ace/ace-step/audio-inpaint
Ace Step Audio Inpaint by ace - advanced AI model for audio-to-audio. Delivers high-quality results with fast inference, suitable for both creative and production workflows.
Input
URL of the audio file to be inpainted.
Lyrics to be sung in the audio. If not provided or if [inst] or [instrumental] is the content of this field, no lyrics will be sung. Use control structures like [verse], [chorus] and [bridge] to control the structure of the song.
0200
Guidance scale for the generation. Range: 0 to 200.
Random seed for reproducibility. If not provided, a random seed will be used.
Type of CFG to use for the generation process. Allowed values: cfg, apg, cfg_star.
-100100
Granularity scale for the generation process. Higher values can reduce artifacts. Range: -100 to 100.
Scheduler to use for the generation process. Allowed values: euler, heun.
01
Guidance interval for the generation. 0.5 means only apply guidance in the middle steps (0.25 * infer_steps to 0.75 * infer_steps) Range: 0 to 1.
0200
Minimum guidance scale for the generation after the decay. Range: 0 to 200.
0240
start time in seconds for the inpainting process. Range: 0 to 240.
010
Lyric guidance scale for the generation. Range: 0 to 10.
360
Number of steps to generate the audio. Range: 3 to 60.
01
Variance for the inpainting process. Higher values can lead to more diverse results. Range: 0 to 1.
0240
end time in seconds for the inpainting process. Range: 0 to 240.
01
Guidance interval decay for the generation. Guidance scale will decay from guidance_scale to min_guidance_scale in the interval. 0.0 means no decay. Range: 0 to 1.
Whether the start time is relative to the start or end of the audio. Allowed values: start, end.
010
Tag guidance scale for the generation. Range: 0 to 10.
Whether the end time is relative to the start or end of the audio. Allowed values: start, end.
Idle
Example output — click Run to generate your own
Production endpoint
Send your first request
OpenAI-compatible endpoint with unified authentication and usage tracking.
POST
https://api.sandbase.ai/v1/runModel ID
ace/ace-step/audio-inpaint01
Input Schema
19 parameters · 0 required · 19 optional
| Parameter | Type | Required | Description |
|---|---|---|---|
seed | integer | Optional | Random seed for reproducibility. If not provided, a random seed will be used. |
tags | string | Optional | Comma-separated list of genre tags to control the style of the generated audio. |
audio | string | Optional | URL of the audio file to be inpainted. |
lyrics | string | Optional | Lyrics to be sung in the audio. If not provided or if [inst] or [instrumental] is the content of this field, no lyrics will be sung. Use control structures like [verse], [chorus] and [bridge] to control the structure of the song. · Default: "" |
end_time | number | Optional | end time in seconds for the inpainting process. · Min: 0 · Max: 240 · Default: 30 |
variance | number | Optional | Variance for the inpainting process. Higher values can lead to more diverse results. · Min: 0 · Max: 1 · Default: 0.5 |
scheduler | string | Optional | Scheduler to use for the generation process. · Options: euler, heun · Default: "euler" eulerheun |
start_time | number | Optional | start time in seconds for the inpainting process. · Min: 0 · Max: 240 · Default: 0 |
guidance_type | string | Optional | Type of CFG to use for the generation process. · Options: cfg, apg, cfg_star · Default: "apg" cfgapgcfg_star |
guidance_scale | number | Optional | Guidance scale for the generation. · Min: 0 · Max: 200 · Default: 15 |
number_of_steps | integer | Optional | Number of steps to generate the audio. · Min: 3 · Max: 60 · Default: 27 |
granularity_scale | integer | Optional | Granularity scale for the generation process. Higher values can reduce artifacts. · Min: -100 · Max: 100 · Default: 10 |
guidance_interval | number | Optional | Guidance interval for the generation. 0.5 means only apply guidance in the middle steps (0.25 * infer_steps to 0.75 * infer_steps) · Min: 0 · Max: 1 · Default: 0.5 |
tag_guidance_scale | number | Optional | Tag guidance scale for the generation. · Min: 0 · Max: 10 · Default: 5 |
end_time_relative_to | string | Optional | Whether the end time is relative to the start or end of the audio. · Options: start, end · Default: "start" startend |
lyric_guidance_scale | number | Optional | Lyric guidance scale for the generation. · Min: 0 · Max: 10 · Default: 1.5 |
minimum_guidance_scale | number | Optional | Minimum guidance scale for the generation after the decay. · Min: 0 · Max: 200 · Default: 3 |
start_time_relative_to | string | Optional | Whether the start time is relative to the start or end of the audio. · Options: start, end · Default: "start" startend |
guidance_interval_decay | number | Optional | Guidance interval decay for the generation. Guidance scale will decay from guidance_scale to min_guidance_scale in the interval. 0.0 means no decay. · Min: 0 · Max: 1 · Default: 0 |
02
Output Schema
| Field | Type | Description |
|---|---|---|
id | string | Unique identifier for the generation task |
status | string | Task status: pending, running, completed, failed, timeout |
model | string | Model used for the generation |
outputs | array | Array of output items |
outputs[].url | string | URL of the generated artifact |
outputs[].content_type | string | MIME type (e.g. image/png, video/mp4) |
error | object | null | Error details if failed, null on success |
error.type | string | Machine-readable error type code |
error.message | string | Human-readable error description |
Async Workflow
This model uses asynchronous execution. Submit a request and poll for the result.
- Submit — POST to /v1/run, receive an
id - Poll — GET /v1/run/{id} until status is
completed,failed, ortimeout - Retrieve — Read
outputsfrom the completed response
03
Code Examples
Ready-to-run snippets
# Step 1: Submit
curl -X POST https://api.sandbase.ai/v1/run \
-H "Content-Type: application/json" \
-H "Authorization: Bearer YOUR_API_KEY" \
-d '{
"model": "ace/ace-step/audio-inpaint",
"tags": "lofi, hiphop, drum and bass, trap, chill",
"audio": "https://static.sandbase.ai/examples/ace/ace-step/audio-inpaint/input_audio_0.wav",
"lyrics": "",
"end_time": 30,
"variance": 0.5,
"scheduler": "euler",
"start_time": 0,
"guidance_type": "apg",
"guidance_scale": 15,
"number_of_steps": 27,
"granularity_scale": 10,
"guidance_interval": 0.5,
"tag_guidance_scale": 5,
"end_time_relative_to": "start",
"lyric_guidance_scale": 1.5,
"minimum_guidance_scale": 3,
"start_time_relative_to": "start",
"guidance_interval_decay": 0,
"prompt": "a beautiful sunset over mountains"
}'
# Step 2: Poll result (replace <id>)
curl https://api.sandbase.ai/v1/run/<id> \
-H "Authorization: Bearer YOUR_API_KEY"API README
ACE-Step
ACE-Step Audio Inpaint regenerates a selected time region inside an existing audio file while keeping the surrounding material as context. It is intended for repairing or rewriting a musical passage without rebuilding the entire track from the beginning.
Creators can define the replacement interval relative to the start or end, then guide the new passage with tags, lyrics, and a variance setting. The broader ACE-Step sampling and guidance controls remain available for balancing continuity with creative change.
Highlights
Time-range regeneration. Replaces a chosen region inside existing audio instead of regenerating the whole track.
Context-aware continuity. Uses the surrounding recording to help the repaired section connect with adjacent music.
Controllable variation. A variance control balances faithfulness to the source against a more substantial rewrite.
Music-aware guidance. Tags, lyrics, seed, scheduler, and separate guidance scales shape the inserted passage.
Pricing
| Billing unit | Price |
|---|---|
| Per generated second | $0.0002 |
When to Use
| ✅ Good fit | ❌ Consider alternatives |
|---|---|
| A selected time region in existing audio needs regeneration | The entire track should be recomposed |
| A managed asynchronous result is suitable for the production pipeline | A synchronous, interactive editor is essential |
| The documented controls cover the required duration, framing, or format | The project needs controls outside this endpoint's schema |
| Creative iteration benefits from a repeatable request structure | Exact deterministic pixels, frames, geometry, or samples are mandatory |
| A finished downloadable media asset is the desired deliverable | Editable source layers or a native project file are required |
Prompt Guide
For music generation, state the intended result first, then add the subject or source treatment, progression, style, and delivery constraints. Keep one creative variable per phrase, use the documented field names for controls, and change one setting at a time when comparing results.
{
"audio": "https://static.sandbase.ai/examples/ace/ace-step/audio-inpaint/input_audio_0.wav"
}
Technical Specs
| Spec | Value |
|---|---|
| Model ID | ace/ace-step/audio-inpaint |
| Inputs | audio, end_time, end_time_relative_to, granularity_scale, guidance_interval, guidance_interval_decay, guidance_scale, guidance_type, lyric_guidance_scale, lyrics, minimum_guidance_scale, number_of_steps, scheduler, seed, start_time, start_time_relative_to, tag_guidance_scale, tags, variance |
| Required inputs | None |
| Output fields | content_type, url |
| Execution | Async (submit, then poll for result) |
Related Models
ace/ace-step— Compare a nearby route in the same local model family.ace/ace-step/audio-outpaint— Compare a nearby route in the same local model family.ace/ace-step/audio-to-audio— Compare a nearby route in the same local model family.