Will my video get longer after interpolation?

No. The workflow multiplies the output FPS to match the interpolation factor (output_fps = input_fps × factor), so total duration remains the same. This rule is highlighted in the MarkdownNote.

What interpolation factor should I use?

Start with 2x for most footage. Use 3x if you need extra smoothness and the motion is not too complex. Very high factors increase compute time and can introduce ghosting or artifacts on fast action and occlusions.

Can I keep the original audio?

If your VHS_VideoCombine node supports audio passthrough, point it to the original audio or enable the appropriate option to mux it into the output. If not, export the video and remux the audio with a tool like ffmpeg using the original track.

How do I make slow motion instead of keeping the same duration?

This workflow is set up to preserve duration by raising the FPS. For slow motion, keep the output FPS equal to the original (or another lower value) while using a >1x interpolation factor so the added frames extend playback.

GIMM Frame Interpolation - ComfyUI Workflow

This workflow performs video frame interpolation in ComfyUI to make motion look smoother without changing the total playback time. It uses the comfyui-videohelpersuite for I/O and the comfyui-gimm-vfi custom node to synthesize in-between frames. VHS_LoadVideo ingests your source clip and exposes its frames and native FPS. Those frames are passed to the GIMM VFI interpolator node (UUID: 8d69124f-cc0e-4891-b9ca-9c1b04432c40), which inserts synthetic frames between each pair of originals according to an interpolation factor you set (for example, 2x or 3x). Finally, VHS_VideoCombine assembles the expanded frame sequence back into a video file.

Technically, the GIMM VFI node estimates motion between consecutive frames and generates temporally consistent intermediate frames. The MarkdownNote in the graph spells out the key timing rule: output_fps = input_fps × interpolation_factor. By multiplying the output FPS in VHS_VideoCombine to match the factor, the clip’s duration remains identical while motion appears more fluid. No diffusion or checkpoint models are required; everything hinges on the VFI node and reliable video read/write via the Video Helper Suite.

API

Use this workflow from code

Every Comfy workflow is a JSON graph. The payload below is this workflow, exactly as ComfyUI runs it — fetch it from the URL, keep it in version control, or load it in ComfyUI and run it node by node.

utility_gimm_frame_interpolation.json

Fetching workflow JSON…

Run it from TypeScript or Python with the Comfy SDK. The same code targets Comfy Cloud or a ComfyUI you host yourself — only the base URL changes.

// Install (beta)
npm i @comfyorg/sdk

// Run "GIMM Frame Interpolation" (TypeScript)
import { Comfy } from "@comfyorg/sdk";

const client = new Comfy({ apiKey: "comfyui-..." });

// This workflow, exported in API format (see note below)
const wf = await client.workflows.fromFile("utility_gimm_frame_interpolation_api.json");

const job = await client.run(wf);
await job.getOutputs("7")[0].toFile("output.png");  // VHS_VideoCombine

The SDK takes a workflow in API format: open this workflow in ComfyUI and use File → Export Workflow (API).

Comfy Cloud API access requires a plan with an API key.

SDK docs Get an API key

FAQ

Frequently Asked Questions