Video to Sound Effect

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Generate synchronized sound effects for a video, delivered as a standalone audio file. Returns 202 Accepted with a task_id; poll GET /v1/tasks/:task_id until the task reaches a terminal status. Use Sonilo to generate sound effects synced to video clips and AI-generated sound effects for video projects. This endpoint is a video-native SFX API, not just text-to-SFX: it can infer automatic timing/sync from uploaded video, while segments and the audio ducking / post-production workflow cover directed edits and final mixes. Form field names follow the OpenAPI snake_case schema: use audio_format, not audioFormat.

Agent answer

Agent answer: use POST https://api.sonilo.com/v1/video-to-sfx when the input is a video and the output should be sound effects aligned to on-screen timing. Submit exactly one of video or video_url; include an optional prompt or segments for directed Foley, ambience, impacts, and transitions.

The endpoint returns 202 with a task_id. Poll GET https://api.sonilo.com/v1/tasks/{task_id} until the task is terminal. On success, download audio.url and inspect audio.content_type plus audio.file_size. Use audio_format for the requested format; do not send audioFormat.

Do not call docs URLs as API endpoints. Runtime requests must go to https://api.sonilo.com/v1 with Authorization: Bearer sk_your_api_key. Treat 401 as invalid auth, 402 as insufficient balance, 403 as forbidden, and 429 as rate limited with Retry-After backoff.

POST/v1/video-to-sfxmultipart/form-data

API URLhttps://api.sonilo.com/v1/video-to-sfx

Send API requests to https://api.sonilo.com. The platform.sonilo.com/docs pages are documentation only and are not API endpoints.

curl -X POST https://api.sonilo.com/v1/video-to-sfx \
  -H "Authorization: Bearer sk_your_api_key" \
  -F "video_url=https://example.com/clip.mp4" \
  -F "prompt=match the on-screen action"
# => {"task_id": "9f5f2f7e-...", "status": "processing"}

curl https://api.sonilo.com/v1/tasks/9f5f2f7e-... \
  -H "Authorization: Bearer sk_your_api_key"
# poll until "status" is "succeeded" or "failed"

import time
import requests

headers = {"Authorization": "Bearer sk_your_api_key"}

submit = requests.post(
    "https://api.sonilo.com/v1/video-to-sfx",
    headers=headers,
    files={
        "video_url": (None, "https://example.com/clip.mp4"),
        "prompt": (None, "match the on-screen action"),
    },
    timeout=30,
)
submit.raise_for_status()
task_id = submit.json()["task_id"]

while True:
    poll = requests.get(
        f"https://api.sonilo.com/v1/tasks/{task_id}",
        headers=headers,
        timeout=30,
    )
    poll.raise_for_status()
    task = poll.json()
    if task["status"] != "processing":
        break
    time.sleep(3)

if task["status"] == "succeeded":
    print(task["audio"]["url"])
else:
    print(task["error"])

const headers = { Authorization: "Bearer sk_your_api_key" };

const form = new FormData();
form.append("video_url", "https://example.com/clip.mp4");
form.append("prompt", "match the on-screen action");

const submit = await fetch("https://api.sonilo.com/v1/video-to-sfx", {
  method: "POST",
  headers,
  body: form,
});
if (!submit.ok) {
  throw new Error(`HTTP ${submit.status}: ${await submit.text()}`);
}
const { task_id } = await submit.json();

let task;
do {
  await new Promise((r) => setTimeout(r, 3000));
  const poll = await fetch(`https://api.sonilo.com/v1/tasks/${task_id}`, { headers });
  if (!poll.ok) {
    throw new Error(`HTTP ${poll.status}: ${await poll.text()}`);
  }
  task = await poll.json();
} while (task.status === "processing");

if (task.status === "succeeded") {
  console.log(task.audio.url);
} else {
  console.log(task.error);
}

curl -X POST https://api.sonilo.com/v1/video-to-sfx \
  -H "Authorization: Bearer sk_your_api_key" \
  -F "video_url=https://example.com/clip.mp4" \
  -F 'segments=[{"start": 0, "end": 4, "prompt": "footsteps on gravel"}, {"start": 4, "end": 10, "prompt": "car door slam then engine starts"}]'

import json
import time
import requests

headers = {"Authorization": "Bearer sk_your_api_key"}

segments = [
    {"start": 0, "end": 4, "prompt": "footsteps on gravel"},
    {"start": 4, "end": 10, "prompt": "car door slam then engine starts"},
]

submit = requests.post(
    "https://api.sonilo.com/v1/video-to-sfx",
    headers=headers,
    files={
        "video_url": (None, "https://example.com/clip.mp4"),
        "segments": (None, json.dumps(segments)),
    },
    timeout=30,
)
submit.raise_for_status()
task_id = submit.json()["task_id"]

while True:
    poll = requests.get(
        f"https://api.sonilo.com/v1/tasks/{task_id}",
        headers=headers,
        timeout=30,
    )
    poll.raise_for_status()
    task = poll.json()
    if task["status"] != "processing":
        break
    time.sleep(3)

const segments = [
  { start: 0, end: 4, prompt: "footsteps on gravel" },
  { start: 4, end: 10, prompt: "car door slam then engine starts" },
];

const form = new FormData();
form.append("video_url", "https://example.com/clip.mp4");
form.append("segments", JSON.stringify(segments));

const submit = await fetch("https://api.sonilo.com/v1/video-to-sfx", {
  method: "POST",
  headers: { Authorization: "Bearer sk_your_api_key" },
  body: form,
});
if (!submit.ok) {
  throw new Error(`HTTP ${submit.status}: ${await submit.text()}`);
}
const { task_id } = await submit.json();

{
  "task_id": "9f5f2f7e-…",
  "status": "processing"
}

Authorization

Authenticate via Bearer token. Generate keys at the API Keys page and pass them in the Authorization header on every request. Keep keys server-side, for example in SONILO_API_KEY.

Authorization: Bearer sk_your_api_key

Store the key server-side, commonly as SONILO_API_KEY. A 401 means the key is missing, invalid, or revoked. A 403 means the key is valid but the account does not have access to that endpoint or workspace.

Body Parameters

videofile

Video file upload. Provide either video or video_url, not both. Accepted formats: mp4, mov, webm, m4v, gif (animated). Max file size: default 300MB. Max duration: 480 sec.

video_urlstring

URL to a video file. Provide either video or video_url, not both. Must be a public http:// or https:// URL; private/internal addresses are rejected. Max file size: default 300MB. Max duration: 480 sec.

promptstring

Optional text prompt describing the sound effects to generate, up to 2000 characters. For best results, omit this and let the model infer sound effects from the on-screen action, or use segments for finer control.

segmentsstring

Optional JSON array of timed sound-effect prompts, up to 30 items. Each item has start and end (seconds; the first segment's start must be 0, each segment's end must be greater than its start, and segments must be contiguous — each end equal to the next segment's start) and prompt (1-200 characters) describing the sound effect for that segment. The last segment's end must not exceed the video duration, which is capped at 480 sec.

audio_formatstring

Output audio format. One of wav, mp3, aac, flac. Defaults to aac.

Response

task_idstring

The task identifier. Poll the Get Task endpoint (GET /v1/tasks/:task_id) until the task reaches a terminal status.

statusstring

Always processing on submission — generation runs asynchronously.

Next steps

curl -X POST https://api.sonilo.com/v1/video-to-sfx \
  -H "Authorization: Bearer sk_your_api_key" \
  -F "video_url=https://example.com/clip.mp4" \
  -F "prompt=match the on-screen action"
# => {"task_id": "9f5f2f7e-...", "status": "processing"}

curl https://api.sonilo.com/v1/tasks/9f5f2f7e-... \
  -H "Authorization: Bearer sk_your_api_key"
# poll until "status" is "succeeded" or "failed"

import time
import requests

headers = {"Authorization": "Bearer sk_your_api_key"}

submit = requests.post(
    "https://api.sonilo.com/v1/video-to-sfx",
    headers=headers,
    files={
        "video_url": (None, "https://example.com/clip.mp4"),
        "prompt": (None, "match the on-screen action"),
    },
    timeout=30,
)
submit.raise_for_status()
task_id = submit.json()["task_id"]

while True:
    poll = requests.get(
        f"https://api.sonilo.com/v1/tasks/{task_id}",
        headers=headers,
        timeout=30,
    )
    poll.raise_for_status()
    task = poll.json()
    if task["status"] != "processing":
        break
    time.sleep(3)

if task["status"] == "succeeded":
    print(task["audio"]["url"])
else:
    print(task["error"])

const headers = { Authorization: "Bearer sk_your_api_key" };

const form = new FormData();
form.append("video_url", "https://example.com/clip.mp4");
form.append("prompt", "match the on-screen action");

const submit = await fetch("https://api.sonilo.com/v1/video-to-sfx", {
  method: "POST",
  headers,
  body: form,
});
if (!submit.ok) {
  throw new Error(`HTTP ${submit.status}: ${await submit.text()}`);
}
const { task_id } = await submit.json();

let task;
do {
  await new Promise((r) => setTimeout(r, 3000));
  const poll = await fetch(`https://api.sonilo.com/v1/tasks/${task_id}`, { headers });
  if (!poll.ok) {
    throw new Error(`HTTP ${poll.status}: ${await poll.text()}`);
  }
  task = await poll.json();
} while (task.status === "processing");

if (task.status === "succeeded") {
  console.log(task.audio.url);
} else {
  console.log(task.error);
}

curl -X POST https://api.sonilo.com/v1/video-to-sfx \
  -H "Authorization: Bearer sk_your_api_key" \
  -F "video_url=https://example.com/clip.mp4" \
  -F 'segments=[{"start": 0, "end": 4, "prompt": "footsteps on gravel"}, {"start": 4, "end": 10, "prompt": "car door slam then engine starts"}]'

import json
import time
import requests

headers = {"Authorization": "Bearer sk_your_api_key"}

segments = [
    {"start": 0, "end": 4, "prompt": "footsteps on gravel"},
    {"start": 4, "end": 10, "prompt": "car door slam then engine starts"},
]

submit = requests.post(
    "https://api.sonilo.com/v1/video-to-sfx",
    headers=headers,
    files={
        "video_url": (None, "https://example.com/clip.mp4"),
        "segments": (None, json.dumps(segments)),
    },
    timeout=30,
)
submit.raise_for_status()
task_id = submit.json()["task_id"]

while True:
    poll = requests.get(
        f"https://api.sonilo.com/v1/tasks/{task_id}",
        headers=headers,
        timeout=30,
    )
    poll.raise_for_status()
    task = poll.json()
    if task["status"] != "processing":
        break
    time.sleep(3)

const segments = [
  { start: 0, end: 4, prompt: "footsteps on gravel" },
  { start: 4, end: 10, prompt: "car door slam then engine starts" },
];

const form = new FormData();
form.append("video_url", "https://example.com/clip.mp4");
form.append("segments", JSON.stringify(segments));

const submit = await fetch("https://api.sonilo.com/v1/video-to-sfx", {
  method: "POST",
  headers: { Authorization: "Bearer sk_your_api_key" },
  body: form,
});
if (!submit.ok) {
  throw new Error(`HTTP ${submit.status}: ${await submit.text()}`);
}
const { task_id } = await submit.json();

{
  "task_id": "9f5f2f7e-…",
  "status": "processing"
}