⚙ Image Sequence Tweening

Rendering an animation at 30 fps costs 50% more render time than 20 fps - but sometimes you only need 20 real generations and just want a smoother output. Image Sequence Tweening [Dream] is the frame-adder for that situation: it takes your rendered sequence and generates blended in-between frames, multiplying the frame count without asking the sampler to do another minute of work.

It's part of the Dream Project Animation Nodes pack (alt-key-project), the 2023 Deforum-style animation toolkit, sitting in the postprocessing family alongside Image Sequence Blend.

What it does

Two inputs: sequence and multiplier (INT, 2–10, default 2). Output: sequence.

With multiplier of 2, it inserts one interpolated frame between every pair of original frames - your animation effectively doubles its frame rate. A multiplier of 3 adds two in-between frames, and so on. Mechanically each in-between frame is a linear alpha blend of the two surrounding frames; the last frame gets repeated to keep the length consistent.

The output sequence keeps the original timeline semantics, so it still feeds the FFMPEG video encoder the same way - you're just giving it more frames per second of motion.

When it's a good trade

• Smooth motion from low-fps renders. Render at 15–20 fps to save time, tween to 30–60 for playback. The motion is smoother than the source, though it's interpolation, not new information.
• Slow-motion-ish feel. A higher multiplier stretches the visual cadence of a render without touching the sampler.
• Batch previews. Tween a quick test render to approximate the final look before committing to the full-res pass.

Where it's not a fix: real action with fast, complex movement. Linear blending can't invent the detail that optical-flow interpolation would, so fast scenes tween into smears. For subtle drift, camera moves, and slow morphs - the bread and butter of Deforum-style work - it looks great.

The sibling to know

Image Sequence Blend is the same family but a different tool: it softens existing frames for a motion-blurred look without adding frames. Choose tweening when you want more frames; choose blend when you want the same frames to feel smoother. Both are cheap passes over the ANIMATION_SEQUENCE and both are meant to run in series before encoding - never in parallel, per the README's warning.

Installing

cd ComfyUI/custom_nodes
git clone https://github.com/alt-key-project/comfyui-dream-project.git

Or via ComfyUI Manager under "Dream Project Animation". No model downloads; deps are imageio, scipy, torchvision, pilgram, and evalidate, with the pack's numpy<2.0 pin worth remembering. Find it under Dream → animation → postprocessing.