ByteDance Seedance 2.0 Fast First Last Frame (Official Edition)

First-last-frame generation is where you go when you need a clip to start at A and end at B - and the Fast tier does it at a speed and price that make it painless to iterate. This is the Official Edition of that node, which in BizyAir terms means it calls the vendor's official Seedance API surface (seedance-2-0-fast-official/flf-to-video) rather than BizyAir's own channel. Same key, same gateway, but the parameter layout mirrors ByteDance's official API - aspect_ratio instead of ratio, duration as a dropdown rather than a free integer, and a 720p default instead of the channel edition's upscale-heavy 2k.

What that means in practice

Both editions produce the same model's output. The Official edition is the one to use when you want the vendor's documented behavior and don't need the channel's super-resolution tiers - its resolution list tops out at 720p by default, which is honest for a Fast draft tier. The Channel edition hands you the upscale options and free-form duration. Pick per workflow: if you're drafting and want the simplest, vendor-spec defaults, this node is it.

How it works

Cloud execution through BizyAir: your first-frame image (and optional last frame) upload to api.bizyair.ai, the job runs on the official Fast FLF endpoint, and the clip downloads back as a native ComfyUI VIDEO. No local model, no VRAM, metered billing.

Inputs that matter

• first_frame_url - the required starting image; everything the model invents flows from it.
• last_frame_url - the optional ending image (one image, up to 30 MB) to force a specific destination.
• prompt - the motion in between, in plain action language.
• resolution - defaults to 720p here (the vendor-spec ceiling for this tier).
• duration - a dropdown, default "10" seconds. The official API presents duration as a fixed choice set, so it's pick-from-a-list rather than dial-in.
• aspect_ratio - default 16:9.
• seed - integer, default 0.
• generate_audio - default on.
• api_config / skip_error - per-request key/base override and placeholder-on-error.

Outputs: video, request_id, urls.

Install and first run

ComfyUI Manager → "BizyAirPlus", or:

cd /path/to/ComfyUI/custom_nodes
git clone https://github.com/siliconflow/BizyAirPlus.git
cd BizyAirPlus
python -m pip install -r requirements.txt

Restart, register at bizyair.ai, set the key in Settings > BizyAirPlus > API Key (or BIZYAIR_API_KEY), and flip the BizyAirPlus action-bar toggle ON.

Gotchas

The usual setup trio - missing key, toggle off, wrong Python (python -m pip show bizyair-cloudberry). FLF-specific: keep the first and last frames stylistically consistent or the middle will visibly reconcile two different images. And a practical note on the official API surface: because duration is a dropdown here, don't go hunting for a precise 7-second option if the list doesn't offer it - pick the nearest preset, or switch to the Channel edition node if exact durations matter more than vendor-spec behavior.