Seedance 2.5 audio reference: how to send an audio clip
Seedance 2.5 accepts an audio clip as a reference, even without an image or video. The audio_url request on Sume, the vendor's file limits and what to expect.

Seedance 2.5 accepts an audio clip as a reference, and BytePlus's tutorial says an audio-only reference is supported on 2.5 while 2.0 needs an image or video alongside it. On Sume, add an audio_url entry to input_references on seedance-2.5.
Sume's catalog for seedance-2.5 lists image_url, video_url and audio_url as accepted reference types, per its video docs.
How do I send an audio reference?
Host the file at a public HTTPS URL and refer to it in the prompt. Sume normalizes tags like @audio1 to the casing the model expects.
curl -X POST https://api.sume.com/v1/videos \
-H "Authorization: Bearer $SUME_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "seedance-2.5",
"prompt": "A drummer plays in a small club, cuts match the beat of @audio1",
"duration": 10,
"resolution": "720p",
"aspect_ratio": "16:9",
"generate_audio": true,
"input_references": [
{"type": "audio_url", "audio_url": {"url": "https://example.com/beat.mp3"}}
]
}'What audio files does the vendor accept?
The ModelArk tutorial sets these limits.
| Limit | Value |
|---|---|
| Clips | Up to 10 |
| Length per clip | 2 to 30 s |
| Total length | Up to 30 s |
| Formats | wav, mp3 |
| Size per file | Up to 15 MB |
Does the reference audio become the soundtrack?
Do not assume it. The reference guides the generation; whether it appears unchanged in the output is not documented on either page. Check a short 480p clip first, and use generate_audio to control whether the model produces sound; see AI video with sound.
Sources
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ByteDance Seed launched Seedance 2.5 on 2026-07-31 in its own apps. The model id seedance-2.5 is in Sume's video catalog. Dates and access, read 2026-09-29.
Written by Sume