats in every video, quality matters more than quantity, and a flat generation price lets you try several takes.

The brief to send

The brief is tight: one named hit, a clear stop, a bright crisp sound and no vocals.

curl -X POST https://api.sume.com/v1/music-router/generate \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: tech-review-intro-music-a-20-second-stin-001" \
  -d '{
      "model": "sume/music-auto",
      "prompt": "Crisp tech channel intro, 110 BPM, D minor. Clean synth arp, tight kick, short bass pulse, glassy bell accent. Hit at 0:03 for the title, build through 0:12, final stab at 0:20. Sleek modern minimalist production. Instrumental, no vocals. A 20-second track."
    }'

Why each axis is set that way

Getting the length right

Twenty seconds is short enough that overshoot matters. The router has no duration field, so check the real length and trim in the edit. If you render the intro as a stand-alone clip in Timeline, set audio.duration_seconds to 20 and a short fade_out_seconds.

For a channel with many videos, join the intro to each main video in your editor, or render the intro once and reuse it. A clip of 20 seconds bills as one started minute, so there is no saving for a shorter clip.

Before paying for a render, call POST /v1/timeline-1.0/plan with the same body. It is unbilled and reports the billable minutes, which for this 20-second video is 1. Then send the real POST /v1/timeline-1.0/render with an Idempotency-Key, wait up to 30 seconds in sync mode, and poll GET /v1/jobs/:id/status if it is still queued or processing. Statuses are queued, processing, completed, failed and canceled, and a 429 queue_full means try again shortly.

What it costs

Because the render minimum is one started minute, a 20-second intro costs the same $0.10 as a 60-second one. The real saving comes from reusing the file; one intro serves 100 videos for $0.225 once, rather than $22.50 if you generated a new one each time. Scaling is simple arithmetic. One finished video here is $0.225 of audio and assembly, so ten of them are $2.25 and fifty are $11.25, before any retries. Failed jobs are not billed as accepted generations, but a regeneration you ask for is a new job, so budget one or two extra takes for a hero clip.

Check before you publish

Keep the final file and the prompt together. If you ever want a refreshed intro, use the same brief with one axis changed.

A slightly longer outro version can use the same prompt with a 10-second length.

The hand-off between the two calls is the step people miss. When the music job completes, GET /v1/jobs/:id/result returns result.artifacts[] with an audio/mpeg file on media.sume.com. Timeline only accepts workspace media URLs, so import any outside file through POST /v1/media-imports first, and send the resulting URL as soundtrack.url. The Music docs also note that job.request.routed_model names the engine that actually ran, which is worth saving with the file.

• Listen to three takes before committing; this is a signature sound.
• Avoid trending sounds that will date the channel.
• Check that the hit lines up with the title animation.
• Confirm usage terms for generated music with Sume before monetisation.