ComfyUI Node
arkennemasis fal · Flux 3 First Last Frame to Video Draft · $0.06/s
FLUX.3 is Black Forest Labs' frontier audio/video model. Generate fast, low-cost draft previews between a start and an end frame, with a reusable draft cache for full-quality enhancement. Pricing (from fal, 2026-09-29): Your request will be charged at 0.06 $ per second of generated draft video (720p). Model page: https://fal.ai/models/blackforestlabs/flux-3/first-last-frame-to-video/draft Key: FAL_KEY in the .env next to run_nvidia_gpu.bat. Results are saved in output/fal/blackforestlabs_flux-3_first-last-frame-to-video_draft/.
arkennemasis fal · Flux 3 First Last Frame to Video Draft · $0.06/s
- start_image
- end_image
- video
- video_path
- draft_cache_path
- info
◄prompt►
◄aspect_ratioauto►
◄duration5►
◄generate_audiotrue►
◄safety_tolerance2►
◄max_cost_usd20.0►
◄reuse_identical_runtrue►
◄extra_json►
◄max_concurrent1►
Categoryarkennemasis/fal/Video/Flux
Inputs (11)
| Name | Type | Default | Description |
|---|---|---|---|
| prompt | STRING | The text prompt describing the draft video. | |
| aspect_ratio | COMBO | auto | Aspect ratio of the generated draft. `auto` lets the model choose. |
| duration | COMBO | 5 | Draft duration in whole seconds from 5 through 20. An explicit duration pins the two images to the video boundaries. |
| generate_audio | BOOLEAN | true | Whether to generate audio for the draft video. |
| safety_tolerance | INT | 20–4 | The safety tolerance level for the generated video. 0 is the strictest and 4 is the most permissive. |
| start_image | IMAGE | URL or data URI of the image used as the first frame of the draft. | |
| end_image | IMAGE | URL or data URI of the image used as the last frame of the draft. | |
| max_cost_usdopt | FLOAT | 20.00–100000 | Safety cap. If the estimated cost of this run is above this many US dollars the node stops BEFORE sending anything to fal. 0 = no cap. |
| reuse_identical_runopt | BOOLEAN | true | If these exact inputs (the settings AND the same pictures/clips/audio) were already paid for and the files are still in output/fal, return them instead of paying again - also after a ComfyUI restart. Turn off for a fresh take with the same settings. |
| extra_jsonopt | STRING | Advanced: a JSON object merged into the request last, for any fal field this node has no box for. Example: {"seed": 7}. Leave empty normally. | |
| max_concurrentopt | INT | 11–32 | How many paid fal calls may run at the same time in one run, across every fal node. 1 (default) = one after another. This node starts its paid part only while fewer than this many fal calls are running. Once any fal node fails, the ones still waiting are not started, so nothing more is billed. |
Outputs (4)
| Name | Type | Description |
|---|---|---|
| video | VIDEO | — |
| video_path | STRING | — |
| draft_cache_path | STRING | — |
| info | STRING | JSON: request id, cost estimate, saved files and fal's full answer. |