ACE-Step Audio Outpaint
Extend your audio tracks seamlessly with AI-powered music generation. Upload any audio clip and let the model generate new content before or after it — perfectly matching the style, rhythm, and mood of your original track.
Why It Sounds Great
- Style-aware generation: Uses tag-based guidance to match genres like lofi, hiphop, trap, drum and bass, and more.
- Seamless transitions: Generated audio blends naturally with your original track without abrupt cuts or mismatched beats.
- Bidirectional extension: Extend audio at the beginning, end, or both directions simultaneously.
- Lyrics support: Optionally provide lyrics to guide vocal generation in extended sections.
- Reproducible results: Use the seed parameter to recreate exact outputs or explore variations.
Parameters
| Parameter | Required | Description |
|---|
| audio | Yes | Source audio file (upload or public URL). |
| tags | Yes | Comma-separated style tags to guide generation (e.g., "lofi, hiphop, chill, trap"). |
| extend_before_duration | No | Seconds to generate before the original audio. Default: 0. |
| extend_after_duration | No | Seconds to generate after the original audio. Default: 30. |
| lyrics | No | Optional lyrics to guide vocal generation in extended sections. |
| seed | No | Random seed for reproducibility. Use -1 for random. |
How to Use
- Upload your audio — drag and drop or paste a public URL.
- Add style tags — describe the genre and mood (e.g., "lofi, hiphop, chill").
- Set extension duration:
- Use extend_after_duration to add time at the end.
- Use extend_before_duration to add time at the beginning.
- Add lyrics (optional) — provide text if you want vocals in the extended section.
- Set seed (optional) — use -1 for random, or a specific number for reproducible results.
- Run — click the button and wait for generation.
- Download — preview and save your extended audio.
Pricing
Per-second billing based on total output duration.
| Metric | Cost |
|---|
| Per second | $0.0002 |
Billing Formula
Total cost = (original audio duration + extend_before_duration + extend_after_duration) × $0.0002
Examples
| Original | Extend Before | Extend After | Total Duration | Total Cost |
|---|
| 60s | 0s | 30s | 90s | $0.018 |
| 90s | 10s | 30s | 130s | $0.026 |
| 120s | 0s | 60s | 180s | $0.036 |
| 180s | 30s | 30s | 240s | $0.048 |
Best Use Cases
- Music Production — Extend loops, intros, or outros for full-length tracks.
- Content Creation — Generate longer background music for videos and podcasts.
- DJ & Remix Work — Create extended mixes or seamless transitions between tracks.
- Game & Media Audio — Produce adaptive music that can loop or extend dynamically.
- Songwriting — Explore new directions by extending existing ideas with AI assistance.
Pro Tips for Best Results
- Use descriptive, specific tags — "lofi, hiphop, jazzy, chill, piano" works better than just "music".
- For consistent style, keep the original audio and extension durations balanced.
- Experiment with different seeds to find the perfect variation.
- When using lyrics, match the syllable count and rhythm to the expected musical phrasing.
- Start with shorter extensions (15-30s) to test the style match before generating longer segments.
Notes
- If using a URL, ensure it is publicly accessible. A preview player in the interface confirms successful loading.
- Processing time scales with total output duration.
- For best results, use clean source audio with consistent tempo and style.