Frame Interpolate 🆎

Most frame interpolation in ComfyUI thinks in multiples: double the frames, and that's your 2x. But the real world wants 24 to 30, or 23.976 to 29.97, and a 2x node can't do that without hand-built math around it. Frame Interpolate 🆎 is built around frames per second instead: you give it the source rate and the target rate, and it resamples the batch to land on the target. 24→30 works as naturally as doubling.

How it works

Every output frame is either a direct copy (when it lands exactly on a source frame - those are untouched) or an in-between synthesized from its two neighbors. Two methods:

• blend - a crossfade between neighbors. Instant, no downloads, no weights. Soft on fast motion, which is its honest limit.
• optical flow - warps both neighbors along RAFT motion vectors for sharper in-betweens. The catch is in the name: it needs an already-cached RAFT checkpoint and will never download one. If you don't have the weights cached, it falls back or errors - the node says so rather than silently fetching.

scene_cut_threshold (default 0.35) is the smart bit: frames with a mean absolute difference above the threshold count as a hard cut, and instead of morphing across the cut (the smeared-transition look every other interpolator gives you at a scene change), the new frame holds the last frame before it. Set it to 0 to disable cut detection. batch_size just controls how many in-betweens are computed per pass - higher is faster, costs VRAM.

The source_fps tooltip is the hint: wire Load Video's fps output in so the node knows the real rate. The fps output, in turn, is the thing you feed to Save Video so rounding to a whole frame count never drifts the timing.

What comes out

frames - the resampled BHWC batch at the target rate, and fps - the actual output rate. Wire that fps into Save Video 🆎 and the encode stays honest even with fractional rates. Matching target_fps to source_fps passes frames through unchanged, which makes the node a handy no-op gate.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/ausboss/ComfyUI-AusBoss.git

Restart ComfyUI and search for AusBoss (Manager: ComfyUI-AusBoss). No extra Python dependencies; the blend path needs nothing beyond ComfyUI's bundled libraries, the flow path needs your cached RAFT weights. Minimum ComfyUI 0.27.1.

Troubleshooting

Blend-mode ghosting on fast motion is expected, not a bug - that's what the optical flow method is for. If flow mode won't run, the RAFT checkpoint isn't cached; that's the one missing-dependency failure here and the error will say so. Long clips: memory is bounded by planning the work first and streaming results back to the CPU, but the flow path still eats VRAM in proportion to batch_size, so lower it on a long clip. And if the output timing looks wrong, the source_fps is lying to you - check it against the source video's real rate.