Veo 3.1 Fast on eroq (formerly Veo 3 Fast): writing prompts for native sound

Veo 3 Fast was retired on eroq: it now renders on Veo 3.1 Fast, and old links and API ids land there. Veo returns a clip with sound — ambience, effects and dialogue rendered with the picture — and that changes how you write the prompt. Sound is no longer rare on the roster (most third-party engines render it now), but Veo is the family people pick for it. The spec: 4, 6 or 8 seconds, 720p or 1080p, 344 credits for 8 seconds with sound at 720p, Hobby plan and up, moderated upstream by its provider. This guide is mostly about the writing.

What "native sound" means

Native means the soundtrack is generated with the image, from the same prompt, as part of the same render. There is no library of stock clips laid under the video afterward, and no separate audio step to pay for. You describe a shot; you get the shot and what it sounds like.

Three layers come back:

• Ambience — the room tone. Rain, traffic, a crowd, wind, the hum of a fridge.
• Effects — sounds tied to things happening on screen. A door, footsteps, a brake squeal, a glass set down.
• Dialogue — a spoken line from a person in the frame.

One boundary to say plainly: eroq does not offer a lip-sync feature. Dialogue on Veo is a line the engine performs inside the shot, not a tool for matching a recorded voice to a face. Keep lines short and treat the result as a rendered take.

The numbers

• Length: 4, 6 or 8 seconds.
• Resolution: 720p (the default) or 1080p.
• Sound: on by default; switch the Soundtrack off for a cheaper silent clip.
• Price: 43 credits / second with sound at 720p: 344 credits for 8 seconds, about $3.44 at the entry pack, where a credit is roughly a cent.
• Formats: 16:9 and 9:16.
• Modes: text-to-video, image-to-video from a first frame, a last frame or both, up to three reference pictures, and a seed.
• Plan: Hobby ($15, 1,800 credits) and up. Veo 3.1 on Creator renders at full quality; Veo 3.1 Lite runs on every account.
• Content: moderated upstream by the provider; a refused prompt returns content_blocked and costs nothing. When the provider refuses, Motion One — eroq's own uncensored engine, on every account — is the alternative.

A Hobby month is 5 eight-second Veo 3.1 Fast clips if you spend it on nothing else. Failed renders refund automatically and unused credits roll over.

Writing for audio

The visual half of the prompt follows the same register as every engine on eroq: one flowing paragraph — subject, motion, camera, light, mood — 30 to 80 words. Then you add the sound, and the useful habit is to write it as a second, shorter sentence at the end, in the same order as the layers above.

Ambience first. Name the space and what it sounds like. "Steady rain on a station canopy." "Low chatter and an espresso machine." One or two elements — an 8-second clip can't hold a soundscape.

Effects tied to actions you already wrote. If the visual says "the doors hiss open," the sound sentence can say "the door chime and her footsteps on wet concrete." Sound with no visible cause tends to wander; sound that lands on an action tends to land.

Dialogue in quotes, attributed. One line, under ten words, with who says it. Eight seconds is one line, maybe two. Write the line the way the character would say it, not the way a script summarizes it.

Silence is a choice. If you want no dialogue, don't leave a person's mouth idle in the prompt — give them something to do. If you want a quiet room, say "quiet" and name the one sound that is there.

What to skip: music. The engine renders what is in the scene; if you want a score, that is an edit you make afterward. And don't stack adjectives on the sound ("epic, cinematic, immersive audio") — name sources instead.

Example prompts

Ambience and effects, no dialogue, 16:9:

A night train pulls into a rain-soaked platform, brakes squealing as the doors hiss open and a single passenger steps down under the yellow station lamps, pulling her coat closed against the wind. Wide static shot from the far end of the platform, neon noir palette, calm and lonely. Sound of steady rain on the canopy, the brake squeal, the door chime and her footsteps on wet concrete.

Settings: 8 s, 16:9, 1080p, Lighting Practicals, Palette Neon noir; the static camera is already in the prompt.

One line of dialogue, 9:16:

A barista in a small, quiet coffee shop slides a cup across the counter to a customer, glances at the rain outside and says, "Third one today, and it's not even noon." Close-up on the counter, soft cross lighting, warm film palette, gentle and dry. Ambience of an espresso machine hissing, low chatter and rain against the window.

Settings: 8 s, 9:16, Lighting Soft cross, Palette Warm film; the close-up is already in the prompt.

Both prompts put the sound sentence last and tie every effect to something visible. That is the whole method.

Where Veo fits

Eight seconds with sound is a specific shape, and a few jobs fit it exactly:

• Ads. In the Ads Studio, a video ad is a format (UGC testimonial is the first of eight), your product, a presenter and one spoken line, and the studio starts on an engine that speaks and sees the product photo, which Veo does. A testimonial is one person, one line, room tone: an 8-second Veo clip, in other words. The AI ad generator page walks through the flow and UGC ads are the obvious use.
• Shots in a film. Cinema builds a film in its Story tab, scene by scene and shot by shot, up to 24 shots. A Veo shot brings its own sound into the cut. The API side is /docs/films.
• Product moments. A bottle opened, a zipper pulled, a laptop closed — actions with a signature sound.

Where it doesn't fit: anything longer than 8 seconds, square or 21:9 frames, and anything its provider refuses. For long shots, Seedance 2.5 is the engine — /compare/seedance-vs-veo-3 has the side-by-side. The engine page at /models/veo-3-1-fast keeps the current spec.

FAQ

Does Veo 3.1 Fast on eroq generate audio?

Yes. It renders a soundtrack — ambience, effects and dialogue — with the picture, from the same prompt. Sound is on by default and can be switched off for a cheaper silent clip. Many other engines on the roster render sound too; Veo is the one this guide writes for.

How long is a Veo 3.1 Fast clip?

4, 6 or 8 seconds. For longer takes, pick another engine from the roster: Seedance 2.5 and Wan 3.0 go to 30 seconds, plan permitting.

How much does a Veo 3.1 Fast clip cost?

344 credits for 8 seconds with sound at 720p, about $3.44 at the entry pack. It is unlocked on the Hobby plan and up, and failed renders are refunded automatically.

Write the shot, add the sound sentence, and render it — /studio/video.