Video to Music

POST 
https://api.knoxstudio.ai/v1/music/video-to-music

Generate a soundtrack matched to uploaded video. Videos are combined in order. Max 10 videos, 200MB combined, 210MB multipart payload. Billed at $0.20/min. output_format uses the stem allow-list (no auto, no 48 kHz MP3).

Request

Query Parameters

Name	Type	Required	Description
output_format	String	No	Allowed: mp3_22050_32, mp3_24000_48, mp3_44100_32, mp3_44100_64, mp3_44100_96, mp3_44100_128, mp3_44100_192, pcm_8000, pcm_16000, pcm_22050, pcm_24000, pcm_32000, pcm_44100, pcm_48000, ulaw_8000, alaw_8000, opus_48000_32, opus_48000_64, opus_48000_96, opus_48000_128, opus_48000_192.

Request Headers

Name	Type	Required	Description
Authorization	String	Yes	Bearer <token> Knox API key. xi-api-key is also accepted.
Content-Type	String	Yes	multipart/form-data.

Request Body (multipart/form-data)

Name	Type	Required	Description
videos	Files	Yes	One or more video files (videos FormData array). Combined in order.
description	String	No	Music description, max 1000 characters.
tags	List of Strings	No	Style tags, max 10 (for example upbeat, cinematic).
model_id	String	No	music_v1, music_v2, or music_v2_5.
sign_with_c2pa	Boolean	No	C2PA sign MP3 output.

cURL Example

curl -X POST "https://api.knoxstudio.ai/v1/music/video-to-music?output_format=mp3_44100_128" \
     -H "Authorization: Bearer $KNOXCHAT_API_KEY" \
     -F "videos=@clip1.mp4" \
     -F "videos=@clip2.mp4" \
     -F "description=Warm cinematic score, no vocals" \
     -F "tags=cinematic" \
     -F "tags=orchestral" \
     -F "model_id=music_v2_5" \
     -o score.mp3

Response

Success Response (200)

Generated audio file. Content-Type follows output_format (default MP3).

Error Responses

Validation uses HTTP 422:

{
  "detail": [
    {
      "loc": ["body", "field"],
      "msg": "…",
      "type": "value_error"
    }
  ]
}

Other errors use { "detail": "message" }.

Status	When
400	WebSocket path called without Upgrade: websocket.
401	Missing or invalid API key.
402	Insufficient credits.
403	Token is not allowed to use this model.
404	Resource not found.
422	Validation error.
429	Rate limit exceeded.
500	Internal server error.