| prompt | STRING | | The text prompt used to generate the video |
| resolution | COMBO | 720p | Video resolution - 480p for faster generation, 720p for balance, 1080p for high quality. |
| duration | COMBO | auto | Duration of the video in seconds. Supports 4 to 30 seconds, or auto to let the model decide based on the prompt. |
| aspect_ratio | COMBO | auto | The aspect ratio of the generated video. Use 16:9 for landscape, 9:16 for portrait/vertical, 1:1 for square, 21:9 for ultrawide cinematic, or auto to let the model decide. |
| generate_audio | BOOLEAN | true | Whether to generate synchronized audio for the video, including sound effects, ambient sounds, and lip-synced speech. The cost of video generation is the same regardless of whether audio is generated or not. |
| bitrate_mode | COMBO | standard | Output bitrate mode. 'high' requests a higher-quality, larger-file encode from the model; 'standard' uses the default bitrate. |
| codec | COMBO | auto | 'auto' retains default video codec behaviour; 'H264' uses H.264; 'H265' uses H.265. |
| 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. |
