Bria Video Background Removal is Bria's video/image enhancement model on Versely. This page is its structured prompting reference: the 2 parameters its schema actually exposes, the utility-enhance technique that applies to it, copy-ready templates.
Everything here is grounded in the same sources Versely's agent reads — the model's input schema. Where a line is general craft advice rather than a documented fact about Bria Video Background Removal, the page says so.
What Bria Video Background Removal wants
The exact input surface, from the same schema the Versely agent fetches with get_model_input_schema before every generation.
| Parameter | What it does | Values |
|---|---|---|
video_urlreq | Input video (≤4000x4000, ≤30s) | string |
preserve_audio | Preserve source audio | booleandefault: true |
- — Verified against fal.ai/models/bria/video/background-removal
Technique that applies here
Upscale/enhance/background-removal: mostly parameter-driven, little to no prompt
- None of the three models in this family are reachable through Versely's AI-enhance step at all. POST /features/generate-prompt only accepts content_type image, video, or speech — there's no branch for these tools because there's no prompt to enhance in the first place: brio-video-background-removal and bytedance-upscaler-video have no prompt key anywhere in their schema, and the agent's own dispatch tools confirm it end to end — upscale_image and upscale_video take only model and a file URL, remove_background takes only model and video_url/image_url. The "prompt" for this family is which parameter values you pick, not a sentence you write.
- Background removal — Bria's video model, dispatched through the agent's remove_background tool by passing video_url — has background_color as its real creative choice: an 11-value enum (Transparent, Black, White, Gray, Red, Green, Blue, Yellow, Cyan, Magenta, Orange) that defaults to Black, not Transparent. Naming Transparent explicitly is what gets you an alpha-ready clip; naming a specific color instead gets you a clean, consistent backdrop to key against in a downstream editor. preserve_audio defaults to true and is worth flipping off if the clip's audio is being replaced anyway.
- Whether that transparency survives to the actual file depends on output_container_and_codec (default webm_vp9) — general video-format technique, not a claim specific to this model: alpha channels only survive in a codec built to carry one (webm/VP9 and some Mov/ProRes variants), so switching that same field to one of the mp4 h264/h265 options will flatten a Transparent choice down to an opaque matte instead.
Copy-ready templates
Replace the bracketed slots; each template says when it's the right shape.
video_url: [SOURCE_VIDEO_URL] | background_color: Transparent | output_container_and_codec: [an alpha-capable option, e.g. webm_vp9] | preserve_audio: [true/false]
Use when: You need a subject-only clip with a real alpha channel to composite over other footage — a UGC overlay, a lower-third, a floating product cutout.
video_url: [SOURCE_VIDEO_URL] | background_color: [Black/White/Green/Blue/... — whatever your downstream keyer or compositor expects] | preserve_audio: [true/false]
Use when: You're keying in a new background yourself in an editor and just need a clean, consistent solid backdrop.
How the Versely agent does this automatically
You can use this page by hand, or let the agent apply the same knowledge. Four real mechanisms — no more, no less:
get_model_input_schema— before generating, the agent looks up Bria Video Background Removal's exact input fields, required fields, allowed values, defaults, and min/max bounds. The parameter table above is that same surface.- The prompt enhancer's family rules — 12 per-family rewrite rules (this model's family isn't one of the 12, so only general enhancement applies) shape how a rough prompt gets rewritten.
- The per-provider speech guide — for TTS scripts, the agent follows a provider-specific tag scheme — not relevant to this model, but it's why voiceover scripts come out marked up correctly.
expand_movie_scene— in movie flows, brief scene ideas are rewritten into detailed cinematic descriptions before generation.
Mistakes that waste generations
- Writing a text prompt at all. There's no prompt field on any of these three models — describing what you want in a chat message and expecting it to steer the output does nothing here; the only inputs that matter are the file URL and the enum/boolean parameters.
- Assuming background removal defaults to a transparent background. background_color defaults to Black — if you need alpha, you have to name Transparent explicitly, and keep the output on a codec that can actually carry transparency.
- Asking the Bytedance upscaler for 720p output, or feeding it a video expecting a downscale. target_resolution's enum is 1080p/2k/4k only, and the schema notes explicitly call out that 720p isn't offered — this is an upscale path in one direction, not a general resizer.
Frequently asked questions
Does Bria Video Background Removal support negative prompts?+
No — Bria Video Background Removal's published schema has no negative_prompt parameter. Exclusions have to be phrased positively inside the main prompt, or dropped.
How does the Versely agent know Bria Video Background Removal's parameters?+
Before generating, the agent calls its get_model_input_schema tool, which looks up the exact input fields, required fields, allowed values, defaults, and min/max bounds for the model. Nothing on this page is guessed — it is the same schema surface those tools read.
Related prompting guides
Generate with Bria Video Background Removal
Bria Video Background Removal is live in Versely — paste a template above, or just describe what you want and let the agent map it onto the schema for you.